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Copolymerized PEGlyated Acrylate Hydrogels for Delivery of Dicolofenac Sodium
Hydrogels are biocompatible drug delivery systems by which the physical properties can be controlled by the cross-linking density. Hydrogels were prepared by copolymerization of acrylic acid monomers in the presence of poly(ethylene glycol)(PEG) to form polyethylene diacrylate (PEDGA). Various molecular weights of PEGs were used for the synthesis of PEGDA to study the effect of molecular weight of PEG on the properties of hydrogels. These hydrogels were further characterized for free water, swelling..
Table VI: Acrylic acid hydrogel formulations prepared according to 32 factorial design and their properties.
The release data of all the formulations were fitted into these models, and the correlation coefficients, slope, and intercepts
were determined (Table V). From the values of the correlation coefficients, the best fitted data can be predicted (34). The
curve fitting of the release data was carried out mainly by regression analysis, and for zero-order, the release trend is
more significant and has a higher R2
value than that at the first order model of analysis. Most of the formulations of these types generally release the
drug in a mixed-order basis. In the present experiment, the release profile, however, was found to be best fitting in the
zero-order kinetics. It can be assumed, therefore, that the release of the drug from the hydrogel systems follows zero-order
kinetics to some extent.
Table VII: Analysis of variance (ANOVA) of regression on the responses of acrylic acid hydrogels.
Porosity. Like other matrix systems, the porosity (created by the chemical cross-linking using PEGDA in the hydrogels) can be calculated
by the diffusion rate coefficients (25). In the present study, the porosity was calculated using the diffusion coefficients
of the drug from the drug-loaded hydrogels and its aqueous solution. The results of this study (see Table III) confirmed the
prediction that the porosity of the hydrogels increased with the increase in the molecular weight of the PEGDA for the same
percentage w/w content. For example, the porosity of formulation B10 (hydrogel containing PEG 1000) was 0.392 and that of B60 (hydrogel containing PEG 6000) was 0.522.
Statistical analysis. All the data obtained were further analyzed using factorial design and multiple regressions. The effects of weight ratio
and molecular weight were studied on all the parameters. Three levels (high, medium, and low) were chosen for these two factors
(see Table VI). A 32 factorial design was constructed, and properties of nine formulations (see Table VI) were compared. The analysis of variance
(ANOVA) test was applied on the data obtained (see Table VII). The responses were regressed against the factors using the
first order with interaction and the following equation was formed.
The F-significance was < 0.05 in all the cases. The ANOVA test, therefore, showed that the models were quite significant. It can
be predicted, therefore, that the properties of these hydrogels were determined by both the molar percentage of PEGDA as well
as the type of monomer used. From the release pattern observed, it can be suggested that these hydrogel formulations can be
used as sustained-release dosage forms.
Sulekha Bhadra,PhD, is a research officer in Sun Pharmas Advanced Research Center, Vadodara, India.
Articles by Sulekha Bhadra
Dipankar Bhadra
Dipankar Bhadra, PhD, is a research officer in Sun Pharmas Advanced Research Center, Vadodara, India.
Articles by Dipankar Bhadra
Govind Prasad Agrawal
Govind Prasad Agrawal is a professor, Department of Pharmaceutical Sciences, Dr. Hari Singh Gour University, Sagar, Madhya Pradesh, India, 470003, tel. + 91 7582 265457, bhadrasb28@yahoo.com.
Articles by Govind Prasad Agrawal
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