PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “BIOPHARMACEUTICS”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,567 records · Page 87Linked to original sources
PubMed1975

Pharmacokinetics of procainamide intravenously and orally as conventional and slow-release tablets.

Pharmacokinetics of procainamide were studied in healthy volunteers after single doses intravenously and orally as conventional and slow-release tablets and after repeated oral doses to steady state. The initial distribution after intravenous administration was rapid and the overall elimination in the beta-phase corresponded to t1/2 of 2.7 hr. The mean volume of the central compartment was small and only 4 percent of V-d (beta), which was 2.3 l/kg body weight. About 65 percent was excreted unchanged after intravenous administration and about 55 percent after a single oral dose of 500 mg. The recovery of the metabolite N-acetylprocainamide was 12 percent after both routes of administration. Procainamide was completely absorbed from the gastrointestinal tract and the first-pass elimination was very limited. The rates of absorption from the tablet compositions were well correlated to the in vitro dissolution properties. Administration of slow-release tablets every 8 hr gave about the same mean plasma level at steady state as ordinary tablets given every 4 hr, and the availability was the same from both preparations. The occasional high plasma concentration peaks after ordinary tablets were not observed after the slow-release tablets. Renal clearance was about 500 ml/min, indicating an active secretion in the tubules.

Acetylation↗
PubMed1977

Absorption and metabolism of lanatoside C. II. Fate after oral administration.

The absorption, metabolism, and excretion of lanatoside C were studied in hospitalized subjects following oral administration of the tritiated drug. Previous reports of an unusual double peak in plasma levels of radioactivity were confirmed. Fifty plasma samples taken from 31 patients showed that an average of 74% of the radioactive material was digoxin and its metabolites. There was little or no lanatoside C in 36 of the 50 samples of plasma. Similar results were obtained for urine radioactivity. The results confirm that lanatoside C is converted to "digoxin" in the gut prior to absorption as previously proposed by us. "Digoxin" refers to digoxin and its breakdown products, namely, digoxigenin and its mono- and didigitoxosides. According to these proposals, the conversion to "digoxin" takes place partly as a result of acid hydrolysis in the gut and partly by the action of bacteria in the intestine. The effects of concurrent administration of antacid therapy, anticholinergic therapy, and food on the fate of oral lanatoside C were separately studied. There were no significant differences between groups with respect to the amount of radioactive material absorbed or excreted, but there were marked qualitative differences in the plasma profiles. There was a statistically significant increase in the time to the first peak in plasma radioactivity in patients concurrently receiving either food or anticholinergic therapy and there was a significant decrease in the relative height of the first peak in patients treated concurrently with antacid.

Administration, Oral↗
PubMed1977

Disposition of pirprofen, a new anti-inflammatory drug.

Plasma and urine concentrations of 2-(3-chloro-4[3-pyrrolinyl]phenyl) propionic acid, pirprofen, a new nonsteroidal anti-inflammatory compound, are described for normal male volunteers receiving one or more doses of the drug. Orally administered pirprofen is rapidly and almost completely absorbed from the gastrointestinal tract, resulting in maximum plasma levels in 1 to 2 hr. Mean peak levels are 23 microng/ml after an oral pirprofen dose of 200 mg; lower doses given proportionally lower levels. Administration 1 hr after a meal slightly delays the peak plasma level, but the extent of absorption is not affected significantly. Administration of pirprofen, 150 mg, 4 times daily, or 200 mg, 3 times daily, results in nearly identical plasma levels at steady-state. Pirprofen has an apparent elimination half-life of about 7 hr. The results obtained from a 200-mg pirprofen-14C dose indicate that excretion of the drug occurs primarily by the renal route in the form of metabolites and is essentially complete within 24 hr. In urine, less than 5% of the administered dose is accounted for as unchanged drug.

Adolescent↗
PubMed1977

Protriptyline plasma levels and antidepressant response.

Twenty-one depressed outpatients were treated for 4 wk with 20 mg/day of protriptyline. Protriptyline plasma in individuals after 4 wk ranged from 22 ng/ml to 167 ng/ml. There was a negative correlation (-0.50, less than 0.05) between the severity of depression measured by the Hamilton Rating Scale (HRS) and the wk 4 protriptyline concentration. Patients with plasma levels above 70 ng/ml (wk 4) had better outcomes measured by the HRS (p less than 0.05) and the Zung Self-Rating Depression Scale (p less than 0.05) and had greater percent decreases on both scales (p less than 0.05) during treatment than those with lower plasma levels. An upper limit to the therapeutic plasma level range beyond which response to treatment was less satisfactory was not demonstrated in this study.

Adult↗
PubMed1977

Pathophysiologic and pharmacokinetic determinants of the antihypertensive response to propranolol.

The tendency for patients with essential hypertension to differ markedly in antihypertensive response to propranolol could arise from pathophysiologic or pharmacokinetic differences between them. This possibility was investigated in 23 men with mild to moderately severe essential hypertension. At each of three propranolol doses, 40 mg, 80 mg, and 320 mg daily, approximately a 20-fold range in steady-state plasma propranolol concentrations was observed. Clinical response however was unrelated to plasma propranolol: oral dose ratio, since patients with higher plasma levels were less sensitive to the existing plasma drug concentration. When falls in blood pressure and plasma propranolol concentration were compared overall, a biphasic dose-response relationship was noted, with a first component at plasma propranolol concentrations of 3 to 30 ng/ml and a second at concentrations above 30 ng/ml. Only patients with increased sympathetic nervous system activity and high plasma renin activity (PRA) had substantial falls in pressure at propranolol levels of 3 to 30 ng/ml. Cardiac beta adrenergic receptor blockade, not suppression of PRA, seemed to be the antihypertensive mechanism. This relation of pretreatment sympathetic nervous activity and PRA to antihypertensive response existed only at lower plasma propranolol concentrations. With a propranolol dose of 320 mg daily, both plasma norepinephrine concentration and PRA were unrelated to the clinical response.

Adolescent↗
PubMed1977

Effect of antacids on absorption of clorazepate.

The effect of a magnesia and alumina antacid suspension on the absorption of clorazepate dipotassium was studied in 15 normal healthy adult subjects who ingested a 15-mg dose of clorazepate alone or with single or multiple doses of antacid. The results of this three-period randomized complete crossover study showed a trend of initially slower absorption and lower peak nordiazepam plasma levels when administered with the antacid suspension. However, there were no significant differences among treatments in the extent of absorption as measured by the area under the plasma level-time curves. Clorazepate plasma levels were of relatively short duration and similar for all treatments. The urinary excretion pattern was likewise comparable with conjugated oxazepam, the major species measured. Plasma elimination half-lives of nordiazepam and clorazepate were not affected by the antacid treatments.

Adult↗