兽研研究 药物创新杂志 (2027) 22:271 https://doi.org/10.1007/s12247-026-11134-4 Fabiana Ernestina Barcellos da Silva fabianasilva@unipampa.edu.br 1 药物科学研究生项目，潘帕联邦大学，乌拉圭亚纳，南里奥格兰德州 CEP: 97500-220，巴西 2 食品科学与技术研究生项目，圣玛丽亚联邦大学，南里奥格兰德州，圣玛丽亚 CEP 97105-900，巴西 摘要 目的 犬利什曼病是拉丁美洲最重要的地方性人兽共患病之一，影响数千个体。犬的治疗通常涉及使用具有杀利什曼原虫活性的药物，如别嘌醇，通常与米替福新或锑酸葡甲胺联合给药。长期管理常依赖于超说明书使用人用制剂（100或300 mg片剂），需要分割片剂以实现感染犬的剂量调整，这可能影响给药准确性。方法 为解决这一局限性，采用半固体挤出（SSE）3D打印（ALLO-3D）开发了别嘌醇打印片，以实现中小型犬的剂量个性化。研究了打印片的药物溶出和释放动力学。使用印刷药物绿色度评估指数（iGAPP）评估了3D打印的绿色度特征。结果 优化处方由羟丙基甲基纤维素（HPMC）、一水乳糖、交联羧甲纤维素钠（CCS-Na）和水-乙醇（7:3，v/v）黏合剂溶液组成，表现出速释特征（Q = 75%；45 min）。开发的打印片平均重量为390.1 mg（RSD = 1.65），药物含量为39.83 ± 0.75 mg/片，含量均匀度为104.74 ± 2.36%（AV = 5.4）。所有质量控制测试均符合口服固体制剂官方法典规定的要求。药物释放曲线最适合用一级模型描述（R² > 0.95）。结论 这些结果表明，SSE 3D打印是生产含别嘌醇个性化打印片的一种有前景的策略，能够实现精确的剂量调整，并可能改善犬利什曼病的治疗管理。此外，根据iGAPP指标，ALLO-3D制造过程从环境影响角度证明是合适的。关键词 3D · 增材制造 · 利什曼病 · 调配 · 半固体挤出 收稿日期：2026年8月6日 / 接受日期：2026年10月15日 © 作者 2026 兽用3D打印别嘌醇片的开发与评价 Bruna Machado Escobar 1 · Angélica Inês Kaufmann 2 · José Victor Mezadri 1 · Marcelo Donadel Malesuik 1 · Juliano Smanioto Barin 1,2 · Fabiana Ernestina Barcellos da Silva 1 引言 三维（3D）打印的出现因其能够实现精确剂量定制和个性化剂型制造的能力，在制药领域受到越来越多的关注[1–3]。除了多功能性外，该技术已被认为是一种更可持续的制造方法，其特征是减少危险废物的产生和简化生产过程[4]。在药物调配的背景下，与传统小规模制造相比，3D打印的引入提供了进一步的优势，包括过程自动化和降低风险
1 3 271 第2页，共11页《药物创新杂志》(2027) 22:271 与质量偏差相关，从而有助于提高重现性和可靠性[5–7]。在现有的3D打印技术中，半固体挤出（SSE）已成为生产固体口服剂型一种特别可行且具有优势的策略。该方法使用半固体墨水，如凝胶或糊剂，便于活性药物成分的掺入，并能够制造具有高剂量均匀性和重现性的打印片[8–9]。此外，由于SSE在低温下运行，可最大限度降低热降解风险，使其特别适用于热敏性化合物，并有助于最终制剂的整体稳定性[10]。SSE中使用低温还带来与提高能源效率相关的额外优势，使这种打印方式与其他药物打印工艺相比更具可持续性[11]。在此框架下，SSE打印的潜力在兽医学中尤为明显[9, 12–16]。在该领域，种间变异性和体型巨大差异要求个体化给药方案。除剂量调整外，SSE打印还可定制关键属性，如大小、形状以及掺入增强适口性的辅料，这可能改善治疗依从性。此外，从毒理学角度看，个性化制剂可减少动物接触潜在有害辅料的机会，这一问题常与人用药物在兽医实践中的超说明书使用相关。除剂量个体化等药剂技术优势外，SSE打印还具有支持生产具有公共卫生意义的药物的潜力，特别是对于需要可及、经济有效且综合控制策略的被忽视疾病[17]。在流行地区被忽视的人畜共患病背景下，这一差距更为明显，针对个性化药物开发的研究显著匮乏[18]。重要的是，该技术可在复合药房实施，并适应资源有限或难以到达的环境，扩大定制治疗的可及性。尽管有这些优势，3D打印药物的开发必须伴随严格的质量评估。3D打印等增材制造工艺可能引起物理和结构改变，与传统制造的剂型相比可能影响药物释放行为。因此，确保3D打印制剂的质量、安全性和有效性需要实施涵盖所有生产阶段的稳健表征和质量控制策略，从糊剂制备到最终剂型[19]。在此背景下，本研究提出使用SSE 3D打印（ALLO-3D）开发别嘌醇打印片。选择40 mg规格作为概念验证的低剂量制剂，以证明生产适用于犬利什曼病治疗中基于体重剂量个体化的剂型的可行性。利什曼病是拉丁美洲最重要的人畜共患病之一，影响动物和人类[20–22]。在犬利什曼病中，别嘌醇广泛用作利什曼抑制药，通常以10 mg/kg的剂量长期给药[23]。然而，含有别嘌醇的兽用特异性制剂尚无市售，临床实践常依赖最初为人患者开发的100或300 mg片剂的超说明书使用，这些片剂通常需要分割以达到所需剂量。这种做法引起了对剂量准确性和含量均匀性的重大担忧，从而凸显了需要能够提供精确和个体化给药的替代药物策略。材料与方法 材料 别嘌醇购自Fragon ® Ltda（巴西圣保罗），用作活性药物成分（API）以生产3D打印片剂。羧甲基纤维素钠（CMC-Na）、羟丙基甲基纤维素（HPMC）、乳糖一水合物、玉米淀粉（C-淀粉）和交联羧甲基纤维素钠（CCS）购自Pharmakos Compounding Pharmacy（巴西里奥格兰德杜苏尔）。乙醇（96% v/v；Dinâmica ®，巴西）和纯化水（Milli-Q ®，Merck Millipore，法国）用作制备打印制剂的溶剂。所有其他试剂和溶剂均为分析级并按收到状态使用。方法 筛选设计1 – 手动挤出 在本研究中，通过从注射器挤出制剂以模拟打印过程来进行手动可打印性测试。研究了含有不同辅料和组合的多种墨水制剂，以获得适用于兽用片剂半固体挤出（SSE）3D打印的合适糊剂。还评估了粘合剂溶液中纯化水与乙醇的比例。制剂通过混合所有粉末成分制备，包括别嘌醇、HPMC、CMC-Na、CCS、C-淀粉和乳糖，如表1所示。糊剂使用常规研钵和研杵方法制备，如
1 3 第 3 页，共 11 页 271 《药物创新杂志》(2027) 22:271 该方法成本低廉，且对于兽药房中的药物调配而言具有高度可及性[24]。粉末混合物经混合直至获得均匀、无团聚的混合物。随后逐渐加入黏合剂溶液，以防止结块和夹带空气。混合约 5 分钟后，获得具有适合 SSE 3D 打印稠度的黏性制剂。将糊状物转移至 60 mL 注射器中，并通过手动挤压制得片剂。调整挤出物的几何形状和尺寸，使其接近为打印创建的预定模型（环形甜甜圈/环面形状）。选择注射器喷嘴尺寸和挤出体积，以模拟后续阶段所用 3D 打印机的参数。在挤出过程中，由同一操作者在整个试验期间施加恒定压力。对通过手动挤压制得的片剂进行以下评价：形状保持性 形状保持性可表征为挤出后维持设计几何形状的能力。该参数通过尺寸保真度 (DF) 概念进行评价，依据公式 1 [25]。퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷 [ 퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷푑푑퐷퐷푑푑퐷퐷퐷퐷퐷퐷 푑푑푑푑퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷 푑푑퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷 푑푑퐷퐷 ] [ 퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷푑푑푑푑푑푑퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷 ] (1) 质量均匀性 调整挤出参数后，对所有制得单元（挤出后立即、干燥前）逐一称重，以评估该工艺生产质量一致片剂的能力。挤出后干燥时间 手动挤出后立即将湿制剂置于 25 °C 的对流烘箱中，并每 10 分钟使用分析天平监测其质量。干燥时间定义为连续三次称重显示质量不再变化所需的最短时间。干燥温度根据国际人用药品注册技术协调会 (ICH) 稳定性指南针对位于气候 IV 区国家（如巴西）推荐的环境温度选定。因此，API 在生产过程的任何阶段均不暴露于超过环境条件的温度。筛选设计 2 – SSE 打印墨水 在手动挤出阶段选出最有前景的糊状物后，根据预定义的环形甜甜圈/环面设计，使用 3D 食品打印机 (Wiiboox Sweetin，中国) 打印这些制剂。在初始试验中，使用用户友好的 Cura 3D 软件生成模型。将所选糊状物装入注射器，并连接到连接于气动打印头的塑料喷嘴 (0.84 mm)。在受控环境条件下，打印机平台温度维持在 25 °C。表 1 在筛选 1 和 2 中评价的 3D 打印墨水 3D 打印墨水F1F2F3F4F5F6F7F8 Na-CMC-+++++++++-- HPMC------+++ C-淀粉+++++---- 乳糖+---++++ CCS+++++++++++++ 别嘌醇++++++++ 黏合剂溶液 1 * -+------ 黏合剂溶液 2 ** --+----- 黏合剂溶液 3 *** ---+++++ 黏合剂溶液 4 **** +------- 评价打印性低；因过度收缩导致外观形状损失；干燥时间 > 1 小时；打印性中等；因过度收缩导致形状损失；干燥时间 > 1 小时；45 分钟后药物释放 < 25%。打印性中等；因过度收缩导致形状损失；干燥时间 > 1 小时；45 分钟后药物释放 < 25%。打印性高；形状保持性适当；打印片重量可重现；干燥时间适当（40 分钟，25 °C）；45 分钟后药物释放 < 25%。打印性低；手动糊状物匀化困难；注射器部分堵塞；干燥后塌陷。打印性低；手动糊状物匀化困难；注射器完全堵塞。打印性高；形状保持性适当；打印片重量可重现；干燥时间适当（40 分钟，25 °C）；45 分钟后药物释放 > 90%。打印性高；形状保持性适当；打印片重量可重现；干燥时间适当（40 分钟，25 °C）；45 分钟后药物释放 < 25%。阶段筛选 1筛选 1 和 2 筛选 1 和 2 筛选 1 和 2筛选 1筛选 1筛选 1 和 2 筛选 1 和 2 *纯化水；**10% (v/v) 水醇溶液；***30% (v/v) 水醇溶液；****淀粉与纯化水（1:3 比例）在 80 °C 下预热
