The in-vitro pH-dissolution dependence and in-vivo bioavailability of frusemide-PVP solid dispersions

The dependence of the dissolution rate on the pH of the buffered medium, using constant surface area discs, has been examined for crystalline frusemide, a semi-crystalline frusemide-polyvinylpyrrolidone (PVP) solid dispersion and an X-ray amorphous frusemide-PVP dispersion. The marked changes observed in the pH-dissolution profiles indicate that differing dissolution mechanisms operate in the amorphous regions. This conclusion was further supported by the comparison of pH-dissolution and pH-equilibrium solubility profiles that suggested a supersaturation effect to be the relevant term in describing the dissolution enhancing effects of amorphous regions. A marked dissolution enhancement, relative to crystalline frusemide, was shown by the X-ray amorphous solid dispersion in weakly acidic solutions. A similar effect was observed in the dissolution characteristics of gelatin capsule formulations in simulated gastric and intestinal media. In a human bioavailability study, the X-ray amorphous frusemide-PVP solid dispersion exhibited a significant reduction in the time for maximum effect in comparison to crystalline frusemide and a semi-crystalline solid dispersion. This effect, demonstrated by the primary end organ response in seven healthy subjects, concurred with the in-vitro prediction of dissolution enhancement in weakly acidic media.     

Physicochemical characterization of tacrolimus-loaded solid dispersion with sodium carboxylmethyl cellulose and sodium lauryl sulfate

To develop a novel tacrolimus-loaded solid dispersion with improved solubility, various solid dispersions were prepared with various ratios of water, sodium lauryl sulfate, citric acid and carboxylmethylcellulose-Na using spray drying technique. The physicochemical properties of solid dispersions were investigated using scanning electron microscopy, differential scanning calorimetery and powder X-ray diffraction. Furthermore, their solubility and dissolution were evaluated compared to drug powder. The solid dispersion at the tacrolimus/CMC-Na/sodium lauryl sulfate/citric acid ratio of 3/24/3/0.2 significantly improved the drug solubility and dissolution compared to powder. The scanning electron microscopy result suggested that carriers might be attached to the surface of drug in this solid dispersion. Unlike traditional solid dispersion systems, the crystal form of drug in this solid dispersion could not be converted to amorphous form, which was confirmed by the analysis of DSC and powder X-ray diffraction. Thus, the solid dispersion system with water, sodium lauryl sulfate, citric acid and CMC-Na should be a potential candidate for delivering a poorly water-soluble tacrolimus with enhanced solubility and no convertible crystalline.     

Investigation of Ethylene Oxide-co-propylene Oxide for Dissolution Enhancement of Hot-Melt Extruded Solid Dispersions

The optimal design of amorphous solid dispersion formulations requires the use of excipients to maintain supersaturation and improve physical stability to ensure shelf-life stability and better absorption during intestinal transit, respectively. Blends of excipients (surfactants and polymers) are often used within pharmaceutical products to improve the oral delivery of Biopharmaceutical Classification System class II drugs. Therefore, in this study, a dissolution enhancer, poloxamer 407 (P407), was investigated to determine its effect on the dissolution properties and on the amorphous nature of the active pharmaceutical ingredient contained in the formulation. Phase solubility studies of indomethacin (INM) in aqueous solutions of P407 and poly(vinylpyrrolidone-vinyl acetate copolymer) showed an increase in the kinetic solubility of INM compared with the pure drug at 37°C with a K_a value of 0.041 μg/mL. The solid dispersions showed a higher dissolution rate when compared to pure and amorphous drugs when performed in pH buffer 1.2 with a kinetic solubility of 21 μg/mL. The stability data showed that the amorphous drug in solid solutions with poly(vinylpyrrolidone-vinyl acetate copolymer) and P407 remained amorphous, and the %P407 loading had no effect on the amorphous stability of INM. This study concluded that the amorphous solid dispersion contributed to the increased solubility of INM.     

A novel column/buffer combination for chromatographic analysis of basic drugs in simulated gastrointestinal fluids

In vitro dissolution testing of solid pharmaceutical dosage forms has become a routine aspect of data collection for new product submissions and quality control purposes. With increasing frequency, dissolution testing is performed in buffered media, including low pH simulated gastric fluid and/or alkaline pH simulated intestinal fluid. High-performance liquid chromatographic separation of multicomponent formulations is the most convenient method of quantitation for dissolution samples in such aqueous media; however, particularly in the analytical methodology of drugs containing basic moieties, the direct injection of dissolution media may cause spurious peaks, base line disturbances, and other manifestations of column disequilibration. Using a column packing consisting of 16% w/w alumina in unbonded silica and aqueous mobile phases buffered with monofluorophosphate ion, it is possible to achieve stability in a system exposed to injections differing from the mobile phase in pH and composition.     

