Nonionic microemulsions for enhanced solubilization of antibiotics
Azithromycin was solubilized in water/propylene glycol/sucrose laurate/ ethoxylated mono-di-glyceride/isopropylmyristate/R (+)-limonenemicroemulsions for topical applications. Solubilized drug did not affect the area of the microemulsion region. Azithromycin solubilization capacity decreases with the increase in the aqueous phase volume fraction. Dilutionand interfacial factors contributing to azithromycin solubilization microemulsions were evaluated. Structural transitions occurring in the microemulsion region wererevealed by the measurement of electrical conductivityof drug loaded and drug free systems. It was found thatbelow 0.2 aqueous phase volume fraction the water–in-oil microemulsions are present. For aqueous phase volume fraction between 0.3 and 0.5 bicontinuousmicroemulsions are present.