[Studies on the parmacodynamic activity of several drug solvents. 3. 1,2-Propanediol, tetrahydrofurfuryl alcohol-polyethylene glycol ether (THFP), olyoxyethylene sorbitan monooleate (PSM)].

The drug solvents 1,2-propanediol, tetrahydrofurfuryl alcohol polyethylene glycolether (THFP, Tetraglycol), and polyoxyethylene sorbitan monooleate (PSM, Tween 80) were examined for their pharmacodynamic properties in the following tests: i.p. toxicity, "sign pattern", inclined screen test, balance rod test, and potentiation of hexobarbitone sleeping time in mice, spasmolytic activity in the guinea pig isolated ileum, and cardiovascular studies in anaesthetized rats, cats, and dogs including the i.v. toxicity. The solvents showed only small differences in their toxicity in the mouse and rat; PSM, however, was more toxic than 1,2-propanediol and THFP in the cat and dogs. The latter solvent, on the other hand, was the most potent in inducing behavioural changes and in potentiating hexobarbitone sleeping time. In the isolated ileum the solvents showed different spasmolytic potencies, depending on whether histamine, carbachol or BaCl2 was used as a spasmogen. The spasmolytic activity of 1,2-propanediol and THFP is classified as unspecific, whereas PSM seemed to have a specific anticholinergic pattern in the isolated ileum. After i.v. administration in rats, cats, and dogs the solvents caused cardiovascular effects even in very low doses. Based on the pharmacodynamic properties, doses are recommended for each solvent which should not be exceeded without control experiments in the laboratory routine. These tolerable doses do not only depend on the species but also on the test concerned.