AI Article Synopsis
- The study examined the sustained-release and bioavailability of two theophylline formulations, Theolin Retard and Pharphylline Retard, in eight healthy adults over five days with specific dosing regimens.
- The results showed that Theolin Retard had higher minimum plasma concentrations of theophylline, smaller fluctuations in levels, and a longer time period where plasma concentrations exceeded 75% of the maximum compared to Pharphylline Retard.
- Although both formulations had similar maximum concentrations and absorption overall, Theolin Retard demonstrated better sustained-release properties based on in vitro tests.
Article Abstract
The sustained-release properties and relative bioavailability of Theolin Retard and Pharphylline Retard were studied in eight healthy adults after treatment for five days with twice daily 450 mg, respectively 425 mg. During the day-time dosing interval on the fourth and fifth day theophylline plasma concentrations were assayed by HPLC. After intake of Theolin Retard, minimum theophylline plasma concentrations were significantly higher, fluctuations in theophylline plasma concentrations were significantly smaller and t75 (the period within a dosing interval during which the plasma concentration exceeds 75% of the maximal concentration) was significantly longer than after Pharphylline Retard. Maximal concentrations and AUC values were not significantly different. For both products the plasma concentration time-curves on day 5 were significantly lower than on day 4. In vitro dissolution tests confirmed the more sustained release of theophylline from Theolin Retard. These results indicate an equal extent of absorption from the two products but better sustained-release properties for Theolin Retard.
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| http://dx.doi.org/10.1007/BF01966430 | DOI Listing |
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Comparison of the in vitro dissolution properties and in vivo steady-state pharmacokinetics of two sustained-release theophylline preparations.
Pharm Weekbl Sci
February 1988
Department of Analytical, Chemistry and Toxicology, State University of Groningen, the Netherlands.
Article Synopsis
- The study examined the sustained-release and bioavailability of two theophylline formulations, Theolin Retard and Pharphylline Retard, in eight healthy adults over five days with specific dosing regimens.
- The results showed that Theolin Retard had higher minimum plasma concentrations of theophylline, smaller fluctuations in levels, and a longer time period where plasma concentrations exceeded 75% of the maximum compared to Pharphylline Retard.
- Although both formulations had similar maximum concentrations and absorption overall, Theolin Retard demonstrated better sustained-release properties based on in vitro tests.
A group of 10 patients with chronic asthmatic bronchitis was titrated with slow-release theophylline (Theolin Retard) to a steady state plasma theophylline level of 10 mg/l. After one week of this treatment a single s.c.
View Article and Find Full Text PDFPharmacokinetics and pharmacodynamics of three sustained-release theophylline preparations (Theograd, 350 mg Theolair Retard, and 300 mg Theolin Retard) in steady state in six normals and six patients with chronic asthmatic bronchitis--Part II: Lung function.
Int J Clin Pharmacol Ther Toxicol
July 1985
The lung function profiles of a group of six healthy volunteers and six patients with moderately severe asthmatic bronchitis were compared after one theophylline infusion and after oral administration of Theograd (350 mg), Theolair Retard (350 mg), and Theolin Retard (300 mg) all given twice daily for 1 week. The group of patients showed a good reversibility of bronchoconstriction after intravenous theophylline administration; however, only minor improvement was observed at the levels reached after relatively low oral doses.
View Article and Find Full Text PDFThe pharmacokinetic profiles of three oral sustained-release theophylline preparations in steady state (350 mg Theograd, 350 mg Theolair Retard [= Nuelin Retard], and 300 mg Theolin Retard [= Theodur]) were compared in a group of six normal subjects and six patients with moderately severe asthmatic bronchitis. All preparations were given twice daily for 7 days. Before this study, an intravenous infusion of aminophylline had been administered (5.
View Article and Find Full Text PDFIn order to achieve the greatest chance for maximum benefit from theophylline in the management of chronic asthma, the serum concentration should be maintained in the therapeutic range of 10 to 20 micrograms/ml. Conventional rapid release formulations produce excessive fluctuations in serum concentrations that can result in variability in clinical response between doses. In contrast, slow release formulations have the potential to achieve relatively constant serum concentrations with 12-hour dosing intervals, thus providing around-the-clock stabilisation of the hyper-reactive airways that characterise chronic asthma.
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