Conclusion
The permeation rate of drug was markedly affected
by the composition of microemulsion formulations
including the ratio of surfactant/aqueous/IPM,
HLB value of surfactant
and type of
co-surfactant. A sunscreen agent (padimate O) as a permeation
enhancer could increase the in vitro permeation rate. The hesperetin
microemulsion incorporating PG and padimate O of 3%
showed significant skin whitening effect.