Formulation and Evaluation of Capecitabine-Loaded Microsponges for Colon Targeting

Capecitabine (CAP) is a chemotherapeutic drug used via oral administration for the management of metastatic cancers of the breast and colon. CAP is a prodrug of 5-fluorouracil, which inhibits DNA synthesis and slows tumor growth. The objective of the current research was to develop colon-targeting CAP-loaded microsponges by using the quasi-emulsion solvent diffusion technique employing Hydroxypropyl Cellulose (HPC) and Ethyl Cellulose (EC) as constituent polymers at different ratios with varying stirring speeds (rpm).

In the present study, CAP-loaded microsponges were formulated by using the quasiemulsion solvent diffusion method with HPC and EC as polymers at different ratios with varying stirring speeds. The 32-factorial design was used to perform the statistical optimization of CAPloaded microsponges. The in vivo pharmacokinetic study of the optimized formulation of CAP-loaded microsponges was performed using Albino Wistar Rats.

Based on the statistical optimization, the F1 formulation prepared using a 1:1 ratio of HPC and EC with 1000 rpm stirring speed was selected for its effective drug release (31.13 ± 1.73% after 8 hours and 69.57 ± 2.53% after 12 hours) and the highest drug entrapment efficiency (73.09 ± 3.54%). The high Cmax, low tmax, and 1.48-fold improvement in AUC0-∞ indicated that the optimized formulation of CAP-loaded microsponges, compared to an aqueous solution of CAP, revealed a significant (p<0.05) improvement in bioavailability of CAP when administered orally.

These findings indicated the potential delivery of CAP by these CAP-loaded microsponges to the colon, enabling sustained delivery and improving the bioavailability of CAP. However, comparative evaluation with existing market formulation and stability studies is essential to validate its therapeutic implications.

The developed CAP-loaded microsponges could serve as an effective carrier for the sustained release of CAP, thereby improving the oral bioavailability of CAP for the management of colon cancer.