Physicochemical and in vitro antimicrobial evaluation of cream and vaginal suppository formulations of the extract of the flower buds of Syzygium aromaticum (Myrtaceae)

Abstract

Clove also known as Syzygium aromaticum (Myrtaceae) has been used for centuries due to its known antimicrobial properties. The aim of this study is to formulate and evaluate cream and vaginal suppository formulations containing the ethanol extract of clove. Crushed clove buds were macerated in ethanol (70 %) for 24 h at room temperature, the resulting extract (Cx) was used to prepare water-in-oil cream formulations at concentrations of 5, 10 and 40 %w/w, a macrogol-based suppository at 40 %w/w was also prepared. The creams were evaluated for organoleptic and physicochemical properties; color, odor, texture, pH, and spreadability. The suppository was evaluated for appearance, weight uniformity, pH, liquefaction time, melting point and adhesion/erosion time. Incompatibility was determined using the Fourier Transform Infrared (FTIR). In vitro antimicrobial evaluation of the formulations against selected microorganisms were also carried out using the agar dilution and agar diffusion method. Creams were brown to dark brown in color, had a characteristic odor and smooth texture and had good spreading ability, pH was between 6.08 and 9.17 and concentration dependent. The suppositories were brown in color, had an aromatic odor and were whole without pitting, exudates or sedimentation. The pH was 4.78 ± 0.09 with liquefaction time of 13.00 ± 3.61 min and melting point of 35.5 ± 0.5 ºC. Adhesion time of the suppositories on an excised cow vagina was about 2 h. FTIR returned spectra with no interaction. The cream and vaginal suppository formulations showed most significant antimicrobial activity against Gram-negative bacteria and Candida albicans. This study shows the propensity of clove extract to be formulated into standardized dosage forms for treatment of vaginal infections.