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.

Chlortetracycline (trade name Aureomycin, Lederle) is a tetracycline antibiotic, the first tetracycline to be identified. It was discovered in 1945 by Benjamin Minge Duggar working at Lederle Laboratories under the supervision of Yellapragada Subbarow. Duggar identified the antibiotic as the product of an actinomycete he cultured from a soil sample collected from Sanborn Field at the University of Missouri. The organism was named Streptomyces aureofaciens and the isolated drug, Aureomycin, because of their golden color. Chlortetracycline inhibits cell growth by inhibiting translation. It binds to the 16S part of the 30S ribosomal subunit and prevents the amino-acyl tRNA from binding to the A site of the ribosome. In veterinary medicine, chlortetracycline is commonly used to treat conjunctivitis in cats.

Resorcinol is a benzenediol. Resorcinol is commonly used in hair dyes and acne medication. Resorcinol works by breaking down rough, scaly, or hardened skin. Resorcinol also disinfects the skin to help fight infection. Resorcinol topical (for the skin) is used to treat pain and itching caused by minor cuts and scrapes, burns, insect bites, poison ivy, sunburn, or other skin irritations. Resorcinol topical is also used to treat acne, eczema, psoriasis, seborrhea, corns, calluses, warts, and other skin disorders. Resorcinol is included in the FDA final rule list of all permitted active ingredients for OTC topical acne products. Permitted combination active ingredient product - Resorcinol in 2 percent concentration in combination with sulfur in concentrations of between 3 and 8 percent. In oxidative hair dyes, resorcinol is regulated to 5% or below in practice, however, many manufacturers limit the level of free resorcinol in oxidative hair dyes to 1.25%. Resorcinol is limited to 0.5% in shampoos and hair lotions. Resorcinol is usually present in anti-acne preparations at a maximum concentration of 2%. The concentration of resorcinol can be much higher in peels, in some cases around 50%. Jessner’s solution (resorcinol in ethyl alcohol, 14% w/v; lactic acid, 14%; and salicylic acid, 14%) is commonly used in chemical peeling. A specialized medical use of resorcinol is in biological glues (gelatin–resorcinol–formaldehyde glue) for cardiovascular surgery, in particular aortic operations.

Rifamycin SV is a derivative of antibiotic rifamycin B (the natural fermentation product of S. mediterranei broths). The primary target of rifampicin on whole bacteria is the synthesis of RNA. Rifamycin belongs to the ansamycin class of antibacterial drugs and acts by inhibiting the beta subunit of the bacterial DNA-dependent RNA polymerase, blocking one of the steps in DNA transcription. This results in inhibition of bacterial synthesis and consequently growth of bacteria. Rifampicin exhibits bactericidal activity on Gram-positive and Gram-negative bacteria and on mycobacteria. Rifamycin SV MMX® (AEMCOLO), a non-absorbable rifamycin antibiotic formulated using the multi-matrix system, was designed to exhibit its pharmacological action on the distal small intestine and colon. AEMCOLO is indicated for the treatment of travelers’ diarrhea (TD) caused by non-invasive strains of Escherichia coli in adults.

Lomefloxacin hydrochloride (marketed under the following brand names in English speaking countries Maxaquin, Okacyn, Uniquin) is a fluoroquinolone antibiotic used to treat bacterial infections. It is used to treat chronic bronchitis, as well as complicated and uncomplicated urinary tract infections. It is also used as a prophylactic or preventative treatment to prevent urinary tract infections in patients undergoing transrectal or transurethral surgical procedures. Flouroquinolones such as lomefloxacin possess excellent activity against gram-negative aerobic bacteria such as E.coli and Neisseria gonorrhoea as well as gram-positive bacteria including S. pneumoniae and Staphylococcus aureus. They also posses effective activity against shigella, salmonella, campylobacter, gonococcal organisms, and multi drug resistant pseudomonas and enterobacter. Lomefloxacin is a bactericidal fluoroquinolone agent with activity against a wide range of gram-negative and gram-positive organisms. The bactericidal action of lomefloxacin results from interference with the activity of the bacterial enzymes DNA gyrase and topoisomerase IV, which are needed for the transcription and replication of bacterial DNA. DNA gyrase appears to be the primary quinolone target for gram-negative bacteria. Topoisomerase IV appears to be the preferential target in gram-positive organisms. Interference with these two topoisomerases results in strand breakage of the bacterial chromosome, supercoiling, and resealing. As a result DNA replication and transcription is inhibited.

