盐酸西替利嗪巴布膏剂的药动学和生物利用度研究

目的研究盐酸西替利嗪巴布膏剂在大鼠体内的药代动力学特征,并与口服给药的药动学进行比较,考察生物利用度。方法选用SD大鼠,分为巴布膏剂组和口服给药组,采用高效液相色谱法测定血药浓度;并剥取剩余的西替利嗪巴布膏剂,测定剩余药量。结果西替利嗪巴布膏剂组的T_(max)为2.35 h,C_(max)为2.68μg/mL,AUC为21.01μg·h/mL,MRT为23.26 h;西替利嗪口服组的T_(max)为1.11 h,C_(max)为11.65μg/mL,AUC为35.62μg·h/mL,MRT为12.13 h。扣除巴布膏剂中的剩余药量,按照实际进入皮肤的剂量计算得西替利嗪巴布膏剂相当于片剂的生物利用度为30.81%;不扣除巴布膏剂中的剩余药量,西替利嗪巴布膏剂相当于片剂的生物利用度为14.75%。结论西替利嗪巴布膏剂的血药浓度平稳而持久,具有缓释的特征。     

Mechanical activation of Efavirenz: the effects on the dissolution and inhibitory behavior

Abstract

A poorly water-soluble drug (Efavirenz) was mechanically activated by ball-milling. The effect of the mechanical activation on the dissolution behavior and bioavailability was investigated revealing possible correlations with the grinding action, in terms of crystallinity, particle size and morphology.With proper selection of the grinding parameters the dissolution kinetics can be controlled, both in terms of dissolution velocity and as amount of dissolved drug. In vitro biological tests show that milling does not impair the ability of Efavirenz to inhibit HIV-1 infection (p value?>0.05); the IC50 values of ground Efavirenz is indeed lower than values for the pristine micronized powder.     

Renewable poly(δ-decalactone) based block copolymer micelles as drug delivery vehicle: in vitro and in vivo evaluation

Polymers from natural resources are attracting much attention in various fields including drug delivery as green alternatives to fossil fuel based polymers. In this quest, novel block copolymers based on renewable poly(δ-decalactone) (PDL) were evaluated for their drug delivery capabilities and compared with a fossil fuel based polymer i.e. methoxy-poly(ethylene glycol)-b-poly(ε-caprolactone) (mPEG-b-PCL). Using curcumin as a hydrophobic drug model, micelles of PDL block copolymers with different orientation i.e. AB (mPEG-b-PDL), ABA (PDL-b-PEG-b-PDL), ABC (mPEG-b-PDL-b-poly(pentadecalactone) and (mPEG-b-PCL) were prepared by nanoprecipitation method. The size, drug loading and curcumin stability studies results indicated that mPEG-b-PDL micelles was comparable to its counterpart mPEG-b-PCL micelles towards improved delivery of curcumin. Therefore, mixed micelles using these two copolymers were also evaluated to see any change in size, loading and drug release. Drug release studies proposed that sustained release can be obtained using poly(pentadecalactone) as crystalline core whereas rapid release can be achieved using amorphous PDL core. Further, mPEG-b-PDL micelles were found to be non-haemolytic, up to the concentration of 40?mg/mL. In vivo toxicity studies on rats advised low-toxic behaviour of these micelles up to 400?mg/kg dose, as evident by histopathological and biochemical analysis. In summary, it is anticipated that mPEG-b-PDL block copolymer micelles could serve as a renewable alternative for mPEG-b-PCL copolymers in drug delivery applications.     

