Doxofylline

The objective of this research work was to prepare sustained release matrix tablets of doxofylline. Doxofylline is a  xanthine bronchodilator having reduced affinity for A1 & A2 adenosine receptors. Different grades of hydrophilic polymers( HPMC K4M, HPMC K15 cps, HPMC K100 M, Sodium carboxymethylcellulose) and hydrophobic polymer (ethyl cellulose) were used. FTIR study shows that drug and other excipients are compatible with each other. Tablets were prepared by wet granulation technique using non-aqueous solvent IPA and PVP K90D as a binder. Under stage I of preliminary study, tablets were formulated using polymers alone. In stage II polymers were used in combination, with an objective of sustaining release up to 12 hrs. The effect polymer concentration on drug release profile was  investigated. The amounts of HPMC K100 M & NaCMC were selected as independent variables. The results of  final batches indicated that a low concentration of HPMC K100 M & high amount of Sodium CMC favours sustained release of doxofylline from matrix tablets. Accelerated stability study for 8 weeks  confirmed that the best selected formulation F 15 was stable

Simple, specific, accurate, precise and reproducible method have been developed and validated for the simultaneous estimation of both drugs in their combined dosage form. UV spectrophotometric method was a determination using the solvent extraction method at 277 nm and 279 nm over the concentration range 10-50 and 20-60 μg/ml for Doxofylline in chloroform and terbutaline sulphate in water respectively. The % recoveries of the both the drugs were found to be 100.34% – 100.72 % and 98.25– 99.19 % respectively. Method was statistically validated for accuracy, precision, specificity, LOQ, robustness and ruggedness according to ICH guidelines and can be used for analysis of combined dosage form. Key words: Doxofylline, Terbutaline sulphate, Solvent Extraction Spectrophotometric method.