Formulation and Evaluation of Once Daily Sustained Release Matrix Tablets of Terbutaline Sulphate for the Treatment of Nocturnal Asthma

Terbutaline sulphate is a 2-adrenergic agonist bronchodilator and used to treat bronchospasm associated with lung diseases such as asthma, bronchitis, and emphysema. Bioavailability of terbutaline sulphate about 14.8 %. The drug half-life is 3-4 hrs. In nocturnal asthma, lung function is usually highest at 4 PM and lowest at 4 AM, the latter time is generally when asthma symptoms are most prevalent. Based on these findings drug delivery and therapy should be modified to achieve an effective drug level at the required time. This can be achieved by adapting a sustained drug delivery system of a suitable drug which when administered during night releases the drug till early morning hours. So, in order to improve bioavailability and efficacy we have designed once a day sustained release tablets of terbutaline sulphate. The tablets were prepared by wet granulation technique using HPMC K200M, Ethylcellulose and combination of both. The sustained release tablets were subjected to preformulation studies, in- vitro drug release, postcompression studies, kinetic studies and stability studies. FTIR studies shown there was no interaction between drug and polymers. The percentage of drug content from the tablets was determined by UV-Spectroscopy and ranged from 97.20±0.50 to 99.12±0.92. The in-vitro percentage release of terbutaline sulphate from the optimized tablets at the end of 24hrs was 99.69±0.91 %. The kinetic studies revealed that the drug was released by first-order kinetics. The optimized formulation was subjected to stability studies and shown there were no significant changes in drug content, physicochemical parameters and release pattern.