Effect of Antacid on Bioavailability of a Sustained-Release Theophylline Preparation

1983 ◽  
Vol 17 (7-8) ◽  
pp. 555-557 ◽  
Author(s):  
Lazarus J. Darzentas ◽  
Ronald B. Stewart ◽  
Stephen H. Curry ◽  
Richard L. Yost
Keyword(s):  
Serum Concentration ◽  
Sustained Release ◽  
High Potency ◽  
Time Curve ◽  
Time To Peak ◽  
Sustained Release Theophylline ◽  
Study Interval ◽  
Rate Of Absorption ◽  
Theophylline Absorption ◽  
Tablet Preparation

The effect of coadministration of an antacid on bioavailability of a sustained-release theophylline tablet preparation (Theo-Dur) was studied by crossover comparison in five young, healthy, nonsmoking volunteers. Water 90 ml, or “high potency” aluminum-magnesium hydroxide antacid (Mylanta II) 10 ml and water 80 ml were administered concurrently with sustained-release theophylline 600 mg. Eleven blood samples were collected over the next 24 hours. Serum was analyzed with high pressure liquid chromatography technique to determine theophylline concentration. Peak serum concentration (Cmax) and time to peak concentration (tmax) were determined, and area under the 24-hour serum concentration-time curve (AUC) was calculated by the trapezoidal rule for each subject at each study interval. The Student's paired t-test was used to compare Cmax, tmax, and AUC for both treatments. A uniform difference was found between groups in Cmax. Cmax was higher in subjects when treated with the antacid (10.45 ± 3.03 vs. 8.30 ± 2.90 μg/ml, p < 0.05) than when given theophylline alone. The mean tmax for the two treatments did not differ (10.4 ± 1.67 h—combination vs. 10.8 ± 1.1 h—theophylline, p > 0.05). Likewise, mean AUC was unchanged by the coadministration of antacid (140.65 ± 41.6 μg/ml·h—combination vs. 155.13 ± 46.6 μg/ml·h—theophylline, p > 0.05). The use of a high-potency antacid product did not decrease the extent of theophylline absorption from this sustained-release product, but did increase Cmax and, presumably, rate of absorption. High-potency aluminum-magnesium antacids can probably be used in combination with this sustained-release theophylline tablet without detriment to therapy.

SUBCUTANEOUS AND INTRAVENOUS ADMINISTRATION OF DESMOPRESSIN (DDAVP) TO HEMOPHILIACS: PLASMA PHARMACOKINETICS AND FACTOR VIII (VIII:C) RESPONSES

1987 ◽  
Author(s):  
P M Mannucci ◽  
V Vicente ◽  
I Alberca ◽  
E Sacchi ◽  
A S Harris ◽  
...  
Keyword(s):  
Hemophilia A ◽  
The Body ◽  
Intravenous Route ◽  
Maximum Increase ◽  
Time Curve ◽  
Patient Response ◽  
Routes Of Administration ◽  
Time To Peak ◽  
Rate Of Absorption ◽  
Plasma Pharmacokinetics

Reported studies dealing with the clinical use of DDAVP in mild and moderate hemophilia A patients show a very large between-patient variability for the maximum increase of VIII:C after the drug given intravenously (i.v.) or subcutaneously (s.c.). By measuring DDAVP plasma levels with a sensitive and specific RIA method, we elected to evaluate whether or not between-patient response variability was related to the variability of DDAVP levels achieved in their plasma. To this purpose 14 moderate or mild hemophilic volunteers (baseline VIII : C 4 to 31 U/dL) were randomly given 0.3 pg/Kg of i.v. or s.c. DDAVP with a between-treatment interval of 15 - 30 days. Plasma DDAVP pharmacokinetics in relation to the routes of administration are shown in the table.Pack levels (Cmax) were higher after i.v. DDAVP (p < 0.02). Time to peak levels (tmax) was shorter for i.v. DDAVP (p < 0.001). There was no difference between i.v. and s.c. DDAVP for plasma time curve (AUC) and half-life (t½).The bioavailability of the s.c. route relative to the i.v. route was 85 ° 32%. Of further interest, was the greater variability of the i.v. pharmacokinetics compared to the s.c. data. These differences were reflected in the VIII:C response. Maximum VIII:C increase over baseline levels was 3.2 ° 2.4 fold (i.v.) and 3.2 ° 1.3 fold (s.c.) (n.s.).Thus the i.v. route gave a marginally greater response but the effect was more variable than the s.c. route. Finally, no significant correlation was found between the VIII:C response and plasma DDAVP levels for either route of administration (i.v. route r = 0.03, s.c. route r = 0.23).These findings establish the subcutaneous route to be bioequivalent in effect to the intravenous route with less variation. This study also demonstrates that the VIII:C response to DDAVP is neither a function of the rate of absorption of the corrpound into the body nor the magnitude of the plasma concentration.

