Impact of protein deficient diet on the pharmacokinetics of glibenclamide in a model of malnutrition in rats.

PURPOSE: The present investigation deals with the impact of protein energy malnourished condition on the pharmacokinetic profile of glibenclamide. Protein energy malnourished condition leads to malnutrition related diabetes mellitus (MRDM), Fibrocalculus pancreatic diabetes mellitus (FCPD) or Lean body mass diabetes mellitus (LBMDM).

METHOD: In the present study, malnutrition was developed in female wistar rats using a modified protein deficient diet (0.5%). The experiment was performed on 12 animals, each group containing 6 female wistar rats. The control group animals were fed with standard pellet diet (AIN 93 G diet) while group 2 received the low protein diet (0.5%) for 75 days. Glibenclamide (Gli) suspension (30 mg/kg) was administered orally to these rats on 75 days and kinetic parameters were evaluated by HPLC analysis.The pharmacokinetic interpretation done by pksolver software version 2.0, statistical comparison done by applying student T test.

RESULTS: The results of body weight and hematological parameters indicated a significant decreased in the body weight in protein deficit rats to 124.1 ± 6.2 g compared to 235.5 ± 8.4 g (p < 0.01) control rats; whereas a decrease in the hemoglobin to 5.8 ± 0.6 g/dL, total blood protein level to 6.9 ± 0.6 g/dL and blood albumin levels to 2.7 ± 0.4 g/dL in protein deficit rats compared to 15 ± 0.7 g/dL(p < 0.05), 8.1 ± 0.4 g/dL(p < 0.05), and 4.5 ± 0.2 g/dL(p < 0.05), respectively in control rats. All these findings reflect the malnourished condition and weight loss due to a protein deficit diet in experimental animals. There was an increase in the fasting blood glucose levels up to 150 ± 17.4 mg/dL in the protein deficit diet group as compared to 98.7 ± 14.1 mg/dL(p < 0.05) in control rats reflect the prediabetes state in malnourished animals. The results of the pharmacokinetic study reflect a significant lowering of half-life (T½) of glibenclamide to 96.8 ± 0.8 min. in malnourished rats compared to 166.7 ± 0.74 min. (p < 0.001) in control rats. The maximum concentration (Cmax) of glibenclamide in the malnourished rats was significantly higher 20.74 ± 0.65 μg/mL and also took double time i.e. about 180 min. to reach maximum concentration (Tmax) compared to the control rats values 7.9 ± 0.84 μg/mL (p < 0.001) and 90.0 ± 0.24 min. (p < 0.001) respectively. The area under the plasma concentration-time curve [AUC(0-∞)] in malnourished rats increased 4439.1 ± 40.6 μg/ml*min as compared to 1235.9 ± 55.8 μg/ml*min (p < 0.001) in control rats. There was a lowering in the total body clearance (CL) to 0.4 ± 0.02 L/hr and volume of distribution (Vd) to 1.75 ± 0.07 L of glibenclamide in the protein deficit group compared to 1.4 ± 0.3 L/hr (p < 0.001) and 3.14 ± 0.8 L (p < 0.01), respectively in the control rats.

CONCLUSION: From this study it concludes that there is an increase in the T½, Cmax, Tmax and AUC(0-∞) of glibenclamide in malnourished rats while the total body clearance and volume of distribution is lowered. Therefore this study proposes to conduct an adequate pharmacokinetic study in malnourished patients to decide whether the standard glibenclamide dose should be adapted according to the nutritional status of the individual.