Mycophenolic acid (MPA) possesses antibacterial, antifungal, antiviral, immunosuppressive and anticancer properties. Mycophenolic acid (MPA) is a fungal metabolite that was initially discovered by Bartolomeo Gosio in 1893 as an antibiotic against anthrax bacillus, Bacillus anthracis. It is an uncompetitive and reversible inhibitor of inosine monophosphate dehydrogenase (IMPDH), and therefore inhibits the de novo pathway of guanosine nucleotide synthesis without incorporation to DNA. It was approved under the brand name Myfortic for the prophylaxis of organ rejection in adult patients receiving a kidney transplant and is indicated for the prophylaxis of organ rejection in pediatric patients 5 years of age and older who are at least 6 months post kidney transplant. Myfortic is to be used in combination with cyclosporine and corticosteroids.

Lodoxamide is a mast-cell stabilizer for topical administration into the eye. This compound belongs to the class of organic compounds known as alpha amino acids and derivatives. Lodoxamide inhibits the in vivo Type I immediate hypersensitivity reaction. In vitro, Lodoxamide stabilizes mast cells and prevents antigen-stimulated release of histamine. In addition, Lodoxamide prevents the release of other mast cell inflammatory mediators and inhibits eosinophil chemotaxis. Although Lodoxamide's precise mechanism of action is unknown, the drug has been reported to prevent calcium influx into mast cells upon antigen stimulation. Among side effects to Lodoxamide, the most frequently reported ocular adverse experiences were transient burning, stinging, or discomfort upon instillation. Nonocular events reported were headache and heat sensation, dizziness, somnolence, nausea, stomach discomfort, sneezing, dry nose, and rash.

Rifabutin is an antibiotic that inhibits DNA-dependent RNA polymerase activity in susceptible cells. Specifically, it interacts with bacterial RNA polymerase but does not inhibit the mammalian enzyme. It is bactericidal and has a very broad spectrum of activity against most gram-positive and gram-negative organisms (including Pseudomonas aeruginosa) and specifically Mycobacterium tuberculosis. It is FDA approved for the prophylaxis of disseminated Mycobacterium avium complex (MAC) disease in patients with advanced HIV infection. Multiple dosing of rifabutin has been associated with induction of hepatic metabolic enzymes of the CYP3A subfamily. Rifabutin’s predominant metabolite (25-desacetyl rifabutin: LM565), may also contribute to this effect. Similarly, concomitant medications that competitively inhibit the CYP3A activity may increase plasma concentrations of rifabutin. Common adverse reactions include discoloration of skin, rash, diarrhea, disorder of taste, indigestion, loss of appetite, nausea, vomiting, increased liver aminotransferase level (mild), ocular discoloration, uveitis, abnormal color of body fluid.

Tenivastatin (well known as simvastatin acid or simvastatin hydroxy acid) is a pharmacologically active metabolite, which is formed in the mammalian organism from lactone prodrug, simvastatin. Tenivastatin is a potent reversible inhibitor of HMGCR (HMG-CoA reductase), reduces cholesterol synthesis and increases low-density lipoprotein (LDL) receptors on cell membranes of liver and extrahepatic tissues. It is also a substrate of organic anion transporting polypeptide 1B1 (OATP1B1/Oatp2), an influx transporter expressed on the sinusoidal membrane of hepatocytes. Recent studies have shown that OATP1B1 plays a clinically important role in the hepatic elimination of several drugs including statins, via mediating the hepatic uptake. In addition, was discovered, that the tenivastatin was a substrate of another transporter protein, human organic anion transporting polypeptide 3A1 (OATP3A1), which is predominately expressed in the heart. Presence of OATP3A1 in cardiomyocytes suggested that transporter could modulate the exposure of cardiac tissue to simvastatin acid due to its enrichment in cardiomyocytes. Increases in the uptake of simvastatin acid by OATP3A1 when combined with OATP substrates suggest the potential for drug-drug interactions that could influence clinical outcomes.

