Processing and evaluation of locally sourced Kaolin for pharmaceutical production

Abstract

Cheaper and readily available natural clay deposits in Nigeria, may serve as good sources of pharmaceutical raw material. This work sought to process, characterize and evaluate locally sourced kaolin for drug production. Kaolin samples were locally sourced from Abia state and Ogun state of Nigeria. Purification was done through wet processing and chemical treatment of the samples. Chemical leaching was done using 2mol/l, 4mol/l and 8mol/l concentrations of hydrochloric acid with subsequent boiling for 6 hours. They were subjected to identification test for kaolin, carbonate test and iron limit test. The physicochemical properties were assessed. Samples were characterized using X-Ray Flourescence (XRF), Fourier Transform Infrared (FT-IR), X-Ray Diffraction (XRD) and micrograph. The raw, treated and standard kaolin samples were assessed for microbiological quality. The physicochemical properties and microbial limit tests for their formulated suspensions were also assessed. All the treated powdered samples, complied with pharmacopoeial standards for kaolin. The micrograph showed that the particles are small, clustered and granular. Bacillus subtilis, E. coli, Aspergillus spp. and Histoplasma spp. were identified only in the raw kaolin samples, while the Acid treated samples had acceptable pharmacopoeial standards for microbial limit. XRF, XRD and FT-IR results revealed that 2 mol/l HCl treated samples gave better pharmaceutical grade kaolin. The suspensions formulated from the treated kaolin samples showed good physicochemical properties and microbial limit. This research reveals that Wet Processing Technique and 2 mol/l HCl leaching is suitable for processing locally sourced kaolin for drug production.