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At least 19 recordsLinked to original sources
PubMed1995

Multicenter, placebo-controlled trial comparing acarbose (BAY g 5421) with placebo, tolbutamide, and tolbutamide-plus-acarbose in non-insulin-dependent diabetes mellitus.

BACKGROUND: Acarbose delays release of glucose from complex carbohydrates and disaccharides by inhibiting intestinal alpha-glucosidases, thereby attenuating postprandial increments in blood glucose and insulin. This multicenter, double-blind, placebo-controlled study compared the efficacy and safety of diet alone, acarbose, tolbutamide, and acarbose-plus-tolbutamide in non-insulin-dependent diabetes mellitus (NIDDM) patients. PATIENTS AND METHODS: A total of 290 patients with NIDDM and fasting plasma glucose levels of at least 140 mg/dL were randomized to receive treatment TID with acarbose 200 mg, tolbutamide 250 to 1,000 mg, a combination of both drugs, or placebo. A 6-week run-in period was followed by double-blind treatment for 24 weeks, then a 6-week follow-up period. RESULTS: All active treatments were superior (P < 0.05) to placebo in reducing postprandial hyperglycemia and HbA1c levels. The ranking in order of efficacy was: acarbose-plus-tolbutamide, tolbutamide, acarbose, and placebo. The postprandial reductions in glucose were approximately 85 mg/dL for acarbose-plus-tolbutamide, 71 mg/dL for tolbutamide, 56 mg/dL for acarbose, and 13 mg/dL for placebo. Tolbutamide was associated with increases in body weight and postprandial insulin levels when taken alone, but these were ameliorated when tolbutamide was taken in combination with acarbose. Acarbose alone or in combination with tolbutamide caused significantly more gastrointestinal adverse events (mainly flatulence and soft stools or diarrhea) than tolbutamide or placebo, but these were generally well tolerated. Clinically significant elevations in hepatic transaminase levels occurred in 3 patients in the acarbose group and 2 in the acarbose-plus-tolbutamide group. Transaminase levels returned to normal when therapy was discontinued. CONCLUSIONS: Acarbose was effective and well tolerated in the treatment of NIDDM. Control of glycemia was significantly better with acarbose compared with diet alone. Acarbose-plus-tolbutamide was superior to tolbutamide alone.

Acarbose↗
PubMed1984

Effect of sulfaphenazole on tolbutamide distribution in rabbits: analysis of interspecies differences in tissue distribution of tolbutamide.

The effect of sulfaphenazole on the distribution of tolbutamide was examined by comparing the change in the steady-state volume of distribution (Vdss) determined from in vivo plasma elimination with the tissue-to-plasma concentration ratio of various tissues (Kp) in rabbits; this effect was compared with that previously reported in rats. In rabbits, the Kp values of six tissues studied (i.e., brain, heart, spleen, small intestine, muscle, and skin) increased in the presence of sulfaphenazole ; except for brain, lung, and adipose tissue, the tissue-to-plasma unbound concentration ratio (Kp,f) of other tissues did show a significant decrease. This suggested that both the tissue and plasma protein binding of tolbutamide were affected by sulfaphenazole and that the increase in Kp was due mainly to the displacement of plasma protein binding of tolbutamide by sulfaphenazole , which was greater than that of tissue binding, while no change in Kp was due to a parallel change in both the plasma protein binding and tissue binding of tolbutamide. In both rabbits and rats, the Vdss calculated from plasma concentration versus time curve was very close to that calculated from the Kp values and volumes of various tissues in the presence and absence of sulfaphenazole , respectively. The interspecies difference of the effect of sulfaphenazole on the tissue distribution of tolbutamide between rabbits and rats was elucidated from both in vivo tissue distribution and in vitro plasma protein binding studies.

Animals↗
PubMed1975

Physicochemical study of drug binary systems. Part 3: Tolbutamide-urea and tolbutamide-mannitol systems.

