Formulation and evaluation of capsules containing extracts of Cassia sieberiana for improved therapeutic outcome

Abstract

In Ghana, the encapsulated blend of the powdered stem and root bark of Cassia sieberiana is prescribed and dispensed to patients at the Centre for Plant Medicine Research (CPMR), for the management of dysmenorrhea and gastric ulcer pain. This current formulation has significant challenges in manufacturing and optimization of therapeutic outcomes due to lack of standardization of actual quantities of the extracts obtained from ingestion of the product. The study sought to formulate and evaluate capsules of Cassia sieberiana using the stem and root bark. Extraction was undertaken with different solvents: absolute ethanol (F1) and 70% ethanol (F2). These 2 formulations were compared to the existing product (MP1) by CPMR. Granules for encapsulation were prepared by wet granulation and their flow properties compared with MP1. Drug-excipient compatibility was studied using FT-IR, TLC and UV. Quality control tests on MP1, F1 and F2 capsules were conducted using pharmacopoieal methods. From the results obtained, organoleptic and physicochemical properties of the extracts demonstrated its suitability for use in oral capsule formulation. MP1, F1 and F2 recorded a λmax of 278 nm, 278 nm and 276 nm, respectively. The extract per dose of capsules was found to be 27.84 ± 0.11 mg and 36.65 ± 0.03 mg for F1 and F2, respectively. Granules of F1 and F2 had good flow properties whereas MP1 demonstrated a fair flow property. FT-IR spectra showed possible interaction between extracts and excipients. However, TLC results indicated similar compounds present in the extracts and granules. The UV marker analysis also indicated no interaction since the percentage drug contents in F1 and F2 capsules were found to be 98.0% ± 1.40 and 98.90% ± 2.80 respectively. All 3 formulations passed the disintegration and uniformity of weight tests except MP1 which failed the latter. F1 capsules recorded the highest dissolution efficiency (99%) while MP1 recorded the lowest (22%). There was significant difference (p < 0.0001) in the release of Cassia sieberiana among the three formulations. This study has demonstrated the potential replacement of Cassia sieberiana capsules on the market with capsules developed from its extract with F1 capsules being the most desirable.