Formulation and Evaluation of Colon Targetted Drug Delivery System of Theophylline for the Treatment of Nocturnal Asthma

Y. Swetha, Venugopalaiah .P*, D. Sravanthi
Ratnam Institute of Pharmacy, Pidathapolur, Muthukur, Nellore, Andhra Pradesh, India

A B S T R A C T
The site specific release in the colon affects a time delay between administration and onset of action, which can be useful for diseases with various degrees of severity, such as asthma and arthritis. In the present study development of time controlled formulation to treat the nocturnal symptoms of asthma was formulated and administered in the night at 10.00 pm, symptoms that are experienced in early morning hours could be avoided. Theophylline possesses good oral bioavailability and adequate colon absorption. Hence it is selected as an ideal candidate for the colon targeted drug delivery system. This system when administered in evening is aimed to achieve an elevated Theophylline levels overnight where the risk of asthma is found to be maximum. Matrix tablets and Compression coated tablets of Theophylline are proposed to be developed by employing guar gum as rate controlled polymer. Tablets were prepared by wet granulation method and granules were evaluated for various physicochemical properties. Results revealed that matrix tablets prepared with guargum which are compression coated with CAP released the drug up to 24 hrs which were found to be suitable for chronotherapeutic delivery of theophylline to treat the symptoms of nocturnal asthma. Drug release kinetics revealed that F6 follows Zero Order Kinetics with R2=0.98. Diffusional exponent ‘n’ and mechanism of diffusional release from swellable controlled release systems was found to be Super Case-2 transport.
Keywords: Theophylline, Guargum, Cellulose acetate phthalate (CAP), Chronotherapeutics