scholarly journals The new trends in theophylline therapy

2002 ◽  
Vol 2 (1-2) ◽  
pp. 62-65
Author(s):  
Aida Mehmedagić ◽  
Edina Vranić ◽  
Sabira Hadžović ◽  
Milena Pokrajac ◽  
Jela Milić ◽  
...  
Keyword(s):  
Lung Function ◽  
Serum Concentration ◽  
Sustained Release ◽  
Serum Levels ◽  
Serum Theophylline ◽  
Once Daily ◽  
Asthmatic Patients ◽  
Sustained Release Theophylline ◽  
Evening Administration

Sustained-release theophylline pellets formulation for once-daily evening administration significantly improved patients compliance and adjusted serum levels profile of the drug. The patients conversion from i.v. to p.o. therapy is one of the most critical steps in the treatment of asthma according to its chronopathophysiological character. In our study we have examined safety and efficiency of this conversion in twelve hospitalised asthmatic patients who were given the new sustained-release theophylline pellets formulation for once-daily evening administration. The lung function parameters (FEV1, VC, RV, and Rt) and serum theophylline concentrations were monitored. So, the values obtained for the last day of i.v. therapy and the fifth day of p.o. therapy were compared. We found that 75% of the patients had no change or improved lung function on the conversion. Our results indicate that this conversion from i.v. to p.o. theophylline therapy is safe and could be efficacious. Also, the maximum theophylline serum levels could safely be predicted by measuring only one serum concentration in p.o. therapy with sustained-release theophylline pellets formulation for once-daily evening administration.

The Effects of Charcoal and Sorbitol (Alone and in Combination) on Plasma Theophylline Concentrations after a Sustained-Release Formulation

1990 ◽  
Vol 9 (3) ◽  
pp. 179-182 ◽  
Author(s):  
A.H. Al-Shareef ◽  
D.C. Buss ◽  
E.M. Allen ◽  
P.A. Routledge
Keyword(s):  
Sustained Release ◽  
Slow Release ◽  
Maximum Plasma ◽  
Time Curve ◽  
Release Formulation ◽  
Sustained Release Formulation ◽  
Concentration Time ◽  
Plasma Theophylline ◽  
Healthy Female ◽  
Sustained Release Theophylline

1 The effects of charcoal and sorbitol, alone and in combination, were investigated in eight healthy female volunteers who received 600 mg slow-release theophylline (two 300 mg capsules) . 2 The area under the plasma concentration time curve to 24 h (AUC0-24) after theophylline alone was significantly greater than after both the charcoal and charcoal plus sorbitol phase. 3 Charcoal and charcoal with sorbitol also significantly reduced the maximum plasma theophylline concentration ( Tmax) and time to maximum concentration ( Cmax). 4 Sorbitol significantly increased Cmax and shortened Tmax. 5 Although sorbitol did not reduce the adsorptive efficacy of charcoal, its use alone may be deleterious in poisoning with sustained-release theophylline products.

Prevention of drug absorption in simulated theophylline overdose

1995 ◽  
Vol 14 (2) ◽  
pp. 170-174 ◽  
Author(s):  
Neil A. Minton ◽  
Edward Glucksman ◽  
John A. Henry
Keyword(s):  
Sustained Release ◽  
Healthy Volunteers ◽  
Drug Absorption ◽  
Activated Charcoal ◽  
Gastric Lavage ◽  
First Line ◽  
Sustained Release Theophylline ◽  
The Mean ◽  
Theophylline Absorption ◽  
First Line Treatment

