Formulation Study and Evaluation of Matrix and Three-Layer Matrix Tablets Oral Controlled Drug Delivery System Based on Xanthan Gum and Locust Bean Gum

The present study was carried out to develop oral controlled release matrix tablets and three layer matrix tablets of highly water soluble diltiazem HCl using natural polymers Xanthan gum (XG), locust bean gum (LBG) and a mixture XG: LBG in 1:1 ratio as matrix forming agent, and anionic Sodium Carboxyl Methyl Cellulose as release retardant layer on the matrix core, Di calcium Phosphate (DCP) and Micro crystalline Cellulose (MCC) as fillers. Matrix core tablets were prepared with by granulation technique.The characterization of physical mixture of drug and excipeints was performed by infra red spectroscopy. The finding of the study indicated that the matrix tablets prolonged the release, but predominantly in a first order fashion, layering with SCMC granules on the matrix core, provided linear drug release with zero order kinetics. The influence of layers on matrix core and release rate was described by the peppas equation, model independent approach, Mean dissolution time (MDT) and dissolution efficiency (D.E 8%). The addition of SCMC layers on the matrix core could notably influence the dissolution behavior and mechanism of drug release. Increasing the quantity of layers caused decreased values of k and increased n value, in a linear relationship. MDT for matrix tablet (S6) and three layer matrix tablets (S6L3) was found to be 5.16h and 11.97h, D.E 8% was 76.23% and 66.21% respectively. These indicated that the release of drug is slower from the three layer matrix tablets. Type of fillers has a limited effect on the drug release mechanism from matrix tablets. Stability studies revealed that the formulation was stable at 45°±2°C and 75±5%RH. Hence natural polymer as matrix core and anionic polymer SCMC as retardant layer in the form of three layer matrix tablets provided the zero order release of highly water soluble Diltiazem HCl.