Preparation, Characterization, and In Vitro Evaluation of Ezetimibe Binary Solid Dispersions with Poloxamer 407 and PVP K30

Ezetimibe (EZE), a water insoluble drug, depicts variable bioavailability. The objective of the present investigation was to improve dissolution characteristics of EZE, which might offer improved bioavailability. The solid dispersions were prepared using poloxamer 407 (L 127) and polyvinyl pyrrolidone by melt and solvent method, respectively. Phase solubility studies indicated linear relationship between drug solubility and carrier concentration. In vitro release studies revealed improvement in the dissolution characteristics of EZE in solid dispersions. Solid dispersion with L 127 gave better rate and extent of dissolution. The best fit model indicating the probable mechanism of drug release from solid dispersions was found to be Korsemeyer–Peppas. The results of characterization of solid dispersions by Fourier transform infrared spectroscopy, differential scanning calorimetry, and powder X-ray diffraction revealed reduction in drug crystallinity which might be responsible for improved dissolution properties. The tablets of solid dispersion, containing L 127 prepared by direct compression, exhibited better drug release as compared to marketed formulation.     

环孢素-泊洛沙姆188固体分散体的体外评价

目的以泊洛沙姆188（F68）为载体制备环孢素（CsA）固体分散体并考察其体外溶出。方法以溶剂一熔融法制备固体分散体，以差示扫描量热法（DSC）和X．射线衍射法鉴定CsA在体系中的存在状态，以FTIR表征药物与载体的相互作用，以摇瓶法测定CsA的溶解度，按《中国药典》溶出度第三法测定CsA从物理混合物和固体分散体中的溶出。结果X-射线衍射图谱显示CsA结晶衍射峰消失，提示药物以无定形或分子状态存在于固体分散体中。FTIR结果表明药物与载体间无相互作用。药物溶解度和溶出度均随着F68比例的增加而增大，固体分散体和物理混合物60min的累积溶出百分率分别为99．32％和75．41％，两者具显著性差异（P〈0．01）。结论F68能提高CsA的溶解度和溶出度，可用来制备CsA的固体剂型。     

间尼索地平固体分散体的研制

目的:将难溶性药物间尼索地平制备成固体分散体,以增加其溶解度及体外溶出度。方法:以泊洛沙姆为载体,共沉淀法制备间尼索地平固体分散体。采用差示扫描量热分析(DSC)方法鉴别药物在载体中的存在状态,并进行溶解度和体外溶出度研究。结果:DSC显示间尼索地平与泊洛沙姆形成了低共熔物,间尼索地平原料药及其与泊洛沙姆不同比例的固体分散体(1∶3、1∶5、1∶7)的溶解度分别为0.89、4.50、15.35、23.03mg·L-1,120min时的累积溶出百分率分别为26.80%、38.57%、41.38%、45.92%,固体分散体的溶出度高于同比例的物理混合物。结论:以泊洛沙姆为载体制备间尼索地平固体分散体,可增加药物的体外溶出度和溶解度。     

Improvement in Dissolution Rate of Cefuroxime Axetil by using Poloxamer 188 and Neusilin US2

A combination of fusion and surface adsorption techniques was used to enhance the dissolution rate of cefuroxime axetil. Solid dispersions of cefuroxime axetil were prepared by two methods, namely fusion method using poloxamer 188 alone and combination of poloxamer 188 and Neusilin US2 by fusion and surface adsorption method. Solid dispersions were evaluated for solubility, phase solubility, flowability, compressibility, Kawakita analysis, Fourier transform-infrared spectra, differential scanning calorimetry, powder X-ray diffraction study, in vitro drug release, and stability study. Solubility studies showed 12- and 14-fold increase in solubility for solid dispersions by fusion method, and fusion and surface adsorption method, respectively. Phase solubility studies showed negative ΔG⁰_tr values for poloxamer 188 at various concentrations (0, 0.25, 0.5, 0.75 and 1%) indicating spontaneous nature of solubilisation. Fourier transform-infrared spectra and differential scanning calorimetry spectra showed that drug and excipients are compatible with each other. Powder X-ray diffraction study studies indicated that presence of Neusilin US2 is less likely to promote the reversion of the amorphous cefuroxime axetil to crystalline state. in vitro dissolution studies, T50% and mean dissolution time have shown better dissolution rate for solid dispersions by fusion and surface adsorption method. Cefuroxime axetil release at 15 min (Q15) and DE15 exhibited 23- and 20-fold improvement in dissolution rate. The optimized solid dispersion formulation was stable for 6 months of stability study as per ICH guidelines. The stability was ascertained from drug content, in vitro dissolution, Fourier transform-infrared spectra and differential scanning calorimetry study. Hence, this combined approach of fusion and surface adsorption can be used successfully to improve the dissolution rate of poorly soluble biopharmaceutical classification system class II drug cefuroxime axetil.     

