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Tropical Journal of Pharmaceutical Research
Pharmacotherapy Group, Faculty of Pharmacy, University of Benin, Benin City, Nigeria
ISSN: 1596-5996
EISSN: 1596-5996
Vol. 10, No. 2, 2011, pp. 195-201
Bioline Code: pr11027
Full paper language: English
Document type: Research Article
Document available free of charge

Tropical Journal of Pharmaceutical Research, Vol. 10, No. 2, 2011, pp. 195-201

 en Evaluation of Controlled Release Theophylline Microspheres Prepared with Cellulose Acetate Using Solvent Evaporation Method
Sahoo, Sunit K; Barik, Satyabrata; Dehury, Gourhari; Dhala, Subhakanta; Kanungo, Subhakanta; Barik, Bhakti B & Puhan, Kishore K


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.

Microsphere, Emulsion solvent evaporation, Theophylline, Temperature, HLB value

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