介孔硅材料提高难溶性药物生物利用度的研究进展

介孔二氧化硅作为近年来比较热门的无机介孔载体材料,因其具有孔道排列规整、水热稳定性良好、生物相容性好,可以储存药物并保持药物的无定形态等特点,非常适合装载水难溶性药物。本文通过查阅国内外的相关文献,就难溶性药物口服生物利用度低的原因进行分析,并归纳总结了国内外关于介孔二氧化硅载体提高难溶性药物生物利用度方面的最新研究进展,为设计和制备具有特定结构和性能的介孔二氧化硅载体,提高难溶性药物的生物利用度及其临床应用提供参考。     

A physiologically based kinetic (PBK) model describing plasma concentrations of quercetin and its metabolites in rats

Biological activities of flavonoids in vivo are ultimately dependent on the systemic bioavailability of the aglycones as well as their metabolites. In the present study, a physiologically based kinetic (PBK) model was developed to predict plasma concentrations of the flavonoid quercetin and its metabolites and to tentatively identify the regiospecificity of the major circulating metabolites. The model was developed based on in vitro metabolic parameters and by fitting kinetic parameters to literature available in vivo data. Both exposure to quercetin aglycone and to quercetin-4′-O-glucoside, for which in vivo data were available, were simulated. The predicted plasma concentrations of different metabolites adequately matched literature reported plasma concentrations of these metabolites in rats exposed to 4′-O-glucoside. The bioavailability of aglycone was predicted to be very low ranging from 0.004%-0.1% at different oral doses of quercetin or quercetin-4′-O-glucoside. Glucuronidation was a crucial pathway that limited the bioavailability of the aglycone, with 95–99% of the dose being converted to monoglucuronides within 1.5–2.5 h at different dose levels ranging from 0.1 to 50 mg/kg bw quercetin or quercetin-4′-O-glucoside. The fast metabolic conversion to monoglucuronides allowed these metabolites to further conjugate to di- and tri-conjugates. The regiospecificity of major circulating metabolites was observed to be dose-dependent. As we still lack in vivo kinetic data for many flavonoids, the developed model has a great potential to be used as a platform to build PBK models for other flavonoids as well as to predict the kinetics of flavonoids in humans.     

Preclinical Pharmacokinetic Evaluation of β-Lapachone: Characteristics of Oral Bioavailability and First-Pass Metabolism in Rats

β-Lapachone has drawn increasing attention as an anti-inflammatory and anti-cancer drug. However, its oral bioavailability has not been yet assessed, which might be useful to develop efficient dosage forms possibly required for non-clinical and clinical studies and future market. The aim of the present study was thus to investigate pharmacokinetic properties of β-lapachone as well as its first-pass metabolism in the liver, and small and large intestines after oral administration to measure the absolute bioavailability in rats. A sensitive HPLC method was developed to evaluate levels of β-lapachone in plasma and organ homogenates. The drug degradation profiles were examined in plasma to assess the stability of the drug and in liver and intestinal homogenates to evaluate first-pass metabolism. Pharmacokinetic profiles were obtained after oral and intravenous administration of β-lapachone at doses of 40 mg/kg and 1.5 mg/kg, respectively. The measured oral bioavailability of β-lapachone was 15.5%. The considerable degradation of β-lapachone was seen in the organ homogenates but the drug was quite stable in plasma. In conclusion, we suggest that the fairly low oral bioavailability of β-lapachone may be resulted from the first-pass metabolic degradation of β-lapachone in the liver, small and large intestinal tracts and its low aqueous solubility.     

Nanocrystals for enhancement of oral bioavailability of poorly water-soluble drugs

Nanocrystals, a carrier-free colloidal delivery system in nano-sized range, is an interesting approach for poorly soluble drugs. Nanocrystals provide special features including enhancement of saturation solubility, dissolution velocity and adhesiveness to surface/cell membranes. Several strategies are applied for nanocrystals production including precipitation, milling, high pressure homogenization and combination methods such as NanoEdge™, SmartCrystal and Precipitation-lyophilization-homogenization (PLH) technology. For oral administration, many publications reported useful advantages of nanocrystals to improve in vivo performances i.e. pharmacokinetics, pharmacodynamics, safety and targeted delivery which were discussed in this review. Additionally, transformation of nanocrystals to final formulations and future trends of nanocrystals were also described.     

