Abstract
Physical properties of powders and gels of tragacanth prepared from Astragalus gummifer, A. kurdicus and A. microcephalus, all of Turkish origin, are reported. All samples comply with the requirements of the
British Pharmacopoeia 1973 monograph on tragacanth with the exception of the A. microcephalus sample which has a sub-standard gel viscosity. All the gels show pseudoplastic flow
behaviour which, for the A. gummifer and A. kurdicus gel samples, is temperature dependent. Measurements of the Redwood efflux times immediately
after preparation and 12 months later indicates that the gels are unaffected by storage.
Measurements of the pH of the gels suggests that the gum substance is totally neutral
in reaction.
