EFFECTS OF EXCIPIENTS ON SWELLING AND DRUG-RELEASE FROM COMPRESSED MATRICES

Polymers, and particularly hydrogels, are becoming very popular in for mulating controlled-release tablets because they are excellent drug ca rriers. The effects of hydrophilic and hydrophobic polymers, incorpora ted in matrices containing soluble (propranolol HCl) or less soluble ( flurbiprofen) drugs, on swelling and release kinetics were investigate d. The results indicate that swelling and release profiles were affect ed by the amount of ingredients, the characteristics of the polymer, a nd the drug substances incorporated in the matrices. Swelling may infl uence the release rate of the drugs from the matrices. The data obtain ed from the in vitro dissolution study were evaluated on the basis of a theoretical dissolution equation, by linear transformation of the di ssolution curve, and by the Peppas equation. The release mechanisms ap peared complex and are affected by the composition of the matrix.