Polyacrylic acid polymers hydrogels intended to topical drug delivery: preparation and characterization
Giovana Calixto1, Ana Carolina Yoshii, Hilris Rocha e Silva
1Department of Drugs and Pharmaceuticals, School of Pharmaceutical Sciences, São Paulo State University - UNESP , Araraquara, SP , Brazil.
Context:
Bioadhesiviness of polyacrylic acid polymers make them promising hydrogels to design topical drug delivery systems, allowing a close contact with biological substrate as well as an enhanced local concentration gradient, both factors that may improve the biological performance of the drugs.
Aim:
Texture and bioadhesive properties of hydrogels were assessed by using texture analyzer and they were correlated with their rheological behavior and performance as drug delivery systems.
Methods:
Aqueous dispersions of both polymers were prepared at 0.5%, 1.0% and 1.5% w/v. Hardness, compressibility, adhesiveness, cohesiveness, bioadhesion, continuous flow, oscillatory dynamic test and in vitro drug release were evaluated.
Results:
Rheological and texture parameters were dependent on polymer concentration and C974P polymer built the strongest structures. Both 1.5% hydrogels presented high bioadhesion values. About 50% of the metronidazole (MTZ) was sustained released from hydrogels within 2 h with an initial burst release at early stage. After, the release rates were decreased and 10% of the MTZ was released in the next 10 h. The drug release process was driven by Fickian diffusion and complex mechanism for PP and C974P hydrogels, respectively.
Conclusion:
The set of results demonstrated that these hydrogels are promising to be used as topical controlled drug delivery system.