他克莫司固体分散体的制备及体外溶出度测定

目的:制备他克莫司固体分散体,提高他克莫司的体外溶出度。方法:以体外溶出度为指标,从泊洛沙姆188(Poloxamer188)、聚维酮K30(PVP K30)、羟丙甲纤维素(HPMCE3)、聚乙二醇6000(PEG6000)中筛选最优载体及其比例。并采用差示热量扫描(DSC)、红外光谱(FTIR)、电子扫描电镜(SEM)等进行物相表征。结果:4种不同载体制成的固体分散体均能增加他克莫司体外溶出度,通过比较优选出HPMCE3为最佳载体。物相鉴定表明,他克莫司大部分以无定型状态分散于HPMCE3中。结论:制备他克莫司-HPMCE3固体分散体可以明显提高其体外溶出度,且制备方法简单可行。     

Dissolution rate enhancement and physicochemical characterization of carbamazepine-poloxamer solid dispersions

This study investigates the potential of poloxamers as solid dispersions (SDs) carriers in improving the dissolution rate of a poorly soluble drug, carbamazepine (CBZ). Solid dispersions were prepared with poloxamer 188 (P188) and poloxamer 407 (P407) by melting method in different drug:carrier ratios (1:1, 1:2 and 1:3). Prepared samples were characterized using differential scanning calorimetry (DSC), hot-stage polarized light microscopy (HSM), powder X-ray diffraction (PXRD) and Fourier transform infrared spectroscopy (FT-IR) to investigate drug physical state within the SDs matrix, possible polymorphic transitions and drug-polymer interactions. The interactions between CBZ molecules and polymeric chains were also evaluated using molecular dynamics simulation (MDS) technique. The most thermodynamically stable polymorphic form III of CBZ was present in all SDs, regardless of the type of poloxamer and drug-to-carrier ratio. The absence of drug-polymer interactions was observed by FT-IR analysis and additionally confirmed by MDS. Formation of persistent hydrogen bond between two CBZ molecules, observed by MDS indicate high tendency of CBZ molecules to aggregate and form crystalline phase within dispersion. P188 exhibit higher efficiency in increasing CBZ dissolution rate due to its more pronounced hydrophilic properties, while increasing poloxamers concentration resulted in decreasing drug release rate, as a consequence of their thermoreversible gelation.     

Formulation and in vivo hypoglycemic effect of glipizide solid dispersion

The present study was carried out with a view to enhance dissolution rate of poorly water-soluble drug glipizide (GZ) (BCS class II) using polyethylene glycol (PEG) 6000, PEG 8000 and poloxamer (PXM) 188 as carriers. Solid dispersions (SDs) were prepared by melting method using different ratios of glipizide to carriers. Phase solubility study was conducted to evaluate the effect of carrier on aqueous solubility of glipizide. SD was optimized by drug content estimation and in vitro dissolution study and optimised SD was subjected to bulk characterization, Scanning electron microscopy (SEM), Fourier transformation infrared spectroscopy (FTIR), Differential scanning calorimetry (DSC) and X-ray diffraction study (XRD). Preclinical study was performed in mice to study the decrease in blood glucose level from prepared SD compared with pure drug. Due to high solubility and drug release, PXM 188 in weight ratio of 1:2 was optimized. Decrease in blood glucose level in mice from SD was significantly higher (p < 0.05) compared to pure glipizide. Thus, solid dispersion technique can be successfully used for the improvement of the dissolution profile of GZ.     

托伐普坦固体分散体的制备及体外溶出特性考察

目的 采用固体分散技术提高难溶性药物托伐普坦的体外溶出度。方法 选用聚维酮K_29/32为载体材料,以溶剂蒸发法制备托伐普坦固体分散体。采用差示扫描量热法(DSC)、X-射线粉末衍射法(XRPD)对所得固体分散体进行鉴定, 并进行溶解度、体外溶出实验。结果 固体分散体的DSC 图谱及X-射线粉末衍射确定了托伐普坦以无定形态分散在载体中, 体外溶解实验表明其溶出较原料药、物理混合物均有明显提高。结论 将托伐普坦与PVP K_29/32制成固体分散体,其分散状态发生了改变,溶出性能明显提高。     

