Effect of binary and ternary solid dispersions on the in vitro dissolution and in-situ rabbit intestinal absorption of gliclazide

Solid dispersion technique is widely used to improve the dissolution rate of drugs. Most investigators relied on the in-vitro characterization and considered the enhanced dissolution as an indication of improved bioavailability. The current study investigated the effects of binary and ternary solid dispersions of gliclazide with polyethylene glycol 6000 (PEG 6000) and/or pluronic F68 (PL F68) on the dissolution of gliclazide. The study also investigated the intestinal absorption in presence of solid dispersion components. The latter employed the in-situ rabbit intestinal perfusion technique. Preparation of binary solid dispersion with PEG 6000 or PL F68 significantly enhanced the dissolution rate compared to pure drug. The ternary solid dispersion of gliclazide with both polymers resulted in rapid drug dissolution with most drug being released in the first five minutes. The intestinal perfusion indicated the possibility of complete drug absorption from the small intestine. This, together with slow dissolution of pure drug suggested that the absorption of gliclazide is dissolution rate limited. The presence of PEG 6000 did not alter the intestinal absorption but PL F68 showed a trend of enhanced intestinal absorption of the drug. Ternary solid dispersion can thus provide rapid absorption due to rapid dissolution and potential increase in intestinal permeability.

Formulation and evaluation of Ficus glomerata mucilage sustained release matrix tablets of gliclazide

The main aim of present investigation was to develop sustained release matrix tablets of Gliclazide using fruit mucilage from the plant Ficus glomerata. Varying ratios of drug and polymer viz. 1:0.25, 1:0.5, 1:0.75, 1:1.0 and 1:1.25 were selected for the study. The flow properties of powdered mucilage and physical properties of matrix tablets were performed. The swelling behavior and release rate characteristics were studied. The in vitro drug release data was analyzed by zero order, first order, Higuchi plot, Peppas plot and Hixon-Crowell Models. It was observed that as the proportion of mucilage increased the release of drug from the matrix tablets was retarded. Stability studies were conducted at 40±2ºC and RH 75±5% for 3 months indicates that Gliclazide was stable in the matrix tablets. The Differential Scanning Calorimetric (DSC) and Fourier Transform Infrared (FTIR) study revealed that there was no negative chemical interaction between drug and the mucilage used. From the dissolution study, it was concluded that dried Ficus glomerata mucilage can be used as an excipient for making sustained release matrix tablets.

Comparison of the dipeptidyl peptidase-4 inhibitor vildagliptin and the sulphonylurea gliclazide in combination with metformin, in Muslim patients with type 2 diabetes mellitus fasting during Ramadan: results of the VECTOR study

OBJECTIVE

To compare the incidence of hypoglycaemic events (HEs) in a real-world setting in Muslim patients with type 2 diabetes mellitus fasting during Ramadan.

RESEARCH DESIGN AND METHODS

We performed a ≤16-week prospective, non-interventional, two-cohort study. Data were collected 1-6 weeks before and ≤6 weeks after fasting. Patients were enrolled who had been receiving vildagliptin (50 mg twice daily) or sulphonylurea (SU) as add-on to metformin at least 4 weeks prior to fasting.

MAIN OUTCOME MEASURES

The primary efficacy endpoint was incidence of HEs during the Ramadan fast. Changes in glycated haemoglobin (HbA(1c)) and body weight, as well as adherence to treatment, were also assessed.

RESULTS

Seventy-two patients were enrolled (vildagliptin, n = 30; SU, n = 41; no treatment, n = 1), of whom 23 (76.7%) and 36 (87.8%), respectively, completed the study. With vildagliptin, there were no HEs or severe HEs, compared with 34 HEs (15 patients, 41.7%) and one severe (grade 2) HE with SU. The mean between-group difference in the proportion who experienced at least one HE was -41.7% (95%CI -57.8%, -25.6%), p = 0.0002. Vildagliptin lowered mean HbA(1c) from 7.6% (SD 0.9%) at baseline to 7.2% (SD 0.7%) post-Ramadan, whereas SU had no effect (7.2% [SD 0.6%] vs 7.3% [SD 0.7%]; mean between-group difference -0.5% [95% CI -0.9%, -0.1%], p = 0.0262). The mean number of missed doses was markedly lower with vildagliptin (0.2 [SD 0.8] vs 7.6 [SD 14.9]; mean between-group difference -7.4 [95% CI -13.7, -1.20] doses; p = 0.0204). Body weight remained unchanged in both groups.

CONCLUSION

Vildagliptin caused no hypoglycaemia, was well adhered to and improved HbA(1c), making it a suitable treatment option for managing fasting. Study limitations are the sample size and the lack of diet and exercise data. When extrapolated to the global Muslim population with a similar clinical background, these findings could have considerable public health and clinical implications.

