Avorelin is a superagonist of natural luteinizing-hormone-releasing-hormone. Avorelin has been formulated in high molecular weight polylactic glycolic acid to afford protracted and continuous release of the peptide from subcutaneous implants. Avorelin has been in phase II clinical trials by Mediolanum for the treatment of prostate cancer, breast cancer and endometriosis. However, this research has been discontinued. Adverse events mainly related to androgen suppression (hot flushes, decreased libido and impotence) or the nature of the disease (skeletal pain).

Vapreotide (Sanvar) is cyclic octapeptide analog of somatostatin with higher metabolic stability than the parent hormone and developed by Debiopharm Group for the treatment of esophageal variceal bleeding in patients with cirrhotic liver disease and AIDS-related diarrhea. Somatostatin inhibits the secretion of vasodilatory peptides from the gastrointestinal tract, including glucagon, which has been shown to contribute to the maintenance of portal hypertension. While natural somatostatin has a very short half-life (3 min), the elimination half-life of vapreotide is reported to be approximately 10 times longer than that of its parent compound. Pharmacodynamic studies of healthy volunteers demonstrated suppression of gastric acid secretion and inhibition of the secretion of pancreatic enzyme, which is similar to somatostatin. Vapreotide has demonstrated efficacy in the early management of acute variceal hemorrhage but only based on combined primary endpoints of hemostasis and survival after 5 days. In addition, vapreotide’s efficacy is limited to only one major study performed in Europe and not yet in the United States. Although it did not show a significant reduction in mortality, vapreotide’s observed the effect on hemostasis, as well as its favorable safety profile. Adverse effects that occurred in the vapreotide trials were generally mild and primarily included gastrointestinal symptoms and alterations of the gastrointestinal hormonal system. Vapreotide not recommended for approval by an FDA Advisory Panel due to Insufficient evidence that the drug provided a benefit in the treatment for acute esophageal variceal bleeding.

Atosiban (brand name Tractocile) is a competitive antagonist of human oxytocin at receptor level. In rats and guinea pigs, atosiban was shown to bind to oxytocin receptors, to decrease the frequency of contractions and the tone of the uterine musculature, resulting in a suppression of uterine contractions. Atosiban was also shown to bind to the vasopressin receptor, thus inhibiting the effect of vasopressin. Tractocile is indicated to delay imminent pre-term birth in pregnant adult women with: − regular uterine contractions of at least 30 seconds duration at a rate of ≥ 4 per 30 minutes − a cervical dilation of 1 to 3 cm (0-3 for nulliparas) and effacement of ≥ 50% − a gestational age from 24 until 33 completed weeks − a normal foetal heart rate. Atosiban does not have U.S. Food and Drug Administration (FDA) approval for use in the United States.

Buserelin is a synthetic peptide analog of the luteinizing hormone-releasing hormone (LHRH) agonist, which stimulates the pituitary gland's gonadotrophin-releasing hormone receptor (GnRHR). Buserelin is used for palliative treatment of prostate cancer, and for treatment of endometriosis. Buserelin is also used for infertility treatment to prepare the pituitary gland before starting treatment with gonadotrophins (FSH and LH) to artificially stimulate ovulation.

Aceclidine is a parasympathomimetic agent used in the treatment of open-angle glaucoma as topical eye drop solution. It is as a muscarinic acetylcholine receptor agonist with weak anticholinesterase activity. Acting directly on the motor end-plate (cholinergic nerve endings) it decreases intraocular pressure and mediates the contraction of iris muscle. Aceclidine increased outflow facility in human eyes in vitro by a direct stimulation of the outflow tissues in the absence of an intact ciliary muscle. This effect was biphasic, occurring at concentrations of 10 uM and lower with no effect at higher concentrations. Passed numerous clinical trials in Russia, France, Italy and other countries and was widely used in Europe but never been in clinical use in USA.

