Sulphonamides are conjugated by:
Conjugation of Drugs (phase I metabolite with endogenous substrates): -
a. Glucuronide conjugation - eg. chloramphenicol, aspirin, phenacetin, morphine, metronidazole, bilirubin, steroid hormones, and thyroxine.
b. Acetylation: conjugated with help of Acetyl CoA →eg. sulfonamide isoniazid, PAS, Hydralazine, procainamide, (by enzyme Acetyl transferase)
c. Methylation - Methionine and cysteine acting as methyl donors, eg. Adrenaline, histamine nicotinic acids.
d. Sulfate conjugation eg. Phenolic compounds (chloramphenicol) and, Adrenal and sex steroids.
e. Glycine conjugation — eg. salicylates and drugs having carboxylic acid groups. For example aspirin.