依托泊苷固体分散体的溶出与大鼠在体肠吸收研究

目的:制备依托泊苷(VP-16)固体分散体,对其在大鼠小肠各部位的吸收进行研究,以期提高口服生物利用度.方法:采用溶剂-熔融法制备VP-16-硬脂酸聚氧烃酯(S-40)或泊洛沙姆188(F68)固体分散体,按中华人民共和国药典2005年版溶出度第二法测定VP-16固体分散体的溶出,以差示扫描量热法(DSC)法和X-射线衍射法鉴定VP-16在体系中的状态,运用大鼠在体肠循环模型,采用HPLC法测定药物浓度,考察药物的吸收.结果:固体分散体中VP-16的溶出比原料药和物理混合物均有显著提高,随着载体质量比增加而增大.DSC图谱显示VP-16的特征峰消失,X-射线衍射图谱显示VP-16的结晶衍射峰消失,药物以无定形或分子状态分散在固体分散体中.VP-16在小肠上半段吸收较好,当载体对药物质量比≥3时,固体分散体在空肠段吸收有显著增加,且VP-16/S-40固体分散体的吸收比VP-16/F68固体分散体的吸收好.结论:S-40和F68两种表面活性剂均能显著提高VP-16的溶出度,并对VP-16在大鼠小肠的吸收有明显促进作用,S-40的吸收促进作用显著大于F68.     

Improving the dissolution rate of poorly water soluble drug by solid dispersion and solid solution: pros and cons

The solid dispersions with poloxamer 188 (P188) and solid solutions with polyvinylpyrrolidone K30 (PVPK30) were evaluated and compared in an effort to improve aqueous solubility and bioavailability of a model hydrophobic drug. All preparations were characterized by differential scanning calorimetry, powder X-ray diffraction, intrinsic dissolution rates, and contact angle measurements. Accelerated stability studies also were conducted to determine the effects of aging on the stability of various formulations. The selected solid dispersion and solid solution formulations were further evaluated in beagle dogs for in vivo testing. Solid dispersions were characterized to show that the drug retains its crystallinity and forms a two-phase system. Solid solutions were characterized to be an amorphous monophasic system with transition of crystalline drug to amorphous state. The evaluation of the intrinsic dissolution rates of various preparations indicated that the solid solutions have higher initial dissolution rates compared with solid dispersions. However, after storage at accelerated conditions, the dissolution rates of solid solutions were lower due to partial reversion to crystalline form. The drug in solid dispersion showed better bioavailability in comparison to solid solution. Therefore, considering physical stability and in vivo study results, the solid dispersion was the most suitable choice to improve dissolution rates and hence the bioavailability of the poorly water soluble drug.     

难溶性药物水飞蓟宾固体分散体的制备及评价(英文)

采用溶剂法制备水飞蓟宾的PVP K30固体分散体以提高其溶解度和溶出速率;通过平衡溶解度、溶出速率、DSC和FTIR等方法验证和定性分析制备的固体分散体。水飞蓟宾的固体分散体与原料药及物理混合物相比,改善了药物的溶解度和溶出速率。DSC曲线显示水飞蓟宾的吸热峰消失,表明水飞蓟宾以无定形物分散于载体材料中;FTIR的研究结果表明水飞蓟宾的羟基和PVP K30的羰基发生了反应。固体分散技术可应用于难溶性药物以改善其体外溶出及进一步的体内吸收。     

Preparation, characterization and in vitro dissolution studies of solid dispersion of meloxicam with PEG 6000

The poor solubility and wettability of meloxicam leads to poor dissolution and hence showing variations in bioavailability. The present study is aimed to increase solubility and dissolution of the drug using solid dispersion techniques. The solid binary systems were prepared at various drug concentrations (5-40%) with polyethylene glycol 6000 by different techniques (physical mixing, solvent evaporation). The formulations were characterized by solubility studies, differential scanning calorimetry, fourier transform infrared spectroscopy and in vitro dissolution rate studies. The solubility of drug increased linearly with increase in polymer concentration showing A(L) type solubility diagrams. Infrared spectroscopy studies indicated the possibility of hydrogen bonding with polymer. The differential scanning calorimetry and powder X ray diffraction demonstrated the presence of polymer as eutectica or monotectica in solid dispersion along with the physical characteristics of the drug (crystalline, amorphous or a mixture of both). The solid dispersions of the drug demonstrated higher drug dissolution rates than physical mixtures and pure meloxicam, as a result of increased wettability and dispersibility of drug in a solid dispersion system.     