1 The effects of emesis, gastric lavage and oral activated charcoal on theophylline absorption were compared in healthy volunteers. 2 One of four regimes (ipecacuanha-induced emesis, gas tric lavage, oral activated charcoal and no treatment) was randomly chosen one hour after a simulated over dose with sustained-release theophylline on four sepa rate occasions in twelve healthy volunteers. 3 Syrup of ipecacuanha produced emesis in all twelve volunteers but only seven vomited any tablets. Gastric lavage yielded tablets in only one volunteer. 4 The mean systemic availabilities (areas under the con centration-time curves relative to control) of theo phylline for ipecacuanha-induced emesis, gastric lavage and charcoal, were 107.1%, 101.1% and 16.9%, respectively. 5 Oral activated charcoal was thus highly effective, while gastric lavage and emesis were ineffective in pre venting theophylline absorption. Activated charcoal is potentially the most effective first-line treatment for acute overdosage with sustained-release theophylline tablets.

Effect of Altering Small Bowel Transit Time on Sustained Release Theophylline Absorption

1989 ◽  
Vol 29 (8) ◽  
pp. 733-738 ◽  
Author(s):  
Judy C. Bryson ◽  
George E. Dukes ◽  
M. Gray Kirby ◽  
William D. Heizer ◽  
J. Robert Powell
Keyword(s):  
Small Bowel ◽  
Sustained Release ◽  
Transit Time ◽  
Small Bowel Transit ◽  
Small Bowel Transit Time ◽  
Sustained Release Theophylline ◽  
Theophylline Absorption

Effect of Food on Nifedipine Sustained-Release Preparation

DICP ◽  
1989 ◽  
Vol 23 (9) ◽  
pp. 662-665 ◽  
Author(s):  
Kazuyuki Ueno ◽  
Syuichi Kawashima ◽  
Kiyotaka Uemoto ◽  
Tomoko Ikada ◽  
Kazuyoshi Miyai ◽  
...  
Keyword(s):  
Serum Concentration ◽  
Sustained Release ◽  
Time Curve ◽  
Maximum Serum ◽  
Sustained Release Preparation ◽  
Concentration Time ◽  
Release Preparation ◽  
Effect Of Food ◽  
Maximum Serum Concentration ◽  
The Mean

The effect of food on the bioavailability of a nifedipine sustained-release preparation was studied. Each of seven male volunteers received a single oral 20 mg dose with 100 mL of water under two conditions, fasting and after a meal, with a crossover after a seven-day wash-out period. Blood samples were drawn at time zero (just prior to dose), and 1, 2, 3, 4, 6, 8, 10, and 12 hours after dosing. Nifedipine assays were performed by gas chromatography. The area under the serum concentration-time curve (AUC) from 0 to 12 hours and maximum serum concentration (Cmax) were significantly increased by food. Blood pressure was significantly decreased by food. The mean AUC for fasting and meal conditions were 315.0 and 411.4 ng•h/mL, and the mean Cmax were 42.6 and 86.6 μg/mL, respectively. The results indicate that food may increase the bioavailability of nifedipine sustained-release preparation.

Clinical Experience with Two Twice Daily Slow Release Theophylline Preparations. Relation between Serum Theophylline Concentrations, Effectiveness, Tolerability and Compliance in Elderly Patients

1987 ◽  
Vol 15 (3) ◽  
pp. 170-178 ◽  
Author(s):  
S. Ruggeri ◽  
D. Bernocchi ◽  
F. Berte' ◽  
R. D'Anneo ◽  
C. Gramolini
Keyword(s):  
Serum Concentration ◽  
Elderly Patients ◽  
Sustained Release ◽  
Slow Release ◽  
Serum Theophylline ◽  
Hospitalized Elderly ◽  
Significant Difference ◽  
Sustained Release Theophylline ◽  
The Mean ◽  
Hospitalized Elderly Patients

The relation between serum theophylline concentrations, effectiveness, tolerability and compliance were evaluated in 14 hospitalized elderly patients with broncho-obstructive pathology, using a new twice daily sustained release theophylline suspension compared to standard twice daily slow release tablets. The results showed that the mean theophylline serum concentration remains within the therapeutic range with both preparations. No significant difference exists between the two treatments with regard to effectiveness. Tolerability and compliance of the theophylline suspension, however, were higher.

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