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At least 19 recordsLinked to original sources
PubMed1991

Comparison of beta-cell function after long-term treatment with either insulin, insulin plus gliclazide or gliclazide in neonatal streptozotocin-induced non-insulin-dependent diabetic rats.

There are no definite guidelines in the treatment of non-insulin-dependent diabetes mellitus (NIDDM) as to whether the treatment of choice is insulin, a sulfonylurea or a combination of insulin and sulfonylurea. We have therefore tried to evaluate the long-term effects of these treatments on beta-cell function in a rat model of NIDDM. NIDDM rats were prepared by the injection of streptozotocin (60 mg, i.p.) on the 5th day after birth. At 10 weeks, an oral glucose tolerance test (2 g/kg) was performed and rats were divided into 4 groups, each of which had the same mean glucose tolerance. The treatment of each group with either NPH insulin (4 U/kg/day), or oral gliclazide (10 mg/kg/day by a stomach cannula), or a combination of the above two, or a control (vehicle for gliclazide) was started from 12 weeks of age and continued for 6 months. Rats were fed ad libitum with standard rat chow. The weight gain of diabetic rats treated with gliclazide alone and of the vehicle-treated diabetic rats during 6 months was less than that of the other groups receiving insulin. The fasting plasma glucose of the insulin-only treated group stayed at the initial level for 6 months, but that of the other groups increased gradually. The frequency of deterioration of glucose tolerance for oral glucose loading (2 g/kg) in the insulin-only treated group was smaller than that in the other diabetic groups at 3 at 6 months after the start of treatment. The increase in plasma IRI after the oral glucose loading of the insulin-only treated group was the largest among the 4 groups at 6 months. In the pancreas perfusion experiment, the insulin response to glucose in the insulin-only treated group was more preserved than that in the other groups of diabetic rats after 6 months of treatment. These results suggest that treatment with insulin is effective in preserving beta-cell function in a rat model of NIDDM, whereas treatment with a sulfonylurea agent is not only ineffective but might negate the protective effect of insulin because the insulin-plus-gliclazide treated group elicited results similar to those of the gliclazide-only treated group except for the weight gain.

Animals↗
PubMedDate not supplied

Serum gliclazide concentration in diabetic patients. Relationship between gliclazide dose and serum concentration.

Serum levels of gliclazide were determined by radioimmunoassay in seven healthy controls and in 18 diabetic in-patients receiving single oral dosing and consecutive dosing over 5 days. Following a single oral dose of 40 mg in the seven controls and eight diabetic patients, and 120 mg in ten diabetic patients, the serum levels of gliclazide peaked on average at 2 h, followed by a slow decline, the t1/2 being 16.5 h in the volunteers, 12.3 h in the diabetic patients receiving 40 mg, and 10.5 h in those receiving 120 mg. During consecutive administration, the serum levels both at fasting and at the peak reached a plateau in 2 days and no further accumulations were observed. The steady-state peak levels of gliclazide in the diabetic patients revealed a strongly positive correlation with the dose per m2 body surface area (r = 0.78, P less than 0.001), and their steady-state fasting levels correlated positively but weakly with the dose per m2 body surface area (r = 0.48, P less than 0.05). Thus, measuring either the fasting or the peak concentration of gliclazide will be useful for monitoring drug concentration in the serum. Pharmacokinetics of gliclazide will contribute to the elucidation of the relationship of serum level and clinical effectiveness in diabetic subjects.

Administration, Oral↗
PubMed1981

Influence of blood proteins on biomedical analysis. III. Pharmacokinetics and protein binding of gliclazide.

