title: Gastric emptying in patients with insulin dependent diabetes mellitus and bioavailability of thioctic acid-enantiomers.
abstract: The objective of this study was to determine the impact of prolonged gastric emptying in patients with insulin dependent diabetes mellitus (IDDM) on the bioavailability of the R(+)- and S(-)-thioctic acid (TA) enantiomers. Gastric emptying time (GET) was assessed in 30 healthy volunteers and 22 patients with IDDM using sequential ultrasonography after a standardized solid-liquid test meal. Pharmacokinetics and absolute bioavailability (F) of the TA-enantiomers were studied using a randomized, open two-way crossover design with administrations of oral and intravenous single doses of 200 mg rac-TA. GET in healthy subjects was 134.7+/-21.6 min, the normal range was calculated from 88.3 to 181.1 min. The mean GET in all IDDM patients was significantly prolonged (178.2+/-28.1 min; P<0.001). Only 50% of the patients (n=11) were found to have normal GET (group A), the other half of the population (n=11) were considered to have delayed GET (group B). Mean GET values were 156.9+/-21.5 in group A (P=0.028) and 199.4+/-13.9 min in group B, respectively, suggesting that gastric motility is significantly different from non-diabetic controls even in patients with apparently normal gastric emptying. Times to peak plasma concentrations (t(max)) of both TA-enantiomers were similar in both groups and thus, unrelated to measures of gastric emptying. In contrast, maximum concentrations (C(max)) and area-under-the-curve values (AUC) of both enantiomers were reduced by about 30% in patients with delayed GET. Although these differences resulted in statistical significance for the AUC of both enantiomers (P<0.05), linear regression analysis showed only modest correlation between GET and the extent of TA-enantiomer absorption (r2=0.31 and 0.22 for R(+)-/S(-)-TA, respectively). The study suggests that prolonged gastric emptying is frequently present in IDDM. Delayed gastric emptying, however, does not substantially affect the rate and extent of absorption of both TA-enantiomers.
authors.affiliation: Department of Clinical Pharmacology, Medical Research, ASTA Medica AG, 60314 Frankfurt/Main, Weismüllerstr. 45, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Hermann
authors.forename: H J
authors.initials: HJ
authors.lastname: Wildgrube
authors.forename: P
authors.initials: P
authors.lastname: Ruus
authors.forename: G
authors.initials: G
authors.lastname: Niebch
authors.forename: H
authors.initials: H
authors.lastname: Nowak
authors.forename: C H
authors.initials: CH
authors.lastname: Gleiter
mesh_terms: D000284:Administration, Oral; D000328:Adult; D019540:Area Under Curve; D001682:Biological Availability; D018592:Cross-Over Studies; D003922:Diabetes Mellitus, Type 1 / Q000150:complications / Q000378:metabolism / Q000503:physiopathology*; D005260:Female; D005746:Gastric Emptying / Q000502:physiology*; D006801:Humans; D007275:Injections, Intravenous; D008297:Male; D008657:Metabolic Clearance Rate; D008875:Middle Aged; D010523:Peripheral Nervous System Diseases / Q000150:complications / Q000378:metabolism / Q000503:physiopathology; D013237:Stereoisomerism; D008063:Thioctic Acid / Q000008:administration & dosage / Q000737:chemistry / Q000493:pharmacokinetics*; D014803:Vitamin B Complex / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics
chemical_list: D014803:Vitamin B Complex; D008063:Thioctic Acid