Abstract

Dried natural extracts demand challenges to the production process, especially when encapsulated in hard shells to avoid compromising the integrity of the capsule and extract. The present study describes a preliminary comparative approach on the changes in properties of hard gelatin and hypromellose capsules containing senna (Cassia angustifolia Vahl) leaf dry extract under two storage conditions. Therefore, loss on drying, disintegration, resistance to breakage, water activity, and microbial contamination after 6 mo at 30°/65% RH and 40°/75% RH were evaluated using Pharmacopoeia, AOAC and the manufacturer´s methods. The contents of sennoside A and sennoside B in the capsules were assessed by HPLC. Fine-tosuperfine powder of the extract presenting 0.14% total ash and 2.9% loss on drying was applied. Uniformity of mass was repeatable independently of gelatin and hypromellose shells (p > 0.05, t-test). The hypromellose capsules were more resistant to breakage than those of gelatin (maxima broken of 1/100 versus 42/100), in which the water content (2.9% to 5.7%) and water activity (0.33 to 0.43 aw) of the extract were intensively increased and, additionally, an acceptable increase in microbial contamination was observed. Compared to hypromellose shells, gelatin capsules did not maintain the same levels of both sennosides at 40°/75% RH, while sennoside B was lower. In conclusion, hypromellose performed better than gelatin to provide stable capsules, for resistance to breakage and disintegration unchanged, and offered higher protection to senna dry extract against humidity, microbial contamination and sennoside degradation. Overall, these preliminary results suggest the use of hypromellose encapsulation as a good alternative to gelatin in the production of medicinal capsules containing herbal dry extracts, mainly those with high hygroscopicity, and provide preliminary support for designing stability studies of capsules containing dry extracts that present high hygroscopicity.