Both pharmacokinetics of total and free gliclazide, a potential hypoglycemic drug, were studied in the healthy (n = 12) and diabetic subjects (n = 11). The blood level of gliclazide was determined by a high-performance liquid chromatography, and the free gliclazide (unbound to proteins) in the serum separated by means of an ultrafiltration. The binding ratio of gliclazide to the blood proteins was about 96% during the periods of 24 hr after administration of the drug. Several pharmacokinetic parameters for the blood gliclazide were derived from the decay curves of the blood drug levels. Each pharmacokinetic parameter was not changed by differences between the healthy and diabetic subjects, the total and free drug levels, and method of administration of the drug; each mean parameter, the elimination rate (ke), the time to peak level (tmax), the elimination half-life (t1/2) and the volume of distribution (Vd beta) was 0.07 hr-1, 2.8 hr, 12.3 hr and 16.4 1 (total level), respectively. The serum from healthy subject receiving orally administered gliclazide was gel-filtered on a Sephadex G-150 column. Each fractionated serum protein of macroglobulin (IgM), gamma-globulin (IgG), albumin (A) and small molecular substances (F), contained gliclazide at average of 3.7, 0.7, 82.3 and 13.2%, respectively, during the periods of 24 hr after administration. In in vitro experiment, it was found that the ratio of gliclazide-albumin binding kept a constant level at 96.5% in the range of normal protein levels (3.3--4.8 g/100 ml). In conclusion, the present result shows that the pharmacokinetics of the total blood level of gliclazide reflect the free gliclazide level, moreover, gliclazide predominantly binds with albumin in the blood and its binding ratio is not constant, but variable according to the dose-relation between the drug and the serum protein.

Adult↗
PubMed1984

Pharmacokinetics of gliclazide in healthy and diabetic subjects.

The pharmacokinetics of total and free gliclazide, 1-(3-azabicyclo[3,3,0]oct-3-yl)-3-(p-tolylsulfonyl)urea, a potential hypoglycemic drug, was studied in healthy (n = 12) and diabetic (n = 12) subjects. The serum level of gliclazide was determined by a high-performance liquid chromatographic method (HPLC). The free fraction of gliclazide was obtained from serum by an ultrafiltration technique using a collodion membrane. The mean adsorption of gliclazide to the membrane was approximately 50% when the membrane was used more than twice. Therefore, the gliclazide level in the filtrate was corrected by doubling the apparent value. The ratio of gliclazide-protein binding remained constant at approximately 92% in serum after administration to healthy and diabetic subjects. The mean pharmacokinetic parameters of elimination rate (ke), time to reach the peak level (tmax), elimination half-life (t 1/2), and volume of distribution (Vd) were 0.07 h-1, 2.8 h, 12.3 h, and 17.4 L, respectively. The parameters did not differ significantly between healthy and diabetic subjects or between single and successive administrations; moreover, they did not differ between the free and total drug level. Although there were intersubject variations, the therapeutic effects of oral administration of gliclazide on serum glucose and insulin levels were found in four diabetic patients. The results of this study show that the pharmacokinetics of the total gliclazide level reflect those of the free gliclazide in serum.

Adult↗
PubMed1991

Improvement in glucose-induced insulin secretion in diabetic rats after long-term gliclazide treatment: a comparative study using different models of non-insulin-dependent diabetes mellitus induced by neonatal streptozotocin.