In sight into tadalafil - block copolymer binary solid dispersion: Mechanistic investigation of dissolution enhancement

Tadalafil is a phosphodiesterase-5 inhibitor that is characterized by low solubility and high permeability. Solid dispersion approach represents a promising carrier system for effective enhancement of dissolution and oral bioavailability of poorly soluble drugs. In the present work, novel tadalafil-loaded solid dispersions employing various block copolymers (Pluronics(?)) were prepared through fusion technique. Their solubility and dissolution properties were compared to the drug alone. In order to elucidate the mechanism of dissolution enhancement, solid state characteristics were investigated using scanning electron microscopy, Fourier transform infrared spectroscopy, differential scanning calorimetry and powder X-ray diffraction. Furthermore, contact angle measurements were carried out. The sign and magnitude of the thermodynamic parameters indicated spontaneity of solubilization process. The phase solubility studies revealed A(L) type of curves for the carriers. Unlike traditional solid dispersion systems, the crystal form of drug in the formulated systems could not be converted to amorphous form. Most of the studied grades showed dissolution improvement vis-à-vis pure drug, with Pluronic F-127 as the most promising carrier. Mathematical modeling of in vitro dissolution data indicated the best fitting with Korsemeyer-Peppas model. Thus, the results demonstrated that tadalafil/Pluronic F-127 solid dispersion system is a direct and feasible technology which represents a potential candidate for delivering a poorly water-soluble drug with enhanced solubility and dissolution.     

尼莫地平固体分散体的研究

目的 制备尼莫地平固体分散体,增加其溶出速度.方法 应用聚乙烯吡咯烷酮（PVP）为载体,采用喷雾干燥制备尼莫地平固体分散体,通过差示扫描量热分析（DSC）和X-射线粉末衍射分析鉴别药物在载体中的存在状态,并进行了体外溶出度研究.结果 尼莫地平在载体中以分子状态存在,尼莫地平固体分散体的溶出度与尼莫地平原料药和原料药载体物理混合物相比有显著提高,载体比例越大,药物溶出越快,药物载体比例为1：3时t50仅0.972 6 min,结论聚乙烯吡咯烷酮（PVP）作为尼莫地平固体分散体的载体载药量大;喷雾干燥工艺重现性好,分散体颗粒无需粉碎可满足各类固体制剂的制备要求,是一种较理想的尼莫地平固体分散体的制备方法.     

槲皮素PVP固体分散体的制备及物相鉴定

目的用溶剂法制备槲皮素-PVP固体分散体并考察其溶出特性并对物相进行鉴定。方法采用溶剂法制备槲皮素-PVP固体分散体,通过溶出实验对槲皮素溶出率的测定研究固体分散体的溶出性质,利用差热分析（Differentialscanning calorimetry,DSC）、红外光谱分析（Infrared spectroscopy,IR）、粉末X衍射（X-ray powder diffractometry,PXRD）、扫描电镜（Scanning electron microscopy,SEM）等方法对其进行物相鉴定。结果槲皮素-PVP固体分散体的溶出速率相对其物理混合物有了明显的改善; 溶解实验显示固体分散体中槲皮素的溶解度有了显著的提高;热差分析及粉末X衍射结果表明固体分散体中槲皮素呈非结晶形式;扫描电镜下固体分散体中无槲皮素晶体。结论采用溶剂法制备槲皮素-PVP固体分散体可显著提高槲皮素的溶解度及溶出速度。     

壬二酸固体分散体的制备及其表征

目的:制备壬二酸固体分散体,改善壬二酸的溶出度,从而提高其生物利用度。方法:分别以聚乙二醇6000(PEG)、泊洛沙姆188为载体并选取药物与其不同比例(1:3、1:6、1:9),采用熔融法、溶剂-熔融法制备壬二酸固体分散体,并对其进行体外溶出度的考察及比较;采用差示扫描量热法、X射线粉末衍射法鉴别壬二酸在固体分散体中的存在状态。结果:以PEG为载体的固体分散体的药物溶出优于以泊洛沙姆188为载体的固体分散体(90min内溶出分别为100%和80%);且当药物与PEG的比例为1:9时,药物的溶出效果最好,与原料药比较药物溶出50%所需的时间大大缩短(12.65、45.65min)。壬二酸-PEG固体分散体中药物部分呈分子状态分散,部分呈微晶状态分散。结论:壬二酸与PEG(1:9)的固体分散体能显著提高药物的溶出度。     

The dissolution enhancement of piroxicam in its physical mixtures and solid dispersion formulations using gluconolactone and glucosamine hydrochloride as potential carriers

