الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
The goal of the current research was to investigate the release of diclofenac sodium and
leflunomide, poorly water-soluble drugs from microemulsion gel formulations in vitro.
This study is providing a new type of drug delivery that combines the advantages
of a microemulsion with transdermal administration and combination therapy for
rheumatoid disease.
The combination therapy, immunomodulatory (leflunomide) and NSAIDs (diclofenac sodi
um) were formulated, optimized and evaluated after loaded into a micro-emulsionbased
gel for active rheumatoid arthritis (RA). Various surfactants and cosurfactants were
screened for their ability to emulsify the selected oily phase. The pseudoternary diagrams
were constructed to identify the area of microemulsion existence. A microemulsion (ME)
was prepared using isopropyl myristate (IPM) as oil phase, tween 80 as surfactant and 1-
pentanol as co-surfactant were assessed for droplet size, polydispersability index, zeta
potential. The average droplet size and zeta potential values for selected formulation were
31.54±5.37 nm and -7.14±2.91 respectively. Optimized microemulsion systems were
formulated into gel form to enhancing the viscosity, carbopol was used to form a MEbased
gel then the ME gel evaluated for pH, spreadability, viscosity, drug content,
differential scanning calorimetry (DSC), Fourier transform infrared spectra analysis (FTIR)
and in vitro drug release using dialysis bag. For selected ME
gel formulations, in vitro release has been studied and F2C formula showed appropriate
cumulative drug release (77.36% for leflunomide and 89.90% for diclofenac sodium) after
24 hr. The in vitro result suggested that ME systems are powerful topical vehicles for
enhanced penetration of leflunomide and diclofenac sodium. A 28-day antiarthritic
evaluation (body weight, paw edema, haematological parameters
and histopathology) on carrageenan-induced arthritic rat model after topical application of
microemulsion-based combination therapy gel in rats showed
significant reversal of arthritic symptoms.