Design invitro characterization and optimization of suppositories of <i>Vernonia amygdalina</i> leaf extract for possible clinical trials in the treatment of <i>vulvovaginal candidosis</i>

Abstract

The antifungal properties of bitter leaf extracts have been widely reported. Full clinical use of this material in both orthodox and alternative medicines especially through the oral route is hampered by its extreme bitter taste and the absence of formal clinical trial studies required for establishing its effectiveness, safety and posology. The aim of the current work was to formulate bitter leaf extract as suppositories thereby enabling its administration through the vagina and therefore avoiding the bitter taste and low patient acceptability associated with the oral route delivery. The extract was obtained from the fresh leaves of the plant by hot maceration for 24 h in distilled water maintained at a temperature of 60 oC. The solution obtained was concentrated on a rotary evaporator to a sticky mass which was then oven-dried for 24 h at 60 oC. Phytochemical analysis, visible/ultraviolet light absorption and Fourier’s transform infrared spectroscopies as well as acute toxicity studies were conducted on the extract. Varied weight proportions of the extract were incorporated into five selected suppository bases including cocoa butter, witepsol and three different grades of polyethylene glycol by the melt fusion technique. The formed suppositories were optimized for some physico-pharmaceutical and fungicidal activities. Parameters investigated, including hardness, pH, melting point and disintegration time were in the ranges of; 2.0 ± 0.84 - 3.1 ± 0.05 (kg/cm2), 5.95 – 6.89, 35.03 – 37.44 oC and 16.02 ± 0.35 - 27.45 ± 0.60 min respectively. All the formulations complied with official specifications for weight uniformity and active ingredient contents. The average dissolution rate of the various formulations was 2.325 ± 0.87 mg/min. Formulation SP8 which contained 40 % of the extract and 60 % PEG-4000 exhibited comparatively better formulation profiles and highersustained release of extract and was, as such, adjudged as the optimized formulation. The formulation exhibited a 19.86 ± 0.37 mm zone of inhibition diameter on the C. albican-inoculated Sabouraud dextrose agar media. The current work concluded that aqueous leaf extracts of the V amygdalina plant possess antifungal properties and that intra-vaginal delivery of the extract via PEG-600 based suppository provided sustained release profile of the extract with potential for further clinical trials in the treatment of VVC.