Acitretin is all-Trans-9-(4-methoxy-2, 3, 6¬ trimethylphenyl)-three, 7-dimethyl-2, 4, 6, 8-nonatetraenoic acid. It is a metabolite of exterminate and is related to both retinoic acid and retinol (vitamin A). It is taken orally, and is typically used for psoriasis. The mechanism of action of is unknown. However it is believed to work by targeting specific receptors (retinoid receptors such as RXR and RAR) in the skin, which help normalize the growth cycle of skin cells. Studies on nuclear retinoic acid receptors have shown that acitretin activates all 3 receptor subtypes (RAR-alpha, -beta, and -gamma) without measurable receptor binding; this paradox remains unexplained.

Nisoldipine is a 1,4-dihydropyridine derivative with an outstanding vascular selectivity. As a specific calcium antagonist, it shortens the action potential and causes electromechanical uncoupling in ventricular myocardium. However, this effect, resulting in a negative inotropic action, appears at 100–1000 times higher concentrations of nisoldipine in comparison with its inhibition of calcium-dependent vascular contractions. Detailed analyses of pharmacological effects revealed additional properties such as enhancement of sodium excretion, an interaction with the reninangiotensin-aldosterone system and a protective effect against acute renal ischaemia, that may contribute to its therapeutic efficacy. Nisoldipine was developed at Bayer then licensed to Zeneca and marketed in the United States as SULAR. SULAR is indicated for the treatment of hypertension. It may be used alone or in combination with other antihypertensive agents. The mechanism of the therapeutic effect of nisoldipine is complex. It involves a decrease of the total peripheral vascular resistance (reduction of afterload) and an increase in coronary blood flow. Moreover, nisoldipine obviously normalises the impaired volume homoeostasis by improving renal function and thus reduces the need for activation of the ANP system. In the advanced stages of hypertension, nisoldipine prevents deleterious calcium overload and the resulting tissue damage.

Epoprostenol (marketed as FLOLAN, VELETRI) is a prostaglandin that is a powerful vasodilator and inhibits platelet aggregation. Epoprostenol (PGI2, PGX, prostacyclin), a metabolite of arachidonic acid, is a naturally occurring prostaglandin with potent vasodilatory activity and inhibitory activity of platelet aggregation. FLOLAN (epoprostenol sodium) for Injection is a sterile sodium salt formulated for intravenous (IV) administration. Epoprostenol has two major pharmacological actions: (1) direct vasodilation of pulmonary and systemic arterial vascular beds, and (2) inhibition of platelet aggregation. In animals, the vasodilatory effects reduce right and left ventricular afterload and increase cardiac output and stroke volume. The effect of epoprostenol on heart rate in animals varies with dose. At low doses, there is vagally mediated brudycardia, but at higher doses, epoprostenol causes reflex tachycardia in response to direct vasodilation and hypotension. No major effects on cardiac conduction have been observed. Additional pharmacologic effects of epoprostenol in animals include bronchodilation, inhibition of gastric acid secretion, and decreased gastric emptying. No available chemical assay is sufficiently sensitive and specific to assess the in vivo human pharmacokinetics of epoprostenol. FLOLAN is indicated for the long-term intravenous treatment of primary pulmonary hypertension and pulmonary hypertension associated with the scleroderma spectrum of disease in NYHA Class III and Class IV patients who do not respond adequately to conventional therapy.

Moexiprilat is the pharmacologically active metabolite of Moexipril. Formation of Moexiprilat is caused by hydrolysis of a Moexipril’s ethyl ester group. Moexiprilat competitively inhibits ACE, thereby blocking the conversion of angiotensin I to angiotensin II. This prevents the actions of the potent vasoconstrictor angiotensin II and leads to vasodilatation. This agent also prevents angiotensin II-induced aldosterone secretion by the adrenal cortex, thereby promoting diuresis and natriuresis. Moexiprilat showed an extended duration of action owing to a long terminal pharmacokinetic half-life and produced a persistent ACE inhibition.

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.

Latanoprost (free acid) is a metabolite of latanoprost which has been approved for use as an ocular hypotensive drug. Latanoprost is an isopropyl ester prodrug which is converted to the Latanoprost-acid by endogenous esterase enzymes. The free acid is pharmacologically active and is 200 times more potent than latanoprost as an agonist of the human recombinant Prostaglandin F receptor. However, the free Latanoprost-acid is more irritating and less effective than Latanoprost when applied directly to the eyes of human glaucoma patients.

