Physico-chemical characterization of microemulsions containing plant extract using non-ionic surfactant

Abstract

Microemulsions of both blank and with plant extract were formulated by using propylene glycol and Tween 80 as non-ionic surfactant with isopropyl myristate oil and water. The chemical compositions of Tween 80 surfactant strongly affect the stability study of formulation. Surfactant-cosurfactant mixture in ratio of 2:1 (Smix) along with isopropyl myristate (oil) was selected and phase diagrams were constructed. The n-hexane extract of Red Carica papaya pulp was prepared and analyzed lycopene by UV-visible spectrophotometric method at 470 nm. The percentage of lycopene was measured by calibration curve. The physico-chemical stability of microemolsions blank and plant extract were evaluated regarding their particle size, zeta potential, conductivity, stability, viscosity, scanning electron microscopy, refractory index (RI) and pH. This study established that a stable microemulsion containing Carica papaya fruit extract was dependent upon the contents of S/C ratio, oil and water in formulations. Physicochemically and physically extract containing microemulsion with 2:1 was found to be stable therefore it can be used for topical application to deliver natural antioxidant.