Tamam Mahmoud Nasser and Aliasgar Shahiwala* Pages 138 - 147 ( 10 )
Objective: The aim of the present investigation was to carry out a comparative evaluation of skin permeation potential of microemulsion (ME) and niosome based topical gel formulations along with marketed gel products containing diclofenac sodium (DS).Methods: For ME formulation, solubility studies were done to select optimum oil, surfactant (S) and co-surfactant (CoS). Pseudoternary phase diagrams were constructed using water titration method at different S: CoS ratios to determine ME region. Niosomes were optimized for % drug entrapment using sequential optimization approach for four different factors, surfactant type, solvent ratio, S:Cholesterol ratio and drug amount (mg) at 3 levels. Optimized ME and niosomes were incorporated into carbopol gel base to obtain 1% DS carbopol gel. Both the ME gel and Niosome gel were compared with marketed diclofenac gels. Prepared ME, Noisome gels and marketed A, B and C gels (coded) were evaluated for visual appearance, pH, viscosity, spreadability, mechanical stress studies, % assay and ex vivo skin permeation and retention studies using rabbit skin. Result and Discussion: The pH, spreadability, results of mechanical stress studies and drug content were within the acceptable limits. All gels exhibited pseudoplastic behavior, ME gel showed the highest flowability. The percent drug permeations from different gels were found to be in the range of 19.35% to 57.86 % through rabbit skin over twelve hrs. Marketed gel B showed the highest permeation followed by niosomal gel and ME. However, the release of DS from niosomal gel showed more uniform drug release pattern. Also, the drug retention in the skin after 12 hrs for niosomal gel was significantly higher (44.35%, p < 0.01) followed by ME gel (32.24%, p < 0.05) compared to marketed gels. Conclusion: Our results suggest that the DS niosomal gel significantly enhances both skin permeation and retention and provides more uniform drug permeation through the skin compared to prepared ME and marketed gels.
Diclofenac sodium, niosomes, microemulsion, gel, skin permeation, skin retention, transdermal drug delivery.
Out Patient Incharge Pharmacist, Al Qassimi Hospital, Sharjah, Dubai Pharmacy College, Dubai