Erectile dysfunction and later cardiovascular disease in men with type 2 diabetes: prospective cohort study based on the ADVANCE (Action in Diabetes and Vascular Disease: Preterax and Diamicron Modified-Release Controlled Evaluation) trial

OBJECTIVES

The aim of this study was to examine the relationship between erectile problems in men and cardiovascular disease (CVD) mortality.

BACKGROUND

Although there are plausible mechanisms linking erectile dysfunction (ED) with coronary heart disease (CHD) and stroke, studies are scarce.

METHODS

In a cohort analysis of the ADVANCE (Action in Diabetes and Vascular Disease: Preterax and Diamicron Modified-Release Controlled Evaluation) trial population, 6,304 men age 55 to 88 years with type 2 diabetes participated in a baseline medical examination when inquiries were made about ED. Over 5 years of follow-up, during which study members attended repeat clinical examinations, the presence of fatal and nonfatal CVD outcomes, cognitive decline, and dementia was ascertained.

RESULTS

After adjusting for a range of covariates, including existing illness, psychological health, and classic CVD risk factors, relative to those who were free of the condition, baseline ED was associated with an elevated risk of all CVD events (hazard ratio: 1.19; 95% confidence interval: 1.08 to 1.32), CHD (hazard ratio: 1.35; 95% confidence interval: 1.16 to 1.56), and cerebrovascular disease (hazard ratio: 1.36; 95% confidence interval: 1.11 to 1.67). Men who experienced ED at baseline and at 2-year follow-up had the highest risk for these outcomes.

CONCLUSIONS

In this cohort of men with type 2 diabetes, ED was associated with a range of CVD events.

Effects of metformin plus gliclazide compared with metformin alone on circulating endothelial progenitor cell in type 2 diabetic patients

Circulating endothelial progenitor cells (EPCs) play an important role in the development and progression of diabetic vascular complications. The aim of this study was to investigate the effects of gliclazide plus metformin (GLIMET) compared with metformin alone (MET) on number and function of circulating EPCs in T2DM patients. Patients with newly diagnosed T2DM were randomly divided into two groups, receiving the following treatments for 16 weeks: MET group (assuming metformin 500-2500 mg/day, n=24) and GLIMET group [assuming gliclazide (modified release, 30-60 mg/day)+metformin (250-1000 mg/day), n=23]. Circulating EPCs were quantified by flow cytometry, and the ability to uptake LDL and stain for lectin were used as another method of characterizing EPCs ex vivo. The functions of circulating EPCs were evaluated by colony-forming units (CFU) and migration. The status of oxidative stress was analyzed by serum-free malonaldehyde (MDA) and superoxide dismutase (SOD). There were no significant differences in clinical characteristics and number and function of circulating EPCs between two groups at baseline. Glycemic responses were similar after treatments. Compared with MET group, GLIMET group was associated with an increase in circulating EPCs number, DiLDL-lectin-positive EPCs, and migration. The mean improvements in MDA and SOD of GLIMET group were more strongly upregulated than those of MET group. This study demonstrated that both metformin mono-treatment and metformin plus gliclazide combination treatment provided with improvements in number and function of circulating EPCs. Compared with metformin mono-treatment, early use of combination therapy with gliclazide plus metformin made more effective improvements in circulating EPCs.

Maintenance of glycaemic control with the evening administration of a long acting sulphonylurea in male type 2 diabetic patients undertaking the Ramadan fast

BACKGROUND

In Ramadan, misuse of hypoglycaemic agents, alterations in diet and hypoglycaemia are frequent. This study assessed whether switching to an evening administration of a long acting sulphonylurea during the 29-day, dawn to dusk fast, can maintain glycaemic control in patients with type 2 diabetes.

PATIENTS AND METHODS

Male type 2 diabetic patients from Bangladesh, Pakistan and India, under glycaemic control with gliclazide modified release (MR) 60 mg monotherapy, switched to evening administration of the same dose during Ramadan, and reverted to the morning schedule thereafter. The primary outcome was the difference in fasting plasma glucose (FPG) before and after Ramadan.

RESULTS

In 136 patients, mean (95% CI) FPG decreased by 0.01 mmol/l (0-0.2, p = 0.3) with evening medication by the end of the fast, and increased by 0.2 mmol/l (0.1-0.3, p = 0.01) after reverting to morning medication 20 days later. There were 5 (3.7%) hypoglycaemic episodes before, 3 (2.2%) during and 2 (1.5%) after Ramadan.

CONCLUSION

Male type 2 diabetic patients undertaking the Ramadan fast can safely maintain glycaemic control with evening administration of gliclazide MR 60 mg during the fast, and reverting to a morning schedule thereafter.

A comparison of efficacy and safety of vildagliptin and gliclazide in combination with metformin in patients with Type 2 diabetes inadequately controlled with metformin alone: a 52-week, randomized study

AIM

To demonstrate non-inferiority of vildagliptin compared with gliclazide, as an add-on therapy, in patients with Type 2 diabetes inadequately controlled with metformin in a 52-week, randomized, double-blind, active-controlled study.

