Abstract
Purpose: The
objective of the present study is to formulate and evaluate a new microemulsion
(ME) for topical delivery of griseofulvin.
Methods: The
solubilities of griseofulvin in different combinations of surfactant to
co-surfactant (S/Co ratio) were determined. Accordingly, based on their phase
diagrams, eight microemulsions were formulated and then evaluated with respect
to their particle size, surface tension, viscosity, conductivity, zeta
potential and stability. Their release behavior, Scanning Electron Microscopy
(SEM), Differential Scanning Calorimetry (DSC), refractory index (RI), pH and
Small-angle-X-ray scattering (SAXS) were also assessed.
Results: The
results indicated that the mean droplet size of the MEs ranged from 30.9 to
84.3 nm. Their zeta potential varied from -4.5 to -20.8. Other determined
characteristics were viscosity: 254-381 cps, pH: 5.34-6.57, surface tension:
41.16- 42.83 dyne.cm-1, conductivity: 0.0442 – 0.111 ms.cm-1.
The drug release was in the range of 22.4 to 43.69 percent. Also, hexagonal,
cubic and lamellar liquid crystals were observed in SAXS experiments.
Conclusion: It can be concluded that any alteration in MEs
constituents directly affects their microstructure, shape, droplet size and
their other physicochemical properties.