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PEG modulated release of etanidazole from implantable PLGA/PDLA discs

Paper ID Volume ID Publish Year Pages File Format Full-Text
13295 849 2002 12 PDF Available
PEG modulated release of etanidazole from implantable PLGA/PDLA discs

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. We observed the release characteristics of etanidazole in the dosage forms of microspheres and discs, subjected to different preparation conditions. The release characteristics, morphology changes, particle size, and encapsulation efficiency of microspheres are also investigated. The release rate of etanidazole from implantable discs (13 mm in diameter, 1 mm in thickness, fabricated by a press) is much lower than microspheres due to the reduced specific surface. After the initial burst of 1% release for the first day, the cumulative release within the first week is less than 2% until a secondary burst of release (caused by polymer degradation) occurs after one month. 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.

Discs; Spray dryer; Microspheres; Etanidazole; Polyethylene glycol (PEG)
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PEG modulated release of etanidazole from implantable PLGA/PDLA discs
Database: Elsevier - ScienceDirect
Journal: Biomaterials - Volume 23, Issue 17, September 2002, Pages 3555–3566
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Physical Sciences and Engineering Chemical Engineering Bioengineering