FORMULATION STUDIES OF ACACIA SIEBERIANA GUM IN CHOROQUINE AND METRONIDAZOLE MATRIX TABLETS

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Department of Pharmaceutical Sciences

ABSTRACT
The crude plant gum from African Acacia sieberiana was purified and investigated for use as a matrix excipient for chloroquine phosphate and metronidazole tablet formulations. The chromatographic analysis of the acid hydrolysed gum revealed the presence of rhamnose, galactose, ribose, xylose and fructose. The viscosity was found to increase with increase in concentration of the gum. Ten percent mucilage had pH of 5 and pH change has no effect on the viscosity of the mucilage Both the swelling and hydration capacity showed that water penetration and retention of the gum were very high, as such it could not maintain slow release for a long period. The various particle size fractions of the gum had good flow rate with angle of repose less than 30o. The compressibility (densification) of the different particle sizes was investigated and found to be highly compressible at low compression pressure (1.8 to 3.1 x 105 N/m2 ). The compactibility studies revealed that radial tensile strength of the gum increases with increase in compression pressure. The compactness was found to increased with decrease in particle size, while the dissolution rate decreased with decrease in particle size of the gum. The t90% for the matrices made of >125-150 μm and >150-250 μm particle sizes were 2h 12 min and 38 min respectively. The effects of concentration of the gum on compactness and dissolution rate of compacts directly compressed revealed decrease in compactness with decrease in concentration of gum. Increase in concentration of gum was found to have profound effects on drug release rate from tablets formulated by direct compression method. The chloroquine phosphate matrices containing 60 %,50 %, and 40 %, corresponding to batches 1, 2 and 3 respectively, were subjected to dissolution test. The t90% s for the three batches were 3 h 30 min, 1 h 45 min and 1 h 40 min respectively. The dissolution efficiencies (DE) at 1 h for the three batches were found to be 37 %, 71 % and 75 % respectively. The release rate of chloroquine and metronidazole (wet granulation method) was evaluated based on t90% and dissolution efficiency (DE) at 1 h. The DE ( 1 h ) for the batches 1 of test gum chloroquine matrix, test gum metronidazole matrix and standard [Acacia Senegal] gum chloroquine matrix were: 98 %, 34 %, and 92 % respectively. The USA,FDA similarity factor “f2 “value for the dissolution data between test and standard gum was found to be >50, this signifies that, there is no significant difference in dissolution. While the f2 value for the test gum matrices of chloroquine and metronidazole dissolution data was <50, this indicate a significant difference in dissolution between the two formulations. In conclusion, Acacia sieberiana gum has been found to be directly compressible, a good material for wet granulation, and a potential gum matrix excipient for delaying the release of drug, particularly poorly soluble drugs.