Quantification of porogen effect on the drug release from single- and multi-layered ethylcellulose coated pellets containing single or combined drugs

The aim of this work was to develop a mathematical model to estimate the drug release from a conventional single-compartment reservoir pellet and extend its applicability to multi-compartment reservoir pellets. Conventional pellets were prepared by layering the drug onto starter-core then applying various ethylcellulose / HPC coatings for drug release control.

Multi-layered pellets comprised a first drug layer of propranolol HCl (D1) followed by a first controlled release coating (C1) and consecutively a second drug layer of carbamazepine or caffeine (D2) and then a second controlled-release coating (C2). Drug release from single- and multi-compartment pellets generally increased with an increase of the water-soluble HPC in the coatings.

The response described a sigmoidal curve, which agreed with a cumulative normal distribution function. The developed mathematical model was facilitating quantifications of the drug release of pellets as a function of the porogen content and the coating level. Additionally, the model can be applied successfully in multi-compartment pellets to estimate the release of drugs with a broad range of aqueous solubility. More on porogen effect on drug release of pellets