8. A novel approach to sustained montelukast sodium release: Differentially coated mini-tablets in HPMC capsules

Montelukast is used in the treatment of chronic asthma. Montelukast biological half life is 2.5 to 5.5 h, thereby decreasing bioavailability up to 64%. In order to improve the bioavailability, encapsulated coated mini-tablets systems comprising of immediate-release and sustained release coated mini-tablets, was developed. These coated mini-tablets were encapsulated in HPMC capsule. The prepared mini-tablets were subjected for pre and post-compressional parameters. The drug-excipient compatibility studies were performed using FTIR and DSC techniques. The stability studies were conducted for the optimized formulation as per ICH guidelines. The values of pre-compression parameters evaluated were within prescribed limits and indicated good free flowing property. All the post-compressional parameter are evaluated were prescribed limits and results were within acceptable IP limits. The core mini-tablet of immediate-release coated mini-tablets was found to disintegrate within 16 min. The in-vitro performance of our best encapsulated coated mini-tablet system showed nearly 25.99% of the drug released within the first 60 min, and 98.74% of drug was sustained for a period of 24 h. Release of drug from all the formulations was first-order kinetics. FTIR and DSC results revealed that there was no interaction between dug and excipients used in the formulation. The stability study revealed that the formulations were found to be stable. From this, study it can be concluded that, encapsulated coated mini-tablets could be prepared to improve the bioavailability of montelukast sodium.