Telbivudine is an antiviral drug used in the treatment of hepatitis B infection. It is marketed by Swiss pharmaceutical company Novartis under the trade names Sebivo (Europe) and Tyzeka (United States). Clinical trials have shown it to be significantly more effective than lamivudine or adefovir, and less likely to cause resistance. Telbivudine is a synthetic thymidine nucleoside analogue; it is the L-isomer of thymidine. It is taken orally in a dose of 600 mg once daily with or without food. TYZEKA is the trade name for telbivudine, a synthetic thymidine nucleoside analogue with activity against hepatitis B virus (HBV). The chemical name for telbivudine is 1-((2S,4R,5S)-4-hydroxy-5-hydroxymethyltetrahydrofuran-2-y1)-5-methyl-1H-pyrimidine-2,4-dione, or 1-(2-deoxy-β-L-ribofuranosyl)-5-methyluracil. Telbivudine is a synthetic thymidine nucleoside analogue with activity against HBV DNA polymerase. It is phosphorylated by cellular kinases to the active triphosphate form, which has an intracellular half-life of 14 hours. Telbivudine 5'-triphosphate inhibits HBV DNA polymerase (reverse transcriptase) by competing with the natural substrate, thymidine 5'-triphosphate. Incorporation of telbivudine 5'-triphosphate into viral DNA causes DNA chain termination, resulting in inhibition of HBV replication. Telbivudine is an inhibitor of both HBV first strand (EC50 value = 1.3 ± 1.6 µM) and second strand synthesis (EC50 value = 0.2 ± 0.2 µM). Telbivudine 5'-triphosphate at concentrations up to 100 µM did not inhibit human cellular DNA polymerases α, β, or γ. No appreciable mitochondrial toxicity was observed in HepG2 cells treated with telbivudine at concentrations up to 10 µM.

French pharmaceutical company Hoechst Marion Roussel (later Sanofi-Aventis) began phase II/III clinical trials of telithromycin (HMR-3647) in 1998. Telithromycin was approved by the European Commission in July 2001 and subsequently went on sale in October 2001. In the US, telithromycin received U.S. Food and Drug Administration (FDA) approval on April 1, 2004 Telithromycin is the first ketolide antibiotic to enter clinical use and is sold under the brand name of Ketek. After significant controversy regarding safety and research fraud, the US Food and Drug Administration sharply curtailed the approved uses of the drug in 2007. Telithromycin is a semi-synthetic erythromycin derivative. It is created by substituting a ketogroup for the cladinose sugar and adding a carbamate ring in the lactone ring. An alkyl-aryl moiety is attached to this carbamate ring. Furthermore, the carbon at position 6 has been methylated, as is the case in clarithromycin, to achieve better acid-stability. For the treatment of Pneumococcal infection, acute sinusitis, acute bacterial tonsillitis, acute bronchitis and bronchiolitis, lower respiratory tract infection and lobar (pneumococcal) pneumonia. KETEK tablets contain telithromycin, a semisynthetic antibacterial in the ketolide class for oral administration. Telithromycin blocks protein synthesis by binding to domains II and V of 23S rRNA of the 50S ribosomal subunit. By binding at domain II, telithromycin retains activity against gram-positive cocci (e.g., Streptococcus pneumoniae) in the presence of resistance mediated by methylases (erm genes) that alter the domain V binding site of telithromycin. Telithromycin may also inhibit the assembly of nascent ribosomal units.

Gemifloxacin is an oral broad-spectrum quinolone antibacterial agent used in the treatment of acute bacterial exacerbation of chronic bronchitis and mild-to-moderate pneumonia. Gemifloxacin mesylate is marketed under the brand name Factive, indicated for the treatment of bacterial infection caused by susceptible strains such as S. pneumoniae, H. influenzae, H. parainfluenzae, or M. catarrhalis, S. pneumoniae (including multi-drug resistant strains [MDRSP]), M. pneumoniae, C. pneumoniae, or K. pneumoniae. Gemifloxacin has in vitro activity against a wide range of Gram-negative and Grampositive microorganisms. Gemifloxacin is bactericidal with minimum bactericidal concentrations (MBCs) generally within one dilution of the minimum inhibitory concentrations (MICs). Gemifloxacin acts by inhibiting DNA synthesis through the inhibition of both DNA gyrase and topoisomerase IV (TOPO IV), which are essential for bacterial growth. Streptococcus pneumoniae showing mutations in both DNA gyrase and TOPO IV (double mutants) are resistant to most fluoroquinolones. Gemifloxacin has the ability to inhibit both enzyme systems at therapeutically relevant drug levels in S. pneumoniae (dual targeting), and has MIC values that are still in the susceptible range for some of these double mutants.

