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1938条结果
  • 机译 乳清蛋白/多糖稳定的乳液:聚合物类型和pH对水杨酸释放和局部递送的影响
    摘要:Emulsions are widely used as topical formulations in the pharmaceutical and cosmetic industries. They are thermodynamically unstable and require emulsifiers for stabilization. Studies have indicated that emulsifiers could affect topical delivery of actives, and this study was therefore designed to investigate the effects of different polymers, applied as emulsifiers, as well as the effects of pH on the release and topical delivery of the active. O/w emulsions were prepared by the layer-by-layer technique, with whey protein forming the first layer around the oil droplets, while either chitosan or carrageenan was subsequently adsorbed to the protein at the interface. Additionally, the emulsions were prepared at three different pH values to introduce different charges to the polymers. The active ingredient, salicylic acid, was incorporated into the oil phase of the emulsions. Physical characterization of the resulting formulations, i.e., droplet size, zeta potential, stability, and turbidity in the water phase, was performed. Release studies were conducted, after which skin absorption studies were performed on the five most stable emulsions, by using Franz type diffusion cells and utilizing human, abdominal skin membranes. It was found that an increase in emulsion droplet charge could negatively affect the release of salicylic acid from these formulations. Contrary, positively charged emulsion droplets were found to enhance dermal and transdermal delivery of salicylic acid from emulsions. It was hypothesized that electrostatic complex formation between the emulsifier and salicylic acid could affect its release, whereas electrostatic interaction between the emulsion droplets and skin could influence dermal/transdermal delivery of the active.
  • 机译 水溶液中9-氨基喜树碱的理化特性
    摘要:The present manuscript provides a detailed physicochemical and thermodynamic characterization of 9-aminocamptothecin (9AC) which can be used as a tool to develop novel formulation strategies for optimum pharmacological activity. The pKa of 9AC was determined to be 2.43 at 37°C, while the basicity of quinoline nitrogen of 9AC was found to decrease with increasing temperature due to a positive enthalpy of deprotonation of 10.36 kJ mol−1. The equilibrium solubility as well as the intrinsic solubility of the drug was found to increase with increasing temperature and decreasing pH. The enthalpies of solution of unionized and ionized forms of 9AC obtained from isothermal and iso-pH equilibrium solubility measurements were found to be 36.01 and 24.72 kJ mol−1, respectively. Equilibrium hydrolysis studies revealed the hydrolytic susceptibility of 9AC with only 14% of active lactone species remaining at physiological pH 7.4. The intrinsic partition coefficient log P of the free base, 9AC–lactone, was estimated to be 1.28 (a characteristic of molecules suitable for oral absorption). The estimated pKa and log P values of 9AC, combined with its increased solubility at lower pH, are features that can be utilized to develop novel drug delivery systems to optimize the antitumor activity of 9AC.
  • 机译 基于生理的吸收模型在低溶解度,低渗透性弱碱配方开发中的应用:食物效应的机理研究
    摘要:Physiologically based pharmacokinetic (PBPK) modeling has been broadly used to facilitate drug development, hereby we developed a PBPK model to systematically investigate the underlying mechanisms of the observed positive food effect of compound X (cpd X) and to strategically explore the feasible approaches to mitigate the food effect. Cpd X is a weak base with pH-dependent solubility; the compound displays significant and dose-dependent food effect in humans, leading to a nonadherence of drug administration. A GastroPlus Opt logD Model was selected for pharmacokinetic simulation under both fasted and fed conditions, where the biopharmaceutic parameters (e.g., solubility and permeability) for cpd X were determined in vitro, and human pharmacokinetic disposition properties were predicted from preclinical data and then optimized with clinical pharmacokinetic data. A parameter sensitivity analysis was performed to evaluate the effect of particle size on the cpd X absorption. A PBPK model was successfully developed for cpd X; its pharmacokinetic parameters (e.g., Cmax, AUCinf, and tmax) predicted at different oral doses were within ±25% of the observed mean values. The in vivo solubility (in duodenum) and mean precipitation time under fed conditions were estimated to be 7.4- and 3.4-fold higher than those under fasted conditions, respectively. The PBPK modeling analysis provided a reasonable explanation for the underlying mechanism for the observed positive food effect of the cpd X in humans. Oral absorption of the cpd X can be increased by reducing the particle size (<100 nm) of an active pharmaceutical ingredient under fasted conditions and therefore, reduce the cpd X food effect correspondingly.
