Sulazuril (also known as Hoe 092 V) is a phenyltriazolone derivative patented by Hoechst A.-G. as agrochemical protozoacide. Sulazuril is effective against a broad spectrum of fish and crustacean parasites.

Sanfetrinem cilexetil (formerly known as GV 118819), a beta-lactam antibiotic, is the oral prodrug of sanfetrinem. Experiments on rodents have revealed that sanfetrinem cilexetil had strong antibacterial activity in vitro and good pharmacokinetic behavior in mice. This drug was suitable for the treatment of infections caused by a variety of bacteria and participated in a phase II clinical trial. However, this study was discontinued.

Alovudine (3’ -deoxy-3’ fluorothymidine) is a nucleoside reverse transcriptase inhibitor (NRTI) initially tested in the early 1990s, before the era of combination therapy and before the availability of plasma viral load measurement. Initial toxicity studies showed that the primary target organ of toxicity was the bone marrow. A lack of clear advantages in activity over zidovudine, the only drug approved in the early 1990s, and the potential for bone marrow toxicity caused alovudine development to be stopped [6]. However, later in vitro studies found alovudine to be very effective at suppressing several NRTI-resistant HIV-1 mutants, including isolates with multiple thymidine-associated mutations (TAMs) or multi-NRTI-resistance mutations. Alovudine at a dose of 7.5 mg/day added to a failing antiretroviral combined regimen in patients with isolates resistant to other NRTIs yielded a median viral load decline after a 4-week period in patients not receiving concomitant stavudine. In July 2003, Medivir out-licensed it's HIV antiviral MIV-310 to Boehringer Ingelheim. Under the terms of the agreement, Boehringer Ingelheim will make upfront and milestone payments to Medivir totaling up to 122 million euro in the event that all development and performance milestones are met. In March 2005, Boehringer Ingelheim recently completed a clinical trial of MIV-310 (alovudine) in HIV/AIDS. The efficacy exhibited by MIV-310 at the doses tested showed antiviral activity but did not achieve the target level of efficacy which had previously been defined. Boehringer Ingelheim, therefore, decided to stop the development of this investigational drug.

Lersivirine (UK-453,061) is a novel second-generation non-nucleoside reverse transcriptase inhibitor (NNRTI). It binds reverse transcriptase in a distinct way leading to a unique resistance profile. Lersivirine is a second-line NNRTI, which was investigated in a Phase IIb clinical trial. Lersivirine has shown encouraging virologic efficacy in a Phase IIa monotherapy study in NNRTI-naive patients. In a Phase IIb clinical trial in ART naive patients, clinical efficacy of lersivirine was compared with efavirenz, each administered together with tenofovir disoproxil fumarate/emtricitabine. After 48 weeks, lersivirine exhibited a slightly lower virologic response but similar immunologic efficacy. However, the trial was not powered for formal hypothesis testing of noninferiority of lersivirine. The development of lersivirine was recently stopped because the developing company determined that the compound would not provide an improvement over existing NNRTIs.

Sulfasymazine is a sulfanilamide derivative patented by American Cyanamid Co. as antibacterial agents for Staphylococcus and Streptococcus infections. In preclinical models, Sulfasymazine shows activity on a dosage basis ranged from 2- to 10-fold that of sulfisoxazole, and from 1/3 to equal on a blood-level basis, but was not as potent as sulfadiazine.

Cefetrizole is aminocephalosporanic acid derivative with broad antibacterial activity against penicillin-resistant strains patented by Spanish pharmaceutical company Ferrer Internacional S. A.

Cefclidin is a fourth-generation cephalosporin antibiotic effective against a clinical strain of Citrobacter freundii. The affinity of cefclidin for the β-lactamase isolated from these mutants was lower than that of ceftazidime, and the kinetic parameters of enzymatic hydrolysis showed that cefclidin was hydrolyzed more slowly at a low concentration than was ceftazidime. It is suggested that the high activity of cefclidin against strains derepressed for β-lactamase plays a major role in the absence of emergence of resistant mutants.

Cefazaflur (INN) is a semisynthetic first-generation cephalosporin antibiotic patented by Smithkline Corp. For treatment of bacterial infections.

Ravuconazole is a triazole with antifungal properties that inhibits cytochrome P450 sterol 14a-demethylase, an enzyme involved in sterol synthesis, resulting in lysis of the fungal cell wall and fungal cell death. It was investigated for the treatment of aspergillosis, candidiasis, and onychomycosis, but these studies were discontinued. Ravuconazole is now in phase II clinical trials to investigate efficacy in preventing fungal infections in patients undergoing chemotherapy and stem cell transplantation.

Parvaquone, an antitheilerial compound that was developed for the treatment of East Coast fever. Experiments on animals have shown that this drug was effective in the treatment of cattle infected with Theileria annulata.