In-vitro and In-vivo Evaluation of Niosomes Containing Celecoxib

Niosomes as a vesicular system are well documented for delivering drugs, in controlled manner to enhance bioavailability and get better therapeutic effect over a longer period of time. Celecoxib is a NSAID, selective COX-2 inhibitor, which is used for treatment of rheumatoid arthritis, osteoarthritis and acute pain. The present study dealt with the preparation and characterization of celecoxib niosomes. The selected niosomes was incorporated into gel as an effective transdermal formulation of celecoxib with the aim to improve skin permeability and sustained delivery of celecoxib. Celecoxib loaded niosomes were prepared by the thin-film hydration method using different proportions of Span 60 or 40, cholesterol with or without adding stearylamine and dicetyl phosphate as a positive and negative charge-inducing agents. The results showed that, neutral niosomes gave the highest encapsulation efficiency, more than 90%. All formulations were characterized using transmission electron microscopy, differential scanning calorimetry, vesicle size and zeta potential. The vesicle size of celecoxib niosomes ranged from 132 to 826 nm. The in-vitro release studies revealed that most celecoxib niosomal formulations released more than 90% of its drug content within 48 hours. Physical stability study conducted on the two selected celecoxib niosomal formulations gave better stability, upon storage. In-vivo performance of niosomal celecoxib gel was evaluated by assessing anti-inflammatory activity by carrageenan-induced rat paw edema model using digital plethysmometer. The application of niosomal gel produced significant reduction of rat paw edema compared to control and conventional celecoxib gel especially after 24 hrs, indicating better skin permeation and prolonged drug release. INTRODUCTION: Vesicular systems are considered as novel means of delivering drug in controlled manner to enhance bioavailability and get therapeutic effect over a longer period of time.