  • 机译 儿科生物制药分类系统(BCS)的注意事项:在五种药物中的应用
    摘要:It has been advocated that biopharmaceutic risk assessment should be conducted early in pediatric product development and synchronized with the adult product development program. However, we are unaware of efforts to classify drugs into a Biopharmaceutics Classification System (BCS) framework for pediatric patients. The objective was to classify five drugs into a potential BCS. These five drugs were selected since both oral and intravenous pharmacokinetic data were available for each drug, and covered the four BCS classes in adults. Literature searches for each drug were conducted using Medline and applied to classify drugs with respect to solubility and permeability in pediatric subpopulations. Four pediatric subpopulations were considered: neonates, infants, children, and adolescents. Regarding solubility, dose numbers were calculated using a volume for each subpopulation based on body surface area (BSA) relative to 250 ml for a 1.73 m2 adult. Dose numbers spanned a range of values, depending upon the pediatric dose formula and subpopulation. Regarding permeability, pharmacokinetic literature data required assumptions and decisions about data collection. Using a devised pediatric BCS framework, there was agreement in adult and pediatric BCS class for two drugs, azithromycin (class 3) and ciprofloxacin (class 4). There was discordance for the three drugs that have high adult permeability since all pediatric permeabilities were low: dolasetron (class 3 in pediatric), ketoprofen (class 4 in pediatric), and voriconazole (class 4 in pediatric). A main contribution of this work is the identification of critical factors required for a pediatric BCS.
  • 机译 生物相关压力测试条件下富马酸喹硫平缓释片的释放特性
    摘要:The aim of the present work was the investigation of robustness and reliability of drug release from 50 to 400 mg quetiapine extended release HPMC matrix tablets towards mechanical stresses of biorelevant intensity. The tests were performed under standard conditions (USP apparatus II) as well as under simulated gastrointestinal stress conditions. Mechanical stresses including pressure and agitation were applied by using the biorelevant dissolution stress test apparatus as it has been introduced recently. Test algorithms already established in previous studies were applied to simulate fasting gastrointestinal conditions. The dissolution experiments demonstrated striking differences in the product performance among standard and stress test conditions as well as dose strengths. In USP apparatus II, dissolution profiles were affected mainly by media pH. The dissolution experiments performed in biorelevant dissolution stress test device demonstrated that stress events of biorelevant intensity provoked accelerated drug release from the tablets.Electronic supplementary materialThe online version of this article (doi:10.1208/s12249-013-0050-2) contains supplementary material, which is available to authorized users.
  • 机译 从替补席到人类:水溶性差的药物的配方开发可减轻食品影响
    摘要:This study presents a formulation approach that was shown to mitigate the dramatic food effect observed for a BCS Class II drug. In vitro (dissolution), in vivo (dog), and in silico (GastroPlus®) models were developed to understand the food effect and design strategies to mitigate it. The results showed that such models can be used successfully to mimic the clinically observed food effect. GastroPlus® modeling showed that food effect was primarily due to the extensive solubilization of the drug into the dietary lipid content of the meal. Several formulations were screened for dissolution rate using the biorelevant dissolution tests. Surfactant type and binder amount were found to play a significant role in the dissolution rate of the tablet prototypes that were manufactured using a high-shear wet granulation process. The performance of the lead prototypes (exhibiting best in vitro dissolution performance) was tested in dogs and human subjects. A new formulation approach, where vitamin E TPGS was included in the tablet formulation, was found to mitigate the food effect in humans.
  • 机译 冷冻干燥工艺对预热两性霉素B胶束系统理化和生物学特性的影响
    摘要:The moderate heat treatment of amphotericin B (AmB) in its micellar form (M-AmB) results in superaggregates (H-AmB) that present a substantially lower toxicity and similar activity. The aim of this work was to evaluate the H-AmB behavior after a freeze-drying process. H-AmB and M-AmB micelles were evaluated before and after freeze-drying concerning their physicochemical and biological properties by spectrophotometry and activity/toxicity assay, respectively. Four concentrations of M-AmB and H-AmB were studied aiming to correlate their aggregation state and the respective biological behavior: 50 mg L−1, 5 mg L−1, 0.5 mg L−1, and 0.05 mg L−1. Then, potassium leakage and hemoglobin leakage from red blood cells were used to evaluate the acute and chronic toxicity, respectively. The efficacy of M-AmB and H-AmB formulations was assessed by potassium leakage from Candida albicans and by the broth microdilution method. After heating, in addition to an evident turbidity, a slight blueshift from 327 to 323 nm was also observed at the concentrations of 50 and 5 mg L−1 for H-AmB. Additionally, an increase in the absorbance at 323 nm at the concentration of 0.5 mg L−1 was detected. Concerning the toxicity, H-AmB caused significantly lower hemoglobin leakage than M-AmB. These results were observed for H-AmB before and after freeze-drying. However, there was no difference between H-AmB and M-AmB concerning their activity. Accordingly, the freeze-drying cycle did not show any influence on the behavior of heated formulations, highlighting the suitability of such a method to produce a new AmB product with a long shelf life and with both greater efficiency and less toxicity.
