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Biomedical subjects

P U Nwangwu

Publications and source records attributed to P U Nwangwu.

9 recordsLinked to original sources
PubMed1983

Perspectives on digoxin absorption from small bowel resections.

Digoxin is a commonly prescribed medication for a variety of cardiovascular abnormalities. The therapeutic index of digoxin is considered narrow and drug is absorbed predominantly from the duodenum and upper jejunum. When the small intestine is intact, the absorption can vary; therefore, in the case of a small bowel resection or bypass, this erratic absorption may be accentuated. There is some controversy concerning the effect of small bowel resection or bypass on the absorption of digoxin. Some investigators have shown that small bowel resection or bypass decreases the absorption of oral digoxin, whereas others report no change in absorption. When the study methodologies were evaluated, certain common factors that support each view were found. In most studies reporting malabsorption, a solid dosage form of digoxin was used. Studies reporting no change in absorption investigated a solution dosage form.

Biological Availability↗
PubMed1982

Legal aspects of clinical pharmacy practice.

Recent trends in pharmacy have emphasized the concept of a more clinical professional role and a new level of skilled practice for pharmacists. These new roles and responsibilities create a number of legal questions concerning the clinical activities pharmacists can legally perform, and the liabilities pharmacists must bear in the performance or negligence of these duties. The law is not completely clear on all aspects of clinical pharmacy practice. This paper explores the legal basis of certain specific functions performed by pharmacists, and the inherent liabilities involved in the performance of these functions.

Clinical Competence↗
PubMed1980

A comparative study on the antiarrhythmic activity and acute toxicity of quinidine and four new analogs in mice.

We have compared the ED50 value for antiarrhythmic activity and the acute toxicities in mice of quinidine and 4 recently synthesized analogs. For the ED50 studies, groups of mice were treated intravenously with equally spaced logarithmic doses of 6'-methoxycinchonine (quinidine), 6'-hydroxycinchonine (cupreidine), 6'-isovaleryloxycinchonine, 6'-acetyloxycinchonine and 6'-benzoyloxycinchonine. For the actue toxicity studies, mice were treated intraperitoneally with quinidine and the 4 analogs. Mice were observed over a 24-h period, and thereafter for each additional 24-h period for a total of 120 h. Tests for parallelism of acute toxicity indicated that with the exception of the 6'-isovaleryloxy derivative the drug treatment regression lines were parallel to that of quinidine (P > 0.05). The results indicated decreases of 50% (843 mumol/kg), 52% (857 mumol/kg), and 61% (910 mumol/kg) in the acute toxicities of the 6'-acetyloxy, 6'-hydroxy, and 6'-benzoyloxycinchonine, respectively. The 6'-acetyloxy (18.5 mumol/kg) and 6'-benzoyloxy (14.6 mumol/kg) derivatives had significantly lower ED50 values than quinidine (60.1 mumol/kg). The results suggest that the 6'-acetyloxy and 6'-benzoyloxy derivatives may have much greater antiarrhythmic effectiveness than quinidine.

Aconitine↗
PubMed1979

Partial synthesis of 6'-hydroxycinchonine and its antiarrhythmic activity in mice.

The synthesis of 6'-hydroxycinchonine [8R,9S)-cinchonan-6',9-diol] was achieved by demethylating quinidine with boron tribromide in dichloromethane at -75 degrees C. The antiarrhythmic activities of 6'-hydroxycinchonine and quinidine were compared following the infusion of aconitine into the tail veins of mice to induce arrhythmias. Comparative ED50 and LD50 studies for quinidine and 6'-hydroxycinchonine revealed equivalent antiarrhythmic potencies for the two drugs but a smaller acute toxicity for 6'-hydroxycinchonine.

Aconitine↗
PubMed1977

A rapid in vivo technique for preliminary screening of antiarrhythmic agents in mice.

The search for new and better antiarrhythmic agents is complicated by the fact that currently there is no generally accepted, rapid, highly reproducible, in vivo screening technique which allows the use of large numbers of small animals for the purpose of statistical evaluation. Most of the methods available for use with small animals employ visual observation of the animal to assess electrophysiological events occurring in the heart. A rapid, inexpensive, in vivo screening technique is discribed, using aconitine as the arrhythmogenic agent. Arrhythmias induced by aconitine were measured by electrocardiogram (lead II). The times to onset of initial cardiac arrhythmias and ventricular tachycardia were determined and compared for significance in animals pretreated with physiological saline (control group), standard antiarrhythmic agents, and two drugs lacking antiarrhythmic activity. The results indicate that the method is a sensitive, rapid technique for preliminary in vivo screening of antiarrhythmic drugs.

Aconitine↗
PubMedDate not supplied

Hemodynamic properties of a new quinidine analog, cupreidine (6'-hydroxycinchonine).

Cupreidine 96'-hydroxycinchonine) is a recently synthesized analog of quinidine (6'-methoxycinchonine). Previous studies in mice have shown that quinidine and cupreidine have equivalent antiarrhythmic potencies, whereas the acute toxicity of cupreidine is about 50% less than that of quinidine. Many of the serious adverse effects of quinidine are due to undesirable cardiovascular properties. We have, therefore, compared the effects of the two drugs on blood pressure, heart rate, and peripheral vasodilation in rats, and on myocardial contractility in isolated rabbit hearts at a series of comparable doses. Quinidine produces a more marked bradycardia and depression of blood pressure than does cupreidine. The vasodilation produced by intraarterial administration of quinidine was significantly greater than cupreidine. Furthermore, quinidine elicited a greater negative inotropic effect. Cupreidine exhibited a much more favorable hemodynamic profile than quinidine with regard to the properties that were examined. These results, coupled with the fact that cupreidine has significant antiarrhythmic activity and a lower acute toxicity profile, suggest that this drug may be useful in the therapy of cardiac arrhythmias.

Animals↗