Biodegradable polymers have been extensively used in controlled drug delivery. They have the advantage of not requiring surgical removal after they serve their intended purposes. PGA, PLA, and especially their copolymers PLGA are the most commonly used family of biodegradable polymers. PGA was used as a biodegradable suture material in the 1970s, and it has led the largest volume production in the biomedical polymer markets, when its production was combined with those of PLA and PLGA.5 Since then, they have found a broad range of pharmaceutical and biomedical applications based on their unique properties, including versatile degradation kinetics, non-toxicity, and biocompatibility.6 The general properties and typical applications of PGA, PLA, and PLGA are summarized