Selegiline HCl is a levo-rotatory acetyl-enic derivative of phenthylamine. It is chemically designated as (-)-(R)-N, a-dimethyl-N-2-propynylphenethyl-amine HCl. Its empirical formula is C₁₃H₁₇N • HCl, and its molecular weight is 223.75. Figure 1 illustrates the agent’s chemical structure.

This white to almost-white crystalline powder is supplied as a pale yellow tablet containing 1.25 mg of generic selegiline HCl. Each lyophilized orally disintegrating tablet contains the following inactive ingredients: gelatin, mannitol, glycine, as-partame, citric acid, yellow iron oxide, and grapefruit flavor.

Because of the progression of PD over time and because of the effect of sustained levodopa treatment, the efficacy and quality of levodopa diminish. Selegiline is a selective inhibitor of MAO-B. Intestinal MAO is predominantly type A (MAO-A), and most MAO in the brain is type B (MAO-B). In the CNS, MAO plays an important role in the catabolism of serotonin and certain catecholamines, such as dopamine and norepinephrine. By blocking this catabolism of dopamine, selegiline increases the net amount of dopamine available. Kamagra Oral Jelly

PHARMACOKINETICS

Selegiline orally disintegrating tablets (selegiline ODT, Zelapar) dissolve within seconds after they are placed on the tongue. They are rapidly absorbed, and detectable levels of selegiline can be measured five minutes after administration. The formulation results in pre-gastric selegiline absorption and the avoidance of first-pass metabolism, resulting in higher selegiline and lower metabolite concentrations, compared with conventional selegiline tablets that are swallowed. The relative bioavailabil-ity of selegiline ODT is greater than that of the swallowed formulation.

The maximum time to concentration (T_max) for selegiline ODT ranges from 10 to 15 minutes; the T_max for conventional selegiline tablets ranges from 40 to 90 minutes. Mean plasma concentrations reached after a single dose of selegiline ODT 1.25 mg and 2.5 mg are 3.34 and 4.47 ng/mL, respectively, compared with 1.12 mg/mL for the swallowed selegiline tablets (given as 5 mg twice daily).
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Food intake decreases the drug’s peak concentration (C_max) and its area-under-the-curve (AUC) concentration by 60%, in contrast to when the drug is given with the patient fasting. Intake of foods and liquids should be avoided by at least five minutes before and after Zelapar is administered.

The half-life of the 1.25-mg tablet after a single-dose ad­ministration is 1.3 hours and increases to 10 hours after steady state is reached. Steady state is usually achieved after eight days.

Selegiline ODT produces active amphetamine metabolites (N-desmethyl selegiline, L-amphetamine, and L-meth-amphetamine) to a lesser degree than conventional selegiline tablets. These metabolites are subsequently metabolized and converted to their hydroxy-metabolites.

Selegiline ODT is metabolized via the cytochrome CYP 2B6 and CYP 3A4 pathways. It is believed that the CYP 2A6 pathway plays a minor role in the drug’s metabolism as well. Following hepatic metabolism, the drug is excreted primarily in the urine. canadian pharmacy cialis