Thiamphenicol Chemische Eigenschaften,Einsatz,Produktion Methoden
S-Sätze Betriebsanweisung:
S22:Staub nicht einatmen.
S24/25:Berührung mit den Augen und der Haut vermeiden.
Chemische Eigenschaften
Off-White Solid
Verwenden
Thiamphenicol is an antibiotic. Thiamphenicol is the methyl-sulfonyl analogue of chloramphenicol and has a similar spectrum of activity, but is 2.5 to 5 times as potent. Thiamphenicol is used particul
arly for the treatment of sexually transmitted infections and pelvic inflammatory disease.
Antimicrobial activity
It is generally less active than chloramphenicol,
but is equally active against Str. pyogenes, Str. pneumoniae,
H. influenzae and N. meningitidis, including some strains resistant to chloramphenicol. It is more actively bactericidal
against Haemophilus and Neisseria spp.
Acquired resistance
There is complete cross-resistance with chloramphenicol in
those bacteria which elaborate acetyltransferase, although the
affinity of the enzyme for thiamphenicol is lower. Organisms
that owe their resistance to other mechanisms may be
susceptible.
Pharmakokinetik
An oral dose of 500 mg produces a peak plasma level of
3–6 mg/L after about 2 h. The plasma half-life is 2.6–3.5
h. It is said to reach the bronchial lumen in concentrations
sufficient to exert a bactericidal effect on H. influenzae.
Unlike chloramphenicol it is not a substrate for
hepatic glucuronyl transferase; it is not eliminated by conjugation,
and its half-life is not affected by phenobarbital
induction.
About 50% of the dose can be recovered in an active form
in the urine within 8 h and 70% over 24 h. The drug is correspondingly
retained in the presence of renal failure, and
in anuric patients the plasma half-life has been reported to
be 9 h, a value not significantly affected by peritoneal dialysis.
Biliary excretion is believed to account for removal of
the antibiotic in anuric patients. The plasma concentration
is elevated and half-life prolonged in patients with hepatitis
or cirrhosis.
Clinical Use
Similar to that of chloramphenicol.
Nebenwirkungen
There are no reports of irreversible bone-marrow toxicity.
This has been related to the absence of the nitro group, and
hence its reduction products, and differences in the biochemical
effects of thiamphenicol and chloramphenicol on mammalian
cells. It exerts a greater dose-dependent reversible
depression of hemopoiesis and immunogenesis than chloramphenicol,
and has been used for its immunosuppressive effect.
Therapeutic doses (1–1.5 g) are likely to depress erythropoiesis
in the elderly or others with impaired renal function.
läuterung methode
Recrystallise thiamphenicol from H2O or CHCl3. The UV has max at 224, 266 and 274nm ( 13,700, 800 and 700) in 95% EtOH. The 1S,2S-isomer [1478651-7] has m 164.3-166.3o (from H2O/EtOAc/pet ether) and [] D 25 -12.6o (c 1, EtOH); and the racemate 1RS,2RS-Racefenical [847-25-6] has m 181-183o (dec) from CHCl3/EtOAc/pet ether. [Cutler et al. J Am Chem Soc 74 5475, 5482 1952, UV: Nachod & Cutler J Am Chem Soc 74 1291 1952, Suter et al. J Am Chem Soc 75 4330 1953, Cutler et al. J Am Pharm Assoc 43 687 1954, Beilstein 13 IV 2957.]
Thiamphenicol Upstream-Materialien And Downstream Produkte
Upstream-Materialien
Downstream Produkte