印刷片的尺寸设定为直径15 mm、高度5 mm，打印速度为7 mm/s，每单位打印时间约为1.3 min。为防止干燥过程中内部塌陷，选择了100%填充密度。使用60 mL注射器作为供料器，打印前特别注意排除气泡。印刷片的后处理使用带气流的干燥箱，在25 °C下干燥至恒重。除手动挤出阶段所述的评估外，还对印刷片进行了以下评估：药物含量 别嘌醇含量采用《巴西药典》别嘌醇片专论中所述的含量测定程序进行测定。简言之，将印刷片的混合样品粉碎，取相当于三个ALLO-3D单位的量转移至100 mL容量瓶中。随后加入20 mL 0.1 M NaOH，超声处理15 min。然后用纯化水定容并混匀。过滤所得溶液，用0.1 M HCl作为溶剂进行系列稀释，得到最终浓度为10 μg·mL⁻¹的溶液。构建五点校准曲线（2–14 μg·mL⁻¹）。样品使用UV–VIS分光光度计在250 nm处进行分析。结果以平均值±标准差表示。药物含量以每片印刷片的药物毫克数（mg·单位⁻¹）计算。药物溶出度 溶出度测试按照《巴西药典》别嘌醇片专论规定的条件（0.01 N HCl、桨法装置、75 rpm、Q = 75%）进行，使用Varian® VK 7000溶出仪。该分析主要旨在识别具有速释特征的处方。ALLO-3D印刷片的表征 处方选定后，按照“筛选设计2 – SSE打印墨水”中所述的相同打印条件生产印刷片，并按照以下标准进行表征。外观、尺寸和质量均匀性 对印刷片的外观进行目视检查并通过数字成像记录。使用游标卡尺测量尺寸，以验证与设计方案的保真度（形状保持性）。对于质量均匀性，将20个单位分别在天平上单独称重。计算平均质量、标准差和变异系数。接受标准遵循《巴西药典》，即不得有两个以上单位的质量偏离平均质量±5%。药物含量和剂量单位均匀性 药物含量采用前述UV分光光度法测定。剂量单位均匀性按照《巴西药典》中所述口服固体制剂的含量均匀度试验进行评估。由于所 proposed 处方相对于单位质量含有少于25%的API，评估基于含量均匀性（CU）试验。将十个单个单位分别溶于容量瓶中，经过适当的系列稀释后，对每个样品中的药物量进行定量。接受值（AV）根据官方药典中提供的公式计算。别嘌醇体外溶出和药物释放动力学 印刷片的体外溶出测试按照《巴西药典》专论使用USP Apparatus II（桨法）进行。将六个印刷片分别置于含有900 mL溶出介质（0.01 M HCl）的溶出杯中。桨以75 rpm和37 ± 0.5 °C操作。45 min后，收集样品，通过0.22 μm PTFE过滤器过滤，并按照“药物含量”部分所述进行分析。片剂规定的接受标准要求不少于75%（Q）的标示量别嘌醇（C₅H₄N₄O）在45 min内溶解。尽管该规格尚未正式建立用于兽用制剂，但采用相同标准来评估所 proposed 的剂型。此外，将溶出数据拟合至常见动力学模型（零级、一级和Higuchi模型），以阐明潜在的释放机制。根据最高决定系数（R²）和最低Akaike信息准则（AIC）选择最佳拟合模型。还在不同pH条件（0.01 M HCl；pH 6.0磷酸盐缓冲液；pH 7.5磷酸盐缓冲液）和体积（200、500和900 mL）下，在5–60 min采样间隔内评估ALLO-3D印刷片的溶出曲线。此外，使用摇瓶法评估ALLO的饱和溶解度，以确认溶出介质提供了足够的漏槽条件（相对于药物溶解度至少三倍过量）。本研究中选择的不同溶出条件旨在表征所 proposed 处方在不同实验条件下的体外释放行为。溶出效率（DE%）作为溶出曲线的综合指标进行计算，允许在所评估的条件下对药物释放进行定量比较。含量测定、含量均匀性和溶出度测试所采用的方法已按照ICH Q2(R2)建立的指南进行验证。
1 3 第5页，共11页 271 《药物创新杂志》(2027) 22:271 印刷药物绿色度评估指数(iGAPP) 采用Youssef等人(2022)提出的印刷药物绿色度评估指数(iGAPP)对所提出工艺的绿色度特征进行了评估[26]。iGAPP通过三个主要部分展示绿色度特征，分别代表3D打印过程的各个阶段：预处理参数（第1–4项）、打印过程（第5–8项）和后固化（第9–10项）。第四部分提供整体工艺评分（10分），如表2所示。与所提出ALLO 3D打印片生产工艺绿色度特征相关的结果也呈现在同一表中（改编自Youssef等人，2022），未包含原作者最初提出的象形图。结果与讨论 3D打印油墨的制备与评价——筛选设计1和2 选择具有公认安全性特征的成熟辅料是兽用剂型的合理策略，因为动物可能对某些制剂成分表现出不同的敏感性，这进一步强化了基于风险的选择策略的必要性[27]。因此，在受试制剂中辅料选择所采用的第一个标准是其对本研究目标物种（犬和猫）的毒理学适用性。因此，在筛选设计1和2中评估了含C-淀粉或乳糖作为填充剂辅料、Na-CMC或HPMC作为纤维素衍生聚合物、CCS作为崩解剂的制剂。表1列出了本研究中考察的制剂以及所得打印片所表现出的特性，考虑了手动挤出性、糊剂可打印性、形状保持性（重量重现性、变形和收缩）以及药物溶出百分比等属性。不含聚合物并使用80 °C预热的C-淀粉作为粘合剂溶液制备的制剂(F1)表现出手动挤出性不足，且在初始阶段未能保持形状（筛选1）。基于这些发现，随后评估了含聚合物CMC-Na（F2–F6）和HPMC（F7和F8）的新制剂，这些聚合物以粉末形式加入制剂中并与水醇溶液作为粘合液组合使用。总体而言，含C-淀粉与CMC-Na组合的糊剂（F2–F4）表现出手动挤出性适当且糊剂可打印性令人满意，其中粘合剂溶液中乙醇比例最高的制剂(F4)形状保持性最佳。然而，所有相应打印片均表现出药物释放不良，无论所用粘合液如何。为以乳糖替代C-淀粉（因其具有更良好的适口性特征），测试了新的乳糖/CMC-Na基制剂（F5和F6）。然而，所得制剂(F5)在手动挤出后无法适当保持其形状。降低CMC-Na浓度(F6)并未改善可打印性性能。随后，在乳糖存在下评估了含HPMC而非CMC-Na的制剂（F7和F8）。对于这些制剂，手动挤出性 表2 ALLO 3D打印的iGAPP 参数绿色（评分=100%）黄色（评分=50%）红色（评分=0%）ALLO 3D SSE打印颜色评分（分）1. 溶剂环境影响（1分）环境影响评分：≥8环境影响评分：4–7环境影响评分：≤3绿色1 2. 温度(°C)（1分）< 3030–60> 60绿色1 3. 溶剂去除（1分）无需去除溶剂 室温蒸发 温度> 25蒸发 绿色1 4. 活性成分数量（1分）> 221红色0 5. 能耗（2分）SSE（< 100 kPa）SSE（100–500 kPa）SSE（> 500 kPa）绿色2 6. 温度(°C)（1分）室温26–10> 110绿色1 7. 每产品打印时间（分钟）（1分）< 2.52.5–10> 10绿色1 8. 废弃物处理（1分）无废弃物废弃物被回收废弃物被处置绿色1 9. 后固化过程（0.5分）无后固化/非耗能过程 温度< 60 °C干燥 更高能耗的后固化过程 黄色0.25 10. 后固化过程时间（小时）（0.5分）无后固化< 1> 1黄色0.25 总分> 7.55–7.5< 5绿色8.5
1 3 271 第6页，共11页《药物创新杂志》(2027) 22:271 且可打印性优异，形状保持充分。然而，只有处方F7表现出与速释剂型一致的药物释放曲线。相比之下，含有较高HPMC浓度的处方(F8)保持了优异的可打印性，但所制备的打印片表现出较慢的溶出曲线(120分钟时为75%)。在所有测试的处方中，含有6.25% ALLO、2.0% HPMC、5.0% CCS、46.75%乳糖和40%粘合剂溶液的处方F7，根据为该产品定义的关键质量属性，表现出最佳性能。处方F7制备的打印片具有优异的手动挤出性、打印过程中令人满意的可打印性以及适当的药物释放，符合所提出的速释曲线(快速溶出曲线，30分钟时为85%)。乳糖作为填充剂包含在所选处方中，是兽用片剂处方中常用的辅料，可产生具有可接受崩解性能的硬片[28]。除了有助于实现适当可打印性的药学特性外，乳糖的存在还可能因其清淡的味道而提供与适口性相关的优势。因此，其在所提出处方中的使用可能满足对适口性增强剂的需求，替代兽用制剂中通常用于此目的的辅料，如猪肝或鸡肝，这些辅料脂肪含量高，可能潜在地延迟药物释放。然而，所提出处方的潜在适口性相关益处需要通过专门设计用于评估犬可接受性和自愿摄入的研究进一步调查。本研究选择3D Food Printer作为商业模型，是因为其能够每小时打印约45个打印片(60 mL注射器容量)，并且可以清洁或更换塑料注射器，从而最大限度地降低交叉污染的风险。在本研究中，使用了专用料筒，并从设备中清除了处方残留物，随后用洗涤剂清洁并对相关表面进行消毒。除这些特点外，食品打印机的成本与配药药房中药物的小规模生产相兼容。尽管它不是药品级打印机，但该设备执行的工艺，如挤出精度，满足了生产具有所需质量且符合良好生产规范的药物剂型所必需的要求。打印片的表征 图1包括CAD模型(图1a)和ALLO-3D打印片(图1b)的代表性图片。ALLO-3D打印剂型设计尺寸为W × L × H = 15 × 15 × 5 mm，表现出的平均尺寸为12.11 ± 0.05 × 12.3 ± 0.05 × 4.91 ± 0.06 mm (DF W = 80.73%，DF L
