Occurs as fine, needle-like, white crystals which frequently cohere in masses or as a fine, white powder.
味道：
Very bitter taste
溶解度：
Slightly sol in water and soluble in alcohol.
稳定性/保质期：
Quinidine gluconate, quinidine polygalacturonate, and quinidine sulfate darken on exposure to light and should be stored in well closed, light-resistant containers. Solutions of quinidine salts slowly acquire a brownish tint on exposure to light. Only colorless, clear solutions of quinidine gluconate injection should be used. Quinidine gluconate injection should be stored at 15-30 °C. When diluted to a concentration of 16 mg/ml with 5% dextrose injection, quinidine gluconate injection is stable for 24 hr at room temperature and up to 48 hr when refrigerated. /Quindine salts/
分解：
When heated to decomposition it emits very toxic fumes of /nitrogen oxides and sulfur oxides/.
MOST URINARY METABOLITES ARE HYDROXYLATED AT ONLY ONE SITE, EITHER ON THE QUINOLINE RING OR ON THE QUINUCLIDINE RING; SMALL AMOUNTS OF DIHYDROXY COMPOUNDS ARE ALSO FOUND. THE FRACTION OF A DOSE OF QUINIDINE THAT IS METABOLIZED & THE METABOLIC PATHWAY APPEAR TO VARY CONSIDERABLY FROM PATIENT TO PATIENT.
Quinidine is metabolized in the liver, principally via hydroxylation to 3-hydroxyquinidine and 2-quinidinone. The metabolites may be pharmacologically active. Approximately 10-50% of a dose is excreted in urine (probably by glomerular filtration) as unchanged drug within 24 hr. /Quinidine/
IDENTIFICATION: Quinidine is a class lA antiarrhythmic drug. Origin of the substance: Quinidine is the d- isomer of quinine. Quinidine is an alkaloid that may be derived from various species of Cinchona. Cinchona barks contain 0.25 to 3.0% quinidine. Quinidine is also prepared from quinine. Quinidine is a powder or white crystals, odorless with a bitter taste. Quinidine bisulfate is colorless crystals which is odorless and has a bitter taste. Quinidine gluconate is a white powder which is odorless and has a bitter taste. Quinidine poly-galacturonate is a powder. Quinidine sulfate is a white powder or odorless crystals with a bitter taste. Indications: Description: Premature ventricular extrasystoles and ventricular tachycardia; supraventricular arrhythmia; maintenance of sinus rhythm after cardioversion of atrial flutter or fibrillation. HUMAN EXPOSURE: Main risks and target organs: Cardio-toxicity is the main risk of quinidine poisoning. Quinidine may induce central nervous system symptoms. Summary of clinical effects: Toxic effects appear within 2 - 4 hours after ingestion but the delay may vary according to the quinidine salt and to the preparation forms. Symptoms may include disturbances of cardiac rhythm (especially in patients with underlying cardiovascular disease), neurotoxicity and respiratory depression. Diagnosis: Cardiac disturbances: circulatory arrest, shock, conduction disturbances, ventricular arrhythmias, ECG changes, Neurological symptoms: tinnitus, drowsiness, syncope, coma, convulsions, delirium. Respiratory depression. Quinidine concentrations may be helpful in diagnosis but are not useful for clinical management. Contraindications: Allergy or idiosyncrasy to cinchona alkaloids; atrioventricular or complete heart block; intraventricular conduction defects; absence of atrial activity; digitalis intoxication; myasthenia gravis and ventricular dysrhythmia of the torsades de pointes type Precautions include the following: Congestive heart failure, hypotension, renal disease, hepatic failure; concurrent use of other antiarhythmic drugs; old age and breast-feeding. Routes of entry: Oral: Oral absorption is the most frequent cause of intoxication. Parenteral: Intoxication after IV administration is rare but has been reported in patients treated with IV quinidine for cardiac dysrhythmia. Absorption by route of exposure: Oral: Quinidine is almost completely absorbed from the gastrointestinal tract. However, because of hepatic first-pass effect, the absolute bioavailability is about 70 to 80% of the ingested dose and may vary between patients and preparations. The time to plasma peak concentration is 1 to 3 hours for quinidine sulfate, 3 to 6 hours for quinidine gluconate and about 6 hours for quinidine polygalacturonate. Sustained-release quinidine is absorbed continuously over 8 to 12 hours. Parenteral: Absorption of quinidine after intramuscular injection may be erratic and unpredictable with incomplete absorption of the administered dose, probably due to precipitation of drug at the site of injection. Other studies indicate no difference between the rate of quinidine absorption when given by intramuscular injection or oral absorption. Distribution by route of exposure: Oral: Protein binding: About 70 to 80% of the drug is bound to plasma protein. Plasma protein binding is decreased in patients with chronic liver disease. Tissue: Quinidine concentrations in liver are 10 to 30 times higher than those in plasma. Skeletal and cardiac muscle, brain and other tissues contain intermediate amounts. The red cell plasma partition ratio is 0.82. Biological half-life by route of exposure: Elimination half-life: The half-life is about 6 to 7 hours. It is increased in chronic liver disease and in the elderly. It does not appear to be altered in congestive heart failure or renal failure. Metabolism: 50 to 90% of quinidine is metabol