METHODS

Patients receiving a stable dose of metformin (> or = 1500 mg) were randomized (1 : 1) to receive vildagliptin (50 mg twice daily; n = 513) or gliclazide (up to 320 mg/day; n = 494).

RESULTS

Non-inferiority of vildagliptin was demonstrated (95% confidence interval -0.11%, 0.20%) with a mean change (se) from baseline glycated haemoglobin (HbA(1c)) (approximately 8.5% in both groups) to a 52-week endpoint of -0.81% (0.06) with vildagliptin and -0.85% (0.06) with gliclazide. Although a similar proportion of patients reached HbA(1c) < 7.0%, the total number of hypoglycaemic events was lower in the vildagliptin group (6 vs. 11 events). Vildagliptin was non-inferior (margin 0.6 mmol/l) to gliclazide in reducing fasting plasma glucose (1.31 vs. 1.52 mmol/l, P = 0.257). The overall incidence of any adverse events was similar in both groups (approximately 61%), but the number of serious adverse events was higher in the gliclazide group (8.7 vs. 6.7%). The number of patients who discontinued as a result of an unsatisfactory effect was higher in the vildagliptin group (n = 22 vs. 13, respectively) compared with gliclazide, but vildagliptin did not induce weight gain.

CONCLUSION

In patients with Type 2 diabetes inadequately controlled with metformin, addition of vildagliptin provided similar HbA(1c)-lowering efficacy compared with gliclazide after 52 weeks of treatment. Although both treatments were well tolerated, vildagliptin-treated patients had fewer hypoglycaemic events and did not gain weight.

In-vitro and in-vivo correlation for two gliclazide extended-release tablets

The aim of this study was to perform an in-vitro-in-vivo correlation (IVIVC) for two 60-mg gliclazide extended-release formulations (Fast and Slow release) given once a day and to compare their plasma concentrations over time. In-vitro release rate data were obtained for each formulation using the USP apparatus II, paddle stirrer at 50 and 100 rev min−1 in 0.1 M HCl and pH 7.4 phosphate buffer. The similarity factor (f2) was used to analyse the dissolution data. Eighteen healthy subjects participated in the study, conducted according to a completely randomized, two-way crossover design. The formulations were compared using area under the plasma concentration-time curve, AUC0-∞′, time to reach peak plasma concentration, Tmax', and peak plasma concentration Cmax', while correlation was determined between in-vitro release and in-vivo absorption. A linear correlation model was developed using percent absorbed data versus percent dissolved data from the two formulations. Predicted gliclazide concentrations were obtained by use of a curve fitting equation. Prediction errors were estimated for Cmax and area under the curve AUC0-∞ to determine the validity of the correlation. 0.1 M HCl at 50 rev min−1 was found to be the most discriminating dissolution method. Linear regression analysis of the mean percentage of dose absorbed versus the mean percentage of in-vitro release resulted in a significant correlation (r2 &gt; 0.98) for the two formulations. An average percent prediction error for Cmax was 4.15% for Fast release and 3.99% for Slow release formulation whereas for AUC0-∞ it was 6.36% and 4.66% for Fast release and Slow release formulation, respectively.

[Dynamics of structural-functional parameters of cardiovascular system during use of complex therapy of women with type 2 diabetes mellitus]

Aim of the work was to study dynamics of parameters of cardiovascular system in women during use of various sugar lowering drugs in complex multifactorial therapy of type 2 diabetes mellitus (DM). We included in this 12 months study 182 women older than 55 years with type 2 DM, abdominal obesity and artrerial hypertension (AH). All women received angiotensin converting enzyme inhibitors and statins. As sugar lowering drugs we used metformin (n = 46), metformin with glyclazide (n = 47), monotherapy with insulin (n = 45). Long-term use of metformin in complex multifactorial therapy of women with decompensated type 2 diabetes DM, AH and abdominal obesity provides improvement of carbohydrate and lipid metabolism, lowering of arterial pressure, diminishment of albuminuria, diastolic dysfunction, and stiffness of left ventricular myocardium. The use of combination of metformin with glyclazide MB provides advantages in lowering of insulin resistance, contol glycemia, and lessening of hypertrophy of left ventricular myocardium.

[Capabilities of hypoglycemic therapy in women with decompensated type 2 diabetes mellitus]

AIM

to comparatively evaluated the efficiency of various sugar-lowering therapy (SLT) options in patients with decompensated type 2 diabetes mellitus (T2DM).

SUBJECTS AND METHODS

One hundred and eighty-two women who were over 55 years of age with a more than 3-5-year history of T2DM and more than one-year decompensation, abdominal obesity (AO), arterial hypertension, and concomitant treatment-matched were randomized into 4 groups: (1) metformin (n=46); (2) a combination of metformin and gliclaside MB (n=47); (3) metformin and insulin (n=44); and (4) insulin (n=45). A follow-up was 12 months.

