Formulation Design and Ex Vivo Evaluation of Carbopol -Incorporated Mucoadhesive Thermoreversible gels of Sucralfate for Rectal Drug Delivery

Aim: The present research is focused on preparation of Thermoreversible gels and screening ex vivo anti-inflammatory activity using croton oil induced hemorrhoid model.

Study Design: The animals were divided into four groups, n=8. After overnight fasting, hemorrhoids were induced by inserting sterile cotton swabs soaked in croton oil preparation into the anus of all group animals except normal control group.

Place and Duration of Study: Depart of Pharmacology, Sree Vidyanikethan College of Pharmacy, Tirupati. between October 2021 to December 2021

Methodology: Experimental runs for optimization of formulation with the help of 23 factorial designs were designed [1]. Design of Expert program 6.0.6 (Stat-Ease Inc. Minneapolis, MN) was used to create formulations. Formulations were optimized using full factorial de­sign. In situ rectal gel was prepared by the cold meth­od [2]. As shown in Table 1, P188 was dissolved in DDW (de-ionized distilled water) including drug (1% w/v) at room temperature, and it was stored at 4°C for complete solubilization of P188. Carbopol solubilized in DDW, HPMC K4M and other mu­coadhesive polymers were then slowly added to the prepared solution with continuous agitation at 4°C, and were kept for 24 h before their use. The composi­tion of developed gel formulations is summarized in Table 1.

Results: Results In the first set of experiment, the application of croton oil to recto anal portion of rats induced significant increase in the Recto anal coefficient and serum level of pro inflammatory cytokines such as IL-6, and TNF \(-a\) it also showed a significant increase in recto anal portion compared to normal control animals. However, the treatment with Sucralfate containing Thermoreversible gels has maintained the RAC and Interleukin -6 levels near to normal control group. These findings were further supported by histopathological examination wherein the animals treated with optimized formulation showed significant reversal in the severity of inflammation, vasodilatation in the recto anal portion, and presence of inflammatory cells.

Conclusion: The findings of the present study suggest that the improved experimental model described in the present work has advantages and the model has a provision for quantifying the inflammatory exudates in the induced experimental hemorrhoids. Also, it was found that, the optimized formulation ameliorated the croton oil-induced hemorrhoids in rats.