ABSTRACT
Objective: The purpose of the present study is to develop optimised compression coated time release tablets (CCTRTs) containing theophylline, a bronchial dilator in the inner core for chronotherapeutic drug delivery system using Grewia mollis and Anacardium occidentale gums as binders.
Method: The CT (core tablet) containing the theophylline as active drug was prepared using maize starch, magnesium stearate, grewia or anacardium gum, theophylline, lactose, using the wet granulation method. The CCTRTs containing theophylline in the inner core were prepared using an admixture of granulated lactose, Grewia or anacardium gum and sodium starch glycolate in different concentrations in order to achieve a predetermined lag time for chronotherapy. The CCTRTs were compressed at 30unit in the arbitrary load scale. Micromeritic properties were evaluated for the granules while the tablets were evaluated for hardness, friability, drug content, disintegration and dissolution. Fourier Transform Infra – Red (FTIR) studies was carried out to test for compatibility of ingredients
Results: All formulated granules were free flowing with angle of repose and Carr’s index ≤ 26.6º and ≤ 17% respectively for tablets formulated with Anacardium gum while the values were ≤ 28º and 15% for tablets formulated with Grewia gum. The tablet hardness values for the core tablet and the CCTRTs were 6.5 and ≤9.5Kparespectively, using grewia gum; and 5.5 and ≤13.12Kpa, using anacardium gum. The friability values of all the CCTRT formulations were ≤0.6%. The content uniformity of the tablet was ≥98.9%. The disintegration time for the core tablet was ≤6 min. The maximum drug release m∞was ≤ 97% and time to attain maximum drug release ≤ 10 h. The release profile of all the CCTRTs exhibited unique lag times before immediate release of the theophylline. Lag time was dependent on the ratio concentration of sodium starch glycolate in the outer shell. The lag time for all the formulations was between 0.5 - 7 h and lag time increased with decreasing concentration of sodium starch glycolate.FTIR studies showed that the excipients and the Active Pharmaceutical Ingredient (API) i.e. theophylline were compatible.
Conclusion: CCTRT4 formulations with a lag time of 7 h and 5.8 h before the immediate release of the theophylline were taken as the optimised formulations for tablets formulated with Anacardium occidentale and Grewia mollis gums respectively.
