In-vitro and in-vivo evaluation of sustained-release suppositories containing theophylline microspheres

ABSTRACT

The sustained release microspheres of theophylline were formulated using non-solvent addition technique. The in-vitro dissolution of the drug from the fabricated microspheres that having size ranges of 300-600, 600-800 and 800-1000 [micro]m was tested The release of theophylline was extended over 8 hrs and it was found that the drug release decreased nonsignificantly as the particle size increased [p>/=0.05]. incorporating theophylline-containing microspheres into suppository formulation using polyethylene glycol base resulted in a slight increase in dissolution rate, but still in a sustained release pattern over 8 hrs. In-vivo study of the prepared suppositories on beagle dogs revealed that the peak of theophylline serum concentration C[max] [mean +/- S.D] was 11.1+0.3 [micro]g/mL. It was also found that AUC [0-24hrs] value averaged 154.7 +/- 20.3 [micro]g-h/ml. The median peak time [T[max]] was 3.0 hrs and MRT was 13 hrs indicating a sustained effect