Ramipril (sold under the brand name Altace ) is a prodrug belonging to the angiotensin-converting enzyme (ACE) inhibitors. It is metabolized to ramiprilat in the liver and, to a lesser extent, kidneys. Ramiprilat is a potent, competitive inhibitor of ACE, the enzyme responsible for the conversion of angiotensin I (ATI) to angiotensin II (ATII). ATII regulates blood pressure and is a key component of the renin-angiotensin-aldosterone system (RAAS). Ramipril is indicated for the treatment of hypertension, to lower blood pressure; also used to reduce the risk of myocardial infarction, stroke, or death from cardiovascular causes; in addition, this drug is used to reduce the rate of death, myocardial infarction and stroke in individuals at high risk of cardiovascular events.

Benazepril is a prodrug which is metabolized by the liver into its active form benazeprilat via cleavage of the drug's ester group. Benazepril and Benazeprilat inhibit angiotensin-converting enzyme (ACE) in human subjects and animals. Benazeprilat has much greater ACE inhibitory activity than does Benazepril. It is indicated for the treatment of hypertension. It may be used alone or in combination with thiazide diuretics. Adverse reactions reported in controlled clinical trials and rarer events seen in post-marketing experience, include the following: Stevens-Johnson syndrome, pemphigus, apparent hypersensitivity reactions (manifested by dermatitis, pruritus, or rash), photosensitivity, and flushing, nausea, pancreatitis, constipation, gastritis, vomiting, and melena, thrombocytopenia and hemolytic anemia, anxiety, decreased libido, hypertonia, insomnia, nervousness, and paresthesia. Patients on diuretics, especially those in whom diuretic therapy was recently instituted, may occasionally experience an excessive reduction of blood pressure after initiation of therapy with Benazepril. Increased serum lithium levels and symptoms of lithium toxicity have been reported in patients receiving ACE inhibitors (including benazepril) during therapy with lithium.

Azithromycin is one of the world's best-selling antibiotics, used to treat or prevent certain bacterial infections: Acute bacterial exacerbations of chronic bronchitis in adults; acute bacterial sinusitis in adults; uncomplicated skin and skin structure infections in adults; urethritis and cervicitis in adults; genital ulcer disease in men; acute otitis media in pediatric patients; community-acquired pneumonia in adults and pediatric patients; pharyngitis/tonsillitis in adults and pediatric patients. Azithromycin should not be used in patients with pneumonia who are judged inappropriate for oral therapy because of moderate to severe illness or risk factors. A team of researchers at the Croatian pharmaceutical company Pliva, discovered azithromycin in 1980. It was patented in 1981. In 1986, Pliva and Pfizer signed a licensing agreement, which gave Pfizer exclusive rights for the sale of azithromycin in Western Europe and the United States. Pliva put its azithromycin on the market in Central and Eastern Europe under the brand name of Sumamed in 1988. Pfizer launched azithromycin under Pliva's license in other markets under the brand name Zithromax in 1991. Azithromycin is a semi-synthetic macrolide antibiotic of the azalide class. Like other macrolide antibiotics, azithromycin inhibits bacterial protein synthesis by binding to the 50S ribosomal subunit of the bacterial 70S ribosome. Binding inhibits peptidyl transferase activity and interferes with amino acid translocation during the process of translation. Its effects may be bacteriostatic or bactericidal depending of the organism and the drug concentration. Its long half-life, which enables once daily dosing and shorter administration durations, is a property distinct from other macrolides.

Pentostatin, also known as 2’-deoxycoformycin (DCF) under the trade name Nipent, is a potent inhibitor of the enzyme adenosine deaminase and is isolated from fermentation cultures of Streptomyces antibioticus. It was developed by Parke-Davis (now Pfizer) and the National Cancer Institute in the US. Nipent is indicated as single-agent treatment for both untreated and alpha-interferon-refractory hairy cell leukemia patients with active disease as defined by clinically significant anemia, neutropenia, thrombocytopenia, or disease-related symptoms. Pentostatin is a potent transition state inhibitor of the enzyme adenosine deaminase (ADA). The greatest activity of ADA is found in cells of the lymphoid system with T-cells having higher activity than B-cells, and T-cell malignancies having higher ADA activity than B-cell malignancies. Pentostatin inhibition of ADA, particularly in the presence of adenosine or deoxyadenosine, leads to cytotoxicity, and this is believed to be due to elevated intracellular levels of dATP, which can block DNA synthesis through inhibition of ribonucleotide reductase. Pentostatin can also inhibit RNA synthesis as well as cause increased DNA damage. In addition to elevated dATP, these mechanisms may also contribute to the overall cytotoxic effect of pentostatin. The precise mechanism of pentostatin’s antitumor effect, however, in hairy cell leukemia is not known. In several instances, hepatic toxicity from pentostatin appeared to be somewhat dose related, suggesting that the liver injury is a direct effect of the purine analogue. Because pentostatin is a potent immunosuppressive agent, the possibility exists that some cases of hepatic injury are due to reactivation of hepatitis B or other opportunistic infections. While pentostatin has not been shown to cause reactivation of hepatitis B, there is a strong possibility that it might induce this syndrome, and several cases of hepatic injury during pentostatin therapy were described as due to concurrent hepatitis B.

