Reasearch in Pharmaceutical Sciences 1 (2006) 30-39 School of Pharmacy & Pharmaceutical Sciences Received: Dec 2005 Isfahan University of Medical Sciences and Health Services Accepted: Mar 2006 Original Article Comparison of hydrophilic natural gums and cellulosic polymers in formulation of sustained-release matrix tablets of terbutalin sulfate J. Varshosaz 1,2* , J. Emami 1 and E. Jafari 1 1 Department of Pharmaceutics, School of Pharmacy and Pharmaceutical Sciences,Isfahan University of Medical Sciences, Isfahan, I.R.Iran. 2 Isfahan Pharmaceutical Sciences Research Center, School of Pharmacy and Pharmaceutical Sciences, Isfahan University of Medical Sciences, Isfahan, I.R.Iran. Abstract The short half-life of terbutaline sulphate (TBS) requires frequent dosing for controlling chronic pulmanary disorders, such as night asthma. The purpose of the present study was to prepare sustained- release (SR) tablets of TBS to decrease the number of doses frequency and to promote the paitent compliances. It was also desirable to evaluate the capability of natural gums for preparation of SR oral dosage forms in comparison with the cellulosic polymers. SR tablets of TBS (7.5 mg) were prepared using either natural gums; Guar (G) or Xanthan (X) and cellulosic polymers; hydroxypropyl methylcellulose (H) or carboxymethyl cellulose (C) by direct compression method. Different ratios of 0:100, 20:80, 40:60, 60:40 of C : H, G : X, X : H or H : G were used. After evaluation of physical characteristics of tablets, release rate were compared with the standard tablets (Bricanyl ® SR) in phosphate buffer solution (pH 7.4). All tablets met the official physical properties. Tablets with 80:20 ratio of polymers, H 8 X 2 and G 8 X 2 had smaller DE 8% (Dissolution Efficiency) and higher MDT (Mean Dissolution Time) . In the ratio of 60:40 and 40:60 formulations H 4 X 6 and H 6 X 4 had the highest MDT, and the smallets DE 8% . Formulation H 4 X 6 released the drug with zero-order kinetics while H 6 X 4 followed a Higuchi pattern such as standard tablet. It is concluded that formulation containing Guar and Xanthan (G 8 X 2 ) released the drug with a zero-order kinetic and was the most similar formulation to the standard. Key words: Guar, Terbutaline, Sustained-release, Xanthan INTRODUCTION Asthma is an inflammatory disease of the airways that is frequently characterized by marked circadian rhythm. Nocturnal and early morning symptoms are quite common among patients with asthma. Increased mortality and decreased quality of life are associated with nocturnal asthma. According to international guide- lines, patients with persistent asthma should receive long-term daily anti-inflammatory therapy. If preventive environmentally control of the disease and low to moderate doses of inhaled corticosteroids do not eliminate nocturnal symptoms, the addition of a long-acting bronchodilator is warranted (1). It is desirable that broncho- dilator therapy results in an overall 24-h improvement in bronchial patency or at least provides cover for the nocturnal decline. The sustained-release (SR) oral drug delivery may provide this cover and improve therapy, especially if administered at bedtime to cover the night ‘no-dose’ period. A SR preparation will provide available drug over an extended period, which may enhance control of disease *Corresponding author: Dr J. Varshosaz Tel. 0098 311 7922579, Fax. 0098 311 6680011 E-mail: varshosaz@pharm.mui.ac.ir