乙烷硒啉分散片溶出度测定方法的研究*

目的:建立乙烷硒啉分散片的溶出度测定方法。方法:建立溶出度紫外测定方法,分别考察乙烷硒啉分散片在不同条件下的溶出特性,运用Excel办公软件,以Weibull模型处理试验数据,用单因素方差分析及t检验进行统计学分析。结果:在优化的测定条件下,乙烷硒啉分散片60min累积溶出度达到(65.59±0.36)%,批内均一性与批间重现性良好。结论:本品溶出度优化测定条件为:溶出介质量为1000mL,溶出介质组成为0.9%盐酸水溶液-异丙醇(60∶40),采用药典附录ⅩC第二法(桨法),转速为150r.min-1。取样点为60min,限度为60%。     

共研磨法改善枸橼酸莫沙必利的体外溶出度

目的 改善枸橼酸莫沙必利的体外溶出度.方法 采用共研磨法,分别制备枸橼酸莫沙必利与低取代羟丙基纤维素(L-HPC)、羟丙甲纤维素(HPMC)、聚维酮(PVP)或聚乙二醇6000(PEG 6000)(1∶2)的共研磨物,测定原料药、物理混合物和共研磨物的溶出度;运用X射线衍射法和差示扫描量热法鉴别药物在共研磨物中的存在状态,并考察其稳定性.结果 枸橼酸莫沙必利与L-HPC和HPMC共研磨物的溶出度较原料药的显著提高,且稳定性较好.结论 共研磨法能够改善枸橼酸莫沙必利的体外溶出度.     

马来酸氟吡汀固体分散体的制备及体外溶出

目的:制备马来酸氟吡汀-PEG 6000固体分散体以加快药物的体外溶出速度。方法:以PEG 6000为药物载体,采用熔融法制备马来酸氟吡汀固体分散体,采用X-射线衍射法和差示扫描量热法(DSC)观察药物在载体中的存在状态。结果:马来酸氟吡汀以分子状态存在于固体分散体中;药物与载体的比例为1:4时,所制备的固体分散体具有最高的溶出度。结论:固体分散体能显著提高药物溶出度和溶出速率。     

RP-HPLC法测定乙烷硒啉分散片中药物的含量*

目的:建立乙烷硒啉分散片含量测定方法。方法:采用反相高效液相色谱法,使用BDS HYPERSILC18柱(250mm×4.6mm,5μm),检测波长为320nm,柱温为室温,流动相为0.01%磷酸-甲醇(60∶40),流速1.0mL.min-1。结果:溶剂与辅料对分散片中药物的含量测定无干扰,乙烷硒啉在10～400μg.mL-1范围内呈良好的线性关系(r=0.9995),精密度RSD为0.39%;日内精密度为0.57%;平均回收率为101.2%(n=9)。结论:该方法专属性强,操作方便,结果准确,重现性好,可用于乙烷硒啉分散片中药物的含量测定。     

依布硒固体分散体的制备及体外溶出度研究

目的提高依布硒的体外溶出速率。方法以固体分散技术制备依布硒固体分散体,并测定其体外溶出度,采用差示扫描量热法(DSC)进行物相分析。结果DSC分析表明,依布硒是以非晶体状态存在,用水溶性载体普朗尼克制备的分散体体外溶出60min大于60%。结论制备依布硒固体分散体可以提高其体外溶出度。     

阿德福韦酯-PEG6000固体分散体的制备

目的将难溶性药物阿德福韦酯制备成固体分散体,以增加体外溶出度。方法以聚乙二醇6000(polyethylene glycol 6000,PEG6000)为载体,采用熔融法制备阿德福韦酯固体分散体;配合差示扫描量热(differential scanning calorimetry,DSC)与X-射线衍射(X-ray diffraction,XRD)观察药物在载体中的存在状态;考察相对湿度(relative humidity,RH)75%40℃放置3个月固体分散体对溶出度的变化及载体-药物质量比对溶出的影响。结果阿德福韦酯以无定型状态存在于固体分散体中,相对湿度RH75%40℃放置3个月固体分散体对溶出度改善明显,载体-药物质量比不同,药物的溶出度不同。结论将阿德福韦酯制成固体分散体能显著增加阿德福韦酯的体外溶出度。     

热熔挤出技术提高水飞蓟素溶出度的初步研究

目的:研究热熔挤出技术是否提高难溶性药物溶出度.方法:以难溶性水飞蓟素为模型药物,以泊洛沙姆-188为亲水性载体,采用热熔挤出技术和熔融法分别制备挤出物和固体分散体,比较两者的差示扫描量热(DSC)图谱和累积溶出曲线.结果:挤出物是分散程度较高的固体分散体,DSC图谱中药物的吸热峰均消失,载体泊洛沙姆-188的吸热峰向低温方向移动,挤出物中的移行程度大于固体分散体;药物在90 min时从挤出物中溶出90.63%,而在固体分散体中的溶出量为71.06%.结论:热熔挤出技术可提高水飞蓟素的溶出度,且效果优于熔融法.     