Influence of chitosan coating on the oral bioavailability of gold nanoparticles in rats

Gold nanoparticles are one of the most extensively investigated metallic nanoparticles for several applications. It is less toxic than other metallic nanolattices. The exceptional electrical and thermal conductivity of gold make it possible to be administered as non-invasive radiofrequency irradiation therapy that produces sufficient heat to kill tumor cells. Nanoparticles are generally administered intravenously instead of orally due to negligible oral absorption and cellular uptake. This study evaluated the oral bioavailability of gold nanoparticles coated with chitosan (C-AuNPs), a natural mucoadhesive polymer. We employed traditional method of evaluating bioavailability that involve estimation of maximum concentrations and area under the curve of 3?nm chitosan coated gold nanoparticles (C-AuNPs) in the rat plasma following intravenous and oral administrations (0.8?mg and 8?mg/kg body weight respectively). The oral bioavailability of C-AuNPs was found to be 2.46% (approximately 25 folds higher than polyethylene glycol (PEG) coated gold nanoparticles, reported earlier). These findings suggest that chitosan coating could be better than PEG coating for the enhancement of oral bioavailability of nanoparticles.     

One-month of calcium supplementation does not affect iron bioavailability: A randomized controlled trial

ObjectivesCalcium (Ca) and iron (Fe) are essential minerals for normal growth and development. Although previous studies have shown that Ca inhibits acute Fe absorption, there is no evidence of the possible long- or medium-term effects of Ca supplementation on Fe bioavailability. The aim of this study was to determine the effect of 34 d of Ca supplementation on heme Fe and non-heme Fe bioavailability in non-pregnant women of ages 33 to 47 y.MethodsThis was a prospective, randomized, double-blind, placebo-controlled trial. Twenty-six healthy women (40 ± 5 y) were randomly assigned to receive either 600 mg of elemental Ca/d as CaCO₃ (Ca group, n = 13) or a placebo (P group, n = 13) for 34 d. Heme Fe and non-heme Fe bioavailability were determined before and after treatment using ⁵⁵Fe and ⁵⁹Fe radioisotopes. A two-factor, repeated-measures analysis of variance was used to assess differences by treatment and timing.ResultsThe geometric mean (range ± 1 SD) of heme Fe bioavailability before and after treatment was 16.5% (8.3–32.8) and 26% (15.5–43.6) for the Ca group and 21.8% (13.0–36.6) and 25.1% (16.5–38.3) for the P group. Non-heme Fe bioavailability before and after treatment was 39.5% (19.9–78.7) and 34.1% (19.1–60.6) for the Ca group, and 44.6% (24.9–79.7) and 39.3% (24.3–63.4) for the P group. There were no differences in either heme Fe or non-heme Fe bioavailability either at baseline or after treatment.ConclusionThe administration of calcium supplements for 34 d does not affect iron bioavailability. This trial is registered with Controlled-trials.gov, number ISRCTN 89888123.     

Mixed-Micellar Proliposomal Systems for Enhanced Oral Delivery of Progesterone

The objective of our study was to develop a mixed-micellar proliposomal formulation of poorly water-soluble drug progesterone and evaluate the dissolution profile and membrane transport. Several formulations of proliposomes were prepared by mixing different concentrations of lipid, progesterone, polysorbate 80, and microcrystalline cellulose. The mixed-micellar formulation of drug:dimyristoyl-phosphatidycholine:polysorbate 80 (1:20:3.3) exhibited the maximum dissolution (75.27%), while pure progesterone resulted in low dissolution. The above formulation showed a 4-fold increase in transport in Caco-2 cells and a 6-fold increase in transport across the everted rat intestinal sac experiments compared with control. Proliposomal formulations enhance the extent of dissolution and membrane transport of progesterone and serve as ideal carriers for oral delivery of drugs with low water solubility.