The manufacture and characterisation of hot-melt extruded enteric tablets

The aim of this highly novel study was to use hot-melt extrusion technology as an alternative process to enteric coating. In so doing, oral dosage forms displaying enteric properties may be produced in a continuous, rapid process, providing significant advantages over traditional pharmaceutical coating technology. Eudragit^® L100-55, an enteric polymer, was pre-plasticized with triethyl citrate (TEC) and citric acid and subsequently dry-mixed with 5-aminosalicylic acid, a model active pharmaceutical ingredient (API), and an optional gelling agent (PVP^® K30 or Carbopol^® 971P). Powder blends were hot-melt extruded as cylinders, cut into tablets and characterised using powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC) and dissolution testing conducted in both pH 1.2 and pH 6.8 buffers. Increasing the concentration of TEC significantly lowered the glass transition temperature (T_g) of Eudragit^® L100-55 and reduced temperatures necessary for extrusion as well as the die pressure. Moreover, citric acid (17% w/w) was shown to act as a solid-state plasticizer. HME tablets showed excellent gastro-resistance, whereas milled extrudates compressed into tablets released more than 10% w/w of the API in acidic media. Drug release from HME tablets was dependent upon the concentration of TEC, the presence of citric acid, PVP K30, and Carbopol^® 971P in the matrix, and pH of the dissolution media. The inclusion of an optional gelling agent significantly reduced the erosion of the matrix and drug release rate at pH 6.8; however, the enteric properties of the matrix were lost due to the formation of channels within the tablet. Consequently this work is both timely and highly innovative and identifies for the first time a method of producing an enteric matrix tablet using a continuous hot-melt extrusion process.     

Dissolution properties of control released solid dispersion of carvedilol with HPMC and Eudragit RS

In this study, solid dispersion for carvedilol was prepared by using spray-drying method. Solid dispersions were formulated with carvedilol and Eudragit RS and hydroxypropyl methylcellulose to control the dissolution rates of carvedilol. Scanning electron microscope was used to analyze surface of solid dispersion samples. Differential scanning calorimetry and powder X-ray diffraction were used to analyze the crystallinity of solid dispersions. Fourier transform infrared spectroscopy was used to analyze the change in chemical structure of solid dispersions. The release behavior of solid dispersion analyzed at simulated gastric fluid (pH 1.2) in in vitro study. The dissolution rate of carvedilol was higher than active pharmaceutical ingredient. In conclusion, we can control the dissolution rate by solid dispersion using biomedical polymers.     

Investigation of enhancement of solubility of norfloxacin beta-cyclodextrin in presence of acidic solubilizing additives

The present study is aimed at improving the solubility of a poorly water-soluble drug, norfloxacin by incorporating solubilizing additives such as ascorbic acid and citric acid into the beta-cyclodextrin complexes. Norfloxacin, being amphoteric in nature, exhibits a higher solubility at pH below 4 and above 8. Addition of substances like ascorbic acid and citric acid in beta-cyclodextrin complexes reduces the pH of the immediate microenvironment of the drug below pH 4. In the present work, beta-cyclodextrin complexes of norfloxacin were prepared along with solubilizing additives such as citric acid and ascorbic acid in various proportion and the dissolution profile was performed in both HCl buffer, pH 1.2 and phosphate buffer, pH 7.4. The results have shown an enhanced dissolution rate in both media. DSC and IR spectral studies performed on the solid complexes have shown that there is no interaction of the drug with the additives and beta-cyclodextrin. Disc diffusion studies have shown larger diameters of zone of inhibition indicating a greater diffusivity of the drug into the agar medium.     

Design of a drug delivery system with bimodal pH dependent release of a poorly soluble drug

A delivery system which provides bimodal pH dependent release of poorly water soluble carvedilol in gastric and intestinal environment was designed. Preparation of solid dispersion with porous silica ensured a significantly higher dissolution rate of carvedilol in acidic and alkaline media in comparison to pure drug, while granulation of that solid dispersion with enteric polymer dispersion resulted in diminished immediate release in acidic media and fast release of the remaining drug in alkaline media. The ratio in quantities of first vs. second release was controlled with amount of enteric polymer dispersion used for granulation process. Desired 25 mg release of carvedilol at pH values 1.2 and 6.8 was achieved when 1.80 g of polymer per 1.0 g of solid dispersion (drug to silica ratio= 0.25 g : 2.0 g) was used.     

