Gels preparation

Four formulations of gels based on carbopol 940 (Merck) at 1.5% (w/w) were prepared. The formulation A contained a final AgNP concentration of 0.03 mg/g; formulation B contained a final KTZ concentration of 0.03 mg/g; formulation C contained a final AgNP and KTZ concentration of 0.03 mg/g and 0.03 mg/g, respectively. Formulation D without drugs was used as control.

Required quantity of carbopol 940 was weighed and dispersed slowly in the sterile purified water with continuous agitation. After that, the polymer was allowed to stand for 24 h until it was completely wetted. The drug corresponding to each formulation was added with continuous stirring till it was completely dispersed. Finally, the pH of the gel was adjusted to pH 7 using triethanolamine. The prepared gels were packaged under sterile conditions and stored in dark and cool place until time of use.