Cataplasm-based controlled drug delivery: Development and optimization of a novel formulation

The objective of the present study was to study the formulation variables i nvolved in the development of a novel plasterlike preparation (cataplasm) a nd to optimize important formulation variables with an aim to maximize the in vitro release of the drug with minimum lag time. Cataplasm was prepared by dispersing a model drug (ibuprofen), humectant (glycerol), adhesive (Ind opol H100(R)), polymer (Carbopol C934P(R)) with other formulation ingredien ts in a beaker with an open-blade impeller. The paste was cast on a nonoccl usive backing membrane and dried overnight. The diffusion of the model drug was studied across a cellulosic membrane using Franz's diffusion cells. Th e amounts of three formulation variables, carbopol (X-1), glycerol (X-2), a nd indopol (X-3) were studied at three levels, and a face-centered cubic de sign was used to maximize the flux. An optimization procedure for maximum f lux and minimum lag time predicted a flux of 97.22 mcg/cm(2)/hr at X-1 (2% w/w), X-2 (11.75% w/w), and X-3 (6% w/w). An experimental patch prepared wi th the above concentrations yielded a flux of 90.7 mcg/cm(2)/hr.