Investigation of Chrysophyllum africanum (Sapotaceae) seed gum potential as a binder in metronidazole tablet formulation

Abstract

Background and aim: Chrysophyllum africanum (Sapotaceae) seed gum was investigated as a potential binder in metronidazole tablet formulation and to compare same with existing standard binders so as to determine its binding efficiency in the dosage form.

Methods: The seed gum was extracted and phytochemical parameters determined. Polyvinylpyrollidone BP, Acacia gum BP and C. africanum gum mucilage at concentrations of 2.5, 5, 7.5 and 10%w/v each were used to wet granulate the metronidazole/excipient powder blend, and formulated to contain 400 mg main ingredient per tablet. The physicochemical properties (angle of repose, flow rate, bulk and tapped densities, Haunser’s ratio and compressibility index) of the granules were also determined. Granules were compressed using Manesty single punch tableting machine at 30 N/m² compression pressure, and the physicochemical properties of the tablets (hardness, friability, weight uniformity, disintegration time) assessed.

Results and Discussion: Phytochemical screening showed the presence of polysaccharides, and absence of alkaloids, tannins, flavonoids, glycosides, saponins, anthraquinones and terpenoids. The physicochemical properties of the granules were within standard limits for good flowability and compressibility, as revealed by weight uniformity values for all types and concentrations of binders (ranged from 0.5093 mg to 0.5310mg for Acacia, 0.5022mg to 0.5104mg for PVP, and 0.5045mg to 0.5197 mg for CAG respectively. Results for hardness test showed a range of 3.20 – 6.20 kgf for Acacia, 3.85 – 6.75 kgf for PVP, and 3.60 – 6.90 kgf for CAG. Generally, the tablet hardness and disintegration time increased with increased binder concentration.

Conclusion: C. africanum seed gum had a comparable good binding property at concentrations of 5 –10%w/v to those of acacia and polyvinylpyrrolidone BP powders. It can therefore be used as a substitute in the formulation of metronidazole tablets to reduce the unit cost of production of the dosage form thus enhancing affordability and patient compliance.