Doxycyclin Chemische Eigenschaften,Einsatz,Produktion Methoden
Chemische Eigenschaften
Yellow Solid
Verwenden
Doxycycline is a semi-synthetic tetracycline prepared by hydrogenolysis of oxytetracycline to remove the 6-hydroxy group. Although the synthesis was reported in 1958, it was not released for use until 1967. Doxycycline, together with minocycline, is regarded as a ‘third generation’ tetracycline largely replacing the analogues and pro-drugs produced in the early 1960s for mainstream antibiotic applications. Like all tetracyclines, doxycycline shows broad spectrum antibacterial and antiprotozoan activity and acts by binding to the 30S and 50S ribosomal subunits, blocking protein synthesis. Doxycycline has been extensively cited in the literature with over 10,000 references.
Indications
Doxycycline (Vibramycin, Monodox) has similar absorption and durationof-
activity characteristics. Its effectiveness in acne approaches that of minocycline,
when used in the same fashion with similar dosages. Early data suggests
that subantimicrobial doses of doxycycline, 20 mg (Periostat), may play a
therapeutic role in acne by reducing inflammation through anticollagenolytic,
antimatrix-degrading metalloproteinase, and cytokine downregulating properties.
Definition
ChEBI: Tetracycline in which the 5beta-hydrogen is replaced by a hydroxy group, while the 6alpha-hydroxy group is replaced by hydrogen. A semi-synthetic tetracycline antibiotic, it is used to inhibit bacterial protein synthesis a
d treat non-gonococcal urethritis and cervicitis, exacerbations of bronchitis in patients with chronic obstructive pulmonary disease (COPD), and adult periodontitis.
Antimicrobial activity
It
is active against some tetracycline-resistant Staph. aureus and
is more active than other tetracyclines against Str. pyogenes,
enterococci and Nocardia spp. Mor. catarrhalis (MIC 0.5
mg/L), Legionella pneumophila and most strains of Ureaplasma
urealyticum (MIC 0.5 mg/L) are susceptible.
Pharmazeutische Anwendungen
6-Deoxy-5β-hydroxytetracycline. A semisynthetic product
supplied as the hyclate, calcium salt or the hydrochloride for
oral and intravenous administration.
Clinical Use
Like the other tetracyclines, doxycycline inhibits the pathogen’s protein synthesisby reversibly inhibiting the 30S ribosomal subunit.Bacteria and Plasmodium ribosomal subunits differ significantlyfrom mammalian ribosomes such that this group ofantibiotics do not readily bind to mammalian ribosomesand, therefore, show good selective toxicity. Althoughdoxycycline is a good antibacterial, its use for malaria islimited to prophylaxis against strains of P. falciparumn resistantto chloroquine and sulfadoxine–pyrimethamine.This use normally should not exceed 4 months. Becausethe tetracyclines chelate calcium, they can interfere withdevelopment of the permanent teeth in children. Therefore,their use in children definitely should be short term. Also, tetracycline photosensitivity must be kept in mind, particularlybecause areas where malaria is endemic are also theareas with the greatest sunlight.
Nebenwirkungen
Untoward reactions are generally those typical of the group
but gastrointestinal side effects are less common than with
other tetracyclines due to the lower total dosage and the ability
to administer the drug with meals. Esophageal ulceration
as a result of capsule impaction has been reported. Dental and
bone deposition appear to be less common than with other
tetracycline derivatives. Other adverse phenomena include
occasional vestibular toxicity.
Hypersensitivity reactions include photosensitivity and
eosinophilia, but rarely anaphylaxis. In common with demeclocycline
and chlortetracycline it may be a more powerful
sensitizer than other tetracyclines. It is contraindicated in
patients with acute porphyria because it has been demonstrated
to be porphyrinogenic in animals.
Stoffwechsel
Doxycycline is well absorbed on oral administration (90–100% when fasting; reduced by
20% by co-consumption with food or milk), has a half-life permitting once-a-day dosing for mild infections,
and is excreted partly in the feces and partly in the urine.
Doxycyclin Upstream-Materialien And Downstream Produkte
Upstream-Materialien
Downstream Produkte
