Evaluation of pluronic nanosuspensions loading a novel insoluble anticancer drug both in vitro and in vivo

To improve the solubility, stability and the antitumor activity of a novel anticancer drug, 3-(4-bromopheny l)-2-(ethyl-sulfonyl)-6-methylquinoxaline1,4-dioxide (Q39), a poloxamer nanosuspension was developed by precipitation combined with high pressure homogenization in present study. In vitro characterizations of Q39 nanosuspension (Q39/NS), including particle size, polydispersity index (PI), morphology, crystalline, saturation solubility, stability and releases were evaluated. BABL/c nude mice bearing HepG2 cells were used as in vivo tumor models to evaluate the anti-tumor activity of Q39/NS after intravenous administration. The particle size and PI for Poloxamer188 nanosuspension (P188/NS) were (304 ± 3) nm, and (0.123 ± 0.005) respectively, and it was (307 ± 5) nm and (0.120 ± 0.007) for Poloxamer85 nanosuspension (P85/NS) correspondingly. The morphology of P188/NS was spherical shape while elliptoid shape for P85/NS. The crystalline of Q39/NS did not change as shown by the X-ray diffraction analysis. The stability of Q39/NS improved compared with the solution. The solubility of Q39 in P188/NS was 7.3 times higher than the original solubility, while it was 6 times for P85/NS. Sustained release as shown from the in vitro release test, together with the tumor-targeting as shown from in vivo NS distribution, may contribute to the enhanced in vivo antitumor activity of Q39/NS.     

全身麻醉药对脑室内注射β-淀粉样蛋白单体的老年大鼠Morris水迷宫训练成绩的影响

目的通过研究脑室注射β-淀粉样蛋白(Aβ)单体后的老年大鼠异氟醚(I)、七氟醚(S)或异丙酚(P)麻醉对Morris水迷宫训练成绩的影响。方法100只20个月龄的雄性老年大鼠分为对照组、Aβ1组、Aβ2组、Aβ3组、I+生理盐水(NS)组、I+Aβ1组、S+NS组、S+Aβ1组、P+NS组、P+Aβ1组。麻醉后2周进行Mor-ris水迷宫训练。结果Aβ2组、Aβ3组、I+NS组和S+NS组老年大鼠记忆质量下降(P<0.05),I+Aβ1组和S+Aβ1组老年大鼠空间记忆能力进一步下降(P<0.05);P+NS组与P+Aβ1组老年大鼠均表现出学习速度下降(P<0.05)。结论吸入麻醉药和脑室内Aβ1-40单体共同作用下进一步影响老年大鼠学习记忆功能,异丙酚却无此方面作用。     

Structure and hydration properties of hydroxypropyl methylcellulose matrices containing naproxen and naproxen sodium

The present study was conducted to obtain a deeper insight into the mechanism of drug release from HPMC matrices. The microstructure, mobility, internal pH and the state of water within the gel layer of hydrated HPMC matrices (having different molecular weights) containing naproxen sodium (NS) and naproxen (N) were studied using Electron Paramagnetic Resonance (EPR), Nuclear Magnetic Resonance (NMR) and Differential Scanning Calorimetry (DSC) techniques. The study show that matrices composed of various viscosity grades of HPMC are characterized by similar microviscosity values in spite of the difference in their molecular weight. The NMR and DSC results led to the conclusion that higher molecular weights of HPMC are characterized by higher water absorption capacity and higher swelling. Analysis of non-freezable water in HPMC(K4M)–NS system revealed that addition of NS to solution increased the fraction of water bound to K4M+NS compared with the equivalent solutions without NS. The results suggest that the drug is participating in the crystallization of water and leads to the formation of a three dimensional network structure that decreases the freedom of water in K4M+NS samples. Calculation of the number of hydration shells showed that up to 2.2 layers are involved in HPMC-NS hydration compared to 1.5 layers for HPMC gel without NS. This was explained based on the different water ordering in the gel induced by NS as results of its absorption to polymer surface. Microviscosity values measured by EPR for K4M/N and K4M/NS hydrated matrices were found to be higher for K4M/N matrices, especially at initial stage of hydration. Mobile compartment calculations showed lower values for K4M/N compared with K4M/NS matrices. pH measurements by EPR revealed that incorporation of N to HPMC matrix led to lower internal pH value inside the hydrated tablet compared with NS. This behavior led to lower solubility of N which dictates its surface erosion mechanism, compared with NS matrix that was characterized by higher internal pH value and higher drug solubility. These properties of HPMC/NS increased chain hydration and stability, and led to drug release by the diffusion mechanism.     