  • 机译 益生菌递送的进展综述:肠道菌群补充的常规配方与非常规配方
    摘要:Probiotic delivery systems are widely used nutraceutical products for the supplementation of natural intestinal flora. These delivery systems vary greatly in effectiveness to exert health benefits for a patient. Probiotic delivery systems can be categorized into conventional, pharmaceutical formulations, and non-conventional, mainly commercial food-based, products. The degree of health benefits provided by these probiotic formulations varies in their ability to deliver viable, functional bacteria in large enough numbers (effectiveness), to provide protection against the harsh effects of the gastric environment and intestinal bile (in vivo protection), and to survive formulation processes (viability). This review discusses the effectiveness of these probiotic delivery systems to deliver viable functional bacteria focusing on the ability to protect the encapsulated probiotics during formulation process as well as against harsh physiological conditions through formulation enhancements using coatings and polymer enhancements. A brief overview on the health benefits of probiotics, current formulation, patient and legal issues facing probiotic delivery, and possible recommendations for the enhanced delivery of probiotic bacteria are also provided. Newer advanced in vitro analyses that can accurately determine the effectiveness of a probiotic formulation are also discussed with an ideal probiotic delivery system hypothesized through a combination of the two probiotic delivery systems described.
  • 机译 载有多西他赛的热敏壳聚糖/β-甘油磷酸水凝胶的功效,药代动力学和生物分布
    摘要:Docetaxel (DTX) is a widely used anticancer drug for various solid tumors. However, its poor solubility in water and lack of specification are two limitations for clinical use. The aim of the study was to develop a thermosensitive chitosan/β-glycerophosphate (C/GP) hydrogel loaded with DTX for intratumoral delivery. The in vitro release profiles, in vivo antitumor efficacy, pharmacokinetics, and biodistribution of DTX-loaded C/GP hydrogel (DTX-C/GP) were evaluated. The results of in vitro release study demonstrated that DTX-C/GP had the property of controlled delivery for a reasonable time span of 3 weeks and the release period was substantially affected by initial DTX strength. The antitumor efficacy of DTX-C/GP was observed at 20 mg/kg in H22 tumor-bearing mice. It was found that the tumor volume was definitely minimized by intratumoral injection of DTX-C/GP. Compared with saline group, the tumor inhibition rate of blank gel, intravenous DTX solution, intratumoral DTX solution, and DTX-C/GP was 2.3%, 29.8%, 41.9%, and 58.1%, respectively. Further, the in vivo pharmacokinetic characteristics of DTX-C/GP correlated well with the in vitro release. DTX-C/GP significantly prolonged the DTX retention and maintained a high DTX concentration in tumor. The amount of DTX distributed to the normal tissues was minimized so that the toxicity was effectively reduced. In conclusion, DTX-C/GP demonstrated controlled release and significant efficacy and exhibited potential for further clinical development.
  • 机译 脂质体氧化苦参碱在肝纤维化治疗中的作用:制剂,体外和体内评估
    摘要:The aim was to develop a liposomal oxymatrine conjugating d-alpha tocopheryl polyethylene glycol 1000 succinate (OMT-LIP) for enhanced therapeutics of hepatic fibrosis. OMT-LIP was prepared using the remote loading method. The influences of formulation compositions on the encapsulation efficiency of OMT-LIP were investigated. Mean particle size, zeta potential, morphology, in vitro release, fibrotic liver targeting, and therapeutics of OMT-LIP were thoroughly assessed. The intraliposomal buffer composition and concentration, extraliposomal phase composition and pH, types of phospholipid, lipid molar ratio composition, and theoretical drug loading are crucial factors to entrap OMT into liposomes. The optimum OMT-LIP presented spherically unilamellar microstructures with entrapment efficiency of 79.7 ± 3.9%, mean particle size of 121.6 ± 52.9 nm, and zeta potential of −5.87 mV. OMT-LIP significantly increased the accumulation of OMT in the fibrotic liver with an 11.5-fold greater AUC than OMT solution in the dimethylnitrosamine (DMN)-induced hepatic fibrosis animals. OMT-LIP could be a potential strategy to improve treatment outcomes for hepatic fibrosis, showing the protective effects to mice given CCl4 and the enhanced therapeutics to mice with either DMN or CCl4-induced hepatic fibrosis.
