An upconversion nanocomposite for fluorescence resonance energy transfer based cholesterol-sensing in human serum

Upconversion nanophosphors (UCNPs) are extremely useful for analytical applications, since they display a high signal-to-noise ratio, and their photobleaching can be ignored. Herein, a novel upconversion nanocomposite composed of β-cyclodextrin (β-CD) derivative modified UCNPs and rhodamine B (RB) was prepared for the detection of cholesterol (Cho). The upconversion luminescence (UCL) emission can serve as a Cho-sensing signal by an effective fluorescence resonance energy transfer (FRET) process, using UCNPs as the donor and RB as the quencher. The sensor for Cho detection in human serum shows excellent sensitivity and selectivity, which has the potential for clinical applications in the analysis of other biological and environmental samples.

Hydroxypropyl-β-cyclodextrin impacts renal and systemic hemodynamics in the anesthetized dog

Hydroxypropyl-β-cyclodextrin (HPβCD) is a complexation agent used to enhance drug solubilization and formulation stability. Although its toxicity is well characterized, its cardiovascular effects are less known. To investigate them, HPβCD was infused intravenously over 10 min in anesthetized dogs (10-40% (w/v, i.e. 200-800 mg/kg) in non-denervated animals and at 40% in denervated animals). HPβCD increased renal arteriolar resistance and decreased renal blood flow at all doses, almost immediately after infusion start, more drastically in females. A less pronounced increase in total peripheral resistance occurred in females only due to sex difference in sympathetic tone. Pulmonary hemodynamic parameters remained unaffected, suggesting that the renal effect was rather selective. As a consequence of the increased systemic blood pressure, heart rate decreased in normal animals without direct effect on cardiac conductance. This effect was abolished in denervated animals. This suggests that autonomous nervous feedback loops are functional in normal animals and that HPβCD has no direct chronotropic effect. In conclusion, systemic and renal hemodynamic changes should be considered as potential background effects at 200-400 mg/kg. At higher doses (800 mg/kg), changes are more pronounced and could mask/exacerbate hemodynamic response of drug candidate; such doses should be avoided in nonclinical safety studies.

Pharmacokinetics of itraconazole after intravenous and oral dosing of itraconazole‐cyclodextrin formulations

The current research evaluated and compared the efficacy of hydroxybutenyl-beta-cyclodextrin (HBenBCD) and hydroxypropyl-beta-cyclodextrin (HPBCD) as enhancers of itraconazole solubility and oral bioavailability. At 10 wt% cyclodextrin, 17-fold and 3.8-fold increases in itraconazole aqueous solubility were observed in the presence of HBenBCD and HPBCD, respectively. Significant differences in the dissolution of itraconazole in the presence of these two cyclodextrins were also observed. Itraconazole pharmacokinetics is known to exhibit a significant food effect. However, testing in biorelevant media indicated that no food effects should be observed after oral administration of itraconazole:HBenBCD complexes. Formulations of itraconazole with HBenBCD were prepared and these complexes, along with the commercial forms of itraconazole with and without HPBCD (Sporanox) were administered to male Sprague-Dawley rats by oral and intravenous routes. Intravenous administration of itraconazole formulated with HBenBCD resulted in a higher AUC relative to Sporanox. When administered as oral solutions, the itraconazole:HBenBCD formulation provided higher oral bioavailability than the Sporanox oral solution. When administered as solid formulations, the itraconazole:HBenBCD solid formulation provided a 2x increase in oral bioavailability relative to the Sporanox solid formulation. No food effects were observed with the itraconazole:HBenBCD solid dosage forms. Drug/metabolite ratios were dependent upon the dosage form.

[Pharmacokinetics of breviscapine and its beta-cyclodextrin complex in rats]

AIM

To establish RP-HPLC method for determination of plasma scutellarin concentration and study of the pharmacokinetic behavior of scutellarin in rat after ig administration of breviscapine and its beta-cyclodextrin complex (breviscapine-beta-CD).

METHODS

Mobile phase composed of methanol and acetate buffer. The column was Shim-pack C18. Twelve rats randomized into 2 groups were separately given breviscapine and breviscapine-beta-CD at single dose of 10.8 mg.kg(-1). Drug in plasma was extracted and determined by HPLC. The pharmacokinetic parameters were calculated by 3P97 software.

RESULTS

Linearity was obtained over the range of 10-400 ng.mL(-1). The recovery was 95.32%-98.81%. C(max) and AUC(0-12 h) of breviscapine were (154 +/- 18) ng.mL(-1) and (710 +/- 126) ng.h.mL(-1). For breviscapine-beta-CD, C(max) and AUC(0-12 h) were (328 +/- 31) ng.mL(-1) and (1,093 +/- 200) ng.h.mL(-1), respectively. There were significant differences of AUC(0-12 h) between breviscapine and breviscapine-beta-CD (P < 0.01).

CONCLUSION

The assay method was suitable for the determination of scutellarin plasma concentration in rat. Brevescapine-beta-CD showed greater absorption compared with that of brevescapine.

[Pharmacokinetic studies of quercetin-hydroxypropyl-beta-cyclodextrin inclusion compound in rats]

To estabilish a HPLC method for determination of quercetin-hydroxypropyl-beta-cyclodextrin in rats plasma and investigate the pharmacokinetics characteristics of it in rats. The plasma was extracted with methanol-aceitc acid (9:1). The mobile phase was acetonitrilewater. Absorbance of the effluence was monitored at 360 nm. The linear limit of quercetin was within the range of 1 to 150 microg/ml. The lowest limit of quercetin was 0.5 microg/ml. The concentration-time curve of quercetin in rats was considered of a two-compartment open model, and the t1/2 (beta) of the inclusion compound when ig is 2.220 h, the t1/2 (beta) of the inclusion compound when iv is 90.871 min.

Tablet formulation containing meloxicam and beta-cyclodextrin: mechanical characterization and bioavailability evaluation

The purpose of this research was to evaluate beta-cyclodextrin (beta-CD) as a vehicle, either singly or in blends with lactose (spray-dried or monohydrate), for preparing a meloxicam tablet. Aqueous solubility of meloxicam in presence of beta-CD was investigated. The tablets were prepared by direct compression and wet granulation techniques. The powder blends and the granules were evaluated for angle of repose, bulk density, compressibility index, total porosity, and drug content. The tablets were subjected to thickness, diameter, weight variation test, drug content, hardness, friability, disintegration time, and in vitro dissolution studies. The effect of beta-CD on the bioavailability of meloxicam was also investigated in human volunteers using a balanced 2-way crossover study. Phase-solubility studies indicated an A(L)-type diagram with inclusion complex of 1:1 molar ratio. The powder blends and granules of all formulations showed satisfactory flow properties, compressibility, and drug content. All tablet formulations prepared by direct compression or wet granulation showed acceptable mechanical properties. The dissolution rate of meloxicam was significantly enhanced by inclusion of beta-CD in the formulations up to 30%. The mean pharmacokinetic parameters (C(max), K(e), and area under the curve [AUC](0-infinity)) were significantly increased in presence of beta-CD. These results suggest that beta-CD would facilitate the preparation of meloxicam tablets with acceptable mechanical properties using the direct compression technique as there is no important difference between tablets prepared by direct compression and those prepared by wet granulation. Also, beta-CD is particularly useful for improving the oral bioavailablity of meloxicam.