L-Amoxicillin is an isomer of amoxicillin also known as 'amoxicillin related compound B'. It is considered an impurity.

6-amino-penicillanic acid is a common parent amine of various penicillins. 6-amino-penicillinic acid possesses definite antibacterial properties but these are much lower order than these of benzylpenicillin. It is destroyed by penicillinase (Beta-lactamase). The first penicillins to appear as derivatives of 6-APA were in fact phenethicillin and propicillin.

PENICILLIN G HYDRABAMINE, a semi-synthetic antibiotic, is used for the treatment of infections caused by susceptible, usually gram-positive, organisms.

AMINOBENZOATE SODIUM is a salt of Aminobenzoic acid. Aminobenzoic acid is an intermediate in the synthesis of folate by bacteria, plants, and fungi. Many bacteria, including those found in the human intestinal tract such as E. coli, generate Aminobenzoic acid from chorismate by the combined action of the enzymes 4-amino-4-deoxychorismate synthase and 4-amino-4-deoxychorismate lyase. Plants produce Aminobenzoic acid in their chloroplasts, and store it as a glucose ester (pABA-Glc) in their tissues. Humans lack the enzymes to convert Aminobenzoic acid to folate, so require folate from dietary sources such as green leafy vegetables. In humans, Aminobenzoic acid is considered nonessential and, although it has been referred to historically as "vitamin Bx", is no longer recognized as a vitamin, because most people have colon bacteria that generate Aminobenzoic acid. The potassium salt is used as a drug against fibrotic skin disorders, such as Peyronie's disease, under the trade name Potaba.