Department of Pharmaceutical Technology, Faculty of Pharmaceutical Sciences, Prince of Songkla University, Songkhla 90110, Thailand.
School of Pharmacy, Walailak University, Nakhon Si Thammarat 80160, Thailand.
Int J Biol Macromol. 2023 Jan 1;224:725-738. doi: 10.1016/j.ijbiomac.2022.10.161. Epub 2022 Oct 23.
Natural rubber (NR)'s value has become increasingly important for human applications. This study prepared NR beads as floating drug delivery system by dripping NR latex into hardening solution to obtain spherical beads. Theophylline was loaded as a model drug. NR latex formed into harden beads suddenly after dripping droplets in acidic medium. These NR beads floated instantly and buoyant in HCl buffer for over 8 h with prolonged theophylline release. Their morphologies, crystallinity and thermal properties were observed using microscope, X-ray diffractometer, and thermogravimetry, respectively. Addition of 100 phr sodium bicarbonate increased drug release owing to liberation of carbon dioxide promoting porous NR matrix. Composite of 50 and 200 phr shellac in NR beads floated in HCl buffer for over 12 h. Moreover, 200 phr shellac efficiently retarded release of theophylline from NR composite beads (lower than 10 % in 8 h), whereby promoting theophylline release in phosphate buffer (pH 6.8) (approximately 80 % in 8 h). NR-shellac beads had greater water sorption (2.5 times) and erosion (4.9 times) in phosphate buffer than in HCl buffer. Thus, NR beads exhibited desirable attributes as floating drug delivery system. Both sodium bicarbonate and shellac modified matrix properties and drug release of NR beads.
天然橡胶（NR）的价值对于人类应用变得越来越重要。本研究通过将 NR 胶乳滴入硬化溶液中制备 NR 珠作为漂浮药物传递系统，以获得球形珠。茶碱被加载为模型药物。NR 胶乳在酸性介质中滴入液滴后立即形成硬化珠。这些 NR 珠立即漂浮在 HCl 缓冲液中，超过 8 小时持续释放茶碱。使用显微镜、X 射线衍射仪和热重分析仪分别观察它们的形态、结晶度和热性能。由于二氧化碳的释放促进了多孔 NR 基质，添加 100phr 碳酸氢钠增加了药物释放。50 和 200phr 紫胶在 NR 珠中的复合材料在 HCl 缓冲液中漂浮超过 12 小时。此外，200phr 紫胶有效地延缓了 NR 复合珠中茶碱的释放（8 小时内低于 10%），从而促进了磷酸盐缓冲液（pH 6.8）中茶碱的释放（8 小时内约 80%）。NR-紫胶珠在磷酸盐缓冲液中的吸水率（2.5 倍）和侵蚀率（4.9 倍）高于 HCl 缓冲液。因此，NR 珠表现出作为漂浮药物传递系统的理想特性。碳酸氢钠和紫胶都改变了 NR 珠的基质性质和药物释放。
