Propranolol metabolism by Cunninghamella bainieri

Area of Science:

• Microbiology
• Pharmacology
• Drug Metabolism

Background:

• Propranolol is a widely used beta-blocker with known metabolic pathways in mammals.
• Understanding drug disposition and interactions is crucial for effective therapeutic use.
• Microbial models offer potential for cost-effective and efficient drug metabolism studies.

Purpose of the Study:

• To investigate the metabolic capabilities of Cunninghamella bainieri concerning propranolol.
• To explore the potential of C. bainieri as a microbial model for drug disposition and interaction studies.
• To compare microbial metabolism of propranolol with known mammalian pathways.

Main Methods:

• Incubation of racemic propranolol with Cunninghamella bainieri, with and without quinidine or sparteine.
• Analysis of incubation medium using High-Performance Liquid Chromatography (HPLC) and Gas-Liquid Chromatography (GLC).
• Identification and quantification of propranolol metabolites.

Main Results:

• Five known mammalian propranolol metabolites were identified in unhydrolysed extracts.
• The proportion of 4-hydroxypropranolol increased after enzymatic treatment.
• Propranolol exhibited fungistatic effects and induced morphological changes in C. bainieri, correlating with 4-hydroxypropranolol decomposition.
• Drug interaction experiments with quinidine and sparteine yielded results comparable to mammalian studies.

Conclusions:

• Cunninghamella bainieri effectively metabolizes propranolol, producing metabolites similar to those found in mammals.
• The observed drug interactions in C. bainieri mirror mammalian responses, suggesting conserved mechanisms.
• C. bainieri represents a viable microbial model for investigating drug disposition and drug-drug interactions.