  • 机译 聚酰胺胺树枝状聚合物对乙酰紫草素的包封,用于制备显着的纳米粒子。
    摘要:Acetylshikonin (AS) has demonstrated antitumor potential. However, the development of therapeutic applications utilizing AS is inhibited by its poor solubility in water. In the present work, polyamidoamine (PAMAM) dendrimers and their PEGylated derivatives were employed to increase the solubility of AS. A distinct color transition was observed during the encapsulation of AS suggesting strong intermolecular forces between PAMAM and AS. Ultraviolet–visible, high-performance liquid chromatography, and 1H NMR were used to verify the interaction between PAMAM and AS. The maximum amount of combined AS to each PAMAM molecule was determined. The cytotoxicity of AS nanoparticles was evaluated against leukemia (K562) and breast cancer (SK-BR-3) cell lines; the AS nanoparticles were shown to effectively inhibit tumor cells.
  • 机译 关于“根据各成分预测脂质混合物中药物溶解度的评论”
    摘要:
  • 机译 设计和制备难溶于水药物的固体分散体的系统方法
    摘要:
  • 机译 硝苯地平的自纳米乳化递药系统:亲水亲脂平衡和混合表面活性剂分子结构的影响
    摘要:A simple but novel mixed surfactant system was designed to fabricate a self-nanoemulsifying drug delivery system (SNEDDS) based on hydrophilic–lipophilic balance (HLB) value. The impacts of HLB and molecular structure of surfactants on the formation of SNEDDS were investigated. After screening various oils and surfactants, nifedipine (NDP)-loaded liquid SNEDDS was formulated with Imwitor® 742 as oil and Tween®/Span® or Cremophor®/Span® as mixed surfactant. Droplet size of the emulsions obtained after dispersing SNEDDS containing Tween®/Span® in aqueous medium was independent of the HLB of a mixed surfactant. The use of the Cremophor®/Span® blend gave nanosized emulsion at higher HLB. The structure of the surfactant was found to influence the emulsion droplet size. Solid SNEDDS was then prepared by adsorbing NDP-loaded liquid SNEDDS comprising Cremophor® RH40/Span® 80 onto Aerosil® 200 or Aerosil® R972 as inert solid carrier. Solid SNEDDS formulations using higher amounts (30–50% w/w) of Aerosil® 200 exhibited good flow properties with smooth surface and preserved the self-emulsifying properties of liquid SNEDDS. Differential scanning calorimetry and X-ray diffraction studies of solid SNEDDS revealed the transformation of the crystalline structure of NDP due to its molecular dispersion state. In vitro dissolution study demonstrated higher dissolution of NDP from solid SNEDDS compared with NDP powder.
  • 机译 太子参提取物的分子伴侣抑制应激蛋白聚集的潜力
    摘要:This study examined the effect of an aqueous extract of Pulicaria undulata on the 1,4-dithiothreitol (DTT)-induced aggregation of proteins. The effects of the chaperone properties of P. undulata extract on protein aggregation were determined by measuring light scattering absorption, fluorescence, and circular dichroism (CD) spectroscopy. The aqueous extract of P. undulata possesses good chaperone properties but the protection effect was varied in different protein. The extract showed a higher level of protection in high molecular weight proteins than in those of low molecular weight. Using a fluorescence study, the present study provides information on the hydrophobic area of proteins interacting with the P. undulata extract. In fact, by increasing the concentration of the P. undulata extract, the hydrophic area of the protein decreased. CD spectroscopy also revealed that DTT caused changes in both the tertiary and the secondary structure of the proteins, while in the presence of P. undulata extract, there was little change. Our finding suggests the possibility of using P. undulata extract for the inhibition of aggregation and the deposition of protein in disease.
