Abstract
1. Incubations of racemic propranolol alone or in the presence of either quinidine or sparteine were performed with Cunninghamella bainieri.
2. Five mammalian metabolites of propranolol (4-hydroxypropranolol, desisopropyl-propranolol, 1-naphthoxylactic acid, propranolol glycol and 1-naphthoxyacetic acid) were present in unhydrolysed extracts of the incubation medium according to h.p.l.c. and g.l.c. analyses. The relative proportion of 4-hydroxypropranolol increased after enzymic treatment.
3. Propranolol not only had a fungistatic effect, but also caused morphological changes in the organism, which were accompanied by decomposition of 4-hydroxypropranolol and formation of a greenish-brown colour in the incubation medium.
4. Drug interaction experiments yielded results which paralleled those reported in mammals.
5. The findings indicate that C. bainieri may be a useful microbial model for drug disposition and interaction studies.