Doxycycline hyclate (Vibramycin, Periostat, Vibra-Tabs) is salt of tetracycline antibiotic Doxycycline, that used to treat many kinds of infections, like dental, skin, respiratory, and urinary tract infections. It also treats acne, Lyme disease, malaria, and certain sexually transmitted diseases. Doxycycline hyclate is a light-yellow crystalline powder which is soluble in water, while doxycycline monohydrate is very slightly soluble in water. Doxycycline is bacteriostatic, inhibiting bacterial protein synthesis due to disruption of transfer RNA and messenger RNA at ribosomal sites. Doxycycline hyclate is indicated for use in the treatment of chronic adult periodontitis for a gain in clinical attachment, reduction in probing depth, and reduction in bleeding on probing.

Oxytetracycline, a tetracycline analog isolated from the actinomycete streptomyces rimosus, was the second of the broad-spectrum tetracycline group of antibiotics to be discovered The drug is used for the prophylaxis and local treatment of superficial ocular infections due to oxytetracycline- and polymyxin-sensitive organisms for animal use only. These infections include the following: Ocular infections due to streptococci, rickettsiae E. coli, and A. aerogenes (such as conjunctivitis, keratitis, pinkeye, corneal ulcer, and blepharitis in dogs); ocular infections due to secondary bacterial complications associated with distemper in dogs; and ocular infections due to bacterial inflammatory conditions which may occur secondary to other diseases in dogs. Allergic reactions may occasionally occur. Treatment should be discontinued if reactions are severe. If new infections due to nonsensitive bacteria or fungi appear during therapy, appropriate measures should be taken. Oxytetracycline inhibits cell growth by inhibiting translation. It binds to the 30S ribosomal subunit and prevents the amino-acyl tRNA from binding to the A site of the ribosome. The binding is reversible in nature. Oxytetracycline is lipophilic and can easily pass through the cell membrane or passively diffuses through porin channels in the bacterial membrane.