Pharmacokinetic and pharmacodynamic drug interactions of carbamazepine and glibenclamide in healthy albino Wistar rats

Quality and In Vivo Assessment of a Fulvic Acid Complex: A Validation Study

The present work aimed to re-assess the bioavailability enhancement potential of fulvic acid (FA). Carbamazepine (CBZ) and peat were used as a model drug and FA source, respectively. Our group has already evaluated the bioavailability enhancement potential of a less commercially viable source of FA, i.e., shilajit. In the present work, the phase solubility of CBZ was analyzed with varying concentrations of peat-sourced FA (2–12% w/v). The prepared complex (CBZ-FA) was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC). Dissolution, pharmacokinetic, and pharmacodynamic studies were also carried out. The results showed the presence of an interaction between the drug and FA within the complex, which led to 98.99 ± 2.0% enhancement in drug solubility. The results also showed 79.23 ± 2.1% dissolution of the complexed drug over 60 min and 69.32 ± 2.2% permeation from the intestinal gut sac over 90 min, which led to a significant enhancement of bioavailability and a reduction in the duration of epileptic seizures. Thus, this study re-authenticates our earlier results and suggests switching the FA source (shilajit to peat) for commercial product development.

Cinnamic acid exerts anti-diabetic activity by improving glucose tolerance in vivo and by stimulating insulin secretion in vitro

Although the anti-diabetic activity of cinnamic acid, a pure compound from cinnamon, has been reported but its mechanism(s) is not yet clear. The present study was designed to explore the possible mechanism(s) of anti-diabetic activity of cinnamic acid in in vitro and in vivo non-obese type 2 diabetic rats. Non-obese type 2 diabetes was developed by injecting 90 mg/kg streptozotocin in 2-day-old Wistar pups. Cinnamic acid and cinnamaldehyde were administered orally to diabetic rats for assessing acute blood glucose lowering effect and improvement of glucose tolerance. Additionally, insulin secretory activity of cinnamic acid and cinnamaldehyde was evaluated in isolated mice islets. Cinnamic acid, but not cinnamaldehyde, decreased blood glucose levels in diabetic rats in a time- and dose-dependent manner. Oral administration of cinnamic acid with 5 and 10 mg/kg doses to diabetic rats improved glucose tolerance in a dose-dependent manner. The improvement by 10 mg/kg cinnamic acid was comparable to that of standard drug glibenclamide (5 mg/kg). Further in vitro studies showed that cinnamaldehyde has little or no effect on glucose-stimulated insulin secretion; however, cinnamic acid significantly enhanced glucose-stimulated insulin secretion in isolated islets. In conclusion, it can be said that cinnamic acid exerts anti-diabetic activity by improving glucose tolerance in vivo and stimulating insulin secretion in vitro.

Interactions of rosiglitazone and anti-arrhythmic drugs in animal model

BACKGROUND

Diabetes increases the risk of vascular problems by two times compared with a healthy individual, with deposition of fats in blood vessel and this includes cardiovascular disease. The treatment regimens for patients suffering from both diseases generally include prolonged use of anti-diabetic drugs for diabetes and anti-arrhythmic drugs for cardiac arrhythmias.

AIM

The aim of the study is to compare the influence of Mexiletine and Disopyramide on the pharmacodynamics (PDs) of Rosiglitazone in normal and diabetic rats.

MATERIALS AND METHODS

The study was conducted in normal rats and diabetic induced rats (with Alloxan monohydrate 100 mg/kg body weight). Albino rats weighing between 160 and 280 g were administered oral doses of Rosiglitazone 0.72 mg/kg, Mexiletine 36 mg/kg, or Disopyramide 18 mg/kg of bodyweight and their combination, with 1 week of washout between treatments. Eighteen rats were divided into three sub-sets with six rats in each sub-set. After 4 days, the blood glucose was estimated to confirm the diabetes. The Analysis of Covariance (ANCOVA) using MedCalc(®) software Version 11.6.1.0 was performed to analyze mean change in blood glucose between treatments with body weight as co-variable and treatment as factor for normal and diabetic rats.

RESULTS

No statistically significant difference in mean change in blood glucose between Rosiglitazone in comparison with Rosiglitazone + Mexiletine or Rosiglitazone + Disopyramide was observed in normal and diabetic rats (P = 0.606). The maximum mean change in blood glucose for Rosiglitazone and Rosiglitazone + Mexiletine or Rosiglitazone + Disopyramide was observed at 1 h and 8 h in normal and diabetic rats. The post hoc analysis showed baseline correction method has increased the reliability of the results (P < 0.001).

CONCLUSION

The study concludes that PD activity of Rosiglitazone was not affected by the anti-arrhythmic drugs. This study introduced a new statistical methodology for analyzing the blood glucose endpoint.