Formulation and Physicochemical Characterization of Microemulsion System Using Isopropyl Myristate, Medium-Chain Glyceride, Polysorbate 80 and Water

Abstract

Microemulsions are isotropic and thermodynamically stable dispersed micro-heterogeneous systems composed of water, oil and amphiphile.1) Their stability and unique solubilization properties have drawn attention for their use as vehicles for drug delivery. Microemulsions have the ability to protect labile drugs, control their release, increase their solubility and bioavailability and reduce patient variability. It has been proven possible to formulate preparations suitable for different routes of administration viz., oral, topical, ocular, pulmonary and intravenous. Microemulsion contains nanometer-sized droplets of oil or water. If the droplets are non interacting the resulting microemulsion will be low in viscosity. On other hand high viscosity and optically clear (microemulsion gel) microemulsions results due to the interaction of cylindrical or wormlike micelles in microemulsion formulations. Microemulsion systems containing lecithin and low water content leads to the formation of microemulsion gel and the utility of the resulting gels have been reported to deliver the drugs through skin. 2,3)Although various types of microemulsions have been reported as being nontoxic, but microemulsion systems composed of regulatory approved excipients for pharmaceutical uses are limited. The choice of oil is limited to medium chain glycerides or fatty acid esters such as isopropyl myristate (IPM), isopropyl palmitate and ethyl or methyl esters of lauric, myristic and oleic acid.2) Uses of pure plant oils have also been reported in recent literature.4-7) Microemulsification of most widely used oil IPM for topical application has been achieved by using lecithin, polyoxyethylene sorbitan n-acyl esters (polysorbate 85, 80, 60, 40), sodium bis-2-ethyl hexyl sulphosuccinate (AOT), sucrose esters, polyoxyethylene (4) lauryl ether, C(12) Eo(8) as surfactants and short chain alcohols (ethanol, propanol, butanol), amines, alkanoic acid, poly ethylene glycol alkyl ethers, sorbitol, sucrose, sucrose ester, propylene glycol, lysolecithin, 2-acyl lysolecithin, mono alkyl phosphate as co-surfactants. 2,[8][9][10][11][12][13][14] In respect of convenience of formation and use, the oil IPM is better choice in comparison with other physiologically tolerable oils. 13)According to reports, medium chain fatty acids, mono-, di-, and tri-glycerides, particularly caprylic/capric mono-/diglycerides have been used independently in mixed micelle, emulsion and microemulsion formulations and as absorption enhancers for a number of drugs, since they have been found to be physiologically well tolerated.15) Further, mono-/diglycerides or polyol fatty acid esters have also been used as a permeation enhancer. 16,17) In view of the above-mentioned prospects, more investigations on micelle and microemulsion formulation using glycerides of the above categories is warranted.In the present study, IPM has been used as oil phase with poloysorbate 80 (polyoxyethylene sorbiton mono oleate) and caprylic/capric mono-/di-glycerides (MDG) as surfactant and co-surfactan...

Photo-oxidative action in MCF-7 cancer cells induced by hydrophobic cyanines loaded in biodegradable microemulsion-templated nanocapsules

“…Accordingly, the nanocapsule size ranged from 224 to 264 nm for unloaded nanocapsules and from 233 to 276 nm for nanocarriers with encapsulated photosensitizer. The low and moderate values of the polydispersity index (PdI) determined for most of the microemulsions are in the range of 0.08-0.10 (Table I) and for obtained IR-loaded nanocapsules 0.10-0.13 (Table II) and characterize a reasonable monodispersity of the systems (33). All IR-780 loaded nanoparticles had a negative zeta potential ranging from -27.9 to -32.1.…”

Novel isotretinoin microemulsion-based gel for targeted topical therapy of acne: formulation consideration, skin retention and skin irritation studies

“…The solubility of ITTN was found to be highest in IPM (42.92 ± 3.97 mg/gm), a low molecular volume fatty acid ester and one of the most often used oils along with long chain triglycerides and medium chain triglycerides for ME (Subramanian et al 2005). It has been reported that the large solubilizing capacity of ME leads to larger concentration gradient toward the skin, providing superior dermal flux, for which high solubility of ITTN in oily phase can be an added advantage to increase it in ME.…”

“…Also, literature reveals that IPM acts as a chemical enhancer by disordering the prearranged lipids of the horny layer. To study the influence of oil on ME characteristics and penetration-enhancing ability, IPM was chosen for the preparation of MEcontaining ITTN (Patel et al 2009(Patel et al , 2011b(Patel et al , 2013aSubramanian et al 2005).…”

Formulation and Physicochemical Characterization of Imwitor 308 Based Self Microemulsifying Drug Delivery Systems

“…This is in line with previously published data. [31][32][33] The Tween 85 system displayed the characteristic swelling profile observed when the j of dispersed phase (water) is in- creased. The droplet size increased by 47% (w/w) to 3.5 nm as the j increased to 15% (w/w).…”