RESULTS

As compared with the patients receiving insulin monotherapy, the patients taking metformin alone or in combination showed a more effective recovery of carbohydrate and lipid metabolic disturbances, diminished insulin resistance (IR), lowered blood pressure and albuminuria, reduced diastolic dysfunction, and a smaller cardiovascular risk. When metformin was used in combination with gliclaside (Group 2) for 12 months, there was the maximum IR reduction, an increase in insulin sensitivity, and better results in reaching the goal values of carbohydrate metabolism; there was left ventricular myocardial reverse remodeling. In all the groups, quality of life (SF-36v2) improved, reduced depression (CES-D) reduced; the greatest improvement of the mental component of health-related quality (SF-36v2) and the greatest satisfaction with treatment results (DTSO) were noted when metformin was given in combination with gliclaside MB.

CONCLUSION

In patients having a more than 3-5-year history of T2DM in the presence of AO and IR, with a history of DM decompensation, the use of metformin in combination with gliclaside MB is more preferable, by effectively correcting IR, recovering the physiological profile of insulin secretion, and adequately controlling glycemia.

Normal insulin response to short-term intense exercise is abolished in Type 2 diabetic patients treated with gliclazide

BACKGROUND

Physical activity is an essential component of diabetes management; however, exercise is associated with the risk for metabolic decompensation. The aim of the study was to analyze insulin response to the short-term intense exercise in middle-aged Type 2 diabetic patients treated with gliclazide.

MATERIALS AND METHODS

Fourteen Type 2 diabetic patients (47.9+/-1.6 years, mean+/-S.E.M.), treated with gliclazide, and 14 healthy controls (45.1+/-1.0 years) were submitted to standard graduated submaximal (90% HR(max)) exercise treadmill testing at 2 h after standardized breakfast. Serum glucose, insulin, proinsulin, C peptide, growth hormone, insulin-like growth factor-1, and cortisol concentrations; and plasma lactate, glucagon, epinephrine, and norepinephrine concentrations were measured during the periexercise period up to the 60th min of the recovery period.

RESULTS

Significant hemodynamic (heart rate, systolic, and diastolic blood pressure), metabolic (lactate concentration), and hormonal (epinephrine and norepinephrine levels) responses to the exercise were similar in patients and healthy subjects. Glucose, insulin, and proinsulin levels were higher in the diabetic group at the preexercise and at all the next analyzed time points. The insulin concentration increased during the postprandial period in both groups and decreased subsequently during the exercise only in the control group, without concurrent C peptide decline. The C peptide-to-insulin ratio increased during the exercise and decreased immediately postexercise only in the control group.

CONCLUSIONS

The initial decrease of the insulin serum concentration during short-term intense exercise in normal middle-aged men is primarily related to the increased clearance of the hormone. Normal insulin response to the exercise was abolished in Type 2 diabetic patients treated with gliclazide.

Vildagliptin therapy and hypoglycaemia in Muslim type 2 diabetes patients during Ramadan

AIMS

To compare hypoglycaemic events, glycated haemoglobin (HbA(1c)) and changes in bodyweight in metformin-treated Muslim patients with type 2 diabetes receiving adjunctive treatment with vildagliptin or gliclazide during Ramadan fasting.

METHODS

Data were collected from Muslim patients with type 2 diabetes attending primary care practices in North West London, whose HbA(1c) was > 8.5% despite treatment with metformin 2 g daily before Ramadan and who received gliclazide 160 mg twice daily (n = 26) or vildagliptin 50 mg twice daily (n = 26) in addition to metformin. Hypoglycaemic events, HbA(1c) and weight were recorded 2 weeks before and 10 days after the Ramadan fast. All patients received education about how to identify and manage hypoglycaemia during Ramadan.

RESULTS

During Ramadan, at least one hypoglycaemic event (defined as blood glucose < 3.5 mmol/l with or without symptoms) was recorded in two patients receiving vildagliptin (7.7%) and 16 patients receiving gliclazide [61.5%; difference between groups -53.8%, 95% confidence interval (CI) -74.9 to -26.3, p < 0.001]. Vildagliptin was associated with a reduction in the mean number of hypoglycaemic events during Ramadan compared with before Ramadan, whereas gliclazide was associated with an increase (least squares mean difference between groups -0.66, 95% CI -1.20 to -0.13, p = 0.0168). Both gliclazide and vildagliptin were associated with similar reductions in HbA(1c) and a small, but insignificant, increase in weight.

CONCLUSIONS

Appropriate treatment adjustments can lead to improved diabetes management during Ramadan, with avoidance of significant weight gain and improved glucose control without hypoglycaemia. The addition of vildagliptin to metformin therapy during Ramadan in Muslim patients with type 2 diabetes was associated with a reduction in the incidence of hypoglycaemia.