Tegaserod (3‐(5‐methoxy‐1H‐indol‐3ylmethylene)‐N‐pentyl‐carbazimidamide), an aminoguanidine indole derivative of serotonin, is a selective partial agonist highly selective for 5‐HT4 receptor with an affinity constant in the nanomolar range. Tegaserod, by acting as an agonist at neuronal 5-HT4 receptors, triggers the release of further neurotransmitters such as calcitonin gene-related peptide from sensory neurons. The activation of 5-HT4 receptors in the gastrointestinal tract stimulates the peristaltic reflex and intestinal secretion, as well as inhibits visceral sensitivity. In vivo studies showed that tegaserod enhanced basal motor activity and normalized impaired motility throughout the gastrointestinal tract. Zelnorm® (tegaserod maleate) is indicated for the short-term treatment of women with irritable bowel syndrome (IBS) whose primary bowel symptom is constipation. In addition Zelnorm® is indicated for the treatment of patients less than 65 years of age with chronic idiopathic constipation.

Pemirolast is a mast cell stabilizer that acts as an antiallergic agent, it is approved in Japan for the treatment of bronchial asthma and of allergic rhinitis. Pemirolast strongly inhibits extracellular Ca2+ influx and the release of intracellular Ca2+, an important factor in the release of chemical mediators, by inhibiting inositol-phospholipid metabolism in mast cells. It also inhibits the release of arachidonic acid. Furthermore contribution of increasing effect on c-AMP based on inhibiting phosphodiesterase is suggested. Main pharmacological effects is an inhibition of release of chemical mediators, e.g. histamine, LTB4, LTC4, LTD4, PGD2, TXB2 and PAF from human lung tissues, abraded fragments of the nasal mucosa, and peripheral leukocytes, rat peritoneal exudate cells, and rat and guniea pig lung tissues.

Delavirdine is a nonnucleoside reverse transcriptase inhibitor (NNRTI). Delavirdine binds directly to reverse transcriptase (RT) and blocks RNA-dependent and DNA-dependent DNA polymerase activities. Delavirdine does not compete with template:primer or deoxynucleoside triphosphates. HIV-2 RT and human cellular DNA polymerases alfa, gamma, or delta are not inhibited by delavirdine. In addition, HIV-1 group O, a group of highly divergent strains that are uncommon in North America, may not be inhibited by delavirdine. Delavirdine is marketed under the trade name Rescriptor, indicated for the treatment of HIV-1 infection in combination with at least 2 other active antiretroviral agents when therapy is warranted. .

Grepafloxacin is a monofluorinated quinolone with a cyclopropyl group at position 1, a 3-methyl-1piperazinyl group at position 7 and a methyl substitution at the 5 position, that was synthesized by Otsuka in Japan. It exhibited in vitro activity against a wide variety of both Gram-positive and Gram-negative bacteria including anaerobic species. The compound was reported to have a broad spectrum of activity, particularly against pathogens responsible for community-acquired respiratory infections including those caused by beta-lactam and macrolide-resistant strains of Streptococcus pneumoniae and Haemophilus influenzae. Japanese researchers also reported that unlike other quinolones, grepafloxacin reached high levels in the bile and might also be useful in the treatment of biliary tract infection. Grepafloxacin was administered once daily and did not require dosage adjustment for renal insufficiency, but grepafloxacin tablets were contraindicated in patients with hepatic failure. Otsuka Pharmaceutical signed a licensing agreement for grepafloxacin with GlaxoSmithKline. According to this agreement, GlaxoSmithKline had marketing rights to grepafloxacin in Europe, USA, and certain other markets. Otsuka retained rights for Japan and some Asian countries