Understanding of the long-term action of sulfonylureas in humans with non-insulin-dependent diabetes mellitus (NIDDM) may be facilitated by studying the effect of long-term sulfonylurea administration to animal models of the disease. In this study two different versions of the neonatal streptozotocin-induced diabetes (STZ) rat model of NIDDM were used. The n5-STZ model (STZ on day 5 after birth), which is characterized by basal hyperglycemia, a marked reduction of pancreatic insulin stores, and insulin resistance, and the n0-STZ model (STZ on day of birth), which develops mild hyperglycemia, have an approximately 50% reduction in pancreatic insulin content, and no insulin resistance. The diabetic rats were given oral gliclazide (10 mg/kg/day) and compared with untreated diabetic rats and nondiabetic rats. Insulin secretion was studied the day after the last gliclazide dose using the isolated perfused pancreas preparation. In severely hyperglycemic n5-STZ rats (plasma glucose levels greater than 16 mmol/L) the long-term gliclazide treatment did not lower the plasma glucose values, did not affect pancreatic insulin stores, and did not significantly modify in vitro insulin release in response to glucose or arginine. In moderately hyperglycemic n5-STZ rats (plasma glucose levels less than 16 mmol/L) the plasma glucose levels declined progressively and reached a mean of 8 mmol/L at the end of gliclazide therapy. The increase in pancreatic insulin stores in n5-STZ rats remained marginal. In the n0-STZ rats gliclazide treatment did not significantly modify the plasma glucose levels or the pancreatic insulin stores. After gliclazide therapy in both the n5-STZ gliclazide responder group and the n0-STZ group: (a) in vitro glucose-induced insulin secretion was increased three- to fivefold; (b) the response to arginine, which is increased in diabetic rats, was amplified by two- to threefold; (c) insulin release in response to gliclazide was unchanged. In conclusion, long-term gliclazide therapy augments stimulated insulin secretion in these two rat models of NIDDM and does not induce any refractoriness to short-term sulfonylurea administration. The improvement of beta-cell function observed here was not related to the concomitant variations of hyperglycemia and/or pancreatic insulin content.

Animals↗
PubMed1996

Gliclazide potentiates suppression of hepatic glucose production in non-insulin-dependent diabetic patients.

The mechanism of the hypoglycemic action of gliclazide was evaluated in 17 diet-treated non-insulin-dependent diabetes mellitus (NIDDM) patients. In study A, five patients received a 240-minute glucose infusion along with [3-3H]glucose infusion. In study B, seven patients received a 240-minute isoglycemic insulin clamp along with [3-3H]glucose infusion. And in study C, five patients received a somatostatin infusion with basal replacing doses of insulin and glucagon. The three studies (A, B, and C) were repeated twice. Gliclazide (240 mg orally) was administered on one occasion, and placebo was given on the second occasion. Basal hepatic glucose production (HGP) and utilization and plasma glucose, insulin, C-peptide, glucagon, and free fatty acid (FFA) concentrations were similar before administration of gliclazide and placebo. In study A, plasma glucose, its incremental area, and HGP were reduced by gliclazide administration (all P < .05), but glucose utilization was not significantly affected. The increase in plasma insulin and C-peptide concentrations was similar with gliclazide and placebo, although the plasma insulin to glucose ratio was increased with gliclazide. HGP decremental area was correlated with the reduction in plasma glucose incremental area (r = -.63, P < .05). In study B, gliclazide administration produced a larger suppression of HGP, but the overall rate of glucose utilization was not different in the two studies. In study C, plasma glucose concentration and HGP progressively decreased in both studies, without a difference between gliclazide and placebo. These results suggest that under conditions of hyperglycemia and hyperinsulinemia gliclazide elicits a larger suppression of HGP.

Blood Glucose↗
PubMed1997

The effects of gliclazide and other sulfonylureas on low-density lipoprotein oxidation in vitro.

