Physicochemical evaluation of Prinsepia utilis seed oil (PUSO) and its utilization as a base in pharmaceutical soap formulation

Abstract

This study aims to evaluate the standard physicochemical parameters, such as iodine value, acid value, saponification value, ester value, refractive index, peroxide value, and viscosity, of Prinsepia utilis (P. utilis) seed oil (PUSO) obtained as hexane extract from seeds, and to formulate ketoconazole soap (2% w/w) by using extracted oil as a base. The quality control standards of the final ketoconazole soap complied with the standards specified in Indian Pharmacopeia. Pharmaceutical soap was obtained by treating PUSO with potassium hydroxide (KOH), undergoing basic saponification. All physicochemical parameters, such as acid value (21.78 mg KOH/g), saponification value (194.13 mg KOH/g), iodine value (99.7 g I2/100 g), ester value (172.35 mg KOH/g), refractive index (1.464), and viscosity (192 centipoises [cps]), conformed to industrial standards, except the peroxide value (19.23 milliequivalent KOH/g). Besides, evaluation of quality control parameters of pharmaceutical soap suggested that its various parameters, such as pH (7.3), foam-forming ability (14.5 cm), foam retention time (15 min), total fatty matter (69.31%), moisture content (10.35%), and drug content (99.37%), were within the acceptable limit. Overall, our study showed that P. utilis base was physicochemically stable and suitable for manufacturing cosmetic products, soaps, and shampoo in an economical manner, rather than using expensive chemical additives, in the pharmaceutical and cosmeceutical industry. Further, this study suggested that therapeutically and commercially successful ketoconazole soap, with all the required quality control parameters, could be manufactured by using naturally available oil at a low cost.