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Showing 241 - 250 of 55039 results

Ropivacaine is a member of the amino amide class of local anesthetics and is supplied as the pure S-(-)-enantiomer. It produces effects similar to other local anesthetics via reversible inhibition of sodium ion influx in nerve fibers. Ropivacaine is less lipophilic than bupivacaine and is less likely to penetrate large myelinated motor fibers, resulting in a relatively reduced motor blockade. Thus, ropivacaine has a greater degree of motor-sensory differentiation, which could be useful when the motor blockade is undesirable. The reduced lipophilicity is also associated with decreased potential for central nervous system toxicity and cardiotoxicity. Ropivacaine is indicated for the production of local or regional anesthesia for surgery and for acute pain management.
Tizanidine is a short-acting drug for the management of spasticity. Tizanidine is an agonist at a2-adrenergic receptor sites and presumably reduces spasticity by increasing presynaptic inhibition of motor neurons. In animal models, tizanidine has no direct effect on skeletal muscle fibers or the neuromuscular junction, and no major effect on monosynaptic spinal reflexes. The effects of tizanidine are greatest on polysynaptic pathways. The overall effect of these actions is thought to reduce facilitation of spinal motor neurons. Side effects include dizziness, drowsiness, weakness, nervousness, hallucinations, depression, vomiting, dry mouth, constipation, diarrhea, stomach pain, heartburn, increased muscle spasms, back pain, rash, sweating, and a tingling sensation in the arms, legs, hands, and feet.
Olanzapine is a novel antipsychotic agent marketed by Lilly & Co. It has a pleotrophic pharmacology and affects dopaminergic, serotonergic, muscarinic and adrenergic activities. Olanzapine is used to treat the symptoms of psychotic conditions such as schizophrenia and bipolar disorder (manic depression) in adults and children who are at least 13 years old. Olanzapine is sometimes used together with other antipsychotic medications or antidepressants. The mechanism of action of olanzapine, as with other drugs having efficacy in schizophrenia, is unknown. However, it has been proposed that this drug’s efficacy in schizophrenia is mediated through a combination of dopamine and serotonin type 2 (5HT2) antagonism. The mechanism of action of olanzapine in the treatment of acute manic or mixed episodes associated with bipolar I disorder is unknown. Olanzapine treatment led to rapid phosphorylation of kinases from all three pathways in PC12 cells. Phosphorylation of Akt was blocked with selective inhibitors (wortmannin and LY294002), which implicates phosphoinositide 3-kinase (PI3K) in the signaling cascade. Short-term mitogenic effects of olanzapine were abolished with a selective inhibitor of Akt, but not by inhibition of the ERK pathway. Olanzapine is metabolized by the cytochrome P450 system; principally by isozyme 1A2 and to a lesser extent by 2D6. By these mechanisms more than 40% of the oral dose, on average, is removed by the hepatic first-pass effect. Drugs or agents that increase the activity of CYP1A2, notably tobacco smoke, may significantly increase hepatic first-pass clearance of Olanzapine; conversely, drugs which inhibit 1A2 activity (examples: Ciprofloxacin, Fluvoxamine) may reduce Olanzapine clearance. The most common side effects appear to be somnolence and weight gain. About 11% of patients gain weight -especially if on a high starting dose and if they were underweight pre-treatment. Sexual dysfunction is a problem for many patients, although sexual dysfunction in schizophrneia does not appear to be primarily attributable to drugs.
There is no information in the literature about pharmacological and biological application of definite isomer of valsatran, R – form (also known as VALSARTAN, D- or CGP-49309). However there were found, that in the tablets of valsartan, which are used to treat high blood pressure and to heart failure, the R-enantiomer was an impurity.
Ritonavir is a protease inhibitor with activity against Human Immunodeficiency Virus Type 1 (HIV-1). Ritonavir binds to the protease active site and inhibits the activity of the enzyme. It is FDA approved for the treatment of HIV-1 infection. In patients receiving medications metabolized by CYP3A or initiation of medications metabolized by CYP3A in patients already receiving Ritonavir, may increase plasma concentrations of medications metabolized by CYP3A. The most frequently reported adverse drug reactions among patients receiving Ritonavir alone or in combination with other antiretroviral drugs were gastrointestinal (including diarrhea, nausea, vomiting, abdominal pain (upper and lower)), neurological disturbances (including paresthesia and oral paresthesia), rash, and fatigue/asthenia.
Topotecan, a semi-synthetic derivative of camptothecin (a plant alkaloid obtained from the Camptotheca acuminata tree), is an anti-tumor drug with topoisomerase I-inhibitory activity similar to irinotecan. DNA topoisomerases are enzymes in the cell nucleus that regulate DNA topology (3-dimensional conformation) and facilitate nuclear processes such as DNA replication, recombination, and repair. During these processes, DNA topoisomerase I creates reversible single-stranded breaks in double-stranded DNA, allowing intact single DNA strands to pass through the break and relieve the topologic constraints inherent in supercoiled DNA. The 3'-DNA terminus of the broken DNA strand binds covalently with the topoisomerase enzyme to form a catalytic intermediate called a cleavable complex. After DNA is sufficiently relaxed and the strand passage reaction is complete, DNA topoisomerase reattaches the broken DNA strands to form the unaltered topoisomers that allow transcription to proceed. Topotecan interferes with the growth of cancer cells, which are eventually destroyed. Since the growth of normal cells can be affected by the medicine, other effects may also occur. Unlike irinotecan, topotecan is found predominantly in the inactive carboxylate form at neutral pH and it is not a prodrug. Topotecan has the same mechanism of action as irinotecan and is believed to exert its cytotoxic effects during the S-phase of DNA synthesis. Topoisomerase I relieves torsional strain in DNA by inducing reversible single strand breaks. Topotecan binds to the topoisomerase I-DNA complex and prevents religation of these single strand breaks. This ternary complex interferes with the moving replication fork, which leads to the induction of replication arrest and lethal double-stranded breaks in DNA. As mammalian cells cannot efficiently repair these double strand breaks, the formation of this ternary complex eventually leads to apoptosis (programmed cell death). Topotecan mimics a DNA base pair and binds at the site of DNA cleavage by intercalating between the upstream (−1) and downstream (+1) base pairs. Intercalation displaces the downstream DNA, thus preventing religation of the cleaved strand. By specifically binding to the enzyme–substrate complex, Topotecan acts as an uncompetitive inhibitor. Topotecan is used for the treatment of advanced ovarian cancer in patients with disease that has recurred or progressed following therapy with platinum-based regimens. Also used as a second-line therapy for treatment-sensitive small cell lung cancer, as well as in combination with cisplatin for the treatment of stage IV-B, recurrent, or persistent cervical cancer not amenable to curative treatment with surgery and/or radiation therapy. Topotecan is sold under the trade name Hycamtin.

