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Drug release from irradiated PLGA and PLLA multi-layered films.

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.