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Research Article
Evaluation of
Controlled Release Theophylline Microspheres Prepared
with Cellulose Acetate Using Solvent Evaporation Method
Sunit Kumar Sahoo1*, Satyabrata Barik1,
Gourhari Dehury1, Subhakanta Dhala1,
Subhakanta Kanungo1, Bhakti Bhusan
Barik2 and Kishore Kumar Puhan3
1University
Department of Pharmaceutical Sciences, Utkal University,
Vani-Vihar, Bhubaneswar, Orissa. Pin- 751004, 2College
of Pharmacy, Jazan University, P.O. Box 114, Jazan,
45142, Kingdom of Saudi Arabia ,3Glenmark
Research Center, Nasik, India.
* For
correspondence:
E-mail:
sahoosunitkumar@rediffmail.com
Received: 8 July
2010 Revised
accepted: 23 January 2011
Tropical
Journal of Pharmaceutical Research, April 2011; 10(2):
193-201
Abstract
Purpose: To formulate theophylline microspheres
with cellulose acetate using solvent evaporation method
and evaluate the effect of various processing factors on
their characteristics.
Methods: Microspheres containing theophylline
were prepared with a hydrophilic, biocompatible polymer
- cellulose acetate - by an emulsion solvent evaporation
technique using an acetone/liquid paraffin system
containing Span 80 as a surfactant. The effect of
processing factors, e.g., varying drug/polymer ratio
(1:1, 1:2, 1:3) and temperature (10 and 35 °C) on
microsphere characteristics and drug release were
examined. Similarly, microspheres with a drug/polymer
ratio of 1:3 incorporating Span 20 were also
also prepared and evaluated.
Results: The microspheres were white,
free-flowing and spherical. The yield varied from 73.0
to 87.5 % while entrapment efficiency was in the region
of 71.8 to 92.4 %. High drug/polymer ratio, Span 80
(surfactant) and processing temperature between 10 and
30 °C produced formulations with better drug entrapment
efficiency. High drug/polymer ratio, low processing
temperature and low HLB value of surfactant enhanced the
sustained drug release characteristics of the
microspheres.
Conclusion: The combination of three suitable
factors - Span mixture (with HLB value of 4.3),
processing temperature of 10 °C and drug/polymer ratio
of 1:3 - produced a suitable controlled release
theophilline microsphere formulation which could be
effective for the management of asthma.
Keywords: Microsphere, Emulsion solvent
evaporation, Theophylline, Temperature, HLB value. |
