Istradefylline is a first-in-class adenosine A2A receptor antagonist antiparkinsonian agent and has been marketed as the brand name NOURIAST® in Japan since May 30, 2013. NOURIAST is indicated for the improvement of wearing-off phenomena in patients with Parkinson’s disease on concomitant treatment with levodopa-containing products.

Alpelisib (BYL719) is a PI3Kα-selective inhibitor. PI3K-AKT-mTOR pathway is frequently activated in cancer, therefore investigational PI3K inhibitor alpelisib is considered to be effective as an anticancer agent and has been in clinical development by Novartis. Alpelisib have demonstrated activity in preclinical models of solid tumors and had favorable tolerability profiles, with the most common adverse events consistent with “on-target” inhibition of PI3K in early clinical studies. There are ongoing clinical trials of alpelisib in a range of cancer types, including breast cancer, head and neck squamous cell carcinoma, non-small cell lung carcinoma, lymphoma, and glioblastoma multiforme. Combination therapy with other chemo therapeutics may be preferable.

Uridine triacetate is used to treat an overdose of capecitabine or fluorouracil. In addition, it is used as a pyrimidine analog for uridine replacement indicated for the treatment of hereditary orotic aciduria. Following oral administration, uridine triacetate is deacetylated by nonspecific esterases present throughout the body, yielding uridine in the circulation. Uridine competitively inhibits cell damage and cell death caused by fluorouracil. Uridine can be used by essentially all cells to make uridine nucleotides, compensating for the genetic deficiency in synthesis in patients with hereditary orotic aciduria. When intracellular uridine nucleotides are restored into the normal range, overproduction of orotic acid is reduced by feedback inhibition, so that urinary excretion of orotic acid is also reduced. Adverse reactions occurring in >2% of patients receiving uridine triacetate included vomiting, nausea, and diarrhea. In vitro data showed that uridine triacetate was a weak substrate for P-glycoprotein. Due to the potential for high local (gut) concentrations of the drug after dosing, the interaction of uridine triacetate with orally administered P-gp substrate drugs cannot be ruled out.

Regadenoson (Lexiscan), a low affinity agonist of the A2A adenosine receptor, increases coronary blood flow (CBF) and mimics the increase in CBF caused by exercise. Myocardial uptake of the radiopharmaceutical is proportional to CBF creating the contrast required to identify stenotic coronary arteries. It is a pharmacologic stress agent indicated for radionuclide myocardial perfusion imaging (MPI) in patients unable to undergo adequate exercise stress. The most common adverse reactions to Lexiscan are dyspnea, headache, flushing, chest discomfort, dizziness, angina pectoris, chest pain, and nausea. Methylxanthines, e.g., caffeine and theophylline, may interfere with the activity of Lexiscan. Aminophylline may be used to attenuate severe and/or persistent adverse reactions to Lexiscan.

Pemetrexed is a new-generation antifolate, approved for the treatment of mesothelioma and non-small cell lung cancer, currently being evaluated for the treatment of a variety of other solid tumors. Pemetrexed, is a folate analog metabolic inhibitor that exerts its action by disrupting folate-dependent metabolic processes essential for cell replication. In vitro studies have shown that pemetrexed inhibits thymidylate synthase (TS), dihydrofolate reductase (DHFR), glycinamide ribonucleotide formyltransferase (GARFT) and and to a lesser extent aminoimidazole carboxamide ribonucleotide formyltransferase (AICARFT), which are folate-dependent enzymes involved in the de novo biosynthesis of thymidine and purine nucleotides. Pemetrexed is taken into cells by membrane carriers such as the reduced folate carrier and membrane folate binding protein transport systems. Once in the cell, pemetrexed is converted to polyglutamate forms by the enzyme folylpolyglutamate synthetase. The polyglutamate forms are retained in cells and are inhibitors of TS and GARFT. Polyglutamation is a time- and concentration-dependent process that occurs in tumor cells and, is thought to occur to a lesser extent, in normal tissues. Polyglutamated metabolites are thought to have an increased intracellular half-life resulting in prolonged drug action in malignant cells.