分别为82.0%和DF H = 98.2%）在干燥过程之后（图1c）。所选的后处理步骤（25 °C干燥）除了成本低之外，还确保整个制造过程在不使API暴露于高温的情况下进行。干燥时间40分钟和粘合剂溶液的恒定蒸发百分比（36.75 ± 1.97%）始终得以实现，证明了该工艺的可重复性及其保持制剂尺寸稳定性的能力。观察到CAD模型与最终干燥剂型之间的尺寸变化。这些变化可能归因于新沉积结构中液体载体比例相对较高，其在干燥过程中的蒸发可促进聚合物-辅料基质的收缩[45]。在本研究中，打印片重量和药物含量的低变异性表明，尽管干燥过程中发生尺寸变化，打印过程仍提供了可重复的材料沉积。水醇粘合剂溶液中30%（v/v）的乙醇浓度被认为是所提出制剂的最佳浓度，因为较低浓度需要更长时间使剂型达到恒重，而较高浓度则更难获得具有合适稠度的均匀糊状物。因此，将乙醇纳入水醇粘合剂溶液代表了SSE 3D打印中的一种有用策略，因为它可以增强糊状物挤出性并加速沉积后的溶剂蒸发，从而改善形状保真度和尺寸稳定性[29]。然而，最佳水-乙醇比例应针对每种特定制剂进行确定。此外，考虑到犬只暴露于乙醇相关的潜在毒理学风险，风险评估（包括残留溶剂水平的测定）应纳入开发过程。考虑到平均重量（390.1 ± 0.69 mg）、药物含量（39.83 ± 0.75 mg/打印片）和含量均匀度（104.74 ± 2.36%；AV = 5.4）表明，该制剂、几何结构和打印工艺能够制造符合巴西药典片剂质量标准规定的剂型。根据药典规范，所有opurinol片剂质量控制所用的溶出方法要求在45分钟内Q值为75%。ALLO 3D打印片符合根据S1阶段标准（六片中Q + 5%）建立的规定。所提出的制剂相比市售100 mg ALLO片剂具有明显优势，因为它将较低药物剂量与较大剂型尺寸相结合。这
ALLO-3D打印片剂的这一特性使其既可作为完整的药物剂型给药，也可根据动物体重将其分割后给药。此外，还可通过调节打印制剂的最终重量来实现不同的剂量规格。相比之下，使用传统100 mg ALLO片剂（9×9×3 mm）进行剂量调整则完全依赖于手工分割片剂，由于片剂尺寸相对较小，这一过程可能导致含量均匀度出现显著偏差[30–31]。由于本研究未评估分割后ALLO-3D打印片剂的含量均匀度，也未研究不同尺寸和药物规格的打印片剂，因此需要进一步研究以评估分割后的剂量准确性，并探索不同规格和尺寸以实现更广泛犬体重范围内的基于体重的剂量个体化。在几何设计方面，本研究采用的环面几何结构表现出足够的药剂学技术性能，符合口服固体制剂所规定的质量要求。尽管环形3D打印药物可接受性的改善仅在人体研究中有所报道[32]，但从药剂学技术角度来看，环面几何结构可被视为开发小动物兽用药物的一个有前景的模型概念，原因在于：(a) 其有潜力通过利用药物释放可用表面积的不同方面来调节聚合物基质的溶出性能[33–34]；(b) 其有潜力有助于掩味[35]。此外，半固体挤出3D打印能够制造传统直接压片技术无法实现的多种复杂几何结构[36]，从而拓展了个体化兽用药物的设计空间。ALLO-3D体外释放本研究旨在从药物从辅料基质中释放行为的角度研究ALLO 3D的溶出曲线。此类研究可评估制剂材料和制造工艺的影响，同时建立支持制剂设计和开发合适质量控制方法的溶出曲线。考虑到与速释设计相关的40 mg别嘌醇剂量，由于该药物溶解度高，预期可实现快速溶出且不受打印过程的显著影响。然而，由于3D打印生产的口服固体制剂代表一种创新的药物系统，必须对其药物释放曲线进行全面评估。因此，在5–60分钟的采样间隔内，在不同pH条件和体积下评估了ALLO-3D打印片剂的药物释放。图1 CAD模型（A）和ALLO 3D打印片剂（B、C）
1 3 271 第8页，共11页《药物创新杂志》(2027) 22:271 关于不同介质体积下的评价（图2a），在使用900 mL和500 mL进行的研究中观察到溶出曲线之间的相似性（DE% 900 = 80.70 ± 0.13；DE% 500 = 78.63 ± 0.33）。尽管40 mg剂量在200 mL介质中仍保持可溶性并达到漏槽条件，但观察到溶出效率的降低更为明显（DE% 200 = 70.88 ± 0.49）。这种行为可能归因于在该特定条件下使用微型桨和微型溶出杯装置导致打印片与溶出介质之间的流体动力学和接触表面积的改变。需要进一步研究以阐明该行为的潜在原因。然而，尽管在不同实验条件下观察到溶出曲线之间存在差异，所提出的打印片表现出快速溶出（30分钟内> 85%）。尽管微型溶出杯/微型桨装置在低剂量制剂的溶出测试中具有很大潜力，但尚未被欧洲药品管理局（EMA）或美国食品药品监督管理局（FDA）等国际监管机构正式认可。从监管角度来看，当前的溶出指南主要基于面向成人的高剂量制剂，未考虑儿科和老年人群的个性化需求（Brooks等，2026）。对于兽医群体，口服固体制剂溶出测试的指导可通过兽医国际协调会议（VICH）获得；然而，目前未提供针对适用微型化系统的具体建议。微型溶出杯/微型桨系统对于评价个性化兽医用制剂的溶出特别相关，因为其缩小的尺寸使得能够测试含有低药物剂量的制剂，并在研究设计更接近不同动物物种的生理胃容积时使用更小的溶出介质体积。根据Brooks等（2026）[37]，这种监管错位与ICH Q6A和Q8(R2)中确立的原则形成对比，两者均强调产品特定关键质量属性和适当设计的控制策略的重要性。图2b展示了ALLO 3D打印片在既定药典条件下（0.01 M HCl、桨法装置、75 rpm）的溶出曲线。溶出曲线最佳拟合于一级动力学模型（R² = 0.951）。数据展示了特征性速释曲线，初始溶出快速，随后逐渐减速直至达到完全药物释放。图2b还展示了该制剂在pH 1.2–7.5范围内的溶出曲线。0.01 M HCl（DE% = 80.70 ± 0.13）、pH 6.0磷酸盐缓冲液（DE% = 82.17 ± 0.32）和pH 7.5磷酸盐缓冲液（DE% = 81.66 ± 0.94）介质的DE%值证实了所获得溶出曲线之间的相似性，无论pH条件如何，30分钟内药物释放均超过85%。考虑到别嘌醇在100 mg剂量强度（兽医临床常用的市售片剂）下在广泛生理pH范围内均为高溶性药物，这一行为是预期的，其中溶出不被视为药物溶解的限速步骤[38]。因此，可以得出结论，掺入三维基质中的别嘌醇表现出与通过传统制造方法生产的含有高溶性药物的常规速释口服固体制剂相当的溶出行为。图2 ALLO-3D打印片在不同条件下的体外溶出曲线：(a) 200–900 mL，使用0.01 M HCl作为溶出介质；(b) pH 1.2–7.5，使用900 mL溶出介质（假定0.01 M HCl提供pH约为1.2的溶出介质）
尽管赋形剂基质中别嘌醇的释放被认为适合速释固体剂型，但仍应开展进一步研究，在生物相关条件下评估其释放行为，并将3D打印工艺与更接近犬和猫生理条件的溶出介质相结合加以考虑。考虑到动物种属的特定生理特征，为人类建立的标准溶出条件并不能反映犬胃肠道中典型的非漏槽环境，这凸显了采用生物相关溶出介质开展研究的必要性。这些种属特异性特征包括与人类相比更高的胃pH值和更低的胃肠道液体体积，这些因素可能显著影响兽用制剂的药物溶出、释放和吸收行为[39–43]。重要的是，本研究考察的条件并非旨在复制犬的胃肠道环境。未评估生物相关溶出介质，且本实验未提供根据Papich（2015）[46]提出的兽用框架进行生物药剂学分类所需的溶解度和渗透性数据。因此，需要开展纳入种属特异性生理条件和生物相关介质的进一步研究，从生物药剂学角度考察ALLO-3D的体外性能。打印药物绿色度评估指数（iGAPP）与所提出的生产ALLO 3D打印片工艺绿色度特征相关的结果见表2。根据Youssef等（2022）[26]提出的指标，本研究提出的打印工艺在大多数评价参数上主要呈现绿色评分，仅在涉及每种处方中活性成分数量的参数上获得红色评分。SSE的主要优势之一——通过所提出工艺获得的绿色评分得以体现——与整个制造过程中的温度控制有关。在打印前、打印中和打印后阶段，工艺温度均维持在25 °C，与熔融沉积建模等增材制造技术相比降低了能量需求。除降低能耗外，整个过程中维持室温还可将活性药物成分热降解的风险降至最低，从而有助于制剂稳定性。根据Van der Veen等（2025）[44]的观点，绿色硬件——在SSE中表现为能源效率和可重复使用料筒的使用——应与监管措施、绿色赋形剂和绿色实践相结合，以建立绿色3D药物制造的四大支柱，并将其整合到“SSbD：安全与可持续设计评估”概念中。随着药物3D打印技术的不断扩展，仍需要进一步研究以全面评估该技术的环境影响。尽管如此，与其他增材制造技术相比，SSE总体上已展现出良好的特性，且鉴于所获得的总体评分，本文提出的方法被证明是合适的。结论本研究成功开发了通过半固体挤出3D打印生产的含别嘌醇打印片，并证明其具备适合个性化和小规模生产的药学特性。优化处方由HPMC、一水乳糖、CCS-Na和水-乙醇黏合剂溶液组成，表现出速释特征，所有质量控制测试均符合官方药典对口服固体剂型规定的要求。该方法代表剂型开发方面的重要进展，有助于优化治疗效果和临床病症管理，同时强化了3D打印作为兽药学领域创新工具的可行性和相关性。本研究尤其具有相关性，因为它涉及一种被忽视的人兽共患病的治疗，而在包括巴西在内的许多热带国家，该病仍缺乏足够的治疗选择。总体而言，半固体挤出工艺展现出操作简便、与其他增材制造技术相比成本更低以及更易于在分散化环境中实施等优势，使其特别适合兽用配制药房。除这些特征外，从环境影响角度看，该制造工艺也被证明是合适的，达到了iGAPP指标提出的“绿色”分类。因此，本研究结果表明，SSE 3D打印是生产个性化含别嘌醇打印片的一种有前景的策略，能够实现精确剂量调整，并可能改善犬利什曼病的治疗管理。致谢本研究部分由巴西高等教育人员改进协调基金会（CAPES）资助——资助代码001。
