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Original Research Article
Preparation and
Characterization of Isosorbide Mononitrate Hydrogels
Obtained by Free-Radical Polymerization for
Site-Specific Delivery
Nazar Muhammad Ranjha1,
Asadullah Madni2*, Abdullah Abu Bakar1,
Nuzhat Talib1, Saeed Ahmad2 and
Hassan Ahmad2
1Department of Pharmacy,
Bahauddin Zakariya University, 60800-Multan, 2Department
of Pharmacy, The Islamia University of Bahawalpur,
63100-Pakistan
*For correspondence:
Email:
asadpharmacist@hotmail.com
Received: 5 April 2013
Revised accepted: 14
October 2014
Tropical
Journal of Pharmaceutical Research, December 2014;
13(12): 1979-1985
http://dx.doi.org/10.4314/tjpr.v13i12.4
Abstract
Purpose: To prepare and characterize
acrylic acid and ethyl cellulose hydrogels of isosorbide
mononitrate for site-specific delivery.
Methods: Free radical polymerization
method was employed using benzoyl peroxide as initiator
and N, N�-Methylenebisacrylamide (MBA) crosslinked
copolymer of ethyl cellulose and acrylic acid. Benzyl
peroxide and N, N'-Methylenebisacrylamide in varying
amounts were dissolved in acrylic acid. The two
solutions were mixed together to a final weight of 100
g. Hydrogels were evaluated for sol-gel characteristics,
diffusion coefficient, and porosity. Hydrogel formation
was examined by FTIR while drug loading efficiency study
was carried out using 1 % (w/v) drug solution.
Results: Swelling and drug release
decreased with increasing acrylic acid and MBA
concentrations due to high degree of crosslinking.
Increasing acrylic acid content of hydrogel produced a
decrease in drug release from 29.89 to 25.79 %, 75.37 to
67.87 % and 84.91 to 75.85 % at pH 1.2, 6.5 and 7.5,
respectively. Remarkably, high swelling was observed at
higher pH. Gel fraction and porosity results showed that
acrylic acid and crosslinker raised gel fraction but
reduced porosity, while ethyl cellulose exhibited a
reverse effect. FTIR confirmed graft copolymer
formation.
Conclusion: Isosorbide mononitrate
hydrogels prepared with crosslinked copolymer of ethyl
cellulose and acrylic acid can be suitably formulated
for targeted delivery of the drug to the small
intestine.
Keywords: N, N'-Methylenebisacrylamide,
Ethyl cellulose, Acrylic acid, Isosorbide mononitrate,
Free radical polymerization, Graft copolymer,
Site-specific delivery, Hydrogel, pH-sensitive |