Comparative Theophylline Blood Levels Following the Oral Administration of Three Different Theophylline Preparations

Schluger, Joseph; McGinn, Joseph T.; Hennessy, Douglas J.

doi:10.1097/00000441-195703000-00009

Cited by 40 publications

(5 citation statements)

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“…A comparison of the blood levels of theophylline obtainable from plain tablets of aminophylline, the ethylenediamine salt of theophylline, and enteric-coated tablets of the choline salt of theophylline revealed that much lower serum levels were obtained with the enteric-coated choline salt. 43 This result shows that the dosage form can overcome the other properties of a drug that ordinarily provide efficient absorption, since plain tablets of the choline salt are decidely superior to plain tablets of aminophylline in yielding higher maximal serum levels for longer periods of time. 2o In addition, it was found that 4 Gm.…”

Section: Influence Of Dosage Formsmentioning

confidence: 93%

“…Theophylline is more rapidly absorbed when given in solution than when given in rapidly diSintegrating tablets. 43 A remarkable difference between the absorption of amphenone from a solution and from the capsule form was observed in a limited trial. 39 Gelatin capsules of tetracycline hydrochloride were found to be slightly less efficient than a solution of the same material, as judged by the maximal blood levels attained."…”

Section: Influence Of Dosage Formsmentioning

confidence: 99%

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Part XVII. Physicochemical and pharmaceutic properties of drugs that influence the results of clinical trials

Nelson

1962

Clin Pharma and Therapeutics

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Despite the fact that pharmacologists and some clinicians are aware that physical, chemical, and pharmaceutic properties of a drug may influence its actions and effects, little consideration has been given to quantitating the effects of these properties. It is the aim of this article to discuss and illustrate the fact that the rate of gastrointestinal absorption of a drug is often a function of the time needed for the drug to dissolve in the fluid at the site of absorption. Clinical trials of several forms of the same drug may merely confirm a result which should have been predicted on the basis of its properties, such as specific surface area, type of salt, and the form in which it is administered.

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Section: Influence Of Dosage Formsmentioning

confidence: 93%

Section: Influence Of Dosage Formsmentioning

confidence: 99%

Part XVII. Physicochemical and pharmaceutic properties of drugs that influence the results of clinical trials

Nelson

1962

Clin Pharma and Therapeutics

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“…Half-life of plasma antipyrine has been used as an index of the mixed function oxidase system, since antipyrine is completely absorbed when given orally, is completely metabolized by the liver (10), and its metabolism is inducible by the barbiturate class of inducing substances (11). Theophylline is rapidly absorbed when administered orally in an aqueous-ethanol solution (12), and is metabolized primarily by the liver microsomal system (13). Unlike antipyrine, however, theophylline metabolism has been shown to be increased in vitro by pretreatment of rats with the polycyclic hydrocarbon 3-methylcholanthrene (13), and in man its kinetic disposition is accelerated in chronic smokers (14); however, its disposition is not significantly altered by phenobarbital administration in man (15).…”

mentioning

confidence: 99%

Interactions between nutritional factors and drug biotransformations in man.

Alvares¹,

Anderson²,

Conney³

et al. 1976

Proc. Natl. Acad. Sci. U.S.A.

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This study was undertaken to examine the influence of nutritional factors on the activity of the mixed function oxidase system in man, which is cytochrome P450 dependent. Three normal volunteers were fed a low carbohydrate-high protein diet for 2 weeks, followed by a high carbohydrate-low protein diet for the following 2 weeks. At the end of each test diet period, the plasma elimination rates of antipyrine and theophylline were determined. The mean plasma half-life for antipyrine was 17.5 hr on the high carbohydrate-low protein diet and 9.2 hr on the low carbohydrate-high protein diet. The mean plasma half-life for theophylline was 8.9 hr on the high carbohydrate-low protein diet and 5.9 iwr on the low carbohydrate-high protein diet. These data demonstrate marked influences of dietary carbohydrate and/or protein ingestion on oxidative biotransformation of drugs in man. The effects of changes in dietary macronutrient composition on the hepatic microsomal enzymes that metabolize drugs, other foreign chemicals, and endogenous compounds, such as steroid hormones, have been studied extensively in animals (1). These studies show that dietary macronutrient composition, as well as the presence of contaminants and food additives, can influence the activities of these enzymes. Although dietary composition has been shown to be an important environmental determinant in the response of the experimental animal to pharmacological agents, such studies are lacking in man. A significant proportion of normal subjects manipulate their diets in weight-reducing regimens. Similarly, dietary treatments in clinical conditions, including obesity, atherosclerosis, and diabetes, are considered to play a significant role in the management of such disease problems. It is the purpose of these studies to show that nutritional-pharmacological interactions can occur in normal individuals when macronutrient composition of the diet is altered.In animals, in relation to hepatic microsomal enzyme activities, the dietary constituent most studied is protein. A reduction in dietary protein intake has been shown to decrease microsomal oxidations of various substrates, such as pentobarbital, aminopyrine, and zoxazolamine (2), and to increase the toxicity of foreign compounds, such as drugs (2) and pesticides (3, 4). The decreases in microsomal oxidations are accompanied by decreases in hepatic content of the hemeprotein cytochrome P-450, the terminal oxidase of the hepatic mixed function oxidase system. In contrast, the metabolism of the drugs indicated is increased in rats fed a high protein diet (2). A high carbohydrate intake has been shown to increase barbiturate-induced sleeping time in mice (5), to cause cessation of lipid peroxidase activity, and to cause a considerable decrease in liver mixed function oxidase activity in rats (6). A specific lipid role in the mixed function oxidase system was first demonstrated by Strobel et al. (7), who established the requirement for phosphatidylcholine in a reconstituted mixed function oxidase system. ...

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“…3), it may be assumed that theophylline-choline was absorbed equally well in both groups. *These tablets are a simple mixture containing 100 mg. of theophylline (anhydrous Schluger, McGinn and Hennessy (1957), who also reported the rapid appearance of theophylline in blood after the ingestion of uncoated aminophylline tablets.…”

Section: Methodsmentioning

confidence: 99%