非洛地平固体分散体的制备和体外溶出度考察

目的应用固体分散技术,提高非洛地平的体外溶出度。方法以PVPK30、Lutrol F68、Tween80(与吸附剂,如PVPP)为载体,分别采用溶剂法、熔融法、溶剂蒸发-沉积等技术制备非洛地平固体分散体,考察不同载体对固体分散体溶出度的影响。并着重考察以Tween 80为增溶剂,不同种类吸附剂为载体对固体分散体外观、溶出度的影响。应用差示热分析和X射线衍射鉴别药物在载体中的存在状态。结果采用不同载体和方法制备的非洛地平固体分散体均能明显促进药物的溶出,溶出速度依次为Tween 80>Lutrol F68>PVPk30。其中m(药物)∶m(Tween 80)∶m(PVPP)=1∶4∶5时,溶出速度最快,1 h累积释放率达90%以上。差示热分析固体分散体中药物吸热峰前移或消失,X射线衍射固体分散体中药物的结晶衍射峰消失,推测药物在载体中以无定形或分子形式存在。结论制备非洛地平固体分散体可以提高其体外溶出度,尤其是含有表面活性剂的固体分散体可进一步提高药物的溶出。     

新型超分子材料环糊精与俄色黄酮包合物研究

目的：采用3种不同的环糊精[β-环糊精（β-CD）、羟丙基-β-环糊精（ HP-β-CD）、二甲基-β-环糊精（ DM-β-CD）]对藏药俄色黄酮进行包合,比较不同环糊精对俄色黄酮溶解度的影响。方法高效液相色谱测定俄色黄酮相溶解度;采用X-射线衍射法（ XRD）、差示扫描量热分析法（ DSC）对俄色黄酮环糊精超分子进行表征。结果β-环糊精、羟丙基-β-环糊精、二甲基-β-环糊精均能提高俄色黄酮溶解度,增溶能力依次为二甲基-β-环糊精﹥羟丙基-β-环糊精﹥β-环糊精。经X-射线衍射法、差示扫描量热分析法,表明3种俄色黄酮环糊精超分子形成,形成超分子后俄色黄酮溶解度、热稳定性显著提高。结论β-环糊精、羟丙基-β-环糊精、二甲基-β-环糊精均能与俄色黄酮形成超分子,并能显著提高俄色黄酮体外溶解度。     

乙烷硒啉的临床药物动力学和代谢转化特点研究

目的研究肿瘤患者口服乙烷硒啉(1,2-[bis(1,2Benzisoselenazolone-3(2H)-ketone)]ethane,BBSKE)后的药物动力学及体内代谢转化特征。方法3例肿瘤患者单次口服给药剂量为600mg.d-1,采集各个时间点的血浆样品及尿样,用液相色谱-串联四极杆质谱(LC/ESI-MS/MS)联用技术测定血浆样品中BBSKE的含量,用液相色谱-电喷雾离子阱质谱(LC-ESI/MSn)联用技术对尿及血浆中的代谢产物进行分析鉴定。结果得到了BBSKE在血浆中的药时曲线图及主要的药物动力学参数。在尿中共发现了6个BBSKE的氧化、甲基化、葡萄糖醛酸化代谢产物,在血浆中共发现了2个BBSKE的氧化、葡萄糖醛酸化代谢产物。结论BBSKE的血药浓度较低,表观分布容积大。氧化、甲基化、葡萄糖醛酸化反应是BBSKE在人体内的3种重要代谢途径。     

Effect of particle size on the dissolution behaviors of poorly water-soluble drugs

This study examined the effects of the particle size of various poorly water-soluble drugs on their dissolution behavior through physicochemical and mathematical analysis. As model drugs, hydrochlorothiazide, aceclofenac, ibuprofen and a discovery candidate were selected. The materials were crystallized using an evaporation method and milled without transformation behavior of crystal forms. The particles were sieved and divided into four size groups (< 45 μm, 45～150 μm, 150～250 μm, and 250～600 μm). The specific surface area with regard to the particle size was measured using a BET surface area measurement. The specific surface area increased with decreasing particle size of the drug, resulting in an increase in dissolution rate. During the initial period of the dissolution study, significant differences in dissolution rate were observed according to the particle size and specific surface areas. On the other hand, in the later stages, the surface-specific dissolution rate was almost consistent regardless of the particle size. These observations were evaluated mathematically and the results suggested that the dissolution rate of poorly soluble drugs is strongly related to the particle size distribution. Moreover, physicochemical analysis helped explain the effect of particle size on the dissolution profiles.     