Diabetes is associated with increased oxidant stress. This may contribute to the development of diabetic macrovascular complications through increased oxidation of low-density lipoprotein (LDL), which is thought to be a crucial step in the development of atherosclerosis. The sulfonylurea gliclazide has been shown to have free radical-scavenging activity in vitro, but its effects on LDL oxidation, and these effects of other sulfonylureas, are unknown. To investigate this we studied the effects of in vitro supplementation with gliclazide 1 mumol/L on copper-induced oxidation of LDL isolated from 20 control subjects and 22 type II diabetic patients. The effects of 1 mumol/L vitamin C, a known water-soluble antioxidant, were studied simultaneously. The resistance to oxidation, expressed as the lag time between the addition of copper and commencement of oxidation, was significantly increased by both gliclazide and vitamin C, and the effect was similar for LDL from diabetic and control subjects. The baseline oxidation lag time was 63.4 +/- 2.1 minutes, and increased to 108 +/- 4.4 minutes with gliclazide and 88.7 +/- 5.6 minutes with vitamin C (P = .0001, baseline v either treatment). The increase in lag time with gliclazide of 70% +/- 3% was greater than the 30% +/- 5% increase with vitamin C (P < .0005). In a separate experiment, LDL isolated from eight control and 10 diabetic subjects was supplemented with 1 mumol/L gliclazide, glibenclamide, glipizide, and tolbutamide. For each LDL sample, all drugs were studied simultaneously and the oxidation lag time was compared against that of untreated LDL. Gliclazide increased the lag time from 53.7 +/- 2.4 minutes to 108.4 +/- 4.5 minutes (P = .0001). None of the other sulfonylureas had any effect on lag time. These findings demonstrate that gliclazide is an effective inhibitor of in vitro LDL oxidation, and in this respect, it is more potent on a molar basis than vitamin C. This antioxidant property of gliclazide was not shared by the other sulfonylureas studied.

Administration, Oral↗
PubMed1995

Gliclazide hydroxylation by rat liver microsomes.

1. The metabolism of gliclazide to hydroxygliclazide has been investigated in Sprague-Dawley rat liver microsomes. 2. The kinetics of hydroxygliclazide formation are consistent with Michaelis-Menten kinetics (mean (+/- SD, n = 3) apparent K(m) and Vmax = 256 +/- 27 microM and 1.85 +/- 0.10 nmol/ min/mg respectively). 3. Tolbutamide competitively inhibited hydroxygliclazide formation (Ki = 840 microM) and gliclazide competitively inhibited hydroxytolbutamide formation (Ki = 240 microM) with Ki similar to K(m). Therefore gliclazide and tolbutamide may be metabolized by the same enzyme in the rat. In nine livers the formation of hydroxygliclazide correlated with the formation of hydroxytolbutamide (rs = 0.82, p < 0.01). 4. Diclofenac (Ki = 64 microM), phenytoin (Ki = 38 microM), mephenytoin (Ki = 66 microM), glibenclamide (Ki = 14 microM) and glipizide (Ki = 189 microM) were fully competitive inhibitors of gliclazide hydroxylation. The rank order of Ki constants differed for gliclazide and tolbutamide suggesting that gliclazide and tolbutamide hydroxylases are not identical enzymes. 5. Quinine (Ki = 0.3 microM) and quinidine (Ki = 4.3 microM) were partially competitive inhibitors of hydroxygliclazide formation. Hydroxylation of gliclazide was related to the activity of CYP2D1 as assessed by dextrorphan production from dextromethorphan (rs = 0.83, p = 0.01). 6. In the rat gliclazide is metabolized to hydroxygliclazide by at least two cytochrome P450 isoforms, including tolbutamide hydroxylase and 2D1, which have similar affinities for gliclazide.

Animals↗
PubMed1989

Long-term gliclazide treatment improves the in vitro glucose-induced insulin release in rats with type 2 (non-insulin-dependent) diabetes induced by neonatal streptozotocin.

Neonatal rats treated with streptozotocin on the day of birth (n0-STZ) or on day 5 (n5-STZ) exhibited when fully grown a very mild or frank basal hyperglycaemia respectively and a specific failure of insulin release in response to glucose. To determine whether short (1 day) or long-term (30 days) gliclazide treatment modifies the pancreatic insulin content and the B-cell response to secretagogues, diabetic rats were given oral gliclazide (10 mg/kg per day) and compared to control diabetic and non-diabetic rats. Insulin secretion in the isolated perfused pancreas was studied the day after the last gliclazide administration. In severely hyperglycaemic n5-STZ rats (plasma glucose levels greater than 16 mmol/l) long-term gliclazide treatment did not lower the plasma glucose values, did not affect the pancreatic insulin stores, nor did it significantly modify the insulin release in vitro in response to glucose or arginine. In moderately hyperglycaemic n5-STZ rats (plasma glucose levels less than 16 mmol/l) the plasma glucose levels declined progressively reaching 8 mmol/l as a mean at the end of the gliclazide therapy. In the n5-STZ rats responsive to gliclazide the pancreatic insulin stores were increased twofold as compared to values in untreated n5-STZ rats, however, this difference did not reached significance and the pancreatic insulin stores in the responsive gliclazide treated rats remained depleted by 76% compared to normal insulin stores. In the n0-STZ rats (very mild hyperglycaemia) the long-term gliclazide treatment did not significantly modify the plasma glucose levels or the pancreatic insulin stores.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