Olsalazine is an anti-inflammatory drug used in the treatment of inflammatory bowel disease such as ulcerative colitis. Orally administered olsalazine is converted to mesalamine which is thought to be the therapeutically active agent in the treatment of ulcerative colitis. The mechanism of action of mesalamine (and sulfasalazine) is unknown but appears to be topical rather than systemic. Mucosal production of arachidonic acid (AA) metabolites, both through the cyclooxygenase pathways, i.e., prostanoids, and through the lipoxygenase pathways, i.e., leukotrienes (LTs) and hydroxyelcosatetraenoic acids (HETEs) is increased in patients with chronic inflammatory bowel disease, and it is possible that mesalamine diminishes inflammation by blocking cyclooxygenase and inhibiting prostaglandin (PG) production in the colon. After oral administration, olsalazine has limited systemic bioavailability. Based on oral and intravenous dosing studies, approximately 2.4% of a single 1.0 g oral dose is absorbed. Less than 1% of olsalazine is recovered in the urine. The remaining 98 to 99% of an oral dose will reach the colon, where each molecule is rapidly converted into two molecules of 5¬ aminosalicylic acid (5-ASA) by colonic bacteria and the low prevailing redox potential found in this environment. The liberated 5-ASA is absorbed slowly resulting in very high local concentrations in the colon. Olsalazine has been evaluated in ulcerative colitis patients in remission, as well as those with acute disease. Both sulfasalazine-tolerant and intolerant patients have been studied in controlled clinical trials. Overall, 10.4% of patients discontinued olsalazine because of an adverse experience compared with 6.7% of placebo patients. The most commonly reported adverse reactions leading to treatment withdrawal were diarrhea or loose stools (olsalazine 5.9%; placebo 4.8%), abdominal pain, and rash or itching (slightly more than 1% of patients receiving olsalazine).

Fluticasone propionate, a medium-potency synthetic corticosteroid, is used topically to relieve inflammatory and pruritic symptoms of dermatoses and psoriasis, intranasally to manage symptoms of allergic and non-allergic rhinitis, and orally for the treatment of asthma. Fluticasone proprionate is marketed under several different brand names such as Flonase®. Fluticasone propionate is also available as a combination product of azelastine hydrochloride and fluticasone propionate called Dymista™. Dymista™ is indicated in patients over 12 years old for symptomatic relief of seasonal allergic rhinitis. Fluticasone propionate binds to the glucocorticoid receptor. Unbound corticosteroids cross the membranes of cells such as mast cells and eosinophils, binding with high affinity to glucocorticoid receptors (GR). The results include alteration of transcription and protein synthesis, a decreased release of leukocytic acid hydrolases, reduction in fibroblast proliferation, prevention of macrophage accumulation at inflamed sites, reduction of collagen deposition, interference with leukocyte adhesion to the capillary wall, reduction of capillary membrane permeability and subsequent edema, reduction of complement components, inhibition of histamine and kinin release, and interference with the formation of scar tissue. In the management of asthma, the glucocorticoid receptor complexes down-regulates proinflammatory mediators such as interleukin-(IL)-1, 3, and 5, and up-regulates anti-inflammatory mediators such as IkappaB [inhibitory molecule for nuclear factor kappaB1], IL-10, and IL-12. The antiinflammatory actions of corticosteroids are also thought to involve inhibition of cytosolic phospholipase A2 (through activation of lipocortin-1 (annexin)) which controls the biosynthesis of potent mediators of inflammation such as prostaglandins and leukotrienes.