- Like other fluorquinolines, oxifloxacin causes
inhibition of DNA gyrase enzyme.
This enzyme causes small cut in double stranded DNA,
leads to supercoiling and cause re-ligation of cut ends.DNA gyrase comprises of
Aand B subunit,in which A subunit causes small cut in DNA and B subunit is
responsible for negative supercoiling followed by re-ligation of A subunit.
- Moxifloxacin attaches to A subunit of DNA gyrase
with greater affinity and restrict the function of DNA gyrase enzyme
- The predominant target in vram positive bacteria
is an analogous enzyme topoisomerase IV that nicks and separate daughter DNA
strand once the DNA replication is complete.
The damaged DNA leas to formation of exonucleases
resulting in digestion of DNA and this contributes to bacteriocidal action of
moxifloxacin.
Reference: Tripathi K.D.,
“Essentials of Medical Pharmacology”, Jaypee brothers medical publishers, Seventh
edition, New Delhi, page no. 709,711.
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