1 3 271 第10页，共11页《药物创新杂志》(2027) 22:271 作者贡献 作者贡献 构思与设计研究：Silva, F. E. B.；Escobar, B. M.；Barin, J. S.；Malesuik, M. D. 执行实验并分析数据：Escobar, B. M.；Kaufmann, A.I.；Mezadri, J. V. 撰写初稿：Silva, F. E. B.；Escobar, B. M.；Barin, J. S. 撰写与编辑稿件：所有作者。 资助 本研究成果的出版文章处理费（APC）由巴西高等教育人员改进协调委员会（CAPES）资助（ROR标识符：00x0ma614）。本研究部分由巴西高等教育人员改进协调委员会（CAPES）资助——财务代码001。 数据可用性 本研究过程中生成或分析的所有数据均包含在本已发表文章中。 声明 利益冲突 作者声明无利益冲突。 开放获取 本文根据Creative Commons Attribution 4.0国际许可协议授权，允许以任何媒介或格式使用、共享、改编、分发和复制，只要您适当注明原作者和来源，提供Creative Commons许可协议的链接，并说明是否进行了修改。本文中的图片或其他第三方材料包含在本文的Creative Commons许可协议中，除非在材料的署名行中另有说明。如果材料未包含在本文的Creative Commons许可协议中，且您的预期使用不被法定法规允许或超出许可使用范围，您需要直接从版权持有人处获得许可。要查看本许可协议的副本，请访问 http://creativecommons.org/licenses/by/4.0/。 参考文献 1. Auel T, Mentrup AFC, Oldfield LR, Seidlitz A. 药物剂型的3D打印：最新进展与应用. Adv Drug Deliv Rev. 2025;217. https://doi.org/10.1016/j.addr.2024.115504. 2. Das S, Kumar A, Jena R, Singh NK, Harish V. 工程药物：药物3D打印的综合综述. Biomedical Mater Devices. 2026. https://doi.org/10.1007/s44174-026-00656-7. 3. Salama AH. 3D和4D打印在制药技术中的最新进展：应用、挑战和未来前景. Future J Pharm Sci. 2025;11(1):107. https://doi.org/10.1186/s43094-025-00866-8. 4. Sierra-Vega NO, Ashraf M, O'Connor T, Kopcha M, Prima Mdi, Coburn J, Zidan A. 用于固体口服剂型的新兴3D打印技术：实时评估的工艺、材料和分析工具. Int J Pharm. 2025;673. https://doi.org/10.1016/j.ijpharm.2025.125415. 5. Ayyoubi S, Holst AJ, Maduro JE, Van der Kuy PHM, Van Ee RJ, Van de Valkenburg VD, Hennep B, Quodbach C, Ruijgrok J E.J. 基准测试3D打印与传统调配方法在药物个性化方面的药品质量和生产成本. Eur J Pharm Sci. 2025;212:107180. https://doi.org/10.1016/j.ejps.2025.107180. 6. Melnyk LA, Oyewumi MO. 3D打印技术在药物调配中的整合：进展、前景和挑战. Annals 3D Print Med. 2021;4:100035. https://doi.org/10.1016/j.stlm.2021.100035. 7. Beer N, Kaae S, Genina N, Sporrong SK, Alves TL, Hoebert J, de Bruin ML, Hegger I. 3D打印的 magistral 调配：实现个性化医疗的有前景途径. Therapeutic Innov Regul Sci. 2023;57(1):26–36. https://doi.org/10.1007/s43441-022-00436-7. 8. Seoane-Viaño I, Januskaite P, Alvarez-Lorenzo C, Basit AW, Goyanes A. 半固体挤出3D打印在药物递送和生物医学中的应用：针对医疗挑战的个性化解决方案. J Controlled Release. 2021;332:367–89. https://doi.org/10.1016/j.jconrel.2021.02.027. 9. Leão J, Winck VL, Petzhold CL, Collares FM, de Andrade DF, Beck RCR. 匹莫苯丹控释瓜尔胶打印片：为个性化兽药定制药物剂量. Int J Pharm. 2024;655:124017. https://doi.org/10.1016/j.ijpharm.2024.124017. 10. Abdillah Akbar BVEB, Seluk M, Isreb A, da Silva M, Dreiss CA, Royall PG, Gill A, Bracken L, Tomlin S, Giebułtowicz J, Jones SA, Alhnan MA. 个性化儿科微片的精确低温直接颗粒挤出3D打印. Int J Pharm. 2026;697:126871. https://doi.org/10.1016/j.ijpharm.2026.126871. 11. Elbadawi M, Basit AW, Gaisford S. 制药生产中3D打印的能耗和碳足迹. Int J Pharm. 2023;639:122926. https://doi.org/10.1016/j.ijpharm.2023.122926. 12. Sjöholm E, Mathiyalagan R, Prakash R, Lindfors D, Wang L, Wang Q, Ojala X, S., Sandler N. 3D打印兽药剂型——三种半固体挤出3D打印机的比较研究. Pharmaceutics. 2020;12(12):1239. https://doi.org/10.3390/pharmaceutics12121239. 13. Sjöholm E, Mathiyalagan R, Wang X, Sandler N. 通过3D打印在护理点附近调配定制兽用咀嚼片. Pharmaceutics. 2022;14(7):1339. https://doi.org/10.3390/pharmaceutics14071339. 14. Falcone G, Real JP, Palma SD, Aquino RP, del Gaudio P, Garofalo E, Russo P. 漂浮型利考苯达唑递送系统：海藻酸钠和氯化钙共挤出的3D打印方法. Int J Mol Sci. 2022;23(3):1280. https://doi.org/10.3390/ijms23031280. 15. Leão J, Lauermann CA, Winck VL, Petzhold CL, de Andrade DF, Beck RCR. 3D打印油墨和/或其 respective 兽用匹莫苯丹打印片的使用中和长期理化、流变学和生物药剂学稳定性：一项初步研究. Int J Pharm. 2025;684:126134. https://doi.org/10.1016/j.ijpharm.2025.126134. 16. Mathiyalagan R, Westerlund M, Mahran A, Altunay R, Suuronen J, Palo M, Nyman JO, Immonen E, Rosenholm JM, Monaco E, Wang X. 定制兽用双释放片的3D打印：甲氧氯普胺的半固体挤出方法. RSC Pharm. 2025;2(2):413–26. https://doi.org/10.1039/D4PM00322E. 17. Boniatti J, Januskaite P, Fonseca LB, da, Viçosa AL, Amendoeira FC, Tuleu C, Basit AW, Goyanes A, Ré M-I. 直接粉末挤出3D打印吡喹酮以克服儿科人群中被忽视疾病的制剂挑战. Pharmaceutics. 2021;13(8):1114. https://doi.org/10.3390/pharmaceutics13081114. 18. Weld ED, Waitt C, Barnes K, Garcia Bournissen F. 双重被忽视？被忽视人群中的被忽视疾病. Br J Clin Pharmacol. 2022;88(2):367–73. https://doi.org/10.1111/bcp.15148. 19. Deon M, dos Santos J, de Andrade DF, Beck RCR. 对传统和先进表征工具的关键综述，以推动制剂人员合理开发3D打印口服剂型. Int J Pharm. 2022;628:122293. https://doi.org/10.1016/j.ijpharm.2022.122293.