Sivelestat is a neutrophil elastase inhibitor approved in Japan and the Republic of Korea for acute lung injury, including acute respiratory distress syndrome in patients with systemic inflammatory response syndrome. Sivelestat is marketed as Elaspol in Japan. Sivelestat competitively inhibited human neutrophil elastase (IC50 = 0.044 uM, Ki = 0.2 uM). It also inhibited leukocyte elastase obtained from rabbit, rat, hamster and mouse.

Acefylline is a stimulant drug of the xanthine chemical class. It acts as an adenosine receptor antagonist. Acephylline piperazine is a theophylline derivative with a direct bronchodilator action. It has the advantages over theophylline in being far less toxic and producing minimal gastric irritation. It is indicated for the treatment of asthma, emphysema, acute and chronic bronchitis associated with bronchospasm.Acefylline relaxes smooth muscles, relieves bronchospasm & has a stimulant effect on respiration. It stimulates the myocardium & central nervous system, decreases peripheral resistance & venous pressure & causes diuresis. The mechanism of action is still not clear, inhibition of phosphodiesterase with a resulting increase in intracellular cyclic AMP does occur, but not apparently at concentrations normally used for clinical effect. Other proposed mechanisms of action include adenosine receptor antagonism, prostaglandin antagonism & effects on intracellular calcium. Sodium phenobarbital is a non-selective central nervous system depressant that is primarily used as sedative-hypnotic.

Aceclidine is a parasympathomimetic agent used in the treatment of open-angle glaucoma as topical eye drop solution. It is as a muscarinic acetylcholine receptor agonist with weak anticholinesterase activity. Acting directly on the motor end-plate (cholinergic nerve endings) it decreases intraocular pressure and mediates the contraction of iris muscle. Aceclidine increased outflow facility in human eyes in vitro by a direct stimulation of the outflow tissues in the absence of an intact ciliary muscle. This effect was biphasic, occurring at concentrations of 10 uM and lower with no effect at higher concentrations. Passed numerous clinical trials in Russia, France, Italy and other countries and was widely used in Europe but never been in clinical use in USA.

Josamycin is a macrolide antibiotic produced by Streptomyces narbonensis var. josamyceticus. Macrolides are inhibitors of protein synthesis. They impair the elongation cycle of the peptidyl chain by specifically binding to the 50S subunit of the ribosome. Josamycin has antimicrobial activity against a wide spectrum of pathogens. It is similar to erythromycin, but does not induce macrolide resistance in staphylococci and appears to have a lower incidence of gastrointestinal side effects. Josamycin is under investigation in US.

Aldosterone is a hormone secreted by the adrenal cortex that regulates electrolyte and water balance by increasing the renal retention of sodium and the excretion of potassium. Recent findings have shown that the physiological functions of the hormone aldosterone go far beyond its well-known role in blood-pressure regulation and salt/water homeostasis. Aldosterone is for example involved in the regulation of inflammation, and also binds directly to mineralocorticoid receptors in specific brain regions. At the late distal tubule and collecting duct, aldosterone has two main actions: 1) aldosterone acts on mineralocorticoid receptors (MR) on principal cells in the distal tubule of the kidney nephron, increasing the permeability of their apical (luminal) membrane to potassium and sodium and activates their basolateral Na+/K+ pumps, stimulating ATP hydrolysis leading to phosphorylation of the pump and a conformational change in the pump exposes the Na+ ions to the outside. The phosphorylated form of the pump has a low affinity for Na+ ions, hence reabsorbing sodium (Na+) ions and water into the blood, and secreting potassium (K+) ions into the urine; 2) aldosterone stimulates H+ secretion by intercalated cells in the collecting duct, regulating plasma bicarbonate (HCO3−) levels and its acid/base balance; and 3) aldosterone may act on the central nervous system via the posterior pituitary gland to release vasopressin (ADH) which serves to conserve water by direct actions on renal tubular resorption.