Formulation and Evaluation of In Vitro Blood-Brain Barrier Penetration of Emtricitabine Niosomes Using Immobilized Artificial Membrane Phosphatidyl Choline Column Chromatography

The main objective of the study is to formulate emtricitabine, a nucleoside reverse transcriptase inhibitor used in the treatment of Human Immuno deficiency Virus (HIV) infections as a niosomal formulation to improve the Central Nervous System (CNS) penetration of the drug and evaluate its CNS penetration using in vitro blood-brain barrier penetration study using immobilized artificial membrane phosphatidylcholine column chromatography. Emtricitabine encapsulated niosomes were prepared by thin layer evaporation (TLE)-paddle stirring method with Span 60 as main surfactant. Cholesterol (CHL), Solulan C24 (SOL) and N-palmitoyl glucosamine (NPG) were also included in the niosomal formulations. The ratio of Span 60:CHL:SOL:NPG was 50:40:10:10 with total concentration of components as 38 mM.  The hydration temperature was maintained at 65 0C. Sonication method was employed for size reduction of the niosomes. The formulation was evaluated for CNS penetration by in vitro blood-brain barrier penetration study using immobilized artificial membrane phosphatidylcholine column chromatography. The Scanning electron microscopic images showed good formation of the niosomal vesicles. The mean particle size and encapsulation efficiency were found to be 154±4 nm and 64.45±1.14% respectively. In vitro blood-brain barrier (BBB) penetration of emtricitabine from drug loaded NPG niosomes using immobilized artificial membrane phosphatidylcholine column chromatography showed an improved CNS penetration of the drug with (kIAM/MW4) X 1010 values of 2.79±0.05 at pH 5.5 and 8.48±0.18 at pH 7.0. The results showed an increased CNS penetration when the drug was encapsulated in niosomes and may be considered as a potential alternative to improve brain targeting of emtricitabine and thus minimize HIV Associated Neurocognitive Disorders (HAND).