The phase diagram of the tolbutamide-urea system, constructed by data obtained from the microheating table apparatus, was a peritectic type. It showed the possibility of the formation of two molecular compounds with incongruent m. p. at 112 degrees C and 123 degrees C. Metastable and stable eutectic points were observed at 63 degrees C and 92 degrees C respectively. The phase diagram of tolbutamide-mannitol system revealed that in addition to eutectic liquefaction at 102 degrees C and 6% (w/w) mannitol, there was a region [40--80% (w/w) mannitol] in which the two components were not completely miscible in the liquid state. Solubility studies showed an increase of about 2.5 fold in the solubility of tolbutamide with 0.5 g% urea and suggested the possibility of the formation of a low-solubility complex in addition to a soluble higher complex of the two components. No obvious increase in the solubility of tolbutamide was detected in the presence of mannitol. A full description of the nature and composition of the final solidified melts of the two present systems could prove to be helpful in the explanation of the dissolution behaviour of the different studied samples and their corresponding physical mixtures. The fused 90% urea and mannitol solid dispersions showed a fast rate of dissolution in the order of 15 and 10 times (respectively) greater than pure tolbutamide.

Chemical Phenomena↗
PubMed1976

Effect of tuberculostatic agents on the response of serum growth hormone and immunoreactive insulin to intravenous tolbutamide, and on the half-life of tolbutamide.

The effect of drugs used in the chemotherapy of tuberculosis on blood glucose, serum immunoreactive insulin and serum growth hormone, and on the half-life of tolbutamide, were studied in 16 patients with tuberculosis just before starting treatment and four weeks later using an intravenous tolbutamide test. The maximum fall of blood sugar was about 30% on both test occasions. The peak values of serum growth hormone before and after treatment (15.6+/-3.1 ng/ml and 17.3+/-2.9 ng/ml), and the maximum values of serum insulin before or after treatment (37.6+/-5.3muU/ml and 45.6+/-7.0 muU/ml) did not differ significantly from one another. The levels of serum insulin remained slightly higher in the test from 10 minutes onwards after treatment than before, but this was not associated with any particular tuberculostatic drug combination. The half-life of tolbutamide decreased by 43% and the serum concentration of tolbutamide decreased at 180 minutes by 30% and at 360 minutes by 49% after treatment in comparison with the pretreatment values in the patients receiving rifampicin in their drug combination. In patients receiving other tuberculostatic agents, no significant changes were observed.

Adult↗
PubMed1978

Simple, rapid and micro high-pressure liquid chromatographic method for the simultaneous determination of tolbutamide and carboxy tolbutamide in plasma.

A rapid high-pressure liquid chromatographic (HPLC) assay is described for the quantitative analysis of tolbutamide and its major metabolite, carboxy tolbutamide in plasma. An aliquot (25--100 microliter) of plasma was prepared for chromatography by deproteinization as follows. One volume of plasma and 2.5 volumes of acetonitrile were vortex mixed for a few seconds and then centrifuged for approx. 1 min. A 50-microliter sample of the clear supernatant was injected into the chromatograph. A mu Bondapak C18 reversed-phase column was used with a mobile phase acetonitrile--0.05% phosphoric acid (45:55) at a flow-rate of 1.5 ml/min. The column effluent was monitored by a variable-wavelength UV detector set at 200 nm. Tolbutamide and its metabolite had retention times of 5.75 and 3.25 min, respectively. The procedure yuelds reproducible results with sensitivity adequate for routine clinical monitoring of plasma levels or for single-dose pharmacokinetic studies. A number of commonly used drugs do not interfere with the method. A single plasma sample can be analyzed in approx. 9 or 10 min.

Animals↗
PubMed1989

Simultaneous determinations of tolbutamide and its hydroxy and carboxy metabolites in serum and urine: application to pharmacokinetic studies of tolbutamide in the rat.