Norfloxacin is an antibacterial agent, It inhibits inhibits DNA synthesis by inhibiting DNA gyrase enzyme. Norfloxacin was approved in 1986 for treatment of urinary tract infections, gynecological infections, prostatitis, gonorhhea and bladder infections. In ophtalmology, norfloxacin is used for treatment of conjunctivitus.

Netilmicin is a semisynthetic, water soluble antibiotic of the aminoglycoside group, produced by the fermentation of Micromonospora inyoensis, a species of actinomycete. Aminoglycosides are useful primarily in infections involving aerobic, Gram-negative bacteria, such as Pseudomonas, Acinetobacter, and Enterobacter. It is active at low concentrations against a wide variety of pathogenic bacteria including Escherichia coli, bacteria of the Klebsiella-Enterobacter-Serratia group, Citrobacter sp., Proteus sp. (indole-positive and indole-negative), including Proteus mirabilis, P. morganii, P. rettgrei, P. vulgaris, Pseudomonas aeruginosa and Neisseria gonorrhoea. Netilmicin is also active in vitro against isolates of Hemophilus influenzae, Salmonella sp., Shigella sp. and against penicillinase and non-penicillinase-producing Staphylococcus including methicillin-resistant strains. Some strains of Providencia sp., Acinetobacter sp. and Aeromonas sp. are also sensitive to netilmicin. Many strains of the above organisms which are found to be resistant to other aminoglycosides, such as kanamycin, gentamicin, tobramycin and sisomicin, are susceptible to netilmicin in vitro. Occasionally, strains have been identified which are resistant to amikacin but susceptible to netilmicin. The combination of netilmicin and penicillin G has a synergistic bactericidal effect against most strains of Streptococcus faecalis (enterococcus). The combined effect of netilmicin and carbenicillin or ticarcillin is synergistic for many strains of Pseudomonas aeruginosa. In addition, many isolates of Serratia, which are resistant to multiple antibiotics, are inhibited by synergistic combinations of netilmicin with carbenicillin, azlocillin, mezlocillin, cefamandole, cefotaxime or moxalactam. Netilmicin "irreversibly" binds to specific 30S-subunit proteins and 16S rRNA. Specifically netilmicin binds to four nucleotides of 16S rRNA and a single amino acid of protein S12. This interferes with decoding site in the vicinity of nucleotide 1400 in 16S rRNA of 30S subunit. This region interacts with the wobble base in the anticodon of tRNA. This leads to interference with the initiation complex, misreading of mRNA so incorrect amino acids are inserted into the polypeptide leading to nonfunctional or toxic peptides and the breakup of polysomes into nonfunctional monosomes, leaving the bacterium unable to synthesize proteins vital to its growth.

Sulfaphenazole is an oral antibiotic, which was used for the treatment of bacterial infections under the name Sulfabid. The drug was found to block folate synthesis in bacterias by inhibiting the enzyme dihydropteroate synthase. Sulfaphenazole is also known to inhibit CYP2C9 with high potency and specificity. Sulfabid is no longer marketed in the USA.

Idoxuridine is an antiviral agent use in keratitis caused by herpes simplex virus. As a prescription drug it comes as a 0.1% ophthalmic solution/drops (Herplex and Dendrid). The first studies of the compound for treatment of human herpes simplex started in early 1960s. Being a structural analog of thymidine idoxuridine inhibits viral DNA replication by substituting thymidine. The effect of idoxuridine results in the inability of the virus to reproduce and/or infect tissues. Idoxuridine also blocks viral thymidine kinase as its substrate analog.

Sulfamethizole is an oral antiobiotic, which was used against urinary tract infections under the name Thiosulfil. Sulfamethizole blocks bacterial growth by inhibiting folic acid synthesis via enzyme called dihydropteroate synthase. The drug is no longer marketed in the USA.