Microbiological and toxicological studies on cellulose generated from agricultural wastes

Abstract

A pharmaceutical excipient is required to meet certain minimum standards for use in the manufacture of dosage forms. In this study, two of such requirements, microbiological and toxicological suitability, was investigated in respect of cellulose powder derived from an agricultural waste, maize cob.
Microbial count data were obtained by inoculating a suspension of the cellulose into various types of agar. We also studied some of the possible toxicological effects of sub-acute ingestion of the cellulose in 2% tragacanth mucilage on adult male Wistar rats given 1.6 g/kg per day for 14 days. Weight changes, locomotor activity, some haematological parameters and the presence of gastrointestinal lesions were evaluated. Microbiological results indicate a ‘no growth’ status for yeast, fungi as well as for coliform and pseudomonas bacteria. The mesophilic bacterium, Bacillus subtilis returned a count of 100 cfu/g. Toxicological results show that animal weight was significantly (P < 0.05) reduced on the 14th day compared to weights on the 1st and 3rd days. Locomotor activity increased in a similar pattern being significantly higher (P < 0.05) on day 14 than on days 1 and 3. Platelet counts, white blood cell counts, and packed cell volume were not affected. There were no visible gastrointestinal (GI) lesions or morbidity and mortality in the animals. We conclude that the cellulose satisfied the British
Pharmacopoeia requirement for pharmaceutical grade starch that it should be free from the coliform bacterium, Escherichia coli. Furthermore, the results obtained showed that the cellulose neither exerted adverse effects on the haematological status of the animals nor is it associated with any other significant toxicological event.