Rheological evaluation of hog gastric mucin as a model mucus system

The rheological evaluation of preparations containing 10, 15, 20, and 25% powdered hog gastric mucin was carried out over the 13-48 degrees temperature range using rotational and creep viscometry. The preparations were almost viscous, and no elastic behavior was demonstrated. The addition of borate ions frequently produced a slight decrease in viscosity. Tetracycline hydrochloride decreased the viscosity of the 10 and 25% materials, although the addition of this compound to fresh gastric and bronchial mucous gels markedly increased viscosity. The model is, therefore, only suitable in limited circumstances as a basis for the evaluation of the effect of drugs on gastric mucus.