Nanomulsion as a Carrier for Efficient Delivery of Metformin

Abstract

Metformin (MTF) improves hyperglycemia primarily by suppressing glucose production by the liver. The objective of our investigation was to evaluate nanoemulsion as a promising carrier for MTF for sustained hypoglycemic effect. The drug was incorporated into oil phase of nanoemulsion, which finally improved biopharmaceutical properties achieved when compared with lipid based systems. Pseudo ternary phase diagrams were prepared by aqueous titration method. Formulations were selected at a difference of 5% v/v of oil from the o/w nanoemulsion region of phase diagrams, and then thermodynamic stability and dispersibility tests were performed. The composition of optimized formulation was hydrogenated castor oil (5% v/v), 30% v/v of surfactant (tween 80), co-surfactant (transcutol) and distilled water (65% v/v) as an aqueous phase. The preparation showed maximum drug release (98.70%), optimal globule size (92.25 nm), lowest polydispersity value (0.172), lesser viscosity (22.124 cps) and infinite dilution capability. The antidiabetic activity of optimized MTF nanoemulsion formulation evaluated by blood glucose estimation showed significant hypoglycemic effect which was comparable to that observed with conventional marketed formulation in experimental diabetic rats. Optimized formulation was subjected to stability studies at different temperature and relative humidity and was found to be stable. No significant variations were observed in the formulation over a period of 3 months at accelerated storage conditions.

Nanoemulsion: for improved oral delivery of repaglinide

“…Three millilitres of selected oils [oleic acid, isopropyl myristate (IPM), glycerol triacetate (Triacetin), caproyl 90, propylene glycol monocaprylic ester (Sefsol 218), propylene glycol laurate (Lauroglycol), labrafac] were taken in small vials (5.0 ml capacity) and surplus quantity of drug was added in the oils and set aside in biological shaker (Nirmal International, Delhi, India) for 72 h at a steady temperature (25 ± 1.0 C) to achieve to an equilibrium (Lawrence & Rees, 2000;Leonard et al, 2006;Akhtar et al, 2014). The samples were detached from shaker and centrifuged at 3000 rpm for 15 min.…”

“…The samples were detached from shaker and centrifuged at 3000 rpm for 15 min. The supernatant was filtered through a 0.45-mm membrane filter and the concentration of drug was determined by taking absorbance using HPTLC at max of 242 nm after dilution (Akhtar et al, 2014).…”

“…Dissimilar volume ratios (1:0, 1:1, 1:2, 1:3, 2:1 and 3:1) of surfactant (Tween-80) and co-surfactant (Transcutol) mixtures (S mix ) were prepared and stocks of 100 ml from each faction were arranged (Chennamsetty et al, 2005;Parveen et al, 2011;Akhtar et al, 2014). For every phase diagram, 16 dissimilar combinations of oil (Sefsol 218) and S mix [1:9, 1:8, 1:7, 1:6, 1:5, 2:8 (1:4), 1:3.5, 1:3, 3:7 (1:2.3), 1:2, 4:6 (1:1.5), 5:5 (1:1), 6:4 (1:0.7), 7:3 (1:0.43), 8:2 (1:0.25), 9:1 (1:0.1)] were made in unusual volume ratios from 1:9 to 9:1; as a result, maximum ratios were covered for the study (Lawrence & Rees, 2000;Akhtar et al, 2014).…”

“…For every phase diagram, 16 dissimilar combinations of oil (Sefsol 218) and S mix [1:9, 1:8, 1:7, 1:6, 1:5, 2:8 (1:4), 1:3.5, 1:3, 3:7 (1:2.3), 1:2, 4:6 (1:1.5), 5:5 (1:1), 6:4 (1:0.7), 7:3 (1:0.43), 8:2 (1:0.25), 9:1 (1:0.1)] were made in unusual volume ratios from 1:9 to 9:1; as a result, maximum ratios were covered for the study (Lawrence & Rees, 2000;Akhtar et al, 2014). The blend of selected oil and S mix were titrated against distilled water.…”

“…In recent years, lipid-based formulations (incorporation of the active lipophilic component into inert lipid vehicles) are used to improve the oral bioavailability of poorly water-soluble drug compounds, which include micro or nanoemulsions, oils, self-emulsifying formulations, surfactant dispersions, liposomes, solid lipid nanoparticles and lipid nanocarriers. Nanoemulsion offers several advantages over these drug delivery systems such as higher solubilization capacity, rapid onset of action (no extra time for dispersion), reduced intersubject variability in terms of gastrointestinal fluid volume and longer shelf life, toxicological safety, a high content of the lipid phase and the possibility of large scale production by high-pressure homogenization (Mustafa et al, 2009;Shakeel & Faisal, 2010;Parveen et al, 2011;Akhtar et al, 2014).…”