Preparation and In Vitro/In Vivo Evaluation of Gliclazide Loaded Eudragit Nanoparticles as a Sustained Release Carriers

The aim of this study was to formulate and optimize gliclazide-loaded Eudragit nanoparticles (Eudragit L100 and Eudragit RS) as a sustained release carrier with enhanced efficacy. Eudragit L 100 nanoparticles (ELNP) were prepared by controlled precipitation method whereas Eudragit RSPO nanoparticles (ERSNP) were prepared by solvent evaporation method. The influence of various formulation factors (stirring speed, drug:polymer ratio, homogenization, and addition of surfactants) on particle size, drug loading, and encapsulation efficiency were investigated. The developed Eudragit nanoparticles (L100 and RS) showed high drug loading and encapsulation efficiencies with nanosize. Mean particle size altered by changing the drug:polymer ratio and stirring speed. Addition of surfactants showed a promise to increase drug loading, encapsulation efficiency, and decreased particle size of ELNP as well as ERSNP. Dissolution study revealed sustained release of gliclazide from Eudragit L100 as well as Eudragit RSPO NP. SEM study revealed spherical morphology of the developed Eudragit (L100 and RS) NP. FT-IR and DSC studies showed no interaction of gliclazide with polymers. Stability studies revealed that the gliclazide-loaded nanoparticles were stable at the end of 6 months. Developed Eudragit NPs revealed a decreased t(min) (ELNP), and enhanced bioavailability and sustained activity (ELNP and ERSNP) and hence superior activity as compared to plain gliclazide in streptozotocin induced diabetic rat model and glucose-loaded diabetic rat model. The developed Eudragit (L100 and RSPO) NP could reduce dose frequency, decrease side effects, and improve patient compliance.

Intensive blood glucose control and vascular outcomes in patients with type 2 diabetes

BACKGROUND

In patients with type 2 diabetes, the effects of intensive glucose control on vascular outcomes remain uncertain.

METHODS

We randomly assigned 11,140 patients with type 2 diabetes to undergo either standard glucose control or intensive glucose control, defined as the use of gliclazide (modified release) plus other drugs as required to achieve a glycated hemoglobin value of 6.5% or less. Primary end points were composites of major macrovascular events (death from cardiovascular causes, nonfatal myocardial infarction, or nonfatal stroke) and major microvascular events (new or worsening nephropathy or retinopathy), assessed both jointly and separately.

RESULTS

After a median of 5 years of follow-up, the mean glycated hemoglobin level was lower in the intensive-control group (6.5%) than in the standard-control group (7.3%). Intensive control reduced the incidence of combined major macrovascular and microvascular events (18.1%, vs. 20.0% with standard control; hazard ratio, 0.90; 95% confidence interval [CI], 0.82 to 0.98; P=0.01), as well as that of major microvascular events (9.4% vs. 10.9%; hazard ratio, 0.86; 95% CI, 0.77 to 0.97; P=0.01), primarily because of a reduction in the incidence of nephropathy (4.1% vs. 5.2%; hazard ratio, 0.79; 95% CI, 0.66 to 0.93; P=0.006), with no significant effect on retinopathy (P=0.50). There were no significant effects of the type of glucose control on major macrovascular events (hazard ratio with intensive control, 0.94; 95% CI, 0.84 to 1.06; P=0.32), death from cardiovascular causes (hazard ratio with intensive control, 0.88; 95% CI, 0.74 to 1.04; P=0.12), or death from any cause (hazard ratio with intensive control, 0.93; 95% CI, 0.83 to 1.06; P=0.28). Severe hypoglycemia, although uncommon, was more common in the intensive-control group (2.7%, vs. 1.5% in the standard-control group; hazard ratio, 1.86; 95% CI, 1.42 to 2.40; P<0.001).

CONCLUSIONS

A strategy of intensive glucose control, involving gliclazide (modified release) and other drugs as required, that lowered the glycated hemoglobin value to 6.5% yielded a 10% relative reduction in the combined outcome of major macrovascular and microvascular events, primarily as a consequence of a 21% relative reduction in nephropathy. (ClinicalTrials.gov number, NCT00145925.)

Hypoglycemic effects of a sesquiterpene glycoside isolated from leaves of loquat (Eriobotrya japonica (Thunb.) Lindl.)

Sesquiterpene glycoside, nerolidol-3-O-alpha-l-rhamnopyranosyl(1-->4)-alpha-l-rhamnopyranosyl(1-->2)-[alpha-l-rhamnopyranosyl(1-->6)]-beta-d-glucopyranoside was isolated from dried leaves of loquat [Eriobotrya japonica (Thunb.) Lindl., Rosaceae]. Hypoglycemic effects of this natural product were assessed in normal and alloxan-diabetic mice model. Animals received orally administration of the sesquiterpene glycoside in dose of 25 and 75 mg/kg. The anti-hyperglycemic effect was compared with gliclazide's. The dose of 25 and 75 mg/kg both exerted a significant (p<0.05) hypoglycemic effect in alloxan-diabetic mice throughout the test and a slight effect in normal mice.