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RESEARCH Journal of Pharmaceutical Innovation (2027) 22:271 https://doi.org/10.1007/s12247-026-11134-4 Fabiana Ernestina Barcellos da Silva fabianasilva@unipampa.edu.br 1 Programa de Pós-graduação em Ciências Farmacêuticas, Universidade Federal do Pampa, Uruguaiana, Rio Grande do Sul CEP: 97500-220, Brasil 2 Programa de Pós-graduação em Ciência e Tecnologia dos Alimentos, Universidade Federal de Santa Maria, Rio Grande do Sul, Santa Maria CEP 97105-900, Brasil Abstract Purpose Canine leishmaniasis is one of the most important endemic zoonotic diseases in Latin America, affecting thousands of individuals. Treatment in dogs commonly involves the use of agents with leishmanicidal activity such as allopurinol, typically administered in combination with miltefosine or meglumine antimoniate. Long-term management frequently relies on the off-label use of human formulations (100 or 300 mg tablets), requiring tablet splitting to achieve dose adjustment for infected dogs, which may compromise dosing accuracy. Methods To address this limitation, allopurinol printlets were developed using semi-solid extrusion (SSE) 3D printing (ALLO-3D) to enable dose personalization for small- to medium-sized dogs. The drug dissolution and release kinetics of the printlets were investigated. The greenness profile of the 3D printing was evaluated using the Index of Greenness Assessment of Printed Pharmaceuticals (iGAPP). Results The optimized formulation, composed of hydroxypropyl methylcellulose (HPMC), lactose monohydrate, croscarmellose sodium (CCS-Na), and a water–ethanol (7:3, v/v) binder solution, exhibited an immediate-release profile (Q = 75%; 45 min). The developed printlets showed a mean weight of 390.1 mg (RSD = 1.65), drug content of 39.83 ± 0.75 mg printlet⁻¹, and content uniformity of 104.74 ± 2.36% (AV = 5.4). All quality control tests complied with the requirements established in the official codes for oral solid dosage forms. The drug release profile was best described by the First-order model (R² > 0.95). Conclusion These findings demonstrate that SSE 3D printing represents a promising strategy to produce personalized printlets containing allopurinol, enabling accurate dose adjustment and potentially improving therapeutic management in canine leishmaniasis. Additionally, the ALLO-3D manufacturing process proved to be suitable from an environmental impact perspective according to the iGAPP metric. Keywords 3D · Additive manufacturing · Leishmaniasis · Compounding · Semisolid extrusion Received: 6 August 2026 / Accepted: 15 October 2026 © The Author(s) 2026 Development and Evaluation of 3D Printed Allopurinol Tablets for Veterinary Use Bruna Machado Escobar 1 · Angélica Inês Kaufmann 2 · José Victor Mezadri 1 · Marcelo Donadel Malesuik 1 · Juliano Smanioto Barin 1,2 · Fabiana Ernestina Barcellos da Silva 1 Introduction The advent of three-dimensional (3D) printing has garnered increasing attention in the pharmaceutical field due to its ability to enable precise dose tailoring and the fabrication of individualized dosage forms [1–3]. In addition to its versatility, this technology has been recognized as a more sustainable manufacturing approach, characterized by reduced generation of hazardous waste and simplified production processes [4]. In the context of pharmaceutical compounding, the incorporation of 3D printing offers further advantages over conventional small-scale manufacturing, including process automation and a reduction in risks
1 3 271 Page 2 of 11Journal of Pharmaceutical Innovation (2027) 22:271 associated with quality deviations, thereby contributing to improved reproducibility and reliability [5–7]. Among the available 3D printing techniques, semisolid extrusion (SSE) has emerged as a particularly feasible and advantageous strategy for the production of solid oral dosage forms. This approach employs semisolid inks, such as gels or pastes, which facilitate the incorporation of active pharmaceutical ingredients and enable the fabrication of printlets with high dose uniformity and reproducibility [8–9]. Furthermore, as SSE operates at low temperature, it minimizes the risk of thermal degradation, making it especially suitable for thermosensitive compounds and contributing to the overall stability of the final formulation [10]. The use of low temperatures in SSE provides an additional advantage associated with improved energy efficiency, making this printing modality more sustainable when compared with other pharmaceutical printing processes [11]. Within this framework, the potential of SSE printing becomes particularly evident in veterinary medicine [9, 12–16]. In this field, interspecies variability and wide differences in body size demand individualized dosing regimens. Beyond dose adjustment, SSE printing allows the customization of critical attributes such as size, shape, and the incorporation of palatability-enhancing excipients, which may improve treatment adherence. Additionally, from a toxicological perspective, personalized formulations can reduce the exposure of animals to potentially harmful excipients, an issue frequently associated with the off-label use of human medicines in veterinary practice. In addition to pharmacotechnical benefits such as dose individualization, SSE printing offers the potential to support the production of medicines of public health interest, particularly for neglected diseases that require accessible, cost-effective, and integrated control strategies [17]. This gap is even more pronounced in the context of neglected zoonotic diseases in endemic regions, for which there is a notable scarcity of studies addressing the development of personalized medicines [18]. Importantly, this technology may be implemented in compounding pharmacies and adapted to resource-limited or hard-to-reach settings, expanding access to tailored treatments. Despite these advantages, the development of 3D-printed medicines must be accompanied by rigorous quality assessment. Additive manufacturing processes such as 3D printing may induce physical and structural modifications that can influence drug release behavior when compared to conventionally manufactured dosage forms. Thus, ensuring the quality, safety, and efficacy of 3D-printed formulations requires the implementation of robust characterization and quality control strategies encompassing all stages of production, from paste preparation to the final dosage form [19]. In this context, the present study proposes the development of allopurinol printlets using SSE 3D printing (ALLO-3D). A 40-mg strength was selected as a proof-of-concept lowerdose formulation to demonstrate the feasibility of producing dosage forms suitable for weight-based dose personalization in the treatment of canine leishmaniasis. Leishmaniasis is one of the most important zoonotic diseases in Latin America, affecting both animals and humans [20–22]. In canine leishmaniasis, allopurinol is widely used as a leishmanistatic agent, typically administered at a dosage of 10 mg/kg for long-term management [23]. However, veterinary-specific formulations containing allopurinol are not commercially available, and clinical practice frequently relies on the offlabel use of 100 or 300 mg tablets originally developed for human patients, which often require splitting to achieve the desired dose. This practice raises significant concerns regarding dose accuracy and content uniformity, thereby highlighting the need for alternative pharmaceutical strategies capable of delivering precise and individualized dosing. Materials and Methods Materials Allopurinol was obtained from Fragon ® Ltda (São Paulo, Brazil) and used as the active pharmaceutical ingredient (API) to produce 3D-printed tablets. Sodium carboxymethylcellulose (CMC-Na), hydroxypropyl methylcellulose (HPMC), lactose monohydrate, corn starch (C-starch), and croscarmellose sodium (CCS) were purchased from Pharmakos Compounding Pharmacy (Rio Grande do Sul, Brazil). Ethanol (96% v/v; Dinâmica ® , Brazil) and purified water (Milli-Q ® , Merck Millipore, France) were used as solvents in the preparation of the printing formulations. All other reagents and solvents were of analytical grade and used as received. Methods Screening Design 1 – Manual Extrusion In this study, a manual printability test was performed by extruding the formulations from a syringe to simulate the printing process. Several ink formulations containing different excipients and combinations were investigated in order to obtain a suitable paste for semisolid extrusion (SSE) 3D printing of veterinary tablets. The ratio between purified water and ethanol in the binder solution was also evaluated. The formulations were prepared by blending all powdered ingredients, including allopurinol, HPMC, CMC-Na, CCS, C-starch, and lactose, as shown in Table 1. The pastes were prepared using the conventional mortar-and-pestle method, as
