Preparation and release of ibuprofen from polyacrylamide gels

The conditions of preparation of polyacrylamide (polyAC) gels, the incorpor ation of ibuprofen (IB), and the kinetics of IB release under various condi tions have been evaluated. Transparent, opaque, or elastic gels were prepar ed depending on the concentration of acrylamide (AC) and the cross-linking agent, N,N'-methylenebisacrylamide (BIS). Release studies in media below pH 5.0 resulted in opaque gels. The kinetics of IB release was a function of the AC, BIS, and the pH of the medium, but the optimum composition, in term s of gel integrity and release characteristics, was 7% AC cross-linked with BIS at a SO:I ratio. Modulation of the release rate was possible with the incorporation of 10% of certain polymers. The amount of IB that could be in corporated per gram of transparent gel was a function of the amount of poly mer initiator N,N,N',N'-tetramethylene diamine (TEMED) used per gram of gel . More than 200 mg of IB could be incorporated per gram of transparent gel by using 100 mu l of TEMED. The release of IB obeyed matrix/swelling-contro lled kinetics and 70-80% of the IB was released from gels containing 10 to 40 mg IB per gram of gel in 5 hr at pH 7.4 and 37 degrees C.