Studies on dissolution enhancement and mathematical modeling of drug release of a poorly water-soluble drug using water-soluble carriers.

Role of various water-soluble carriers was studied for dissolution enhancement of a poorly soluble model drug, rofecoxib, using solid dispersion approach. Diverse carriers viz. polyethylene glycols (PEG 4000 and 6000), polyglycolized fatty acid ester (Gelucire 44/14), polyvinylpyrollidone K25 (PVP), poloxamers (Lutrol F127 and F68), polyols (mannitol, sorbitol), organic acid (citric acid) and hydrotropes (urea, nicotinamide) were investigated for the purpose. Phase-solubility studies revealed AL type of curves for each carrier, indicating linear increase in drug solubility with carrier concentration. The sign and magnitude of the thermodynamic parameter, Gibbs free energy of transfer, indicated spontaneity of solubilization process. All the solid dispersions showed dissolution improvement vis-à-vis pure drug to varying degrees, with citric acid, PVP and poloxamers as the most promising carriers. Mathematical modeling of in vitro dissolution data indicated the best fitting with Korsemeyer-Peppas model and the drug release kinetics primarily as Fickian diffusion. Solid state characterization of the drug-poloxamer binary system using XRD, FTIR, DSC and SEM techniques revealed distinct loss of drug crystallinity in the formulation, ostensibly accounting for enhancement in dissolution rate.     

Microcrystals for dissolution rate enhancement of poorly water-soluble drugs

Slight dissolution rates related to poor water-solubility are one of the well-known difficulties to be covered during the development of new drug substances. The poorly water-soluble drug ECU-01, a low molecular enzyme-inhibitor with anti-inflammatory properties for oral administration, shows a poor dissolution rate. This study is intended to enhance the drug dissolution rate by using microcrystals. The common way for micronization is the milling of previously formed larger crystals. However, milling shows several disadvantages as the newly created surfaces are thermodynamically activated due to the high energy input and not naturally grown. In this study microcrystals were not produced using any cutting up techniques, but only by association. Naturally grown microcrystals were prepared by a precipitation method in the presence of stabilizing agents (e.g. gelatin, chitosan, different types of cellulose ethers) followed by spray-drying of the formed dispersion. First the drug was dissolved in acetone and then precipitated by rapid pouring an aqueous solution of the stabilizer into the drug solution. Particularly, cellulose ethers were able to form stable and homogeneous dispersions of microcrystals (mean particle size = 1 microm) showing a tight particle size distribution. By spray-drying, the drug powder was obtained. The dissolution rate is significantly enhanced (common drug: 4% after 20 min/microcrystals 93% after 20 min) due to the large surface, which is hydrophilized by adsorbed stabilizers as shown by the decreased contact angle (65 and 30 degrees, respectively).     

The effects of surfactants on the dissolution profiles of poorly water-soluble acidic drugs

The effects of types of surfactants on the solubilization and dissolution of poorly soluble acidic drugs were compared to identify the most suitable surfactant for conducting an acidic drug dissolution test. Cetyltrimethylammonium bromide (CTAB) as a cationic surfactant, sodium lauryl sulfate (SLS) as an anionic surfactant, and polysorbate 80 as a non-ionic surfactant were used in the study. And, mefenamic acid, nimesulide, and ibuprofen were selected as model drugs. The dissolution rates of these acidic drugs were substantially enhanced in medium containing CTAB. Electrostatic interactions between acidic drugs and cationic surfactants were confirmed by measuring UV spectra of each drug. Solubility of drugs in various media and the partition coefficients of drugs into micelles were found to depend on drug characteristics. For acidic drugs, the ability of media containing a cationic surfactant to discriminate rates of dissolution of acidic drugs seemed to be greater than that of media containing other surfactant types.     

Effect of vehicle amphiphilicity on the dissolution and bioavailability of a poorly water-soluble drug from solid dispersions

Solid dispersions of a poorly water-soluble drug [REV 5901; alpha-pentyl-3-(2-quinolinylmethoxy)benzenemethanol; 1] in an amphiphilic vehicle [Gelucire 44/14; 2] and in polyethylene glycol (PEG) 1000, PEG 1450, and PEG 8000 were prepared. The vehicle 2 was a mixture of hydrogenated fatty acid esters with a mp of 44 degrees C, and had a HLB value of 14. Compound 1 was dissolved or dispersed in molten vehicles at elevated temperatures. The pulverization and compression of solid dispersions were avoided by encapsulating the hot solutions directly into hard gelatin capsules. At room temperature, the dispersions solidified forming plugs inside the capsules. On storage, greater than 180 mg of 1 remained dissolved per gram of vehicle, while the excess drug formed fine crystals (less than 20 micron). When mixed with water, the dissolved drug separated as a metastable liquid. Due to the surfactant property of 2, the oily form of 1 that separated from this vehicle formed an emulsified system with a globular size of less than 1 micron, while greater than 80% of 1 that separated from the other three formulations coalesced to form large oily masses. As a result of the large difference in surface area, the dissolution rate of 1 in simulated gastric fluid from capsules containing 2 was much higher than that of a PEG-based formulation. The bioavailability (AUC) of 1 in dogs from capsules containing 2 was also higher than that from PEG 1000-based capsules.     

