Recent Pharmacokinetic Studies in Combination Therapies for Diabetes and Related Vascular Complications.

BACKGROUND: Combination treatment has been a popular therapeutic strategy in diabetes and related vascular complications. However, the reasonable dosing regimen in combination treatment remains unknown. Nowadays, pharmacokinetics (PK) is becoming a useful approach to reveal the mechanisms of drug-drug interactions (DDIs) and reasonable drug compatibility in combination treatment. SCOPE: This article reviews the pharmacokinetics studies on combination therapies for diabetes and its vascular complications to reveal the mechanisms of reasonable drug compatibility for optimizing drug combination treatment. METHODS: Relevant articles were identified through the PubMed search (from January 2006 to December 2012) in English and the CNKI and Wan Wei websites in Chinese (from January 2000 to December 2012). FINDINGS: Thirty-six articles were identified, including 15 on DDIs, 8 on pharmacological mechanism or metabolic pathways, and 6 on non-drug factors. DDIs studies showed the changes of drug-effect in combination treatment, which could guide physicians to administer anti-hyperglycemic agent in best time and in optimal order. PK studies based on pharmacological mechanism or metabolic pathways revealed reasonable compatibility of fixed-dose combination (FDC). A combination of pharmacokinetics/pharmacodynamics (PK/PD) and population pharmacokinetics (PopPK) and the development of PK/PD models in PK studies were good ways to determine the rational use and treatment effects in combined therapies. There were other 7 PK studies on the compatibility of preparations in Chinese medicine, which also outlined the features of DDIs in herbal drugs. CONCLUSION: PK studies may be useful to resolve the growing and complex issue of drug combinations to devise reasonable treatment regimens and to make physicians recognize the mechanisms of combined therapies. However, more longterm, comprehensive PK studies on combination therapy should be conducted in future.

Effects of Bushen Huoxue formula on the learning and memory function and the cerebral neurotransmitters in diabetic mice.

OBJECTIVE: To observe the effects of Bushen Huoxue Formula (Formula for reinforcing the kidney and activating blood circulation) on the learning and memory function and the cerebral neurotransmitters in diabetic mice. METHODS: Forty ICR mice were randomized into the normal control group, model group, Nimotop group and Chinese medicine group, 10 mice in each group. Tail intravenous injection of alloxan was applied to prepare diabetic model. Four weeks later, intragastric administration of Bushen Huoxue Formula for the Chinese medicine group, Nimotop for the Nimotop group, and isometric distilled water for the other two groups were respectively given for 8 weeks. The changes in the blood sugar level were observed; the learning and memory function was detected by Morris labyrinth test; and the contents of norepinephrine (NE), dopamine (DA), 5-hydroxyltryptamine (5-HT) and 5-hydroxyl indole acetic acid (5-HIAA) in cerebral cortex were determined in mice of all the groups. RESULTS: The blood sugar levels in the diabetic model mice significantly increased as compared with those of the normal control group determined 72 h and 12 weeks later (P < 0.05 or P < 0.01). Latencies for Morris labyrinth test in the Nimotop group and the Chinese medicine group were significantly shortened as compared with that in the model group (P < 0.01). The contents of cortical NE in the Chinese medicine group was significantly higher than that in the model group (P < 0.01). CONCLUSION: Bushen Huoxue Formula can improve the learning and memory function in the diabetic mice, and the mechanism is possibly related with change of the cortical NE content.

[Effects of testosterone and cortisol in sports fatigued organism by Chinese material medica of shixiang yaofa].

OBJECTIVE: To study the endogenous hormone of testosterone and cortisol that secretes volume and rhythm in sports fatigued human bodies and animals. To determine secretory volume and rhythm in sports fatigued human bodies and animals when Shixiang yaofa's drug are used. METHOD: Radio-immunity method was used to determine secretory volume and rhythm in sports fatigued human bodies and animals and to analyze secretory volume and rhythm. According to the secretory volume and rhythm of testosterone and cortisol, the Shixiang Yaofa's drugs were used. Doses: wenyang jihuo bead 10 g/sack 2 sack, ziyin xiuyang capsule 0.5 g/pill 8 pill pd in human bodies for 28 days. Wenyang jihuo bead 10 g x kg(-1) of crude drug, ziyin xiuyang capsule 4 g x kg(-1) of crude drug pd for hight doses in animals. Other groups for low doses 5 g x kg(-1) and 2 g x kg(-1) of crude drug pd for 15 days. The blood samples were collected for determination. RESULT: (1) In human bodies the peak value of testosterone was appeared in 8:00 and valley value was appeared in 18:00, ranges: 176.93-281.73 x 10(-5) mg x L(-1). The peak value of cortisol was appeared in 8:00 and valley value was appeared in 22:00, ranges: 1.31-16.13 x 10(-3) mg x L(-1). In the same condition, the mouse peak value of testosterone was appeared in 20:00 and valley value was appeared in 0:00, ranges: (0.56 x 10(-5) - 124.0 x 10(-5)) mg x L(-1). The rhythm in animals was compatible with human bodies, howerer, the peak value was delayed for 12 hours. (2) The testosterone was step up and the cortisol was cut down in sports fatigued human bodies and animals when shixiang yaofa's drug were used (P < 0.05, P < 0.01). CONCLUSION: The secretion of testosterone and cortisol in sports fatigued human bodies and animals are existed conclusive biologic rhythm. The secretory volume can be available accommodation by shixiang yaofa's drugs.