PurposePatients suffering from obesity-related diseases use multiple prescription drugs to control their condition, and it is therefore essential to determine the safety and efficacy of any combination. Gliclazide is one of the most commonly used drug of choice for treatment of type 2 diabetes, and curcumin is a widely used herbal supplement to counter obesity condition. The objective of this study was to investigate the effect of oral administration of curcumin on pharmacodynamics and pharmacokinetics of gliclazide in rats and rabbits to further evaluate the safety and effectiveness of this combination.MethodsInfluence of curcumin on the activity of gliclazide was determined by conducting single- and multiple-dose interaction studies in rats (normal and diabetic) and rabbits. Blood samples collected at predetermined time intervals from experimental animals were used for the estimation of glucose and insulin levels by using automated clinical chemistry analyzer and radioimmunoassay method, respectively. The insulin resistance and β-cell function were determined by homeostasis model assessment. Additionally, serum gliclazide levels in rabbits were analyzed by high-performance liquid chromatography.ResultsGliclazide showed peak reduction in blood glucose levels at 2 and 8 hours in rats and at 3 hours in rabbits. This activity of gliclazide was not altered by single-dose treatment with curcumin. However, in multiple-dose interaction studies, samples analyzed from all time points showed subtle but significantly greater reduction in percent blood glucose ranging from 23.38% to 42.36% in normal rats, 27.63% to 42.27% in diabetic rats, and 16.50% to 37.88% in rabbits. The pharmacokinetics of gliclazide was not altered by single- or multiple-dose curcumin treatments in rabbits.ConclusionThe interaction of curcumin with gliclazide up on multiple-dose treatment was pharmacodynamic in nature, indicating the need for periodic monitoring of glucose levels and dose adjustment as necessary when this combination is prescribed to obese patients.

BackgroundType 2 diabetes is frequently seen in patients suffering from obesity. p-synephrine and gliclazide are widely used medicines for the treatment of obesity and diabetes, respectively.ObjectivesThe present study was undertaken to determine the potential for interactions between p-synephrine and gliclazide, based on the relationship between obesity and diabetes.MethodsInfluence of p-synephrine on the activity of gliclazide was determined by conducting single and multiple dose interaction studies in animal models. Blood samples collected at pre-determined time intervals from experimental animals were used for the estimation of glucose and insulin levels. The insulin resistance and β-cell function were determined by homeostasis model assessment. Additionally, serum gliclazide levels in rabbits were analyzed by high-performance liquid chromatography (HPLC).ResultsGliclazide alone showed peak reduction in blood glucose levels at 2 and 8 h after administration in rats and after 3 h in rabbits. The activity of gliclazide was not altered by a single dose treatment with p-synephrine. However, in multiple dose interaction studies, samples from all the time points analyzed showed significant changes in percent blood glucose reduction ranging from 19.73 to 44.18% in normal rats, 23.76–46.43% in diabetic rats and 16.36–38.34% in normal rabbits. The homeostasis model assessment parameters were also significantly altered in multiple dose interaction studies. The pharmacokinetics of gliclazide was not altered by either single or multiple dose p-synephrine treatments in rabbits.ConclusionThe effect of multiple dose p-synephrine treatments upon gliclazide appeared to be pharmacodynamic in nature, indicating the need for periodic monitoring of glucose levels and dose adjustment as necessary when this combination is prescribed to obese patients.

A HPLC method has been validated for identifying five markers (gallic acid, rosmarinic acid, catechin, andrographolide and curcumin) and quantifying curcumin in Synacinn TM formulation. The validation (bracketed strengths of 10 mg/mL and 100 mg/mL) involved assessment of selectivity, precision, Limit of Detection (LOD), Limit of Quantification (LOQ), linearity, accuracy, stability in diluent and formulation stability. Meanwhile, in vivo bone marrow micronucleus test data was presented to evaluate the toxicity potential of Synacinn™ to cause clastogenicity and/or disruption of the mitotic apparatus, as measured by its ability to induce micronucleated polychromatic erythrocytes (MN PCE) in Sprague Dawley rat bone marrow. The test was conducted in two phases viz., Phase I (Dose Range Finding experiment) and Phase II (Definitive experiment). Phase I was conducted to assess general toxicity and bone marrow cytotoxicity of Synacinn™, and to select the doses for the definitive experiment. In-life observations included mortality, clinical signs of toxicity and body weight. Bone marrow samples were collected and extracted from the femur bone using fetal bovine serum. The pellet obtained after the centrifugation was used for preparing bone marrow smears to evaluate the number of immature and mature erythrocytes.

The present data described the analysis of mutagenicity in Synacinn TM by assessing the point mutations occurring due to Synacinn™ exposure to five tester strains of Salmonella typhimurium (TA1537, TA1535, TA98, TA100 and TA102), in the presence or absence of an exogenous mammalian metabolic activation system (S9). It was conducted in two Phases - Phase I (Dose Range Finding experiment-DRF) and Phase II (Mutagenicity Assay 1 and 2). DRF and Mutagenicity Assay 1 was conducted employing plate incorporation method, while Mutagenicity Assay 2 was performed using pre-incubation method. Formulation analysis pertaining to Synacinn TM was performed for both Mutagenicity Assay 1 and 2. Dose formulations were prepared fresh on each day of the experiment. Adventol 50% v/v in purified water was selected as a suitable vehicle based on the preliminary solubility test. Based on the Phase I analysis, 5 mg/plate was selected as the highest concentration of Synacinn TM followed by lower concentrations of 2.5, 1.25, 0.625 and 0.313 mg/plate for the Mutagenicity Assays. Genetic integrity of all the tester strains used was confirmed by performing genotyping before their use. All the data acceptability criteria were fulfilled confirming the validity of the test.

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