Investigation of preparation parameters to improve the dissolution of poorly water-soluble meloxicam

The rate of dissolution of drugs remains one of the most challenging aspects in formulation development of poorly water-soluble drugs. The meloxicam, a low molecular analgetic for oral administration, exhibits a slow dissolution. To improve the dissolution rate, the drug was formulated in a nanosuspension by using an emulsion–diffusion method, high-pressure homogenization or sonication. Optimization of the technological parameters (organic solvents, stabilizers, homogenization procedure and recovery of particles) allowed the formation of nanosuspensions with a particle size of 200–900 nm. SEM imaging confirmed the nanosized drug particles. Use of an SMCR method on the XRPD patterns of the nanosuspensions revealed the crystalline form of the drug and the strong interaction between meloxicam and the stabilizer. The rate of dissolution of the dried meloxicam nanosuspension was enhanced (90% in 5 min), relative to that of raw meloxicam (15% in 5 min), mainly due to the formation of nanosized particles. These results indicate the suitability of formulation procedure for preparation of nanosized poorly water-soluble drug with significantly improved in vitro dissolution rate, and thus possibly enhance fast onset of therapeutic drug effect.     

有序介孔硅胶提高难溶性药物白藜芦醇的溶出速率

本研究的目的是制备有序介孔硅胶并考察其作为难溶性药物载体的体外药物释放特点。以十六烷基三甲基溴化铵为模板合成了有序介孔硅胶, 以白藜芦醇为模型药物, 采用扫描电镜、透射电镜、N₂吸附-脱附、X-射线衍射和红外光谱对载药前后的有序介孔硅胶进行表征, 并考察药物体外释放行为。结果表明, 合成的有序介孔硅胶比表面积大、粒度均匀, 具有有序六方孔道结构, 载药后药物以无定形态或分子态存在, 释放速率明显提高。有序介孔硅胶有望成为新型的难溶性药物载体。     

Encapsulation of poorly water-soluble drugs into organic nanotubes for improving drug dissolution

Hydrocortisone (HC), a poorly water-soluble drug, was encapsulated within organic nanotubes (ONTs), which were formed via the self-assembly of N-{12-[(2-α,β-d-glucopyranosyl) carbamoyl]dodecanyl}-glycylglycylglycine acid. The stability of the ONTs was evaluated in ten organic solvents, of differing polarities, by field emission transmission electron microscopy. The ONTs maintained their stable tubular structure in the highly polar solvents, such as ethanol and acetone. Furthermore, solution-state ¹H-NMR spectroscopy confirmed that they were practically insoluble in acetone at 25 °C (0.015 mg/mL). HC-loaded ONTs were prepared by solvent evaporation using acetone. A sample with a 3/7 weight ratio of HC/ONT was analyzed by powder X-ray diffraction, which confirmed the presence of a halo pattern and the absence of any crystalline HC peak. HC peak broadening, observed by solid-state ¹³C-NMR measurements of the evaporated sample, indicated the absence of HC crystals. These results indicated that HC was successfully encapsulated in ONT as an amorphous state. Improvements of the HC dissolution rate were clearly observed in aqueous media at both pH 1.2 and 6.8, probably due to HC amorphization in the ONTs. Phenytoin, another poorly water-soluble drug, also showed significant dissolution improvement upon ONT encapsulation. Therefore, ONTs can serve as an alternative pharmaceutical excipient to enhance the bioavailability of poorly water-soluble drugs.     

Preparation of starch macrocellular foam for increasing the dissolution rate of poorly water-soluble drugs

Starch macrocellular foam (SMF), a novel natural bio-matrix material, was prepared by the hard template method in order to improve the dissolution rate and oral bioavailability of poorly water-soluble drugs. Nitrendipine (NDP) was chosen as a model drug and was loaded into SMF by the solvent evaporation method. SMF and the loaded SMF samples (NDP-SMF) were characterized by scanning electron microscopy, differential scanning calorimetry, X-ray powder diffraction and Fourier transform infrared spectroscopy. In vitro drug release studies showed that SMF significantly increased the dissolution rate of NDP. In vivo studies showed that the NDP-SMF tablets clearly increased the oral bioavailability of NDP in comparison with the reference commercial tablets. All the results obtained demonstrated that SMF was a promising carrier for the oral delivery of poor water-soluble drugs.