Physical characterization of naproxen sodium hydrate and anhydrate forms

Naproxen sodium (NS) is a nonsteroidal anti-inflammatory drug used in painful and inflammatory diseases. By crystallization from water or by exposure to relative humidities over 43%, the anhydrate form can be hydrated to a dihydrate species. Different techniques have been used to characterize physically anhydrate naproxen sodium (ANS) and hydrate naproxen sodium (HNS): elemental analysis, atomic absorption, electron scanning microscopy, thermomicroscopy, differential scanning calorimetry, Karl Fisher’s titrimetry, thermogravimetry, spectrophotometric analysis and X-ray diffraction study. The hydration/dehydration mechanism, at different relative humidities, was investigated to evaluate their physical stability. When stored up to 43% relative humidity, ANS shows a good stability, whereas with an increase in relative humidity it is hydrated. HNS equilibrium solubility was determined at different temperatures (21, 26, 31, and 37°C). Due to the metastability and the quick phase changes in the water of ANS, its solubility was calculated from intrinsic dissolution measurements at the same temperatures, as solubility measurements of HNS. Water solubility of ANS is greater than HNS, but the solubility difference decreases when the temperature decreases. This is due to the fact that at higher temperatures the intrinsic dissolution rates (IDR) of ANS are considerably faster and decrease as the temperature falls.     

小儿肾病综合征合并支气管哮喘临床分析

目的分析小儿肾病综合征（NS）与支气管哮喘之间的关系。方法医院2009年1月-2013年3月收治NS患儿228例,其中合并支气管哮喘症状12例,分析其诊断情况及NS与支气管哮喘的关系。结果228例NS患儿合并支气管哮喘12例（5．3％）,其中导致NS复发6例,2例NS患儿在NS未缓解期间,出现尿蛋白增多,服用激素治疗4周后,患儿尿蛋白尚未转阴。12例NS合并支气管哮喘患儿采用支气管扩张剂沙丁胺醇和表面激素布地奈德吸入治疗2-5d后,患儿哮喘症状得到缓解。12例患儿出院后,继续使用氟替卡松治疗,未再出现喘息,且对NS控制非常有效。结论对于NS合并支气管哮喘患儿,要有效控制患儿的哮喘症状,对患儿进行合理用药,能减少NS复发。     

羟丙基-β-环糊精与介质pH值对前列腺素E_1溶解度的综合影响（英文）

目的研究羟丙基-β-环糊精（HP-β-CD）与介质pH值对前列腺素E1（PGE1）溶解度的综合影响并进一步推导出该药物溶解度的理论方程。方法首先测定药物在不同pH值水中的溶解度;然后分别测定在酸性及中性系列浓度的HP-β-CD溶液中,药物的溶解度;最后推导出以HP-β-CD与介质pH值为变量的药物溶解度方程并对其合理性进行验证。结果溶解度测定结果表明,提高介质的pH值或以HP-β-CD为增溶剂,均可增加PGE1的溶解度。分子型药物或离子型药物与HP-β-CD测得的相溶解度图均为典型的AL型,提示药物结构上的五元碳环部分已嵌入HP-β-CD的疏水性孔穴中,从而形成1：1摩尔比包合物。结论以HP-β-CD作为增溶剂,同时提高介质的pH值,可对PGE1的溶解度产生协同增加效应。本研究中导出的PGE1溶解度方程,可有效表征HP-β-CD与介质pH值二者对该药物溶解度的综合影响。     

The effect of dry mixing on the apparent solubility of hydrophobic, sparingly soluble drugs.

The effect of dry mixing on the apparent solubility of two hydrophobic sparingly soluble drugs was studied. The materials were mixed with NaCl or glass beads in a Turbula mixer and the changes in solubility were monitored. It was shown that dry mixing caused an increase in the apparent solubility of test materials. It is suggested that the surfaces of the particles become activated and disordered during the dry mixing process. This peripheral surface disorder appears to be responsible for the increase in solubility. It was also shown that apparent solubility of the drugs after dry mixing was strongly dependent on the amount of drug added to the solvent, increasing with increasing concentrations. A plateau was established gradually at higher proportions of drug to solvent. Finally the applicability of the solubility model described by Mosharraf et al. (1999) [Mosharraf, M., Sebhatu, T., Nystr?m, C., 1999. The effects of disordered structure on solubility and dissolution rates of hydrophilic, sparingly soluble drugs. Int. J. Pharm. 177, 29-51] to the solubility behaviour of the hydrophobic sparingly soluble drugs tested in this study was confirmed. The results suggested that the equilibrium solubility plateau levels of a disordered material are determined by the degree and the location of disorder on the individual particles.     

