Development and characterization of capsaicin creams formulated with Grewia mucilage-HPMC base

Abstract

Purpose: Conventional topical capsaicin creams are often unavailable and unaffordable to the larger patient populations in developing countries. There is a need to formulate cost-effective alternatives using locally available polymers as cream base. This study aimed to formulate oil-in-water Grewia mollis mucilage-hydroxypropyl methylcellulose (GMM-HPMC) based capsaicin creams from locally available capsicum fruits and evaluate their quality attributes. Methods: Capsaicin was quantified from acetone extracts of Capsicum fruits (C. frutescens, C. pubescens and C. chinense) using high performance liquid chromatography (HPLC). Extract of C. chinense which had higher capsaicin content was used to formulate six different cream types with varied concentrations of GMM and/or HPMC as polymeric base. The creams were assessed for their organoleptic properties, pH, specific gravity, conductivity, viscosity, spreadability, oil globule size, microbial load and stability profiles using standard methods and protocols. Results: The FTIR spectroscopic analysis confirmed the presence of capsaicin in all the Capsicum fruit extracts; HPLC quantification of each of the fruit extracts indicated the presence of both capsaicin; C. chinense: (36153 ppm) > C. frutescens: (7860 ppm) > C. pubescens: (4549 ppm) and dihydrocapsaicin; C. chinense (11044 ppm) > C. frutescens (6920 ppm) > C. pubescens (2828 ppm) as constituents. Formulated o/w creams were light to deep brick red in colour, with pH (6.11-6.44); specific gravity (1.00-1.03); electrical conductivity (292-1958 µS/cm); viscosity (2810-9190 mPas); spreadability (4.0-5.5 cm) and globule size (13 ± 8 µm to 91 ± 20 µm). The creams had satisfactory microbial load profiles and remained stable at 25 ± 2 °C but had varying degrees of stability at 40 ± 2 °C storage temperatures. The optimized formulations of the creams (FB, FE and FF) contained GMM as the mono polymeric, GMM10:HPMC10 and GMM15:HPMC10 as their co-polymeric base systems, respectively. Conclusion: This study has shown the suitability of Grewia mollis mucilage singly used or in combination with hydroxypropyl methylcellulose as co-polymeric cream base. Formulated creams had desirable physicochemical properties and they may find better patient acceptance when compared with imported brands as a result of their potential low cost. Keywords: Capsicum fruits, capsaicin, Grewia mollis mucilage-HPMC, creams