Enhanced Oral Bioavailability of Griseofulvin via Niosomes

Abstract

The aim of the present report was to develop nonionic surfactant vesicles (niosomes) to improve poor and variable oral bioavailability of griseofulvin. Niosomes were prepared by using different nonionic surfactants span 20, span 40, and span 60. The lipid mixture consisted of surfactant, cholesterol, and dicetyl phosphate in the molar ratio of 125:25:1.5, 100:50:1.5, and 75:75:1.5, respectively. The niosomal formulations were prepared by thin film method and ether injection method. The influence of different formulation variables such as surfactant type, surfactant concentration, and cholesterol concentration was optimized for size distribution and entrapment efficiency for both methods. Result indicated that the niosomes prepared by thin film method with span 60 provided higher entrapment efficiency. The niosomal formulation exhibited significantly retarded in vitro release as compared with free drug. The in vivo study revealed that the niosomal dispersion significantly improved the oral bioavailability of griseofulvin in albino rats after a single oral dose. The maximum concentration (Cmax) achieved in case of niosomal formulation was approximately double (2.98 microg/ml) as compared to free drug (1.54 microg/ml). Plasma drug profile also suggested that the developed niosomal system also has the potential of maintaining therapeutic level of griseofulvin for a longer period of time as compared to free griseofulvin. The niosomal formulation showed significant increase in area under the curve0-24 (AUC; 41.56 microg/ml h) as compared to free griseofulvin (22.36 microg/ml h) reflecting sustained release characteristics. In conclusion, the niosomal formulation could be one of the promising delivery system for griseofulvin with improved oral bioavailability and prolonged drug release profiles.

Niosomes: A Controlled and Novel Drug Delivery System

“…The collected supernatant is then diluted as specified and estimated using appropriate method as described in monograph of that particular drug. 7,16,45) Both the entrapment efficiency (EE) and yield of niosome depend on the method of preparation as well as physicochemical properties of drug. The number of double layers, vesicle size and its distribution, entrapment efficiency of the aqueous phase, and the permeability of vesicle membranes are influenced by the methodology used for formulation as well as the addition of cholesterol as they make the niosomes less leaky.…”

“…The supernatant thus obtained was used for the determination of drug content using suitable method. 46) Similarly, Jadon et al 45) used male albino rats for this study. After administration of the free drug and drug entrapped in niosomes, the amount of drug in plasma was determined.…”

“…First group was treated as control and was injected with PBS (pH 7.4), the second and third groups were treated with the pure drug and niosomes containing drug respectively by oral route, after predetermined time intervals, blood samples were collected, centrifuged and frozen immediately and then analyzed using HPLC. 45,47) 7.5. Stability Study Stability studies are done by storing niosome at two different conditions, usually 4Ϯ1°C and 25Ϯ2°C.…”

Niosomal carriers enhance oral bioavailability of carvedilol: effects of bile salt-enriched vesicles and carrier surface charge 

“…17, 18 Janga et al 54 studied 14 or anionic 55 niosomes were administered to animals. Thus, available evidence on the effect of surface charge on the oral delivery of vesicles is very limited and inconclusive.…”

“…50,55 To our knowledge, however, no reports have attempted to quantify the role of lymphatic transport in this improvement.…”