Correlation between drug release kinetics from proteineous matrix and matrix structure: EPR and NMR study

The present study was conducted in order to probe the microstructure, microviscosity, and hydration properties of matrices containing two model drugs, naproxen sodium (NS) and naproxen (N), and egg albumin (EA) as matrix carrier. The results suggested that N release from EA matrix was controlled by a bulk erosion mechanism in combination with additional processes (crystal dissolution/crystallization rate) compared with NS matrix, which behaved as a non-erodible matrix and drug release occurred by diffusion through the gel. Using EPR technique it has been shown that incorporating NS into EA matrix strongly influences the microstructure of the protein gel, and hence the transport of the penetrant within the matrix, compared with matrices containing N. The presence of NS increased the protein chain mobility and hydration which supports our previous results showing that NS cause unfolding of EA. In contrast, N caused only marginal effect on EA chain mobility. The gel formed in EA/NS matrices was more porous compared with EA/N matrices as revealed by the lower rotational correlation time of PCA (lower microviscosity) in EA/NS matrices compared with EA/N. However, EA/N gelled matrices were more heterogeneous, i.e., containing a higher number of components having different mobility. The T(1) and T(2) relaxation studies by NMR provided an additional support for the higher chain hydration in EA/NS matrices compared with EA/N as indicated by the higher relaxation rates in the gelled matrices. Internal pH measurements by EPR revealed that the micro-pH inside 100% EA and 50/50 EA/N matrices were lower than 50/50 EA/NS matrices and in all cases lower than the penetrating buffer pH. The lower pH compartment formed in N matrices affected N solubility and crystal dissolution rate, which can explain its lower release rate compared with EA, from the same formulation. The EPR and NMR data supports our findings that NS caused unfolding of the protein, affected matrix structure, and converted it to a hydrophobic non-erodible matrix compared with EA/N matrix in which the native properties of EA were mainly retained.     

增加难溶性药物溶解度方法新进展

如何增加难溶性药物溶解度是药剂学设计的重点。现就近年来微粉化技术、环糊精包含技术、固体分散技术等传统技术和其它一些新方法对增加难溶性药物溶解度的新进展作一综述。     

Nanosuspensions as delivery system for gambogenic acid: characterization and in vitro/in vivo evaluation

Nanosuspensions (NS) can enhance the saturation solubility and dissolution velocity of poorly soluble drugs. PEG as a non-ionic surfactant plays an important role in surface modification of nanoparticles for prolonging in vivo circulation. In this study, anti-solvent precipitation method was introduced to prepare gambogenic acid nanosuspensions (GNA-NS) with PVPK30 and PEG2000 as stabilizers to settle the disadvantages of GNA. The obtained nanoparticles were spherical with a mean particle size of 183.7?nm and a zeta potential of ?22.8?mV. The entrapment efficiency and drug loading of the resultant formulation were 97.3 and 29.73%. X-ray diffraction analysis confirmed the amorphous phase of GNA in NS. Fourier transform infrared indicated there may be hydrogen bond interaction between the drug and excipients. After lyophilization of GNA-NS, the freeze-dried powder displayed sufficient long-term physical stability at 4 and 25?°C. In comparison to GNA solution, in vitro studies of GNA-NS showed much slower release and higher cytotoxicity in HepG2 cells. What’s more, the pharmacokinetic study in rats revealed that the AUC_0–∞ and t_1/2 of GNA-NS were increased 2.63- and 1.77-fold than that of the reference formulation. Taken together, in vitro/in vivo evaluations showed NS would be an effectively strategy to change the poor aqueous solubility and prolong the half-life for GNA. The GNA-NS with enhanced bioavailability and drug efficacy provided a promising delivery system for the application of GNA.     

Attempts at formulation of syrup with theophylline.

The aim of this study was attempt to formulate syrup with theophylline. This form of drug would enable easy adjustment of individual doses of drug for therapeutic purposes in children. Due to poor solubility of theophylline in water, attempts at increasing of its solubility by adding special adjuvant substances, which could increase solubility and stabilise the obtained solution, were of particular importance.     

