Study On Microemulsion-based Organogels For Transdermal Drug Delivery System

Many solvents can be gelated by some compounds of low molecular weight at low concentrations and form thermally-reversible viscoelastic liquidlike or solidlike materials that are called molecular gels or organogels. Such low molecular –weight compounds are called "gelator". This systems are super-molecular configuration and have wide applied foreground in drug-carriers. The organogels which were formed by isopropyl myristate (IPM) gelated by Span 60, glyceryl monostearate(GMS) and glyceryl palmitate (GTP) were studied. The experimental results indicated that Span 60 congregates in IPM a three-dimension network of rod-like tubular aggregate, GMS congregates in IPM a three-dimension network of spherical aggregate and GTP congregates in IPM a three-dimension network of sheet aggregate. It was indicated by determining the viscosity that the viscosity of the organogels formed by Span 60 and GMS was minished with the cutting time. But after a while the viscosity resumed, which showed that the organogels formed by Span 60 and GMS had good rheology and thixotropy. Their viscosity can be increased by increasing the concentration of Tween 20 or gelator. The viscosity of the organogels formed by GTP didn't change with the cutting time, which showed that the organogels formed by GTP hadn't rheology and thixotropy. There was a good linear correlation between the accumulative permeated amount per unit area and the time for triptolide-loaded microemulsion-based organogels. The permeation process accorded with zero order pharmacokinetics. The average permeability through rat skin for triptolide was 19.26ng.cm^-2.h^-1, which was 2.92 times of triptolide unguents obtained commercially available. The configuration and use of noisome are similar to liposome. Noisomes were prepared by the rotary evaporation-sonication method. The size of blank noisomes which are less than 500nm are relatively small and are well-proportionally distributed. The polydispersity indeces are almost between 0.2 and 0.3. The absolute value of the Zate potential of noisomes are almost over 30, which indicate that the system is steady. The size of GMS noisomes are increscent first and then descendent when Tween 20 are added to niosomes.