Abstract

The solid dispersion technique is one of the most effective methods for improving the dissolution rate of poorly water-soluble drugs; however this is reliant on a suitable carrier and solvent being selected. The work presented explores amino sugars (d-glucosamine HCl and d-gluconolactone) as potential hydrophilic carriers to improve dissolution rate of a poorly water-soluble drug, piroxicam, from physical mixtures and solid dispersion formulations. Solid dispersions of the drug and carrier were prepared using different ratios by the conventional solvent evaporation method. Acetone was used as solvent in the preparation of solid dispersions. Physical mixtures of piroxicam and carrier were also prepared for comparison. The properties of all solid dispersions and physical mixtures were studied using a dissolution tester, Fourier transform infrared, XRD, SEM and differential scanning calorimetry. These results showed that the presence of glucosamine or gluconolactone can increase dissolution rate of piroxicam compared to pure piroxicam. Glucosamine or Gluconolactone could be used as carrier in solid dispersion formulations and physical mixtures to enhance the dissolution rate. Solid state studies showed that no significant changes occurred for piroxicam in physical mixtures and solid dispersion.     

Development of novel ibuprofen-loaded solid dispersion with improved bioavailability using aqueous solution

To develop a novel ibuprofen-loaded solid dispersion with enhanced bioavailability, various ibuprofen-loaded solid dispersions were prepared with water, HPMC and poloxamer. The effect of HPMC and poloxamer on aqueous solubility of ibuprofen was investigated. The dissolution and bioavailability of solid dispersion in rats were then evaluated compared to ibuprofen powder. When the amount of carrier increased with a decreased in HPMC/poloxamer ratio, the aqueous solubility of ibuprofen was elevated. The solid dispersion composed of ibuprofen/HPMC/poloxamer at the weight ratio of 10:3:2 improved the drug solubility approximately 4 fold. It gave significantly higher initial plasma concentration, AUC and Cmax of drug than did ibuprofen powder in rats. The solid dispersion improved the bioavailability of drug about 4-fold compared to ibuprofen powder. Thus, this ibuprofen-loaded solid dispersion with water, HPMC and poloxamer was a more effective oral dosage form for improving the bioavailability of poor water-soluble ibuprofen.     

紫杉醇-PVP固体分散体的制备、物相鉴定及细胞药效

用溶剂法制备紫杉醇-PVP固体分散体，对其溶解度及体外溶出特性进行考察并对物相进行鉴定。采用溶剂法制备紫杉醇-PVP固体分散体，对固体分散体中紫杉醇的溶解度和溶出率进行测定，研究固体分散体的溶出性质。同时，利用差热分析（Differential scanning calorimetry，DSC）、粉末X衍射（X-ray powder diffractometry,PXRD）、扫描电镜（Scanning electron microscopy，SEM）等方法对其进行物相鉴定。采用SRB法对紫杉醇-PVP固体分散体对SKOV-3细胞药效进行测定。紫杉醇-PVP固体分散体中紫杉醇的溶解度和溶出速率相对其原料药和物理混合物均有了明显的提高；热差分析及粉末X衍射结果表明固体分散体中紫杉醇呈非结晶形式；扫描电镜下固体分散体中无紫杉醇晶体。细胞药效结果表明紫杉醇-PVP固体分散体的细胞药效强于紫杉醇纯药。采用溶剂法制备的紫杉醇-PVP固体分散体可显著提高紫杉醇的溶解度和溶出速度。     

Solid dispersion of meloxicam: factorially designed dosage form for geriatric population

The objective of the present work was to improve the dissolution properties of the poorly water-soluble drug meloxicam by preparing solid dispersions with hydroxyethyl cellulose (HEC), mannitol and polyethylene glycol (PEG) 4000 and to develop a dosage form for geriatric population. Differential scanning calorimetry, X-ray diffractometry, Fourier transform infrared spectroscopy and scanning electron microscopy were used to investigate the solid-state physical structure of the prepared solid dispersions. Higher in vitro dissolution of solid dispersions was recorded compared to their corresponding physical mixtures and the pure drug. PEG 4000 in 1: 9 drug to carrier ratio exhibited the highest drug release (100.2%), followed by mannitol (98.2%) and HEC (89.5%) in the same ratio. Meloxicam-PEG 4000 solid dispersion was formulated into suspension and optimization was carried out by 23 factorial design. Formulations containing higher levels of methyl cellulose and higher levels of either sodium citrate or Tween 80 exhibited the highest drug release.