Effect of some syrup constituents on the solubility of sorbic acid

The effects of sucrose, glucose, sorbitol, and saccharin on the aqueous solubility of sorbic acid at 20 and 37 degrees C were determined. Sucrose, glucose, and sorbitol decreased the solubility of sorbic acid with increasing concentrations at both temperatures. Increasing the concentrations of these sweetening agents resulted in decreases in the dielectric constants. Calculation of the free energy and enthalpy changes indicated that the dissolution process for sorbic acid became progressively unfavorable with increasing sugar concentration.     

自微乳化释药系统在药物制剂中的应用

很多新活性药物在生物体内溶解度很小,如何增加药物溶解度,提高其生物利用度是药物制剂工作中的一大难题.本文介绍了自微乳化释药系统的基本概述,并对其在难溶性西药制剂中的应用进行综述.     

Solubility of guaifenesin in the presence of common pharmaceutical additives

The aqueous solubility of guaifenesin, a highly water-soluble drug, in the presence of salts, sugars, and cosolvents was determined at 25 degrees C and 40 degrees C. The solubility of drug at both temperatures was reduced with increasing concentrations of salts and sugars. The extent of reduction in drug solubility was dependent on the type of salts and sugars used. The salting-out coefficient of additives was calculated by plotting log-linear solubility profiles of the drug against the concentrations of the additives. The solubility of guaifenesin, a neutral compound, was found to be higher at lower pH values, which could be due to hydrogen-bonding effects. At 25 degrees C, glycerin, PEG 300, and propylene glycol increased the solubility of drug at low solvent concentrations while the solubility was reduced at high concentrations. At 40 degrees C, the solubility of drug was reduced at all concentrations of cosolvents. The thermodynamic events accompanying the solubility process were discussed to explain the solubility phenomena observed in the presence of additives. The reduced aqueous solubility of guaifenesin in the presence of additives greatly improved the entrapment of drug into controlled-release wax microspheres.     

混合型微胞对丁苯酞的增溶性研究

目的研究开发增加丁苯酞溶解度的新方法。方法采用混合型微胞增溶法。结果磷脂混合型微胞能明显增加丁苯酞的溶解度,其溶解度较水溶液增加30倍。结论所建方法工艺简便,产品长期贮存质量稳定,为丁苯酞的注射剂型的开发打下了基础。     

Use of parallel validation high-throughput screens to reduce false positives and identify novel dengue NS2B-NS3 protease inhibitors

Dengue virus (DENV), a mosquito-borne member of the family Flaviviridae, is a significant global pathogen affecting primarily tropical and subtropical regions of the world and placing tremendous burden on the limited medical infrastructure that exists in many of the developing countries located within these regions. Recent outbreaks in developed countries, including Australia (Hanna et al., 2009), France (La Ruche et al., 2010), Taiwan (Kuan et al., 2010), and the USA (CDC, 2010), lead many researchers to believe that continued emergence into more temperate latitudes is likely. A primary concern is that there are no approved vaccines or antiviral therapies to treat DENV infections. Since the viral NS2B-NS3 protease (DENV NS2B-NS3pro) is required for virus replication, it provides a strategic target for the development of antiviral drugs. In this study, proof-of-concept high-throughput screenings (HTSs) were performed to unambiguously identify dengue 2 virus (DEN2V) NS2B-NS3pro inhibitors from a library of 2000 compounds. Validation screens were performed in parallel to concurrently eliminate insoluble, auto-fluorescing, and/or nonspecific inhibitors. Kinetic analyses of the hits revealed that parallel substrate fluorophore (AMC) interference controls and trypsin inhibition controls were able to reduce false positive rates due to solubility and fluorophore interference while the trypsin inhibition control additionally eliminated non-specific inhibitors. We identified five DEN2V NS2B-NS3pro inhibitors that also inhibited the related West Nile virus (WNV) protease (NS2B-NS3pro), but did not inhibit the trypsin protease. Biochemical analyses revealed various mechanisms of inhibition including competitive and mixed noncompetitive inhibition, with the lowest K_i values being 12 ± 1.5 μM for DEN2V NS2B-NS3pro and 2 ± 0.2 μM for WNV NS2B-NS3pro.     

Characterization of the 13-cis-retinoic acid/cyclodextrin inclusion complexes by phase solubility, photostability, physicochemical and computational analysis.