A comparison of treatment with metformin and gliclazide in patients with non-insulin-dependent diabetes.

Twenty-seven obese non-insulin-dependent diabetic patients, treated with dietary carbohydrate restriction and metformin, were recruited from the diabetic outpatient clinic and entered into an open crossover study with gliclazide. Twenty-one patients completed the study. During three months observation on metformin, the mean weight of the group fell by 1.0 kg with 14 patients losing a mean of 1.8 kg with 14 patients losing a mean of 1.8 kg, 3 remaining unchanged and 4 gaining a mean weight of 1.1 kg. Over the subsequent three months on gliclazide, the mean weight of the group rose by 1.4 kg with 16 patients gaining a mean of 2.2 kg, two remaining unchanged and 3 losing a mean of 2.0 kg. In addition, 10 patients were heavier after gliclazide than at the time of recruitment (mean 2.6 kg), 3 were unchanged and 8 had lost weight since commencing the trial (mean 2.1 kg), mostly due to greater loss on metformin than gain on gliclazide. Glycaemic control did not improve significantly during the observed period on metformin but lower concentrations of fasting glucose and total glycosylated haemoglobin were achieved with gliclazide. Mean plasma insulin concentration was significantly higher and mean serum lactate was significantly lower during treatment with gliclazide. In conclusion, gliclazide does not support weight loss in obese non-insulin-dependent diabetic patients to the same extent as metformin but the difference between the two drugs is small. Gliclazide is a suitable oral hypoglycaemic agent for use in the obese diabetic who cannot be controlled by diet alone.

Adult↗
PubMed1991

Effect of 6-month gliclazide treatment on insulin release and sensitivity to endogenous insulin in NIDDM: role of initial continuous subcutaneous insulin infusion-induced normoglycemia.

In 10 obese, new-onset non-insulin-dependent diabetes mellitus (NIDDM) patients (group A), continuous subcutaneous insulin infusion (CSII) was used to induce normoglycemia during 14 days. Fasting blood glucose was 4.6 +/- 0.2 mmol/L and mean daily blood glucose 5.8 +/- 0.2 mmol/L at the end of the CSII period. This excellent glycemic control was obtained with 35 +/- 4.8 U of insulin per day, corresponding to 0.47 +/- 0.06 U/kg/24 hours. Endogenous insulin production was markedly suppressed, since urinary C-peptide was reduced from 18.5 +/- 0.12 to 7.9 +/- 0.25 nmol/24 hours. Gliclazide was given to group A following CSII, and to five obese NIDDM patients (group B) in their habitual hyperglycemic state. Gliclazide maintained in group A, and induced in group B, excellent metabolic control. This was accompanied by the appearance of a small first-phase insulin response to intravenous glucose, and significant increases in the mean-daily-insulin to mean-daily-blood-glucose ratio, as well as in the 24-hour urinary C-peptide-to-glucose ratio. The gliclazide effects tended to be more pronounced in group A. No significant effect was seen on efficacy of endogenous insulin (slope of disappearance of blood glucose divided by insulin levels). During 6 months of gliclazide treatment, excellent glycemic control was maintained in all patients. This was paralleled by unchanged stimulation by gliclazide of first-phase insulin response to glucose, and augmented mean 48-hour insulin-to-glucose and urinary C-peptide-to-glucose ratios. No change in the ratio of glucose disposal to endogenous insulin was noted. We conclude that physiologic insulin replacement may induce normoglycemia in NIDDM, indicating that insulin resistance is not of clinical significance; gliclazide has a beta-cell-stimulating action that is maintained quantitatively unchanged for at least 6 months; the therapeutic effect of gliclazide in NIDDM seems to be mainly, if not exclusively, the result of its beta-cytotrophic action. Initial normoglycemia, induced here by CSII, may have a lasting enhancing effect on the gliclazide action.