1 3 Page 3 of 11 271 Journal of Pharmaceutical Innovation (2027) 22:271 this approach is low-cost and highly accessible for medicine compounding in veterinary pharmacies [24]. Powder blends were mixed until a homogeneous, agglomerate-free mixture was obtained. The binder solution was then gradually added to prevent lump formation and air entrapment. Viscous formulations with suitable consistency for SSE 3D printing were obtained after approximately 5 min of mixing. The pastes were transferred into 60 mL syringes, and tablets were produced by manual extrusion. The geometry and dimensions of the extrudates were adjusted to approximate the predesigned model created for printing (ring doughnut/ ring torus shape). The syringe nozzle dimensions and extrusion volume were selected to mimic the parameters of the 3D printer to be used in the subsequent stage. During extrusion, constant pressure was applied by the same operator throughout the test. The tablets obtained by manual extrusion were evaluated for: Shape Retention Shape retention can be characterized as the ability to maintain the designed geometry after extrusion. This parameter was evaluated by dimension fidelity (DF) concept, according to Eq. 1 [25]. 퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷 [ 퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷푑푑퐷퐷푑푑퐷퐷퐷퐷퐷퐷 푑푑푑푑퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷 푑푑퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷 푑푑퐷퐷 ] [ 퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷푑푑푑푑푑푑퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷퐷 ] (1) Mass Uniformity After adjustment of the extrusion parameters, all produced units (immediately after extrusion and prior to drying) were individually weighed to assess the capacity of the process to produce tablets with consistent mass. Drying Time After Extrusion The wet formulations were placed in a convection oven at 25 °C immediately after manual extrusion, and their mass was monitored using an analytical balance every 10 min. Drying time was defined as the shortest period after which three consecutive weighing showed no further mass variation. The drying temperature was selected based on the ambient temperature recommended by International Conference on Harmonization (ICH) stability guidelines for countries located in Climatic Zone IV, such as Brazil. Accordingly, API is not subjected to temperatures exceeding ambient conditions at any stage of the manufacturing process. Screening Design 2 – SSE Printing Inks After selection of the most promising pastes in the manual extrusion phase, the formulations were printed using a 3D Food Printer (Wiiboox Sweetin, China) according to the predefined ring doughnut/ring torus design. For the initial trials, user-friendly Cura 3D software was used to generate the model. The syringe was filled with the selected paste and connected to a plastic nozzle (0.84 mm) attached to the pneumatic print head. The printer platform temperature was maintained at 25 °C under controlled environmental conditions. Table 1 3D printing inks evaluated in screening 1 and 2 3D printing inksF1F2F3F4F5F6F7F8 Na-CMC-+++++++++-- HPMC------+++ C-starch+++++---- Lactose+---++++ CCS+++++++++++++ Allopurinol++++++++ Binder sol. 1 * -+------ Binder sol. 2 ** --+----- Binder sol. 3 *** ---+++++ Binder sol. 4 **** +------- EvaluationLow printability; visual loss of shape caused by excessive shrinkage; drying time > 1 h; Medium printability; loss of shape caused by excessive shrinkage; drying time > 1 h; drug release < 25% after 45 min. Medium printability; loss of shape caused by excessive shrinkage; drying time > 1 h; drug release < 25% after 45 min. High printability; adequate shape retention; reproducible printlet weight; adequate drying time (40 min, 25 °C); drug release < 25% after 45 min. Low printability; difficulty in manual paste homogenization; partial syringe clogging; collapse after drying. Low printability; difficulty in manual paste homogenization; total syringe clogging. High printability; adequate shape retention; reproducible printlet weight; adequate drying time (40 min, 25 °C); drug release > 90% after 45 min. High printability; adequate shape retention; reproducible printlet weight; adequate drying time (40 min, 25 °C); drug release < 25% after 45 min. PhaseScreening 1Screening 1 and 2 Screening 1 and 2 Screening 1 and 2Screening 1Screening 1Screening 1 and 2 Screening 1 and 2 *Purified water; **10% (v/v) hydroalcoholic solution; ***30% (v/v) hydroalcoholic solution; ****starch preheated at 80 °C with purified water (1:3 ratio)
1 3 271 Page 4 of 11Journal of Pharmaceutical Innovation (2027) 22:271 The printlet dimensions were set at 15 mm in diameter and 5 mm in height, with a printing speed of 7 mm/s, resulting in an approximate printing time of 1.3 min per unit. To prevent internal collapse during drying, 100% infill density was selected. A 60 mL syringe was used as the feeder, and special care was taken to eliminate air bubbles before printing. Post-processing of the printlets was performed using a drying oven with air flow, at 25 °C until constant mass. In addition to the evaluations described for manual extrusion phase, the printlets were further assessed for: Drug Content Allopurinol content was determined using the assay procedure described in the Brazilian Pharmacopoeia monograph for allopurinol tablets. Briefly, a pooled sample of printlets was powdered, and an amount equivalent to three ALLO-3D units was transferred to a 100 mL volumetric flask. Subsequently, 20 mL of 0.1 M NaOH was added, and the mixture was sonicated for 15 min. The volume was then completed with purified water and homogenized. The resulting solution was filtered, and serial dilutions were prepared to obtain a final concentration of 10 μg. mL− 1 using 0.1 M HCl as solvent. A five-point calibration curve (2–14 μg. mL− 1) was constructed. Samples were analyzed using a UV–VIS spectrophotometer at 250 nm. Results are expressed as mean ± standard deviation. Drug content was calculated as milligrams of drug per printlet (mg unit⁻¹) Drug Dissolution Dissolution testing was performed under the conditions established in the Brazilian Pharmacopoeia monograph for allopurinol tablets (0.01 N HCl, paddle apparatus, 75 rpm, Q = 75%), using a Varian® VK 7000 dissolution equipment. This analysis was primarily intended to identify formulations exhibiting immediate-release profiles. Characterization of ALLO-3D Printlets After formulation selection, printlets were produced under the same printing conditions described in Screening Design 2 – SSE Printing Inks and characterized according to the following criteria. Physical Appearance, Dimensions, and Mass Uniformity The physical appearance of the printed tablets was visually inspected and documented by digital imaging. Dimensions were measured using a vernier caliper to verify fidelity to the projected design (shape retention). For mass uniformity, 20 units were individually weighed on an analytical balance. Mean mass, standard deviation, and coefficient of variation were calculated. Acceptance criteria followed the Brazilian Pharmacopoeia, which states that no more than two units may deviate from the average mass by ± 5%. Drug Content and Uniformity of Dosage Units Drug content was determined by UV spectrophotometry as previously described. Uniformity of dosage units was assessed according to the content uniformity test for oral solid dosage forms described in Brazilian Pharmacopoeia. As the proposed formulation contained less than 25% API relative to unit mass, evaluation was based on the Content Uniformity (CU) test. Ten individual units were separately dissolved in volumetric flasks, and after appropriate serial dilutions, the drug amount in each sample was quantified. Acceptance values (AV) were calculated according to the equations provided in the official compendium. In Vitro Allopurinol Dissolution and Drug Release Kinetics In vitro dissolution testing of the printlets was performed according to the Brazilian Pharmacopoeia monograph using a USP Apparatus II (paddle). Six printlets were individually placed in vessels containing 900 mL of dissolution medium (0.01 M HCl). The paddles were operated at 75 rpm and 37 ± 0.5 °C. After 45 min, samples were collected, filtered through 0.22 μm PTFE filters, and analyzed as described in the Drug Content section. The acceptance criterion established for tablets requires that not less than 75% (Q) of the labeled amount of allopurinol (C₅H₄N₄O) be dissolved within 45 min. Although this specification has not been formally established for veterinary formulations, the same criterion was adopted to evaluate the proposed dosage form. Additionally, the dissolution data was fitted to common kinetic models (zero-order, first-order and Higuchi) to elucidate the underlying release mechanism. The best-fitting model was selected based on the highest coefficient of determination (R²) and the lowest Akaike Information Criterion (AIC). Dissolution profiles of ALLO-3D printlets were also evaluated under different pH conditions (HCl 0.01 M; phosphate buffer pH 6.0; phosphate buffer pH 7.5) and volume (200, 500 and 900 mL) over a sampling interval of 5–60 min. Moreover, the saturation solubility for ALLO was evaluated using the shake-flask method to confirm that the dissolution medium provided adequate sink conditions (minimum threefold excess relative to the drug solubility). The different dissolution conditions investigated in the present study were selected to characterize the in vitro release behavior of the proposed formulation under varying experimental conditions. Dissolution efficiency (DE%) was calculated as an integrated measure of the dissolution profiles, allowing quantitative comparison of drug release across the conditions evaluated. The methods employed for assay determination, content uniformity, and dissolution testing were validated in accordance with the guidelines established by ICH Q2(R2).
