Design and evaluation of adhesive type transdermal patches of carvedilol

Abstract

The transdermal adhesive patches of carvedilol were designed using pressure sensitive acrylic adhesives such as DUROTAK® 87-235A, DUROTAK® 87-8301 and DUROTAK® 87-4287. The patches were evaluated for physicochemical characterization, in-vitro drug permeation across dialysis membrane and ex-vivo drug permeation through the pork ear skin using diffusion cell, stability studies and skin irritability study. The Scanning Electron Microscopy (SEM) of patches does not show any evidence of recrystallization indicating the presence of drug in the molecular form in the adhesive matrix. The physicochemical properties of patches were found to be in acceptable limit. Among the three acrylic adhesives used, DUROTAK® 87-4287 exhibited maximum flux (8.47 ± 0.18 μg/cm2.hr). To enhance the drug permeation, peppermint oil was used as penetration enhancers (2%) in the patches. Out of those, formulation A6 exhibited a flux of 10.04 ± 0.83 μg/cm2.hr revealing that formulation A6 was the optimized formulation. The patches of A6 formulation showed excellent in-vitro-ex-vivo correlationship. The stability study was carried out using optimized fresh (A6) formulation for 3 months old patches stored at room (25 ± 2 °C/60 ± 5%RH) and at accelerated condition (40 ± 2 °C/75 ± 5%RH). The investigation reveals that the adhesive type patches of carvedilol were stable and devoid of skin irritation and hypersensitive response. Therefore, may serve as a potential drug delivery system for carvedilol.