  • 机译 辛酸配体离子在稳定人血清白蛋白中的作用
    摘要:Sodium caprylate was added to a pharmaceutical-grade human serum albumin (HSA) to stabilize the product. In this study we have aimed to establish how caprylate ligand protects HSA from thermal degradation. The fatty acid stabilizer was first removed from commercial HSA by charcoal treatment. Cleaned HSA was made to 10% w/v in pH 7.4 buffered solutions and doped with sodium caprylate in serial concentrations up to 0.16 mmol/g-protein. These solutions as well as a commercial HSA, human serum, and enriched-albumin fraction were subjected to differential scanning calorimetry (DSC) within the temperature range of 37–90°C at a 5.0°C/min scanning rate. The globular size of the cleaned HSA solutions was measured by dynamic light scattering. The denaturing temperatures for albumin with sodium caprylate and a commercial one were significantly higher than for albumin only. It was found that the protein globules of cleaned HSA were not as stable as that of the native one due to aggregation, and the caprylate ion may reduce the aggregation by enlarging the globules’ electrical double layer. A rational approximation of the Lumry-Eyring protein denaturation model was used to treat DSC denaturing endotherms. The system turned from irreversible dominant Scheme: to reversible dominant Scheme: with the increase in caprylate concentration from null to ~0.08 mmol/g-protein. It was postulated that the caprylate ligand may decrease the rate of reversible unfolding as it binds to the IIIA domain which is prone to reversible unfolding/refolding and causes further difficulty for irreversible denaturation which, in turn, HSA can be stabilized.
  • 机译 非离子表面活性剂囊泡组成的新型精胺衍生物阳离子脂质作为有效的体外基因载体。
    摘要:In the present study, nonionic surfactant vesicles (niosomes) formulated with Span 20, cholesterol, and novel synthesized spermine-based cationic lipids with four hydrocarbon tails in a molar ratio of 2.5:2.5:1 were investigated as a gene carrier. The effects of the structure of the cationic lipids, such as differences in the acyl chain length (C14, C16, and C18) of the hydrophobic tails, as well as the weight ratio of niosomes to DNA on transfection efficiency and cell viability were evaluated in a human cervical carcinoma cell line (HeLa cells) using pDNA encoding green fluorescent protein (pEGFP-C2). The niosomes were characterized both in terms of morphology and of size and charge measurement. The formation of complexes between niosomes and DNA was verified with a gel retardation assay. The transfection efficiency of these cationic niosomes was in the following order: spermine-C18 > spermine-C16 > spermine-C14. The highest transfection efficiency was obtained for transfection with spermine-C18 niosomes at a weight ratio of 10. Additionally, no serum effect on transfection efficiency was observed. The results from a cytotoxicity and hemolytic study showed that the cationic niosomes were safe in vitro. In addition, the cationic niosomes showed good physical stability for at least 1 month at 4°C. Therefore, the cationic niosomes offer an excellent prospect as an alternative gene carrier.
  • 机译 SN-38-环糊精复合物及其对卵巢癌的溶解度,稳定性和体外抗癌活性的影响
    摘要:SN-38, an active metabolite of irinotecan, is up to 1,000-fold more potent than irinotecan. But the clinical use of SN-38 is limited by its extreme hydrophobicity and instability at physiological pH. To enhance solubility and stability, SN-38 was complexed with different cyclodextrins (CDs), namely, sodium sulfobutylether β-cyclodextrin (SBEβCD), hydroxypropyl β-cyclodextrin, randomly methylated β-cyclodextrin, and methyl β-cyclodextrin, and their influence on SN-38 solubility, stability, and in vitro cytotoxicity was studied against ovarian cancer cell lines (A2780 and 2008). Phase solubility studies were conducted to understand the pattern of SN-38 solubilization. SN-38-βCD complexes were characterized by differential scanning calorimetry (DSC), X-ray powder diffraction analysis (XRPD), and Fourier transform infrared (FTIR). Stability of SN-38-SBEβCD complex in pH 7.4 phosphate-buffered saline was evaluated and compared against free SN-38. Phase solubility studies revealed that SN-38 solubility increased linearly as a function of CD concentration and the linearity was characteristic of an AP-type system. Aqueous solubility of SN-38 was enhanced by about 30–1,400 times by CD complexation. DSC, XRPD, and FTIR studies confirmed the formation of inclusion complexes, and stability studies revealed that cyclodextrin complexation significantly increased the hydrolytic stability of SN-38 at physiological pH 7.4. Cytotoxicity of SN-38-SBEβCD complex was significantly higher than SN-38 and irinotecan in both A2780 and 2008 cell lines. Results suggest that SBEβCD encapsulated SN-38 deep into the cavity forming stable inclusion complex and as a result increased the solubility, stability, and cytotoxicity of SN-38. It may be concluded that preparation of inclusion complexes with SBEβCD is a suitable approach to overcome the solubility and stability problems of SN-38 for future clinical applications.

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