Development, characterization and preliminary clinical evaluation of mucoadhesive vaginal gels containing chlorhexidine digluconate

Gels containing chlorhexidine, based on hydroxyethylcellulose or its mixtures with either hydroxypropylmethylcellulose or chitosan, were prepared and characterized by in vitro drug release, swelling, mucoadhesion and rheological studies. All formulations provided a controlled drug deliver showing in general a decrease in drug release rate with the increase of the total polymer concentration. Formulations containing either hydroxyethylcellulose or its mixtures with hydroxypropylmethylcellulose presented similar strength of gel network that was markedly higher compared to gels based on mixtures with chitosan at the same total polymer concentration. Drug release was more sustained when gel components were mixtures of hydroxyethylcellulose and hydroxypropylmethylcellulose. Mucoadhesion was similar for all preparations. Viscosity measurements gave higher values in correspondence to higher total polymer concentrations. A candidate vaginal gel formulation containing hydroxyethylcellulose at 2.5% (w/w) induced a clinical remission in 93% of patients affected by bacterial vaginosis compared to 76% of patients belonging to a metronidazole treatment group, and in 84% of subjects with Candida infections compared to 83% receiving clotrimazole. No adverse events were reported during the trial in any patient. Patient compliance with the mucoadhesive gel was good.