Formulation, characterization and ex-vivo permeation studies on gentamicin-loaded transdermal patches based on PURASORB polymers

Abstract

Topical administration of gentamicin, an aminoglycoside antibiotic commonly used for treatment of bacterial infections, is limited by toxicity and membrane impermeability. The purpose of this study was to develop an alternative non-invasive, convenient and cost-effective drug delivery system for enhanced skin delivery of gentamicin. The patches were formulated by solvent evaporation technique using PURASORB® polymers and evaluated for drug content, thermal properties, physicochemical performance, stability, skin irritability and ex-vivo drug permeation through rat skin using a modified Franz diffusion cell. The DSC results indicate absence of strong interaction between gentamicin and the polymers. Theformulations showed good drug encapsulation, stability, physicochemical properties, tolerability on rat skin and ex-vivo drug permeation through rat skin.Compared with a commercially available gentamicin sulphate cream the transdermal patches gave higher ex-vivo skin permeation through rat skin with patches of PURASORB® PL 32 showing highest permeation flux (5.161 µg/cm2.h) and permeation coefficient (1.032 × 10-6 cm/h). The results of this study indicates that patches of PURASORB® PL 32 represent a new delivery system for enhnaced skin delivery of gentamicin. Key words: Transdermal patches, gentamicin, PURASORB® polymers,bioadhesive strength, ex-vivo drug release.