In vivo and in vitro evaluation of a solid dispersion system of gliclazide:PEG 6000

OBJECTIVE

Gliclazide is a potent antidiabetic agent because of its capability to decrease blood glucose level via stimulating endogenous insulin secretion from beta-pancreas cells. Gliclazide is insoluble in water and has low dissolution rate. In this study, polyethylene glycol (PEG) 6000 was used as a matrix to disperse gliclazide in the solid state, and the pharmacokinetic profile of this solid dispersion was studied in rats.

DESIGN

The solid dispersion of Gliclazide:PEG 6000 (1:4) was prepared by solvent evaporation method.

MAIN OUTCOME MEASURES

Samples characterization included differential scanning calorimetry (DSC), infrared spectroscopy (IR), X-ray diffraction (XRD), and solubility and dissolution test. In vivo study was carried out in healthy rats, randomly. After a single dose of oral administration, blood samples were collected pre-dose (15 min before) and 1, 2, 3, 4, 5, 6, 8, 10, and 12 h post-dose. Plasma concentration of gliclazide was determined by high pressure liquid chromatography method using C-18 column, with mobile phase KH2PO4 (pH 4.6)-acetonitril (40:60 v/v) and UV detection at 229 nm.

RESULTS

Results showed that there were no differences in DSC, IR spectroscopy, XRD, and dissolution test between the solid dispersion and physical mixture. In vivo data showed that the Tmax of gliclazide in solid dispersion and physical mixture was significantly decreased, while the Cmax, AUC(0-12), and AUC(0-infinity) were significantly increased compared to gliclazide alone. These results indicate that the rapid Tmax was due to rapid absorption of gliclazid across the GI tract membrane. Increased Cmax, AUC(0-12), and AUC(0-infinity) indicate a better absorption of gliclazide in solid dispersion and physical mixture than of gliclazide alone.

CONCLUSION

Increased in gliclazide dissolution in the presence of PEG 6000 was followed by improved in vivo data.

The mushroom Agaricus Blazei Murill in combination with metformin and gliclazide improves insulin resistance in type 2 diabetes: a randomized, double-blinded, and placebo-controlled clinical trial

BACKGROUND

Complementary and alternative medicine use in adults with type 2 diabetes is popular. Although most of the herbs and supplements appear to be safe, there is still insufficient evidence that demonstrates their definitive beneficial effects. This study was done to determine whether the supplement of Agaricus blazei Murill extract improves insulin resistance in type 2 diabetes.

MATERIALS AND METHODS

This study was a clinical randomized, double-blind, placebo-controlled trial. Of a population of 536 registered diabetes patients with 72 subjects (1) aged between 20 and 75 years, (2) being Chinese, (3) having type 2 diabetes for more than 1 year, and (4) having been taking gliclazide and metformin for more than 6 months were enrolled in this study. The enrolled patients were randomly assigned to either receiving supplement of Agaricus blazei Murill (ABM) extract or placebo (cellulose) 1500 mg daily for 12 weeks. Homeostasis model assessment for insulin resistance (HOMA-IR) was used as the major outcome measurement.

RESULTS

At the end of the study, subjects who received supplement of ABM extract (n = 29) showed significantly lower HOMA-IR index (3.6[standard deviation, 2.5] versus 6.6[standard deviation, 7.4], p = 0.04) than the control group (n = 31). The plasma adiponectin concentration increased 20.0(standard deviation, 40.7)% in the ABM group after 12 weeks of treatment, but decreased 12.0(20.0)% among those taking the placebo (p < 0.001).

CONCLUSIONS

Supplement of ABM extract improves insulin resistance among subjects with type 2 diabetes. The increase in adiponectin concentration after taking AMB extract for 12 weeks might be the mechanism that brings the beneficial effect. Studies with longer periods of follow-up should be conducted in the future.

Controlling of systemic absorption of gliclazide through incorporation into alginate beads

This work investigates preparation of biodegradable beads with alginate polymer by ionotropic gelation method to take the advantages of the swelling and mucoadhesive properties of alginate beads for improving the oral delivery of the antidiabetic agent gliclazide. It demonstrates that the ionic gelation of alginate molecules offers a flexible and easily controllable process for manipulating the characteristics of the beads which are important in controlling the release rate and consequently the absorption of gliclazide from the gastrointestinal tract. Variations in polymer concentration, stirring speed, internal phase volume and the type of surfactant in the external phase were examined systemically for their effects on the particle size, incorporation efficiency and flow properties of the beads. The swelling behavior was strongly dependent on the polymer concentration in the formulations and the pH of the medium. The in vitro release experiments revealed that the swelling is the main parameter controlling the release rate of gliclazide from the beads. In vivo studies on diabetic rabbits showed that the hypoglycemic effect induced by the gliclazide loaded alginate beads was significantly greater and more prolonged than that induced by the marketed conventional gliclazide tablet (Gliclazide). The results clearly demonstrated the ability of the system to maintain tight blood glucose level and improved the patient compliance by enhancing, controlling and prolonging the systemic absorption of gliclazide.