Blood Glucose↗
PubMed1991

Increased fibrinolytic potential induced by gliclazide in types I and II diabetic patients.

This study examined the effect of gliclazide on tissue-type plasminogen activator (t-PA)-related fibrinolysis in 23 Type I diabetic patients without residual beta-cell function and 17 Type II diabetic patients initially treated with tolbutamide. The Type I diabetic patients received gliclazide for a period of 6 months; the Type II diabetic patients were shifted from tolbutamide to gliclazide. In Type I diabetic patients, after 2-3 months of treatment with gliclazide, we observed a significant increase in plasma concentrations of total t-PA antigen that remained stable until discontinuation of the drug (p less than 0.0002), whereas the plasma concentrations of plasminogen activator inhibitor (PAI) did not change significantly during the study. Next, we investigated the possibility of gliclazide inducing t-PA-related fibrinolysis in a subset of Type II diabetics without detectable concentrations of t-PA during treatment with tolbutamide. The concentrations of active t-PA increased significantly 3 months after a change in treatment to gliclazide, and active t-PA again decreased in one patient to undetectable levels after 12 months with gliclazide. Moreover, the plasma concentrations of total t-PA antigen increased significantly (p less than 0.02) in this group of diabetic patients while PAI remained unchanged. The changes in t-PA-related fibrinolysis could not be related in either Type I or Type II diabetics to changes in metabolic state evaluated by blood glucose, HbA1c, cholesterol, triglycerides, or apolipoproteins A and B. We conclude that gliclazide has the potential to exert extrametabolic non-insulin-mediated effects on t-PA-related fibrinolysis in diabetic patients.

Adult↗
PubMed1991

Efficacy of gliclazide in comparison with other sulphonylureas in the treatment of NIDDM.

Three studies were performed to assess the efficacy of various sulphonylureas in the management of diet-failed NIDDM patients. In the first study, 224 patients inadequately controlled by diet alone or with oral hypoglycaemics received gliclazide in addition to diet or in place of existing drugs for three months. The dosage was adjusted to obtain adequate control or up to the maximum recommended dosage. Good glycaemic control was achieved in 65% of patients. Conversion from other oral hypoglycaemics to gliclazide led to an improvement in control except in cases previously treated with glibenclamide. In the second study, diabetic control was compared in 112 NIDDM patients treated concurrently for one year with chlorpropamide, glipizide, gliquidone, glibenclamide or gliclazide. On the basis of HbA1 levels, the best results were obtained with glibenclamide and gliclazide, leading to normal HbA1 levels in 74% and 80% of patients, respectively. In the third study, secondary failure rates were assessed in 248 NIDDM patients treated for five years with gliclazide, glibenclamide or glipizide. Gliclazide had the lowest secondary failure rate (7%) and was significantly better than glipizide (25.6% failures in five years), but the difference relative to glibenclamide (17.9%) just failed to reach the threshold of significance. The results of these studies show that gliclazide is a potent hypoglycaemic agent which compares favourably with others of its type. It has a low incidence of side effects, few problems with hypoglycaemia, and retains its efficacy longer than other sulphonylureas. Gliclazide may therefore be considered a first choice for the therapy of diet-failed NIDDM patients.

Blood Glucose↗
PubMed1991

Effect of 6 months' gliclazide treatment on insulin release and sensitivity to endogenous insulin in NIDDM: role of initial CSII-induced normoglycemia.

