Biomaterials
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In this work, etanidazole (one type of hypoxic radiosensitizer) is encapsulated into spray dried poly(D),L-lactide-co-glycolide) (PLGA) microspheres and then compressed into discs for controlled release applications. Etanidazole is characterized by intracellular glutathione depletion and glutathione transferases inhibition, thereby enhancing sensitivity to radiation. It is also cytotoxic to tumor cells and can chemosensitize some alkylating agents by activating their tumor cell killing capabilities. ⋯ Some key preparation conditions such as drug loadings, disc thickness and diameter, and compression pressure can affect the initial burst of etanidazole from the discs. However, none of them can significantly make the release more uniform. In contrast, the incorporation of polyethylene glycol (PEG) can greatly enhance the release rate of discs and also reduces the secondary burst effect, thereby achieving a sustained release for about 2 months.