Answer
The benzathine formulation forms a depot in muscle, allowing benzylpenicillin to be released and absorbed slowly. It is not formulated for intravenous administration.
Sources for this answer
- Benzylpenicillin benzathine 2.4 Million I.U. powder for suspension for injection — Current selected SmPCemc · Summary of Product Characteristics
General medicine information. Follow the instructions for your own medicine and speak to a pharmacist or clinician about your individual circumstances.