In 10 obese, newly diagnosed non-insulin-dependent diabetes mellitus (NIDDM) patients (group A) continuous subcutaneous insulin infusion (CSII) was used to induce normoglycemia over a period of 14 days. Fasting blood glucose was 4.61 +/- 0.22 mmol/l and mean daily blood glucose 5.83 +/- 0.27 mmol/l at the end of the CSII period. This excellent glycemic control was obtained with 35 +/- 4.8 U insulin per day, corresponding to 0.47 +/- 0.06 U/kg/24 h. Endogenous insulin production was markedly suppressed, since urinary C-peptide was reduced from 56 +/- 0.35 to 24 +/- 0.76 micrograms/24 h. Thus, physiological insulin replacement induced normoglycemia in NIDDM, indicating that insulin resistance is not clinically important. Gliclazide was given to group A following CSII and to 5 obese NIDDM patients (group B) in their habitual hyperglycemic state. Gliclazide maintained in group A and induced in group B excellent metabolic control. This was accompanied by the appearance of a small first-phase insulin response to iv glucose and by significant increases in the mean daily insulin to mean daily blood glucose ratio and in the 24-h urinary C-peptide to glucose ratio. The gliclazide effects tended to be more pronounced in group A. No significant effect was seen on sensitivity to endogenous insulin (slope of disappearance of blood glucose as function of insulin response to glucose infusion). During the 6 months of gliclazide treatment, excellent glycemic control was obtained in all patients. This was paralleled by unchanged stimulation by gliclazide of first-phase insulin response to glucose as well as mean by 48-h insulin to glucose and urinary C-peptide to glucose ratios. Again, sensitivity to endogenous insulin was not augmented. We conclude that gliclazide has a beta-cell-stimulating action which is maintained quantitatively unchanged for at least 6 months. The therapeutic effect of gliclazide in NIDDM seems to be mainly, if not exclusively, the result of its beta-cytotrophic action. Initial normoglycemia, induced here by CSII, may have a lasting enhancing effect on gliclazide action.

Blood Glucose↗
PubMedDate not supplied

Hemobiological properties of gliclazide.

Non-insulin-dependent diabetes mellitus (NIDDM) is associated with an increased risk of macro- and microvascular degenerative complications. Gliclazide is a second generation sulfonylurea that is widely used in the treatment of type II diabetes mellitus. Its hypoglycemic activity is well documented. In addition to its metabolic effects, gliclazide has beneficial effects on the hemobiological abnormalities of NIDDM. These effects are mediated by the azabicyclo-octyl ring grafted on to its aulfonylurea core. Numerous studies have demonstrated that gliclazide reduces platelet hyperadhesion and platelet hyperaggregability. These actions have been extensively confirmed in diabetic patients over periods of up to 3 years. With regard to platelet functions, several groups have demonstrated a significant reduction in serum and intraplatelet beta thromboglobulin and thromboxane B2. In animal models, in-vitro and in-vivo gliclazide stimulates endothelial prostacyclin synthesis. The beneficial effects of the compound on thromboxane/prostacyclin balance have been recently confirmed in type II diabetic patients after a 3-month treatment period. Concerning fibrinolysis, gliclazide restores low plasminogen activity to normal in NIDDM patients previously treated with first-generation sulfonyl-ureas. Gliclazide increases fibrinolytic potential by increasing endothelial cell tissue plasminogen activator and pre-kallikrein activity. More recent studies suggest that gliclazide may have effects on fibrin network structure, rendering the fibrin more amenable to fibrinolysis. Finally, it has been shown that gliclazide has a potent free-radical-scavenging activity in vitro. This property has been recently confirmed in vivo in type II diabetic patients and may suggest that platelet reactivity and oxidative stress are related in these patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1981

Determination of a new hypoglycemic drug, gliclazide, in human serum by radioimmunoassay.

