Evaluation of the release and efficacy of two new antibacterial agents from different ointment bases

The in vitro release of rosoxacin (1) and oxolinic acid (2) from three different ointment bases including a revised water washable (NF), an oleaginous, and an O/W emulsion ointment base was studied. Among the bases evaluated, the revised water washable base provided the best release of the two drugs as revealed from the values of the release rate constant (K). The amounts released of both drugs from the revised water washable base showed direct relationship with the concentration of the drug in the ointment. In addition, the effect of some additives on the amount released of both drugs from the different bases has been investigated. The release of 1 from the revised water washable base had been enhanced by adding 0.2% Tween 80 or 10% ethanol, but addition of 10% of N,N-dimethylacetamide and polyvinylpyrrolidone (PVP) led to retardation of the release of the drug. Furthermore addition of 10% polyethylene glycol (PEG) 200, N,N-dimethylacetamide, or ethanol led to enhancement of the release of the drug from both the oleaginous and the emulsion bases. On the other hand, the release of 2 from the revised water washable base had been enhanced only on addition of 0.2% Tween 80 and been retarded by adding 10% ethanol, N,N-dimethylacetamide or PVP to the formula. The release of 2 from the oleaginous, as well as the emulsion bases had been enhanced by 10% PEG 200. However urea was found to show no pronounced effect on the release of the two drugs from the different ointment bases.(ABSTRACT TRUNCATED AT 250 WORDS)