Changes in tramadol enantioselective pharmacokinetics and metabolism in rats with experimental diabetes treated or not with insulin

Streptozotocin-Induced Hyperglycemia Affects the Pharmacokinetics of Koumine and its Anti-Allodynic Action in a Rat Model of Diabetic Neuropathic Pain

Koumine (KM), the most abundant alkaloid in Gelsemium elegans, has anti-neuropathic, anti-inflammatory, and analgesic activities; thus, it has the potential to be developed as a broad-spectrum analgesic drug. However, factors determining the relationship between analgesic efficacy and the corresponding plasma KM concentration are largely unclear. The pharmacokinetics and pharmacodynamics of KM and their optimization in the context of neuropathic pain have not been reported. We investigated the pharmacokinetics and pharmacodynamics of KM after oral administration in a streptozotocin-induced rat model of diabetic neuropathic pain (DNP) using a population approach. A first-order absorption and elimination pharmacokinetics model best described the plasma KM concentration. This pharmacokinetic model was then linked to a linear pharmacodynamic model with an effect compartment based on the measurement of the mechanical withdrawal threshold. KM was rapidly absorbed (time to maximum plasma concentration: 0.14–0.36 h) with similar values in both DNP and naïve rats, suggesting that DNP did not influence the KM absorption rate. However, the area under the curve (AUC_0–∞) of KM in DNP rats was over 3-fold higher than that in naïve rats. The systemic clearance rate and volume of KM distribution were significantly lower in DNP rats than in naïve rats. Blood glucose value prior to KM treatment was a significant covariate for the systemic clearance rate of KM and baseline value of the threshold. Our results suggest that streptozotocin-induced hyperglycemia is an independent factor for decreased KM elimination and its anti-allodynic effects in a DNP rat model. To the best of our knowledge, this is the first study to investigate the role of DNP in the pharmacokinetics and pharmacokinetics-pharmacodynamics of KM in streptozotocin-induced diabetic rats.

A new alternative insight of nanoemulsion conjugated with κ-carrageenan for wound healing study in diabetic mice: In vitro and in vivo evaluation

Astaxanthin and alpha-tocopherol have attracted great attention because of their properties for the management of wound healing in diabetics. This study aimed to investigate the wound healing study of astaxanthin and alpha-tocopherol with κ-carrageenan nanoemulsion (AS-TP@KCNE) and to perform a histopathological study on streptozotocin (STZ)-induced diabetic mice. AS-TP@KCNE were also evaluated with aim of maintaining an effective and prolonged antidiabetic potential. KC@SENE and KC@USNE were obtained by spontaneous and ultrasonication emulsification methods and were characterized for stability, pH, particle size, and zeta potential by standard analysis. In vitro cytotoxicity and wound healing results demonstrated less toxicity and faster cell migration for the nanoemulsions at different concentrations. Based on the promising results, transdermal administration of AS-TP@KCNE can significantly restore the body weight, reduce fasting blood glucose levels, and improve glucose tolerance, which improved the ability to quickly heal of wounds in diabetic mice compared to control. In conclusion, the present study shows that the AS-TP@KCNE are biocompatible and possess healing properties that accelerate wound closure and exhibited better control of hyperglycemia and more superbly reversed the diabetes mellitus complications than STZ-induced diabetic mice. These results suggested that AS-TP@KCNE could be a promising platform for wound healing applications for diabetics.