Methods of analysis of tolbutamide (1) and its hydroxylated (2) and carboxylated (3) metabolites in serum and urine based on high-performance liquid chromatography were developed. The separation was performed on a Apex ODS column in the isocratic mode using a mobile phase composed of 22.5% acetonitrile, 77.5% Sorensen phosphate buffer (pH 7.0), and 0.30 mL of tetrabutylammonium phosphate reagent (Pic A). The compounds were detected at 254 mm. The retention times of 3, 2, 1, and the internal standard chlorpropamide were 3.1, 4.1, 14.8, and 10.0 min, respectively. These conditions were suitable for the simultaneous quantitation of 1, 2, and 3 in serum or plasma samples, but not for the determination of metabolites 2 and 3 in urine. For the analysis of 2 and 3 in urine, the mobile phase was modified to 18% acetonitrile, 82% Sorensen phosphate buffer (pH 7.0), and 0.35 mL of Pic A. Under these conditions, the retention times of the carboxy and hydroxylated metabolites and the internal standard salicylic acid were 4.6, 6.7, and 8.1 min, respectively. These methods were applied to study the pharmacokinetics of 1 administered intravenously and intraperitoneally to the rat. Tolbutamide was almost completely recovered as metabolites 2 and 3 in the urine within 24 h.

Animals↗
PubMed1990

Particle design of tolbutamide by the spherical crystallization technique. III. Micromeritic properties and dissolution rate of tolbutamide spherical agglomerates prepared by the quasi-emulsion solvent diffusion method and the solvent change method.

With the objective of modifying the micromeritic properties of tolbutamide (i.e., to manufacture a highly functional powder form), particle design was attempted using a quasi-emulsion solvent diffusion (QESD) method, and the micromeritic properties and dissolution rate of the obtained spherical agglomerates were evaluated by comparison with agglomerates prepared by the solvent change (SC) method. For the production of tolbutamide agglomerates by the QESD method, a necessary condition was the addition of a sucrose fatty acid ester to the system as an emulsifying agent. The particle diameter of the agglomerates obtained by the QESD method depended on the size of the initially formed quasi-emulsion droplets, which in turn depended on the viscosity of the solution. In addition, the agglomerates were nearly perfectly spherical in shape. In the QESD method, the quasi-emulsion droplets crystallized instantaneously from the droplet surface inward. The resultant agglomerates were dense, had great mechanical strength and showed excellent flowability due to their perfect spherical shape. On the other hand, the agglomerates produced by the SC method were conglomerates of primary crystals, and fine, needle-like crystals formed on their surface. As a result, these agglomerates had a large specific surface area, and they therefore showed greater solubility than the agglomerates prepared by the QESD method.

Chemistry, Pharmaceutical↗
PubMed1975

Dynamics of tolbutamide, glucose, and insulin interrelationships following varying doses of intravenous tolbutamide in normal subjects.

Four healthy adult subjects received intravenous tolbutamide (TOL) at six different doses (twenty-four tests): 0.0625 gm., 0.125 gm., 0.25 gm., 0.5 gm., 1.0 gm. and 1.5 gm. Blood glucose (BG), serum immunoreacctive insulin (IRI) and serum TOL levels were determined before and for 180 minutes after TOL. There was a highly significant correlation of the dose of TOL with the peak IRI (p less than .01), zero to ten minute IRI area (p less than .001), and zero to sixty minute IRI area (p less than .001) and with the decline in BG expressed as zero to sixty minute BG area (p less than .001). Similar significant correlations were observed between levels of TOL and both IRI and BG. At each dose level the IRI response correlated significantly with the BG fall. An additional eighteen subjects received the 1.0 gm. dose. In these, serum TOL levels did not correlate with either BG or IRI. These subjects also received intravenous glucose (0.5 gm. per kilogram body weight). BG levels did not correlate with IRI. However, there were striking correlations between TOL and glucose-stimulated peak IRI (p less than .001), zero to ten minute IRI area (p less than .05). The mean (plus or minus SEM) space of distribution for glucose (G.S.) and tolbutamide (TLS.) was found to be 13.45 plus or minus 0.71 and 6.34 plus or minus 0.31 L., respectively. There was a significant dose-response relationship exists between TOL and IRI. TOL- and glucose-induced IRI secretion dynamics suggest strong similarities between mechanisms of rapid IRI release and/or size of available IRI storage pools.

Adult↗