Relationship of viscoelastic properties of carbopol 940 gel bases to piroxicam diffusion coefficients in gel bases and perceptual attributes

Abstract

Relationships between viscoelastic properties of 1.0%w/w priroxicam gels and prioxicam release were determined. Correlations between visoelastic properties of carbopol 940 gel bases and perveptual attributes perceived by trained panelists were also studied. The piroxicam gels and their gel bases exhibited predominantly elastic solid behavior which depended on corbopol 940 concentration. Their storage modulus (G') and viscosity decreased after they had been kept unprotectd from light for 14 days. However, their rheological properties has not changed within 14 days if they were protected from light. Perparations containing good solvent exhibited more elastic solid chatracters. In contrast, the piroxicam gels containing higher sodium chloride contents possessed more vicous fluid behavior. Analysed by Pearson's test at a p-value of less than 0.05, piroxicam diffusion coefficients (D) were directly proportional to loss tangent (tan phase angle), but were inversely proportional to G', loss modulus, (G") complex modulus (G*) and viscosity. Firmness, stickiness, peaking and tackiness attributes were directly propertional to G',G",G* and viscosity. On the contrary, wetness and spreadability attributs were inversely proportional to G',G",G* and viscosity. Gloss and residue were directly proportional to only viscosity. However, neither relationships between all perceptual attributes versus tan phase angle nor relationships between absorbency and liking versus rheological parameters could be found. Consequently, there was the potential for predicting drugh diffusion coefficients and perceptual attributes correlations to rheological parameter, and therefore it could be beneficial to the formulation design of topical dosage forms design including cosmetic products.