Mibefradil is a calcium channel blocker, chemically unlike other compounds in the class, that was approved by the Food and Drug Administration (FDA), U.S.A. in June 1997 for the treatment of patients with hypertension and chronic stable angina. Shortly following its introduction, mibefradil was withdrawn from the market in the U.S.A. as well as in Europe. The reason for the voluntary withdrawal of the drug by Roche laboratories was claimed to be the result of new information about potentially harmful interactions with other drugs. Mibefradil is calcium channel blocker with moderate selectivity for T-type Ca2+ channels displaying IC50 values of 2.7 uM and 18.6 uM for T-type and L-type channels respectively. Mibefradil is a tetralol calcium channel blocking agent that inhibits the influx of calcium ions across both the T (low-voltage) and L (high-voltage) calcium channels of cardiac and vascular smooth muscle, with a greater selectivity for T channels. Vasodilation occurs in vascular smooth muscle, causing a decrease in peripheral vascular resistance and a resulting decrease in blood pressure. Mibefradil causes a slight increase in cardiac output during chronic dosing. Mibefradil slows sinus and atrioventricular (AV) node conduction, producing a slight reduction in heart rate and a slight increase in the PR interval. It has also been shown to slightly lengthen the corrected sinus node recovery time and AH interval and to raise the Wenckebach point. The mechanism by which mibefradil reduces angina is not known, but is thought to be attributed to a reduction in heart rate, total peripheral resistance (afterload), and the heart rate-systolic blood pressure product at any given level of exercise. The result of these effects is a decrease in cardiac workload and myocardial oxygen demand. Mibefradil has been repurposed from an abandoned antihypertensive to a targeted solid tumor treatment, and it has been rescued from drug-drug interactions by using short-term dose exposure. Tau is using the early success of mibefradil as a proof of concept to build a platform technology of Cav3 blockers for broad antitumor applications in combination with new targeted cancer therapies, well-established.

Cerivastatin (BAYCOL®) is a competitive inhibitor of HMG-CoA reductase, which is responsible for the conversion of 3-hydroxy-3-methyl-glutaryl-coenzyme A (HMG-CoA) to mevalonate, a precursor of sterols, including cholesterol. The inhibition of cholesterol biosynthesis by cerivastatin reduces the level of cholesterol in hepatic cells, which stimulates the synthesis of low-density lipoprotein (LDL) receptors, thereby increasing the uptake of cellular LDL particles. The end result of these biochemical processes is a reduction of the plasma cholesterol concentration. On August 8, 2001 the U.S. Food and Drug Administration (FDA) announced that Bayer Pharmaceutical Division voluntarily withdrew BAYCOL® from the U.S. market, due to reports of fatal rhabdomyolysis, a severe adverse reaction from this cholesterol-lowering (lipid-lowering) product. It has also been withdrawn from the Canadian market.

Sparfloxacin is a synthetic fluoroquinolone broad-spectrum antimicrobial agent in the same class as ofloxacin and norfloxacin. Sparfloxacin has in vitro activity against a wide range of gram-negative and gram-positive microorganisms. Sparfloxacin exerts its antibacterial activity by inhibiting DNA gyrase, a bacterial topoisomerase. DNA gyrase is an essential enzyme which controls DNA topology and assists in DNA replication, repair, deactivation, and transcription. Quinolones differ in chemical structure and mode of action from (beta)-lactam antibiotics. Quinolones may, therefore, be active against bacteria resistant to (beta)-lactam antibiotics. Although cross-resistance has been observed between sparfloxacin and other fluoroquinolones, some microorganisms resistant to other fluoroquinolones may be susceptible to sparfloxacin. In vitro tests show that the combination of sparfloxacin and rifampin is antagonistic against Staphylococcus aureus. The bactericidal action of sparfloxacin results from inhibition of the enzymes topoisomerase II (DNA gyrase) and topoisomerase IV, which are required for bacterial DNA replication, transcription, repair, and recombination. Sparfloxacin is used for the treatment of adults with the following infections caused by susceptible strains microorganisms: community-acquired pneumonia (caused by Chlamydia pneumoniae, Haemophilus influenzae, Haemophilus parainfluenzae, Moraxella catarrhalis, Mycoplasma pneumoniae, or Streptococcus pneumoniae) and acute bacterial exacerbations of chronic bronchitis (caused by Chlamydia pneumoniae, Enterobacter cloacae, Haemophilus influenzae, Haemophilus parainfluenzae, Klebsiella pneumoniae, Moraxella catarrhalis,Staphylococcus aureus, or Streptococcus pneumoniae). Sparfloxacin has trade names Spacin in Bangladesh, Zagam and Zagam Respipac. Zagam is no longer available in the United States.