1 3 Page 5 of 11 271 Journal of Pharmaceutical Innovation (2027) 22:271 Index of Greenness Assessment of Printed Pharmaceuticals (iGAPP) The greenness profile of the proposed process was evaluated using the Index of Greenness Assessment of Printed Pharmaceuticals (iGAPP) proposed by Youssef et al. (2022) [26]. The iGAPP illustrates the greenness profile through three main sections representing each stage of the 3D printing process: pre-processing parameters (items 1–4), printing process (items 5–8), and post-curing (items 9–10). A fourth section provides the overall process score (10 points), as shown in Table 2. The results related to the greenness profile of the proposed process for the production of ALLO 3D printlets are also presented in the same table (adapted from Youssef et al., 2022), without inclusion of the pictogram originally proposed by the authors. Results and Discussion Preparation and Evaluation of 3D Printing Inks - Screening Design 1 and 2 The selection of well-established excipients with recognized safety profiles represents a rational strategy for veterinary dosage forms, since animals may exhibit distinct sensitivities to certain formulation components, reinforcing the need for a risk-based selection strategy [27]. Accordingly, the first criterion adopted for excipient selection in the formulations tested was their toxicological suitability for the target species of this study (dogs and cats). Therefore, formulations containing C-starch or lactose as filler excipients, Na-CMC or HPMC as cellulose-derived polymers, and CCS as a disintegrant were evaluated in screening design 1 and 2. Table 1 presents the formulations investigated in this study and the characteristics exhibited by the resulting printlets, considering the attributes of manual extrudability, paste printability, shape retention (weight reproducibility, deformation, and shrinkage), and percentage of drug dissolved. The formulation prepared without polymers and using C-starch preheated at 80 °C as the binder solution (F1) exhibited inadequate manual extrudability and failed to maintain shape retention during the initial stage (Screening 1). Based on these findings, new formulations containing the polymers CMC-Na (F2–F6) and HPMC (F7 and F8), incorporated as powders into the formulation and combined with hydroalcoholic solutions as binding liquids, were subsequently evaluated. In general, pastes containing C-starch associated with CMC-Na (F2–F4) showed adequate manual extrudability and satisfactory paste printability, with the best shape retention observed for the formulation containing the highest ethanol proportion in the binder solution (F4). However, all corresponding printlets exhibited poor drug release, regardless of the binder solution employed. To replace C-starch with lactose, owing to its more favorable palatability characteristics, new lactose/CMC-Nabased formulations were tested (F5 and F6). However, the formulation obtained (F5) was unable to properly retain its shape after manual extrusion. Reducing the CMC-Na concentration (F6) did not improve printability performance. Subsequently, formulations containing HPMC instead of CMC-Na were evaluated in the presence of lactose (F7 and F8). For these formulations, both manual extrudability Table 2 iGAPP for ALLO 3D printing ParametersGreen (Score = 100%) Yellow (Score = 50%) Red (Score = 0%) ALLO 3D SSE Printing ColorScore (points) 1. Solvent environmental impact (1 point) Environmental impact score: ≥8Environmental impact score: 4–7 Environmental impact score: ≤3 Green1 2. Temperature (°C) (1 point)< 3030–60> 60Green1 3. Solvent removal (1 point)No solvent removal Required Evaporation at room temperature Evaporation at temperature > 25 Green1 4. Nº. active constituents (1 point)> 221Red0 5. Energy consumption (2 points)SSE (< 100 kPa)SSE (100–500 kPa)SSE (> 500 kPa)Green2 6. Temperature (°C) (1 point)Room temperature26–10> 110Green1 7. Printing time per product (min) (1 point) < 2.52.5–10> 10Green1 8. Waste treatment (1 point)No wasteWaste is recycledWaste is disposedGreen1 9. Post curing process (0.5 point)No post-curing/ non-energy consuming process Drying at temperature < 60 °C Higher energyconsuming postcuring process Yellow0.25 10. Time of post-curing process (hours) (0.5 point) No post-curing< 1> 1Yellow0.25 Total score> 7.55–7.5< 5GREEN8.5
1 3 271 Page 6 of 11Journal of Pharmaceutical Innovation (2027) 22:271 and printability were excellent, with adequate shape retention. However, only formulation F7 exhibited a drug release profile consistent with an immediate-release dosage form. In contrast, the formulation containing the higher HPMC concentration (F8) maintained excellent printability, but the produced printlets showed a slower dissolution profile (75% at 120 min). Among all the formulations tested, formulation F7, containing 6.25% ALLO, 2.0% HPMC, 5.0% CCS, 46.75% lactose, and 40% binder solution, showed the best performance according to the critical quality attributes defined for the product. Formulation F7 produced printlets with excellent manual extrudability, satisfactory printability during the printing process, and adequate drug release, in accordance with the proposed immediate-release profile (rapid dissolution profile, 85% at 30 min). Lactose, included in the selected formulation as a filler, is a common excipient used in the formulation of veterinary tablets and produces hard tablets with acceptable disintegration properties [28]. Beyond the pharmaceutical characteristics that contributed to adequate printability, the presence of lactose may also provide palatability-related advantages due to its bland taste. Therefore, its use in the proposed formulation may fulfill the need for a palatability-enhancing agent, replacing excipients commonly employed for this purpose in veterinary formulations, such as pork or chicken liver, which have a high fat content and could potentially delay drug release. Nevertheless, the potential palatabilityrelated benefits of the proposed formulation require further investigation through studies specifically designed to assess acceptability and voluntary intake in dogs. The 3D Food Printer was selected as the commercial model in this study due to its ability to print approximately 45 printlets/h (60 mL syringe volume) and the possibility of cleaning or replacing the plastic syringe, thereby minimizing the risk of cross-contamination. In this study, dedicated cartridges were used and formulation residues were removed from the equipment, followed by cleaning with detergent and sanitization of the relevant surfaces. In addition to these features, food printers present a cost compatible with the small-scale production of medicines in compounding pharmacies. Although it is not a pharmaceutical-grade printer, the processes performed by this equipment, such as extrusion accuracy, met the requirements necessary to produce pharmaceutical dosage forms with the desired quality and in accordance with Good Manufacturing Practices. Characterization of the Printlets Figure 1 includes representative pictures of the CAD model (Fig. 1a) and ALLO-3D printlets (Fig. 1b). The ALLO-3D printed dosage forms, designed with dimensions of W × L × H = 15 × 15 × 5 mm, exhibited mean dimensions of 12.11 ± 0.05 × 12.3 ± 0.05 × 4.91 ± 0.06 mm (DF W = 80.73%, DF L
= 82.0%, and DF H = 98.2%, respectively) after the drying process (Fig. 1c). The selected post-processing step (drying at 25 °C), in addition to its low cost, ensured that the entire manufacturing process was carried out without exposing the API to elevated temperatures. A drying time of 40 min and a constant evaporation percentage of the binder solution (36.75 ± 1.97%) were consistently achieved, demonstrating the repeatability of the process and its ability to preserve the dimensional stability of the formulation. Dimensional changes between the CAD model and the final dried dosage form were observed. These changes may be attributed to the relatively high proportion of liquid vehicle in the freshly deposited structure, whose evaporation during drying can promote contraction of the polymer–excipient matrix [45]. In the present study, the low variability in printlet weight and drug content indicates that the printing process provided reproducible material deposition despite the dimensional changes occurring during drying. An ethanol concentration of 30% (v/v) in the hydroalcoholic binder solution was considered optimal for the proposed formulation, since lower concentrations required a longer time for the dosage forms to reach constant weight, whereas higher concentrations made it more difficult to obtain a homogeneous paste with suitable consistency. The incorporation of ethanol into hydroalcoholic binder solutions therefore represents a useful strategy in SSE 3D printing, as it may enhance paste extrudability and accelerate solvent evaporation after deposition, thereby improving shape fidelity and dimensional stability [29]. Nevertheless, the optimal water–ethanol ratio should be determined for each specific formulation. In addition, a risk assessment, including the determination of residual solvent levels, should be incorporated into the development process, considering the potential toxicological risks associated with ethanol exposure in dogs. Tconsidering for mean weight (390.1 ± 0.69 mg), drug content (39.83 ± 0.75 mg printlet⁻¹), and content uniformity (104.74 ± 2.36%; AV = 5.4) demonstrate that the formulation, geometrical structure and printing process enabled the manufacture of dosage forms in compliance with the quality standards established by the Brazilian Pharmacopoeia for tablets. According to pharmacopeial specifications, the dissolution method for quality control of allopurinol tablets requires a Q value of 75% within 45 min. The ALLO 3D printlets complied with the established specification according to Stage S1 criteria (Q + 5% in six units). The proposed formulation offers a clear advantage over commercially available 100 mg ALLO tablets, as it combines a lower drug dose with a larger dosage form size. This
1 3 Page 7 of 11 271 Journal of Pharmaceutical Innovation (2027) 22:271 feature of the ALLO-3D printlets enables administration either as an intact pharmaceutical dosage form or as a fraction thereof, adjusted according to the animal’s body weight. Alternatively, different dose strengths can be achieved by modulating the final weight of the printed formulation. In contrast, adjustment with conventional 100 mg ALLO tablets (9 × 9 × 3 mm) relies exclusively on tablet splitting, a manual process that may result in significant deviations in content uniformity due to the relatively small tablet dimensions [30–31]. Since the present study did not evaluate the content uniformity of subdivided ALLO-3D printlets or investigate printlets with different dimensions and drug strengths, further studies are required to assess dose accuracy after subdivision and to explore different strengths and dimensions for weight-based dose personalization across a broader range of canine body weights. Regarding geometrical design, the torus geometry adopted in the present study demonstrated adequate pharmacotechnical performance, meeting the quality requirements established for oral solid dosage forms. Although improved acceptability of donut-shaped 3D-printed medicines has only been reported in human studies [32], the torus geometry may be considered, from a pharmacotechnical perspective, a promising model concept for the development of veterinary medicines for small animals due to: (a) its potential to modulate the dissolution performance of the polymeric matrix by exploiting different aspects of the available surface area for drug release [33–34]; and (b) its potential to contribute to taste masking [35]. Furthermore, semi-solid extrusion 3D printing enables the fabrication of a wide variety of complex geometries that cannot be achieved using conventional direct compression techniques [36], thereby expanding the design space for personalized veterinary medicines. In Vitro ALLO-3D Release The present study aimed to investigate the dissolution profile of ALLO 3D from the perspective of drug release behavior from the excipient matrix. Such studies can assess the influence of formulation materials and manufacturing processes, while also establishing dissolution profiles that support formulation design and the development of suitable quality control methods. Considering the 40 mg dose of allopurinol associated with an immediate-release design, rapid dissolution without significant influence of the printing process would be expected due to the high solubility of the drug. However, since oral solid dosage forms produced by 3D printing represent an innovative pharmaceutical system, the drug release profile must be thoroughly evaluated. This way, drug release of ALLO-3D printlets were evaluated under different pH conditions and volume over a sampling interval of 5–60 min. Fig. 1 CAD model (A) and ALLO 3D printlets (B, C)
