Niosome entrapped β-cyclodextrin methotrexate complex as a drug delivery system

Objectives: To entrap methotrexate (MTX) complexed with β-Cyclodextrin (βCD) into niosomes, to characterise niosomes for different physicochemical properties and to investigate the potential of niosome entrapped MTX- β- cyclodextrin complex in tumour treatment. Methods: MTX- βCD complex was entrapped into niosomes by lipid layer hydration method. The entrapment efficiency of the complex within the niosomes was determined by separating the unentrapped drug using dialysis. The in vitro release studies of the drug from niosomes were conducted in phosphate buffered saline pH 7.4. The vesicle stability was assessed by storage at room temperature, 37°C and under refrigeration (4°C) for a period of one month. The niosome entrapped MTX - βCD complex was administered subcutaneously to C57BL/6J mice bearing melanoma B16F1 tumour at 10 mg kg^-1 dose. The volume doubling time and growth delay of the tumour were taken as parameters to assess the antitumour efficacy. Results: The niosomal entrapment efficiency was higher in the case of MTX - βCD complex (84%) than with the plain drug (67%). Comparison of the drug release profile revealed a relatively slow release pattern of the entrapped drug complex from the vesicles as compared to plain MTX encapsulated niosomes. Better stability on storage was also observed with the niosome entrapped complex. The complex entrapped niosomes produced an improved anticancer activity as evident by enhanced volume doubling time and growth delay. Conclusion: This study indicated that complexation of methotrexate with βCD could increase the entrapment of the drug in non ionic surfactant vesicles and could improve the anticancer activity. Additionally, the present approach could be a means to control the duration of drug action in situ in cases where the dissociation constants of cyclodextrin drug complexes can be tailored.