A reservoir-based device constructed of a completely biodegradable elastomer can enable several new implantation and insertion options for localized drug therapy, particularly in the case of urological therapies. We performed an in vitro performance evaluation of an implantable, bio-resorbable device that supplies short-term controlled release of ciprofloxacin-HCl (CIP). The proposed device functions through a combination of osmosis and diffusion mechanisms to release CIP for short-term therapies of a few weeks duration. Poly(glycerol-co-sebacic acid) (PGS) was cast in a tubular geometry with solid drug powder packed into its core and a micro-machined release orifice drilled through its wall. Drug release experiments were performed to determine the effective release rate from a single orifice and the range of orifice sizes in which controlled zero-order release was the main form of drug expulsion from the device. It is demonstrated that PGS is sufficiently permeable to water to allow the design of an elementary osmotic pump for drug delivery. Indeed, PGS's water permeability is several orders of magnitude larger than commonly used cellulose acetate for elementary osmotic pumps.
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