1 3 271 Page 8 of 11Journal of Pharmaceutical Innovation (2027) 22:271 Regarding the evaluation under different medium volumes (Fig. 2a), similarity among dissolution profiles was observed for the studies conducted using 900 and 500 mL (DE% 900 = 80.70 ± 0.13; DE% 500 = 78.63 ± 0.33). Although the 40 mg dose remained soluble and achieved sink conditions in the 200 mL medium, a more pronounced reduction in dissolution efficiency was observed (DE% 200 = 70.88 ± 0.49). This behavior may be attributed to alterations in hydrodynamics and contact surface area between the printlet and the dissolution medium resulting from the use of the mini-paddle and mini-vessel apparatus under this specific condition. Further studies are required to elucidate the underlying causes of this behavior. Nevertheless, despite the variations observed among the dissolution profiles under different experimental conditions, the proposed printlets exhibited rapid dissolution (> 85% within 30 min). Although the mini-vessel/mini-paddle apparatus presents high potential for dissolution testing of low-dose formulations, it has not yet been officially recognized by international regulatory agencies such as the European Medicines Agency (EMA) or the U.S. Food and Drug Administration (FDA). From a regulatory perspective, current dissolution guidelines are primarily based on adult-oriented and highdose formulations, without considering personalization for pediatric and geriatric populations (Brooks et al., 2026). For veterinary populations, guidance regarding dissolution testing of oral solid dosage forms is available through Veterinary International Conference on Harmonization (VICH); however, no specific recommendations addressing miniaturized systems suitable are currently provided. The mini-vessel/ mini-paddle system is particularly relevant for evaluating the dissolution of personalized veterinary dosage forms, as its reduced dimensions enable testing of formulations containing low drug doses and the use of smaller dissolution medium volumes when studies are designed to more closely reflect the physiological gastric volumes of different animal species. According to Brooks et al. (2026) [37], this regulatory misalignment contrasts with the principles established in ICH Q6A and Q8(R2), both of which emphasize the importance of product-specific critical quality attributes and appropriately designed control strategies. Figure 2b illustrates the dissolution profile of the ALLO 3D printlets under the established pharmacopeial conditions (0.01 M HCl, paddle apparatus, 75 rpm). The dissolution profile was best fitted to the first-order kinetic model (R 2 = 0.951). The data demonstrated a characteristic immediate-release profile, with rapid initial dissolution followed by progressive deceleration until complete drug release was achieved. Figure 2b also presents the dissolution profile of the formulation across a pH range of 1.2–7.5. DE% values for 0.01 M HCl (DE% = 80.70 ± 0.13) phosphate buffer pH 6.0 (DE% = 82.17 ± 0.32), and phosphate buffer pH 7.5 (DE% = 81.66 ± 0.94) media confirmed the similarity among the obtained dissolution profiles, with drug release exceeding 85% within 30 min regardless of pH conditions. This behavior was expected considering that allopurinol is a highly soluble drug across a broad physiological pH range at the 100 mg dosage strength (commercial tablets commonly used in veterinary medicine), in which dissolution is not considered the rate-limiting step for drug solubilization [38]. Therefore, it can be concluded that allopurinol incorporated into a three-dimensional matrix exhibited dissolution behavior comparable to conventional immediaterelease oral solid dosage forms containing highly soluble drugs produced by traditional manufacturing methods. Fig. 2 In vitro dissolution profiles of ALLO-3D printlets under different conditions: (a) 200–900 mL using HCl 0.01 M as dissolution medium and (b) pH 1.2–7.5 using a 900 mL dissolution medium (HCl 0.01 M was assumed to provide a dissolution medium with an approximate pH of 1.2)
1 3 Page 9 of 11 271 Journal of Pharmaceutical Innovation (2027) 22:271 Although the release of allopurinol from the excipient matrix was considered adequate for an immediate-release solid dosage form, further studies should be conducted to evaluate its release under biorelevant conditions, considering the 3D printing process in conjunction with dissolution media that more closely reflect the physiological conditions of dogs and cats. Considering the specific physiology of animal species, standard dissolution conditions established for humans do not reflect the non-sink environment typically found in the canine gastrointestinal tract, highlighting the need for studies employing biorelevant dissolution media. These species-specific characteristics include higher gastric pH values and lower gastrointestinal fluid volumes compared to humans, factors that may significantly influence drug dissolution, release, and absorption behavior of the veterinary formulations [39–43]. Importantly, the conditions investigated in this study were not intended to reproduce the gastrointestinal environment of dogs. Biorelevant dissolution media were not evaluated, and the present experiments do not provide the solubility and permeability data required for biopharmaceutical classification according to the veterinary framework proposed by Papich (2015) [46]. Further studies incorporating species-specific physiological conditions and biorelevant media are therefore required to investigate the in vitro performance of ALLO-3D from a biopharmaceutical perspective. Index of Greenness Assessment of Printed Pharmaceuticals (iGAPP) The results related to the greenness profile of the proposed process to produce ALLO 3D printlets are presented in Table 2. According to the metric proposed by Youssef et al. (2022) [26], the printing process proposed in the present study exhibited predominantly green scores across most evaluated parameters, reaching a red score only for the parameter related to the number of active constituents per formulation. One of the main advantages of SSE, highlighted by the green scores obtained in the proposed process, is associated with temperature control throughout the manufacturing procedure. During the pre-printing, printing, and post-printing stages, the process temperature was maintained at 25 °C, reducing energy demand when compared to additive manufacturing techniques such as fused deposition modeling. In addition to the reduced energy consumption, maintaining room temperature throughout the process minimizes the risk of thermal degradation of the active pharmaceutical ingredient, thereby contributing to formulation stability. According to Van der Veen et al. (2025) [44], green hardware — characterized in SSE by energy efficiency and the use of reusable cartridges — should be associated with regulatory measures, green excipients, and green practices to establish the four pillars of Green 3D Drug Manufacturing and their integration into the “SSbD: Safe and Sustainable by Design assessment” concept. With the continuous expansion of pharmaceutical 3D printing technologies, further studies will still be required to comprehensively evaluate the environmental impact of this technology. Nevertheless, SSE has generally demonstrated promising characteristics when compared to other additive manufacturing techniques, and the method proposed herein proved to be suitable considering the overall score achieved. Conclusions Allopurinol-containing printlets produced by semi-solid extrusion 3D printing were successfully developed in the present study and demonstrated suitable pharmaceutical characteristics for personalized and small-scale manufacturing. The optimized formulation, composed of HPMC, lactose monohydrate, CCS-Na, and a water–ethanol binder solution, exhibited an immediate-release profile, with all quality control tests complying with the requirements established by official compendia for oral solid dosage forms. This approach represents a significant advancement in dosage form development, contributing to the optimization of therapeutic efficacy and the management of clinical conditions, while reinforcing the feasibility and relevance of 3D printing as an innovative tool in the field of veterinary pharmacy. The study is particularly relevant because it addressed the treatment of a neglected zoonotic disease for which adequate therapeutic options remain limited in many tropical countries, including Brazil. Overall, the semi-solid extrusion process demonstrated advantages such as operational simplicity, lower cost when compared to other additive manufacturing techniques, and easier implementation in decentralized settings, making it particularly suitable for veterinary compounding pharmacies. In addition to these characteristics, the manufacturing process proved to be appropriate from an environmental impact perspective, achieving the “green” classification proposed by the iGAPP metric. Accordingly, the present findings demonstrate that SSE 3D printing represents a promising strategy for the production of personalized allopurinol-containing printlets, enabling accurate dose adjustment and potentially improving therapeutic management in canine leishmaniasis. Acknowledgements This study was financed in part by the Coordena- ção de Aperfeiçoamento Pessoal de Nível Superior – Brasil (CAPES) - Finance code 001.
1 3 271 Page 10 of 11Journal of Pharmaceutical Innovation (2027) 22:271 Authors’ Contributions Author contributionsConceived and Designed Research: Silva, F. E. B.; Escobar, B. M.; Barin, J. S.; Malesuik, M. D. Performed experiments and analysed data: Escobar, B. M.; Kaufmann, A.I.; Mezadri, J. V. Wrote the first draft: Silva, F. E. B.; Escobar, B. M.; Barin, J. S. Writing and editing the manuscript: All authors. Funding The Article Processing Charge (APC) for the publication of this research was funded by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil (CAPES) (ROR identifier: 00x0ma614). This study was financed in part by the Coordenação de Aperfeiçoamento Pessoal de Nível Superior – Brasil (CAPES) - Finance code 001. Data Availability All data generated or analyzed during this study are included in this published article. Declarations Competing interests The authors declare no competing interests. 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