ADVANCE: breaking new ground in type 2 diabetes

OBJECTIVE AND RATIONALE

ADVANCE (Action in Diabetes and Vascular disease: preterAx and diamicroN-MR Controlled Evaluation) is a large-scale trial designed to investigate the benefits of blood pressure lowering and intensive glucose control in patients with type 2 diabetes, and to address a number of unresolved issues: whether blood pressure-lowering therapy and intensive glucose control therapy will reduce the risk of major vascular disease regardless of initial blood pressure or glucose concentration; whether more intensive glucose control targeting a haemoglobin A1c (HbA1c) level of 6.5% or less will confer greater protection against microvascular disease; and whether the benefits of the two interventions are additive.

DESIGN AND METHODS

ADVANCE is a 2 x 2 factorial randomized clinical trial evaluating the risks and benefits of the low-dose fixed combination of perindopril and indapamide versus placebo to lower blood pressure and of an intensive gliclazide-MR-based glucose control regimen, targeting an HbA1c of 6.5% or less versus standard guidelines based therapy for glucose control. There are two primary outcomes: a composite macrovascular endpoint and a composite microvascular endpoint.

RESULTS

A total of 12 878 participants from 215 centres in 20 countries entered a 6-week run-in phase between June 2001 and January 2003, and 11 140 patients were randomly assigned by March 2003. The average (SD) systolic and diastolic blood pressure fell from 145 (22)/81 (11) to 137 (20)/78 (10) mmHg during the 6-week run-in phase, during which participants received one tablet of open-labelled perindopril 2 mg/indapamide 0.625 mg. Of the 12 878 patients who entered the run-in, only 3.6% withdrew because of suspected intolerance to perindopril/indapamide. The study is half way through follow-up and both the study medications (perindopril 2 mg/indapamide 0.625 mg and gliclazide-MR) continue to be well tolerated. Completion is expected in 2007.

CONCLUSION

Safe and effective blood pressure lowering with the fixed low-dose combination of perindopril and indapamide was confirmed during the run-in phase in 11 140 patients with type 2 diabetes, who were subsequently randomly assigned. Post-randomization study treatments have been well tolerated, and the completion of follow-up is scheduled in 2007.

Clinical observation on effect of Kaixin Capsule in treating 40 patients with diabetic myocardial ischemia

OBJECTIVE

To observe the effect of Kaixin Capsule (KXC) on myocardial ischemia and plasma endothelin (ET) level in patients with diabetic heart disease (DHD).

METHODS

The 72 subjects for observation were randomly selected from inpatients whose diagnosis fit to the standard of DHD. The 32 patients allocated in the control group were treated with conventional Western medicine, and the 40 patients in the treated group were treated with conventional Western medicine in combination with KXC, with the therapeutic course for both groups as 60 days.

RESULTS

On ECG, the total effective rate and markedly effective rate in the treated group was 85.0% and 37.5% respectively, higher than those in the control group's 68.7% and 28.1% respectively, and showing significant difference between the two groups (P < 0.05). The level of ET in patients in both groups was significantly higher than normal range, after treatment, but reduced to different extent, and the comparison between them also showed that the difference was significant (P < 0.05).

CONCLUSION

KXC might, by way of inhibiting and blocking the release of ET, lower its level in plasma so as to improve the myocardial ischemic condition of patients with DHD.

Metrics for external model evaluation with an application to the population pharmacokinetics of gliclazide

PURPOSE

The aim of this study is to define and illustrate metrics for the external evaluation of a population model.

MATERIALS AND METHODS

In this paper, several types of metrics are defined: based on observations (standardized prediction error with or without simulation and normalized prediction distribution error); based on hyperparameters (with or without simulation); based on the likelihood of the model. All the metrics described above are applied to evaluate a model built from two phase II studies of gliclazide. A real phase I dataset and two datasets simulated with the real dataset design are used as external validation datasets to show and compare how metrics are able to detect and explain potential adequacies or inadequacies of the model.

RESULTS

Normalized prediction errors calculated without any approximation, and metrics based on hyperparameters or on objective function have good theoretical properties to be used for external model evaluation and showed satisfactory behaviour in the simulation study.

CONCLUSIONS

For external model evaluation, prediction distribution errors are recommended when the aim is to use the model to simulate data. Metrics through hyperparameters should be preferred when the aim is to compare two populations and metrics based on the objective function are useful during the model building process.

