School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore.
J Pharm Sci. 2010 Jul;99(7):3060-71. doi: 10.1002/jps.22079.
Poly(lactide-co-glycolic acid) (PLGA) and poly(L-lactide) (PLLA) films are widely studied for various biomedical applications. Because of their use for drug delivery, achieving controlled release from these biodegradable films has become an area of intense research. The objective of this study is therefore to investigate how PLGA and PLLA films fabricated through an irradiated-multi-layer approach can be a viable technique to achieve controlled drug delivery. In this study, lidocaine base (lido-base) and lidocaine salt (lido-salt) were used as model hydrophobic and hydrophilic drugs, respectively. Results show that multi-layer PLGA underwent pseudo surface degradation, while multi-layer PLLA degraded to a lesser extent over the same study period. Triphasic release was observed for lido-base, whereas lido-salt was released through a biphasic profile, from both polymer systems. The two dominating release phases for both drugs were diffusion and zero-order release, where the latter is characterized by the onset of mass loss. It was shown that PLGA had a shorter diffusion phase and a longer zero-order phase, while the contrary was true for PLLA. This difference was due to the faster degradation for PLGA. In conclusion, the hydrophilic gradient induced from an irradiated-multi-layer film system shows potential for controlled and sustained release of drugs.
聚（丙交酯-乙交酯）（PLGA）和聚（L-丙交酯）（PLLA）薄膜广泛应用于各种生物医学应用。由于它们用于药物输送，因此实现这些可生物降解薄膜的控制释放已成为一个研究热点。因此，本研究旨在探讨通过辐照多层方法制备的 PLGA 和 PLLA 薄膜如何成为实现控制药物释放的可行技术。在本研究中，利多卡因碱（lido-base）和利多卡因盐（lido-salt）分别用作疏水性和亲水性药物的模型。结果表明，多层 PLGA 经历了伪表面降解，而多层 PLLA 在相同的研究期间降解程度较小。lido-base 观察到三相释放，而 lido-salt 则通过两相释放，两种药物的两个主要释放阶段都是扩散和零级释放，后者的特征是出现质量损失。结果表明，PLGA 的扩散阶段较短，零级阶段较长，而 PLLA 则相反。这种差异是由于 PLGA 降解速度较快所致。总之，辐照多层膜系统诱导的亲水性梯度显示出控制和持续释放药物的潜力。
