Controlled release of atenolol from the ethylene-vinyl acetate matrix.

The present study was carried out to evaluate the possibility of using the polymer EVA membrane as an EVA matrix system for transdermal delivery of atenolol. The effects of drug concentration, temperature, and plasticizers on drug release were studied from the atenolol-EVA matrix. The release rate of drug from the EVA matrix increased with increased temperature and drug loading doses. The flux of atenolol versus the reciprocal of the loading dose yielded a straight line. The release of atenolol from the EVA matrix follows a diffusion-controlled model, where the quantity released per unit area is proportional to the square root of time. Among the plasticizers used such as alkyl citrates and phthalates, tributyl citrate (TBC) showed the best enhancing effects. Enhancement factor of TBC was 1.51 from the EVA matrix at 37 degrees C. The controlled release of atenolol system could be developed using the EVA polymer including the plasticizer.