Double-blind, randomized, multicentre study of the efficacy and safety of gliclazide-modified release in the treatment of Chinese type 2 diabetic patients

BACKGROUND AND AIM

Gliclazide-modified release (gliclazide MR) is a new formulation of the sulfonylurea gliclazide designed for once-daily administration. The hydrophilic matrix of hypromellose-based polymer in the new formulation induces a progressive drug release, which parallels the 24-h glycaemic profile in type 2 diabetic patients. The aim of this study was to compare the efficacy and safety of gliclazide MR (once-daily administration) versus gliclazide (twice-daily administration) in Chinese type 2 diabetic patients.

MATERIALS AND METHODS

Sixty-three type 2 diabetic Chinese patients who had been on diet control alone or on treatment with metformin or on low dose of sulfonylurea were randomized to either gliclazide MR taken once daily or gliclazide taken twice daily. Dosage of metformin was maintained throughout the study, and the sulfonylurea was stopped. The dose of gliclazide MR was increased at 1-month intervals from 30 mg to 120 mg, while that of gliclazide from 80 mg to 320 mg until metabolic control was achieved [fasting plasma glucose (FPG) < or = 7.7 mmol/l] or the maximum dose reached. Efficacy was mainly evaluated by levels of haemoglobin A1c (HbA1c) and FPG.

RESULTS

The mean baseline characteristics of the full analysis set 1 (FAS1) (HbA1c, n = 58) and the FAS2 (FPG, n = 61) were comparable in both groups. The levels of HbA1c decreased similarly in both groups over the treatment period: -1.6 +/- 1.6% (p < 0.001) on gliclazide MR (n = 31) and -1.6 +/- 1.4% (p < 0.001) on gliclazide (n = 27). Decrease in HbA1c was observed irrespective of pre-existing therapy for diabetes: -2.3 +/- 1.5% for patients on diet alone; -0.6 +/- 1.3% for patients switched from sulfonylurea to study drug and -1.4 +/- 0.8% for patients on metformin in combination with study drug. FPG decreased significantly from 177.5 +/- 63.5 to 136.7 +/- 42.2 (p < 0.001, n = 32) on gliclazide MR and not significant from 188.2 +/- 62.6 to 163.7 +/- 67.9 (p = 0.059, n = 29) on gliclazide. Both treatments were very well tolerated with no major hypoglycaemic episodes requiring external assistance; only three patients experienced mild hypoglycaemic episodes.

CONCLUSIONS

Once-daily gliclazide MR showed a better trend in improving blood glucose control in comparison with gliclazide in type 2 diabetic Chinese patients irrespective of the pre-existing anti-diabetic treatment. The safety profiles of gliclazide MR and gliclazide were similar with a small number of patients having reported hypoglycaemic episodes. Once-daily dosing with gliclazide MR should improve patient compliance, an important factor in long-term glycaemic control.

Effects of Isopropyl Palmitate on the Skin Permeation of Drugs

The model penetrants oxaprozin, nimesulide, gliclazide, and ribavirin, because of their different lipophilicities, were selected to assess the enhancing activity of pre-treatment solutions consisting of isopropyl palmitate (IP) in ethanol (5%, 10%, 15%and 20%, w/w, respectively) across excised rat skin using Franz diffusion cells and HPLC detection. All pre-treatment solutions produced a significant increase in the flux and permeation of all four penetrants (p<0.001) and a relationship between penetrant lipophilicity and enhancement effect was observed. The general order of IP effectiveness at concentration was 20%>15%>10%>5% (w/w). The lag-time of drugs did not significantly change except for ribavirin.

Single and multiple dose bioequivalence evaluation of two brands of gliclazide modified release tablets in healthy Chinese male volunteers

Randomized, two-way, crossover, single- and multiple-dose studies were conducted in healthy Chinese male volunteers to evaluate the bioequivalence of two brands of gliclazide (CAS 21187-98-4, 1-(3-azabicylco(3, 3, 0)oct-3-yl)-3-p-tolysulfonylurea) 30 mg tablets, viz. Gliclazide modified release (MR) tablets as test (T) and a commercial gliclazide standard preparation as reference (R) product. Each volunteer received T and R tablets separated by 7 days of a drug-free washout period. The plasma concentrations of gliclazide, determined by a validated LC-ESI-MS method, were employed to assess the pharmacokinetic parameters such as maximum and minimum observed plasma concentration (Cmax and Cmin), time to Cmax (tmax), average plasma concentration at steady state (Cav), area under plasma concentration curve (AUC(0-72), AUC(0-infinity) and AUC(ss), and degree of fluctuation for plasma concentration (DF %). As to these parameters, the analysis of variance (ANOVA) showed no significant difference and 90 % confidence intervals (CI) fell entirely into the acceptable range of bioequivalence. Based on these statistical inferences, the two formulations are considered bioequivalent in the extent and rate of absorption from both single- and multiple-dose studies.