Formulation Development and Application of Natural Clay as Binder in Metronidazole Tablets

Aims: The aim of the work is to study the binder properties of native clay in metronidazole tablets.

Study Design: Extraction of clay, formulation of tablets and in vitro evaluation of the formulations.

Place and Duration of Study: Faculty of Pharmaceutical Sciences, University of Nigeria, Nsukka 410001, Nigeria. The study was carried out from August 2011 to September 2012.

Methodology: Granules were prepared by wet granulation using 7.5, 10 and 12.5% w/w clay and gelatin as binders respectively. The pre-compression test was performed on the granules including the flow rate and the loose densities. The tablets were analysed by determining the weight, disintegration time, friability, hardness and drug content. In vitro drug release was also studied in 0.1 N HCl.

Results: Results show that drug content ranged from 195.3 ± 0.07 to 208.2 ± 0.03 mg in all the formulations and show that metronidazole was not degraded by the clay. Tablets hardness range of 2.38 ± 0.55 to 5.99 ± 0.10 kgf for tablets formulated with 12.5 and 10% w/w of clay, while tablets formulated with gelatin had hardness of 5.99 ± 0.10 and 5.69 ± 0.99 kgf. Tablets containing 7.5, 10 and 12.5.5% w/w of clay exhibited disintegration time of 1.4, 3.6 and 24 min while. About 80.3, 58.2 and 36.8% of metronidazole were released from C1, C2 and C3 tablets formulated with 7.5, 10 and 12.5% of clay as binder respectively at 5 min, while 42.1 and 10.1% were released from tablets formulated with 7.5 and 10% w/w of gelatin as binder. Tablets formulated with clay had higher release of drug than those formulated with gelatin (p < 0.05).

Conclusion: Therefore, clay could be used as binder in formulating metronidazole tablets.