Since its discovery as component of the tea leaf by Albert Kossel in 1888, the history of theophylline (CAS 58-55-9) has been a long and successful one. At the turn of the century, theophylline became less expensive due to chemical synthesis and was primarily used as diuretic in subsequent years. It was Samuel Hirsch who discovered the bronchospasmolytic effect of theophylline in 1992, however, despite this pioneering discovery theophylline continued to be used primarily as diuretic and cardiac remedy. The molecular mechanism of bronchodilatation is inhibition of phosphodiesterase(PDE)3 and PDE4, but the anti-inflammatory effect may be due to histone deacetylase (HDAC) activation, resulting in switching off of activated inflammatory genes. Theophylline is indicated for the treatment of acute exacerbations of the symptoms and reversible airflow obstruction associated with asthma and other chronic lung diseases, e.g., emphysema and chronic bronchitis.

Zinc monocarbonate (Zinc Carbonate) is an inorganic salt. In the United States, Zinc Carbonate may be used as an active ingredient in OTC drug products. When used as an active drug ingredient, the established name is Zinc Carbonate. Zinc monocarbonate is generally recognized as safe by FDA. It is used as skin protectant active ingredient. Zinc carbonate was found to retard the degradation of some poly(lactide-co-glycolide) (PLG) microspheres in vivo and in vitro. Adding Zinc Carbonate is essential during the preparation of PLGA microspheres. It can remarkably improve the stability of drugs in the acid microenvironment inside PLGA microspheres.

Caffeine is a methylxanthine alkaloid found in the seeds, nuts, or leaves of a number of plants native to South America and East Asia that is structurally related to adenosine and acts primarily as an adenosine receptor antagonist with psychotropic and anti-inflammatory activities. Upon ingestion, caffeine binds to adenosine receptors in the central nervous system (CNS), which inhibits adenosine binding. This inhibits the adenosine-mediated downregulation of CNS activity; thus, stimulating the activity of the medullary, vagal, vasomotor, and respiratory centers in the brain. The anti-inflammatory effects of caffeine are due the nonselective competitive inhibition of phosphodiesterases. Caffeine is used by mouth or rectally in combination with painkillers (such as aspirin and acetaminophen) and a chemical called ergotamine for treating migraineheadaches. It is also used with painkillers for simple headaches and preventing and treating headaches after epidural anesthesia. Caffeine creams are applied to the skin to reduce redness and itching in dermatitis. Healthcare providers sometimes give caffeine intravenously (by IV) for headache after epidural anesthesia, breathing problems in newborns, and to increase urine flow. In foods, caffeine is used as an ingredient in soft drinks, energy drinks, and other beverages.

Neladenoson bialanate (BAY1067197) is the first oral partial and highly selective A1R agonist that has entered clinical development for the treatment of heart failure. Neladenoson bialanate maintains the cardioprotective effects of adenosine without the undesired side effects of a full agonist. Of particular importance in this clinical development is the potential influence of concomitant use of β-blockers as they have the potential to increase the risk of AV conduction abnormalities with A1R agonist treatment. Two small phase 2a pilot studies evaluating the short-term safety of neladenoson bialanate in patients with HFrEF pretreated with β-blockers have recently completed, and the results are pending (ClinicalTrials.gov identifiers: NCT02040233 and NCT01945606). In a small phase 1 trial in healthy volunteers pretreated with the β-blocker metoprolol succinate, a single 50 mg oral dose of neladenoson bialanate administered together with metaprolol succinate was found to be well tolerated. Notably, no higher degree AV block, prolongation of the PR interval, or relevant decreases in heart rate or systemic blood pressure were observed.

Binodenoson, a selective adenosine A(2A) receptor agonist, was being developed as a short-acting coronary vasodilator as an adjunct to radiotracers for use in myocardial stress imaging. Binodenoson for injection under the brand name CorVue was developed for use in patients with or at risk for coronary artery disease (CAD) who are unable to perform a cardiac exercise stress test. CorVue was designed to minimize side effects such as dyspnea, flushing, heart block, and chest pain. Binodenoson did not achieve FDA approval in 2009 due to concerns over equivalence of its efficacy with adenosine.