Formulation and Evaluation of Controlled Release Theophylline Tablets using Grewia spp Gum as Binder

The major reason for development of new drug delivery system is based largely on promoting therapeutic outcome and minimizing toxic effect of a drug by increasing the amount and persistence of a drug in target cells areas, while reducing exposure of the drug to non-target cells. In this study, Grewia spp gum obtained from Grewia spp pods was extracted and used as binder and release retardant in the formulation of controlled release theophylline tablets. A total of six (6) batches of the tablets were produced with carried concentrations of the test gum by wet granulation technique. To produce the tablets, various granules were formulated via wet granulation and characterized by measuring flow and packing properties. Granules with adequate flow properties were compressed to tablets. Tablets so formed were evaluated for hardness, percentage friability, weight variability and drug release profiles. The percentage yield was 18.64% and the pH of the test gum was 6.15. The angle of repose, bulk density, tapped density and Carr’s index of the formulated granules ranged from 22.48±0.00 to 24.90±0.00˚, 0.53±0.03 to 0.67±0.00g/ml, 0.67±0.02 to 0.82±0.00g/ml and 18.29±0.00 to 22.06±0.26% respectively. Resultant tablets hardness values of 3.69±0.45 to 13.39±0.65kgF and friability percentage of 0.40± 0.00 to 2.56%±0.01% were also obtained. The formulated theophylline granules showed good flow properties and compressibility. Thus, the study revealed that the test gum has comparable binding effect to Eudragit RS 100 at a ratio of 2:1. We recommend further studies to rule out any interaction of Grewia spp gum with theophylline in controlled release theophylline tablets.