13-cis-Retinoic acid (13-cis-RA) is a synthetic retinoid commonly used in the treatment of severe acne. It has also been found to possess potential chemopreventive activity. It has extremely low aqueous solubility and high photo-sensitivity. This study investigated the effects of the complexation of 13-cis-RA with alpha-cyclodextrin (alpha-CD) and hydroxypropyl-beta-cyclodextrin (HP-beta-CD) on its phase solubility. HP-beta-CD was found to be more effective in increasing the aqueous solubility of 13-cis-RA compared to alpha-CD. Phase solubility studies indicated that the solubility of 13-cis-RA was increased dramatically by the formation of inclusion complex with HP-beta-CD. The solubility was further enhanced by pH adjustment. The photostability of the selected inclusion complex of 13-cis-RA:HP-beta-CD was then evaluated. Complexation with HP-beta-CD was found to delay the photo-degradation of 13-cis-RA in aqueous solution. The physicochemical properties of the solid inclusion complex were characterized by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and X-ray diffractometry (XRD). Molecular modeling with MMFF94s force field (SYBYL V6.6) was utilized to predict the preferred orientation of 13-cis-RA in the CD cavity and the main structural features responsible for the enhancement of its solubility and photostability. The energy scores estimated from the computational analysis were found capable of reflecting the stability constants of the cyclodextrin complexes obtained in the phase solubility studies. The results showed that HP-beta-CD was a proper excipient for increasing solubility and stability of 13-cis-RA.     

HPLC法测定叶黄素的平衡溶解度及表观油水分配系数

目的 测定叶黄素在不同溶剂中的平衡溶解度及表观油水分配系数。方法 建立高效液相色谱法用于测定叶黄素含量,采用摇瓶法考察叶黄素在多种有机溶剂及不同pH值缓冲液中的平衡溶解度,并测定其表观油水分配系数。结果 叶黄素几乎不溶于水及缓冲液,在有机溶剂中溶解度有不同程度提高,其中在四氢呋喃中的溶解度最高（66 mg·mL^-1）;其表观油水分配系数为1.03。结论 叶黄素在多数溶剂中的溶解度均较低,可通过提高溶解度改善溶出和吸收。     

Effect of pH and solubility on in vitro skin penetration of methotrexate from a 50% v/v propylene glycol-water vehicle

In vitro percutaneous absorption of methotrexate from a saturated solution in a 50% v/v propylene glycol-water vehicle was examined across suitably characterized human cadaver skin. A detailed study of solubility and pH parameters in the range of 2–6 pH units was conducted. A clear trend towards increasing steady-state penetration rate with increasing pH was evident. Relatively high lag times were observed even at optimal pH values emphasizing the importance of prolonged application of drug to achieve therapeutic concentrations. From a vehicle at pH 2, the steady-state rate of penetration was very low and the data suggested drug binding with stratum corneum. Although the drug solubility in the vehicle was considerably lower at pH 4 than at pH 2–3, the steady-state rate and extent of penetration were higher. Both drug solubility and steady-state penetration rate were significantly higher at pH 5.29 than at pH 4. Increasing the vehicle pH to 6.34 increased the drug solubility as well as steady-state rate of penetration but the percent amount penetrated declined. The lag times were also large at this pH. Relatively high drug solubility and gradually increasing contribution of shunt pathways probably account for this result. In view of the observed pH-solubility profile, for a 50% v/v propylene glycol-water vehicle, a pH between 4 and 5 would appear to provide the most favorable environment for passive diffusion since the concentration of unionized methotrexate would be optimal.     

Towards the design of antiviral inhibitors against flaviviruses: the case for the multifunctional NS3 protein from Dengue virus as a target

New treatments are urgently needed to combat the increasing number of dengue fever cases in endemic countries as well as amongst a large number of travellers from non-endemic countries. Of the 10 virus encoded proteins, NS3 (non-structural 3) and NS5 carry out all the enzymatic activities needed for polyprotein processing and genome replication, and are considered to be amenable to antiviral inhibition by analogy with successes for similar targets in human immunodeficiency virus and hepatitis C virus. The multifunctional NS3 protein of flavivirus forms a non-covalent complex with the NS2B cofactor and contains the serine-protease activity domain at its N-terminus that is responsible for proteolytic processing of the viral polyprotein and a ATPase/helicase and RNA triphosphatase at its C-terminal end that are essential for RNA replication. In addition, NS3 seems to be also involved in virus assembly. This review covers the recent biochemical and structural advances on the NS2B-NS3 protease-helicase and presents an outlook for the development of small molecules as antiviral drugs targeting this fascinating multifunctional protein.