How the structure of Benzyl penicillin has been developed so to overcome acid senstitvity?

Answer 1

The structure of Benzyl penicillin has not changed and it is still susceptible to gastric acid. Benzyl penicillin is only given by injection routes in modern practice.

If the Benzyl group is removed and replaced with a phenoxymethyl group you have an orally active penicillin that is somewhat resistant to gastric acid.

If you change the structure somewhat you can end up with a 7-[2-amino-2-(4-hydroxyphenyl) -acetyl]amino-3,3-dimethyl-6-oxo -2-thia-5-azabicyclo[3.2.0]heptane -4-carboxylic acid (better known as AMOXYCILLIN). This too is more acid resistant and can be given orally.