Factors influencing the absorption of oxprenolol A pharmacokinetic study

Kendall, M. J.; Mitchard, M.; West, MJ; John, VA; Ebbutt, Alan

doi:10.1007/bf03189270

Cited by 17 publications

(7 citation statements)

References 12 publications

(9 reference statements)

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“…The MAT is itself the sum of the mean dissolution time (MDT) in vivo for the Oros system and the mean residence time at the site of absorption. Oxprenolol is rapidly absorbed from an oral solution (Kendall et al, 1976), and for the present study MAT can be taken as an approximation of MDT.…”

Section: Discussionmentioning

confidence: 99%

“…The area under the plasma drug concentration-time curve (AUC) was estimated by the trapezoidal rule. The AUC for oxprenolol is proportional to the dose administered (Kendall et al, 1976;Mason & Winer, 1976). Consequently, the absolute bioavailability of oxprenolol following administration of the 16/260 Oros system was calculated from the ratio fo the dose normalised AUC values following the Oros system and i.v.…”

Section: Discussionmentioning

confidence: 99%

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Relationship between the rate of appearance of oxprenolol in the systemic circulation and the location of an oxprenolol Oros 16/260 drug delivery system within the gastrointestinal tract as determined by scintigraphy.

Davis

Washington

et al. 1988

Brit J Clinical Pharma

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1. The position in the gastrointestinal tract of an orally administered oxprenolol Oros drug delivery system labelled with technetium‐99m DTPA was followed by gamma scintigraphy, and the corresponding plasma drug concentration‐time profiles after oral and i.v. administration were used to relate pharmacokinetic and transit data. 2. Gastric emptying time (0.8 +/‐ 0.4 h, mean +/‐ s.d.), and the time to arrival in the colon (3.8 +/‐ 0.7 h) were reasonably consistent after administration of the Oros system to fasted subjects, as were the calculated small intestine transit times (3.0 +/‐ 0.7 h). As expected there were wide individual variations in colonic transit, so that recorded values for total transit ranged from 6 to 32 h (median, 24.7 h). 3. Absorption of oxprenolol occurred throughout the GI tract including the colon. Plasma drug concentration‐time profiles and input functions (calculated by deconvolution) could be related to transit behaviour and in vitro release. Inflexions in the calculated rate of drug input when the Oros system was located in the colon corresponded with periods of stagnation at the hepatic and splenic flexures in two subjects and the ileocaecal junction in two others. The mechanism of these changes is unclear.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Relationship between the rate of appearance of oxprenolol in the systemic circulation and the location of an oxprenolol Oros 16/260 drug delivery system within the gastrointestinal tract as determined by scintigraphy.

Davis

Washington

et al. 1988

Brit J Clinical Pharma

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“…The nature and purpose of the study was fully explained to the volunteers and their informed consent was obtained. At this initial visit each volunteer was clinically examined, an electrocardiogram was obtained, and a blood sample was taken for routine biochemical and haematological testing as described in a previous study (6). No abnormalities were found.…”

Section: Experimental Subjectsmentioning

confidence: 99%

Pharmacokinetic and pharmacodynamic studies of single oral doses of metoprolol in normal volunteers

Kendall¹,

Brown²,

Grieve

et al. 1977

European Journal of Drug Metabolism and Pharmacokinetics

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The effects of three orally administered doses of metoprolol, a beta 1 adrenoceptor antagonist, on resting blood pressures, resting pulse rates and heart rates during maximum exercise have been compared with those of placebo in six healthy male volunteers.The differences in blood pressures and pulse rates at rest were small and only statistically significant at isolated time points during the 24 hours study period. The reduction in exercise heart rates reached maximum values at 1.5 to 2 hours after drug administration and thereafter increased linearly with time. The zero-order rate constants for this process were similar for each of the three doses investigated.The mean durations of beta blockade after oral administration of 50,100 and 200 mg. were 13.2,16.9 and 19.2 hours, respectively. An apparent linear relationship between exercise heart rate and logarithm of the drug concentration in plasma was observed for each dose studied.The relationship between area under the plasma concentration curve and dose is statistically compatible with a linear function in the range 50 to 200 mg. The actual areas, however, suggest the possibility of an increased bioavailability for the higher dose.The significance of these results is discussed in relation to the possible use of a single daily dosage regimen in the treatment of angina pectoris and hypertension. IntraductionMetoprolol (Lopresor®, Ciba-Geigy) is a selective beta-adrenergic receptor blocking drug which has been shown to be effectivein the treatment of angina pectoris (1) and hypertension (2). One of the main problems in the management of these conditions is lack of compliance by patients with long-term oral therapy. Compliance is influenced by a number of factors, including the nature and duration of the illness, the treatment administered, the incidence and severity of drug related side-effects,and the frequency of daily dosage.The incidence of side-effectswith beta-receptor blocking drugs is low and unlikely to reduce compliance. Frequency of dosing, however, appears to be an important determinant (3) and simplification of the dosage Send reprint requests to: regimen could lead to a significantimprovement in overall compliance. Most beta-blocking drugs are recommended to be taken two, three or four times a day depending on the elimination half-life of the drug in plasma. Recent studies (4) (5) with other beta-blocking drugs have shown that effective control of blood pressure can be achieved with once daily dosage regimens. Before recommending a similar regimen for metoprolol it would be desirable to have data comparing the efficacy of different dosage regimens in the treatment of angina and hypertension.In the present study the effects of single oral doses of 50, 100 and 200 mg. metoprolol on resting blood pressures, pulse rate and heart rate during maximum dynamic exercise, were compared with those of placebo in healthy volunteers. The plasma concentration and urinary excretion profiles for the three oral doses of metoprolol were also compared to determine whethe...

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“…The common symptoms reported were: irritability (9 cases), fever (8), missed feeds (7), an altered cry (6), drowsiness (6), and pallor (3).…”

Section: Introductionmentioning

confidence: 99%

Effects of inflammatory disease on plasma oxprenolol concentrations.

Kendall¹,

Quarterman²,

Bishop³

et al. 1979

BMJ

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Factors influencing the absorption of oxprenolol A pharmacokinetic study

Cited by 17 publications

References 12 publications

Relationship between the rate of appearance of oxprenolol in the systemic circulation and the location of an oxprenolol Oros 16/260 drug delivery system within the gastrointestinal tract as determined by scintigraphy.

Relationship between the rate of appearance of oxprenolol in the systemic circulation and the location of an oxprenolol Oros 16/260 drug delivery system within the gastrointestinal tract as determined by scintigraphy.

Pharmacokinetic and pharmacodynamic studies of single oral doses of metoprolol in normal volunteers

Effects of inflammatory disease on plasma oxprenolol concentrations.

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