Class (Stereo):
CHEMICAL (RACEMIC)



Donepezil, marketed under the trade name Aricept, is a medication used in the palliative treatment of Alzheimer's disease. Aricept is indicated for the treatment of dementia of the Alzheimer’s type. Efficacy has been demonstrated in patients with mild to moderate Alzheimer’s Disease, as well as in patients with severe Alzheimer’s Disease. Donepezil is postulated to exert its therapeutic effect by enhancing cholinergic function. This is accomplished by increasing the concentration of acetylcholine through reversible inhibition of its hydrolysis by acetylcholinesterase. Donepezil has been tested in other cognitive disorders including Lewy body dementia and Vascular dementia, but it is not currently approved for these indications. Donepezil has also been studied in patients with Mild Cognitive Impairment, schizophrenia, attention deficit disorder, post-coronary bypass cognitive impairment, cognitive impairment associated with multiple sclerosis, and Down syndrome.
Docetaxel was protected by patents (U.S. patent and European patent) which were owned by Sanofi-Aventis, and so was available only under the Taxotere brand name internationally. The European patent expired in 2010. Docetaxel is a clinically well-established anti-mitotic chemotherapy medication used for the treatment of patients with locally advanced or metastatic breast cancer after failure of prior chemotherapy. Also used as a single agent in the treatment of patients with locally advanced or metastatic non-small cell lung cancer after failure of prior platinum-based chemotherapy. It is also used in combination with prednisone, in the treatment of patients with androgen independent (hormone refractory) metastatic prostate cancer. Furthermore, docetaxel has uses in the treatment of gastric adenocarcinoma and head and neck cancer. Docetaxel interferes with the normal function of microtubule growth. Whereas drugs like colchicine cause the depolymerization of microtubules in vivo, docetaxel arrests their function by having the opposite effect; it hyper-stabilizes their structure. This destroys the cell's ability to use its cytoskeleton in a flexible manner. Specifically, docetaxel binds to the β-subunit of tubulin. Tubulin is the "building block" of mictotubules, and the binding of docetaxel locks these building blocks in place. The resulting microtubule/docetaxel complex does not have the ability to disassemble. This adversely affects cell function because the shortening and lengthening of microtubules (termed dynamic instability) is necessary for their function as a transportation highway for the cell. Chromosomes, for example, rely upon this property of microtubules during mitosis. Further research has indicated that docetaxel induces programmed cell death (apoptosis) in cancer cells by binding to an apoptosis stopping protein called Bcl-2 (B-cell leukemia 2) and thus arresting its function.
Sodium phenylbutyrate is a salt of an aromatic fatty acid. The compound is used to treat urea cycle disorders, because its metabolites offer an alternative pathway to the urea cycle to allow excretion of excess nitrogen. Sodium phenylbutyrate is also a histone deacetylase inhibitor and chemical chaperone, leading respectively to research into its use as an anti-cancer agent and in protein misfolding diseases such as cystic fibrosis. It is used as adjunctive therapy for the management of chronic urea cycle disorders due to deficiencies in carbamylphosphate (CPS), ornithine transcarbamylase (OTC), or argininosuccinic acid synthetase. It is indicated in all neonatal- onset efficiency presenting within the first 28 days of life. Also indicated in patients with late-onset, presenting after the first month of life with a history of hyperammonemic encephalopathy. Sodium phenylbutyrate is a pro-drug and is rapidly metabolized to phenylacetate. Phenylacetate is a metabolically active compound that conjugates with glutamine via acetylation to form phenylacetylglutamine. The kidneys then excrete Phenylacetylglutamine. PBA (phenylbutyric acid) is absorbed from the intestine and converted by way of β-oxidation to the active moiety, phenylacetic acid (PAA). PAA is conjugated with glutamine in the liver and kidney by way of N-acyl coenzyme A-l-glutamine N-acyltransferase to form phenylacetylglutamine (PAGN). Like urea, PAGN incorporates two waste nitrogens and is excreted in the urine. On a molar basis, it is comparable to urea (each containing two moles of nitrogen). Therefore, phenylacetylglutamine provides an alternate vehicle for waste nitrogen excretion.