radioimmunoassays have been developed which enable accurate and sensitive determination of gliclazide in human serum. Antisera A and B against gliclazide were obtained from guinea pigs immunized with conjugates A and B prepared by coupling gliclazide homologues, 1-(p-toluenesulfonyl)-3-(4'-carboxypiperidino)urea and 1-(4-methyl-3-carboxybenzenesulfonyl)-3-(3-azabicyclo[3,3,0]oct-3-yl)urea, to bovine serum albumin. 3H-Gliclazide was used as a tracer. Dextran-coated charcoal was used to separate bound and free 3H-gliclazide in the reaction mixture. The assays of gliclazide in serum were possible over a concentration range from 0.25 to 20 microgram/ml with the antiserum A and from 0.1 to 10 microgram/ml with the antiserum B, respectively, using 0.01 ml of human serum without the need for an extraction procedure. The antisera used for the assays were specific for gliclazide. Data obtained by the radioimmunoassay with the antiserum A are in good agreement with those by the radioimmunoassay with the antiserum B and gas-liquid chromatography. Serum levels of gliclazide in healthy volunteers receiving single oral dosing (40 mg/subject) have also been determined.

Antibody Specificity↗
PubMedDate not supplied

Hypoglycemic action and disposition of gliclazide in normal and analbuminemic rats.

The hypoglycemic action and disposition of gliclazide, an oral antidiabetic drug, was investigated in normal and analbuminemic rats. Orally administered gliclazide exhibited a stronger hypoglycemic action in analbuminemic rats than in normal rats. However, the plasma concentration of the drug in the mutant was much lower than that in the normal. This apparent discrepancy may be clarified by measuring the plasma concentration of unbound gliclazide. Analbuminemic rats gave larger values for the total body clearance and steady state volume of distribution of gliclazide than normal rats. The biliary and urinary excretion rates of radioactivity after intravenous bolus administration of [3H]-gliclazide were much greater in the mutant than in the normal. The binding of gliclazide to serum in analbuminemic rats was much lower than that in normal rats. Furthermore, the radioactivities of some tissues after oral administration of [3H]-gliclazide were found to be significantly higher in the mutant than in the normal. These results clearly indicate that albumin plays an important role in the hypoglycemic activity and disposition of gliclazide in rats.

Animals↗
PubMed1997

Gliclazide decreases cell-mediated low-density lipoprotein (LDL) oxidation and reduces monocyte adhesion to endothelial cells induced by oxidatively modified LDL.

Low-density lipoprotein (LDL) oxidation has been suggested to play a key role in the pathogenesis of atherosclerosis, a major complication of diabetes mellitus. Gliclazide, a second-generation sulfonylurea, is widely used in the treatment of type II diabetes mellitus. Recently, a free-radical-scavenging activity of gliclazide has been reported. In the present study, we examined the effects of gliclazide on cell-mediated LDL oxidation and monocyte adhesion to endothelial cells induced by oxidatively modified LDL. Incubation of human monocytes and bovine aortic endothelial cells (BAE cells) with increasing concentrations of gliclazide (0 to 10 micrograms/mL) and native LDL (100 micrograms/mL) resulted in a dose-dependent diminution of cell-mediated LDL oxidation as assayed by measurement of thiobarbituric acid (TBA)-reactive substances (TBARS). In addition, exposure of BAE cells to gliclazide (0 to 10 micrograms/mL) and native LDL (100 micrograms/mL) induced a dose-dependent diminution of the oxidized LDL-induced monocyte adhesion to BAE cells as measured by the myeloperoxidase (MPO) assay. The effects of glyburide, another second-generation sulfonylurea, were also tested on cell-mediated oxidation of LDL and LDL-induced monocyte adhesion to the endothelium. No significant effect of this drug was observed on these two processes. These results therefore demonstrate that gliclazide is effective in vitro in reducing both cell-mediated LDL oxidation and monocyte adhesion to the endothelium. These findings suggest a potential beneficial effect of gliclazide in the prevention of atherosclerosis in diabetic patients.

Animals↗