A study of the fate of gum karaya in the rat.

Rats were fed a diet containing 5% gum karaya for 24 h and faeces and urine were collected over 72 h. Faeces were examined, after methanolysis, by gas chromatography--mass spectometry and the quantity and monosaccharide composition of the faecal polysaccharide were compared with the dose and original composition of the gum polysaccharide. Gum-derived rhamnose was not found in the urine. Indications of minor quantitative changes in composition but no evidence of extensive degradation or absorption of gum polysaccharide, were found.

Comparison of the nuclear magnetic resonance and infrared spectroscopic methods for the quantitative analysis of polydimethylsiloxane.

A method based on nuclear magnetic resonance spectroscopy is described for the quantitative determination of polyimethylsiloxane (PMS) in a variety of pharmaceutical preparations. An extraction procedure using deuterochloroform within the sample tube was devised. In the presence of an internal standard, the PMS concentration was determined directly using integrated peak areas, without the necessity of establishing calibration curves. Accurate quantitative results were achieved with sample, containing at least 2mg PMS, extracted from formulations containing greater than 0.5% PMS. The extraction procedure and nmr assay were both more efficient and convenient than the B.P.C. method.