Formulation and evaluation of Lawsone solid dispersion-based suppository for vaginal candidiasis

The second most frequent factor causing vulvovaginal infections is vulvovaginal candidiasis. The use of medications derived from natural sources is prioritized due to an increasing susceptibility to synthetic antifungal medications. Lawsone is an antifungal drug (BCS class II) having poor aqueous solubility. Preparing the Lawsone solid dispersion-based suppository for treating vulvovaginal candidiasis was the goal of the current investigation. The impact of the different carriers on Lawsone's aqueous solubility was assessed using the phase solubility method. Using Poloxamer 407 as a carrier, solid dispersion of Lawsone was formulated by employing solvent evaporation method in a range of weight ratios (1:0.5, 1:1, and 1:2). FTIR, DSC, XRD, and SEM studies were used to characterize the optimized solid dispersion. Higher solubility (2.11 +/- 0.04 mg/ml) and in vitro release (97.22 +/- 2.16%) were observed for solid dispersion of 1:1 ratio. Hence, it was chosen as the optimal batch for suppository preparation. The suppository batches were prepared and optimized with the help of Design Expert (R) software by D-Optimal mixture design. PEG 4000 and PEG 400 were taken as the factors while the responses studied were melting time, disintegration time, hardness, and in vitro drug release. Based on the responses of the Design expert (R), the ratio of PEG 4000 and PEG 400 (70:30) suppository batch SL1 was the optimized one. Compared to intact Lawsone-incorporated suppositories (66.21 +/- 5.12%), the in vitro release of Lawsone from solid dispersion-incorporated suppositories was significantly enhanced (97.48 +/- 2.12%).