In the case of penicillin G, the fermentation is finished after 200 hours, and the cell mass is separated by filtration.

Food may enhance the extent of absorption for poorly soluble drugs (eg, griseofulvin), reduce it for drugs degraded in the stomach (eg, penicillin g), or have little or no effect.

Blood samples were collected from the superior vena cava at different intervals after the drug was given. Serum levels of penicillin G were determined by microbiological method.