School of Pharmacy

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Browsing School of Pharmacy by Subject "Acacia gums"

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    Evaluation of Local Gum of Acacia Polyacantha as a Binder in Tablet Formulations
    (Addis Ababa University, 2002-06) Aklilu, Tegegne; Gebre-Mariam, Tsige (Professor); Ibrahim, Sayed (Professor)
    Acacia gums are dried gummy exudates obtained from the stems and branches of acaica spp. (fam. Leguminosae). A. senegal is the source of most gum arabic of international trade and it finds wide applications in pharmaceutical, food and cosmetic industries. Other African acacia species of economic importance include A. seyal, A. drepanolobium and A. polyacantha. In this study, a local gum of A. polyacantha was evaluated as a tablet binder. Paracetamol and chloroquine phosphate were used as model drugs. The physico-chemical properties of the purified gum, and its rheological properties were investigated. The gum was found to have similar properties to Acacia BP (odourless, white to yellowish brown, glassy, no tannins, no starch or dextrin present and moisture content of 11.6%). It exhibited Newtonian flow up to 40% w/v solution but less viscosity than Acacia BP. Granules prepared with different concentrations (5 - 30% w/v for paracetamol and 5-20% w/v for chloroquine phosphate) of the gum mucilage were characterised for particle size distribution, bulk, tapped and true densities, friability and flow properties. The granules were mixed with Ac-Di-SolÒ (4%) and magnesium stearate (0.5%) and compressed into tablets at different compression forces. The optimum binder concentration (X1) and compression force (X2) (independent variables) of both substances (paracetamol and chloroquine phosphate) were investigated using 22 factorial design taking crushing strength (H), disintegration (DT) and friability (Fr) as response variables. Polynomial equations were generated for the responses (H = 84.175 + 26.825X1 + 33.375X2 + 5.625X1X2; DT = 9.24 + 8.38X1 + 4.59X2 + 4.45X1X2; Fr = 1.9725 – 0.7775X1 – 1.1225X2 + 0.6275X1X2 for paracetamol and, H = 118.8 + 12.35X1 + 48.05X2 – 1.7X1X2; DT = 8.375 + 1.125X1 + 3.875X2 – 0.375X1X2; Fr = 1.08 – 0.22X1 – 0.42X2 + 0.08X1X2 for chloroquine phosphate). Surface response curves and contour plots were constructed and the xi v optimum regions determined by superimposing the contour plots. The optimum values were re-transformed using the equation: Trans = [2A – (Max + Min)]/ Max – Min, where Trans is the transformed value, A is the actual value of the factor being transformed, and Max and Min are the maximum and the minimum values in the range of the factor being transformed, respectively. Granules of the optimum formulations (6.21% w/w of binder for paracetamol, and 1.386% w/w of binder for chloroquine phosphate) prepared had mean bulk densities of 0.41 and 0.508 g/ml, tapped densities 0.474 and 0.584 g/ml, Carr’s indexes of 13.58 and 13.01% and Hausner ratios of 1.16 and 1.15 for paracetamol and chloroquine phosphate, respectively. Tablets compressed at compression force of 14 KN (paracetamol) and 16 KN (chloroquine phosphate) were compared with predicted values (H: 122 and 119N, DT: 15 and 8.5 minutes and Fr: 0.6 and 0.9% for paracetamol and chloroquine phosphate, respectively). Tablets prepared with the gum showed H of 132 and 116N for paracetamol and chloroquine phosphate, respectively, and Fr of 0.9% for both substances. For comparison purposes, chloroquine phosphate tablets were prepared with 5% w/v PVP solution and H values of 122N and Fr of 0.9% were obtained. The DTs of the tablets made with the gum were 13 and 9.3 minutes for paracetamol and chloroquine phosphate, respectively. Dissolution profiles of the tablets were within the acceptable ranges (³ 80 and ³ 75% of drug release in 30 and 45 minutes for paracetamol and chloroquine phosphate, respectively). The respectiveT50s were 5 and 8 minutes. From the foregoing, it can be concluded that gum of A. polyacantha can be used as an alternative binder in tablet formulations.