Aminolevulinic Acid is the first compound in the porphyrin synthesis pathway. The metabolism of aminolevulinic acid (ALA) is the first step in the biochemical pathway resulting in heme synthesis. Aminolevulinic acid is not a photosensitizer, but rather a metabolic precursor of protoporphyrin IX (PpIX), which is a photosensitizer. The synthesis of ALA is normally tightly controlled by feedback inhibition of the enzyme, ALA synthetase, presumably by intracellular heme levels. ALA, when provided to the cell, bypasses this control point and results in the accumulation of PpIX, which is converted into heme by ferrochelatase through the addition of iron to the PpIX nucleus. Marketed under the brand name LEVULAN KERASTICK for Topical Solution plus blue light illumination using the BLU-U Blue Light Photodynamic Therapy Illuminator, it is indicated for the treatment of minimally to moderately thick actinic keratoses (Grade 1 or 2, see table 2 for definition) of the face or scalp. Aminolevulinic acid is also being studied in the treatment of other conditions and types of cancer. An orally-administered in vivo diagnostic agent, Aminolevulinic acid, is used in photodynamic diagnosis (PDD) whose aim is to help doctors visualize the tumor tissue during surgical resection of malignant glioma, it is already sold in over 20 European countries including Germany and the U.K. According to the presumed mechanism of action, photosensitization following application of aminolevulinic acid (ALA) topical solution occurs through the metabolic conversion of ALA to protoporphyrin IX (PpIX), which accumulates in the skin to which aminolevulinic acid has been applied. When exposed to light of appropriate wavelength and energy, the accumulated PpIX produces a photodynamic reaction, a cytotoxic process dependent upon the simultaneous presence of light and oxygen. The absorption of light results in an excited state of the porphyrin molecule, and subsequent spin transfer from PpIX to molecular oxygen generates singlet oxygen, which can further react to form superoxide and hydroxyl radicals. Photosensitization of actinic (solar) keratosis lesions using aminolevulinic acid, plus illumination with the BLU-UTM Blue Light Photodynamic Therapy Illuminator (BLU-U), is the basis for aminolevulinic acid photodynamic therapy (PDT).

Alendronic acid is a bisphosphonate drug used for osteoporosis, osteogenesis imperfecta, and several other bone diseases. It is marketed alone as well as in combination with vitamin D. Alendronate inhibits osteoclast-mediated bone-resorption. Like all bisphosphonates, it is chemically related to inorganic pyrophosphate, the endogenous regulator of bone turnover. But while pyrophosphate inhibits both osteoclastic bone resorption and the mineralization of the bone newly formed by osteoblasts, alendronate specifically inhibits bone resorption without any effect on mineralization at pharmacologically achievable doses. Its inhibition of bone-resorption is dose-dependent and approximately 1,000 times stronger than the equimolar effect of the first bisphosphonate drug, etidronate. Under therapy, normal bone tissue develops, and alendronate is deposited in the bone-matrix in a pharmacologically inactive form. For optimal action, enough calcium and vitamin D are needed in the body in order to promote normal bone development. Hypocalcemia should, therefore, be corrected before starting therapy. Treatment of post-menopausal women and people with osteogenesis imperfecta over the age of 22 with alendronic acid has demonstrated normalization of the rate of bone turnover, significant increase in BMD (bone mineral density) of the spine, hip, wrist and total body, and significant reductions in the risk of vertebral (spine) fractures, wrist fractures, hip fractures, and all non-vertebral fractures. In the Fracture Intervention Trial, the women with the highest risk of fracture (by virtue of pre-existing vertebral fractures) were treated with Fosamax 5 mg/day for two years followed by 10 mg/day for the third year. This resulted in approximately 50% reductions in fractures of the spine, hip, and wrist compared with the control group taking placebos. Both groups also took calcium and vitamin D.

Levocetirizine dihydrochloride is the R enantiomer of cetirizine hydrochloride, a racemic compound with antihistaminic properties. Levocetirizine is a third-generation non-sedative antihistamine indicated for the relief of symptoms associated with seasonal and perennial allergic rhinitis and uncomplicated skin manifestations of chronic idiopathic urticaria. It was developed from the second-generation antihistamine cetirizine. Levocetirizine was approved by the United States Food and Drug Administration on May 25, 2007 and is marketed under the brand XYZAL. Its principal effects are mediated via selective inhibition of H1 receptors. The antihistaminic activity of levocetirizine has been documented in a variety of animal and human models. In vitro binding studies revealed that levocetirizine has an affinity for the human H1-receptor 2-fold higher than that of cetirizine (Ki = 3 nmol/L vs. 6 nmol/L, respectively). The clinical relevance of this finding is unknown.

Azelaic acid, a naturally occurring saturated dicarboxylic acid found in wheat, rye, and barley, possesses antimicrobial activity, affects keratin production, and reduces inflammation. One of the brand name for azelaic acid is FINACEA,Gel, 15% is indicated for topical treatment of the inflammatory papules and pustules of mild to moderate rosacea. Although some reduction of erythema, which was present in patients with papules, and pustules of rosacea occurred in clinical studies, efficacy for treatment of erythema in rosacea in the absence of papules and pustules has not been evaluated. Rosacea is a common skin condition thought to be primarily an inflammatory disorder. Neutrophils, in particular, have been implicated in the inflammation associated with rosacea and mediate many of their effects through the release of reactive oxygen species. Many effective agents for rosacea, including topical azelaic acid have anti-inflammatory properties. Azelaic acid per se has multiple modes of action in rosacea, but an anti-inflammatory effect achieved by reducing reactive oxygen species appears to be the main pharmacological action. A possible mechanism of action for azelaic acid in the human epidermis includes its possibility to inhibit tyrosinase and of membrane-associated thioredoxin reductase enzymes, this enzyme is shown to regulate tyrosinase through a feedback mechanism involving electron transfer to intracellular thioredoxin, followed by a specific interaction between reduced thioredoxin and tyrosinase.