Rheological investigation and its correlation with permeability coefficient of drug loaded carbopol gel: influence of absorption enhancers.
BACKGROUND
The present study was planned to investigate the effect of absorption enhancers on the microstructure of Losartan potassium gel and hence its influence on the diffusion of Losartan potassium across nasal mucosa.


METHODS
Losartan potassium loaded carbopol gel (1% w/v) with and without absorption enhancers was prepared. Polyethylene glycol (PEG) 4000 and ethanol were used as absorption enhancers. Microstructural elucidation of prepared gels was done using shear rheology. Ex vivo drug release studies were performed on the prepared gels.


RESULTS
It was observed that the absorption enhancers PEG 4000 and ethanol altered the gel microstructure. The prepared gels were viscoelastic in nature suggesting their suitability for topical application. Permeability coefficient of Losartan potassium loaded into gels was found to be inversely proportional to the storage modulus. Thus increase in storage modulus lead to slow drug diffusion.


CONCLUSIONS
The current study emphasizes on the fact that selection of polymeric carrier for nasal drug delivery and/or absorption enhancer strongly influence the microstructure of the gel and hence the pharmaceutical performance of the formulation.
Department of Pharmaceutics, Poona College of Pharmacy, Bharati Vidyapeeth University, Erandwane, Pune, Maharashtra, India.
Prashant B
PB
Pisal
Sharvil S
SS
Patil
Varsha B
VB
Pokharkar
D000042:Absorption / Q000187:drug effects; D000180:Acrylic Resins; D000818:Animals; D000959:Antihypertensive Agents / Q000493:pharmacokinetics*; D004337:Drug Carriers; D004339:Drug Compounding; D000431:Ethanol / Q000737:chemistry*; D005782:Gels / Q000737:chemistry; D006041:Goats; D019808:Losartan / Q000493:pharmacokinetics*; D009297:Nasal Mucosa / Q000378:metabolism*; D010539:Permeability; D011092:Polyethylene Glycols / Q000737:chemistry*; D011145:Polyvinyls / Q000737:chemistry*; D012212:Rheology; D014783:Viscosity
D000180:Acrylic Resins; D000959:Antihypertensive Agents; D004337:Drug Carriers; D005782:Gels; D011145:Polyvinyls; C006912:carboxypolymethylene; D000431:Ethanol; D011092:Polyethylene Glycols; D019808:Losartan