Метациклин

Methacycline was synthesized by Pfizer Research Laboratories in 1961 starting with oxytetracycline. It shows two to fivefold greater in vitro antibacterial activity and in vivo protective activity than tetracycline. Methacycline has been given orally to treat infections by Rickettsia, Chlamydiae, Staphyloccus, Streptococcus, Neisseria, Klebsiella, Proteus, Escherichia coli, and Haemophilus influenzae.

Methacycline is a semi-synthetic tetracycline prepared by dehydration of the 6-hydroxy group of oxytetracycline to yield an exocyclic 6-methylene. Like all tetracyclines, methacycline shows broad spectrum antibacterial and antiprotozoan activity and acts by binding to the 30S and 50S ribosomal subunits, blocking protein synthesis. Methacycline has been extensively cited in the literature with over 400 references.

ChEBI: A tetracycline that is the 6-methylene analogue of oxytetracycline, obtained by formal dehydration at position 6.

6-Methylene-5-hydroxy-tetracycline. A semisynthetic derivative supplied as the hydrochloride for oral administration.
Mean peak plasma concentrations of 2–6 mg/L are found about 4 h after a 300 mg oral dose. Both food and milk reduce uptake by half. Protein binding is 80–90%. The plasma elimination half-life varies between 7 and 15 h and increases to 44 h in severe renal impairment. It is widely distributed, producing lung concentrations similar to, or greater than, the simultaneous plasma concentration. About one-third is excreted in the urine.
Gastrointestinal intolerance is reported to be less frequent than with other tetracyclines, largely because of the lower dosages used. There are no unique adverse drug reactions, although skin and conjunctival pigmentation have been reported.