尼群地平固体分散体及其片剂的体外溶出度评价

目的:运用固体分散技术提高尼群地平的体外溶出速率.方法:采用紫外分光光度法测定药物浓度,以体外溶出为指标,对固体分散体的载体、制备方法及比例进行优化.通过粉末直接压片法制备尼群地平固体分散片,根据日本橙皮书的要求对片剂的体外溶出进行考察.结果:采用泊洛沙姆188为载体,药物与载体比例为1:5,通过熔融法制备的固体分散体体外溶出效果较好,且制成的片剂,在4种介质(含0.15％吐温-80的水溶液、pH 1.2盐酸溶液、pH 4.0醋酸盐缓冲液、pH 6.8磷酸盐缓冲液)中,45 min时最低累积溶出度达80.3%.结论:通过固体分散技术制备的尼群地平片体外溶出能满足日本橙皮书的要求,且工艺简单、易于实施.     

Aqueous Dissolution and Dispersion Behavior of Polyvinylpyrrolidone Vinyl Acetate-based Amorphous Solid Dispersion of Ritonavir Prepared by Hot-Melt Extrusion with and without Added Surfactants

In this study, the lack of complete drug release from amorphous solid dispersions (ASDs), as observed in most published reports, was investigated. ASDs with 20% ritonavir were prepared by HME using polyvinylpyrrolidone vinyl acetate (PVPVA) alone and in combination with 10% poloxamer 407 or Span 20 as carriers. It was established by the film casting technique that ritonavir was molecularly dispersed in formulations, and accelerated stability testing confirmed that extrudates were physically stable. Dissolution of ASDs (100-mg ritonavir equivalent) was performed in 250 mL 0.01 N HCl (pH 2), pH 6.8 phosphate buffer and FeSSIF-V2. Drug concentrations were measured by filtration through 0.45-μm pores and in unfiltered media; the latter gave total amounts of drug present in dissolution media, both as solution and dispersion. Because of low solubility, ritonavir did not dissolve completely in aqueous media. Rather, it formed supersaturated solutions, and the excess drug dispersed in the oily amorphous form with low particle sizes that could crystallize with time. Due to higher drug solubility, the dissolved drug in FeSSIF-V2 was much higher than that in the phosphate buffer. Complete drug release could be observed by accounting for drug both in solution and as phase-separated dispersion. Thus, the present study provides a complete picture of in vitro drug dissolution and dispersion from ASDs.     

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.     

尼莫地平口服固体制剂溶出度的研究

目的 测定尼莫地平口服固体制剂在不同溶出介质中的溶出度,并对测定方法进行评价.方法 采用0.25％十二烷基硫酸钠(SDS)、水、pH=1.2人工胃液、pH=4.5醋酸盐缓冲液、pH=6.8磷酸盐缓冲液作为溶出介质,测定尼莫地平的溶出度并绘制曲线.结果 尼莫地平片在含0.25％ SDS溶出介质中的溶出度与生物利用度不相关,而在其他溶出介质具有一定的相关性.结论 SDS掩盖了该制剂内在品质的表达,不能反映该制剂在体内的溶出情况;中国药典收载的溶出度方法可能难以满足本品的测定需要.     

基于HPMCAS载体的依非韦伦固体分散体溶出模式研究

目的 以依非韦伦为原料药、不同规格（L、M、H）HPMCAS为载体，采用喷雾干燥法制备固体分散体并对其溶出模式进行初步探究。方法 通过X射线粉末衍射（XRPD）、扫描电子显微镜（SEM）对固体分散体理化性质进行制剂学表征；以动力溶解度为指标考察不同药载比、不同规格HPMCAS固体分散体的溶出情况；通过粒度分析仪和透射电子显微镜（TEM）、SEM探讨固体分散体溶出时的不同模式。结果 XRPD分析显示，固体分散体中药物以无定形的形态分散在HPMCAS中；SEM分析显示，L、M、H规格HPMCAS与依非韦伦形成的固体分散体均具有"萎缩葡萄干"形态；在pH 6.8磷酸缓冲盐溶液中溶出时，药载比1：6的固体分散体溶出好，药载比1：1.5的固体分散体溶出差且相同药载比时L规格HPMCAS的固体分散体溶出更快。结论 以不同规格HPMCAS为载体制备的依非韦伦固体分散体在pH 6.8磷酸缓冲盐溶液中溶出时，存在多种溶出模式。药载比1：6时，L、M规格HPMCAS的固体分散体以药物纳米颗粒的形式溶出；药载比1：1.5时，L、M规格HPMCAS的固体分散体存在类似溶蚀的溶出模式，药物从载体骨架中释放。     

Preparation and characterization of emulsified solid dispersions containing docetaxel

An emulsified solid dispersion of docetaxel was prepared and characterized in vitro. In contrast to conventional solid dispersions, emulsifying pharmaceutical excipients and hydroxypropyl methylcellulose (HPMC) as a supersaturation promoter were introduced into the PEG6000-based solid dispersion to further improve its solubilizing capability. The solubility, dissolution in vitro and stability of the prepared emulsified solid dispersions were studied taking into consideration of the effects of different emulsifying excipients, preparation methods and the media. Results of the emulsified solid dispersion of docetaxel showed that the solubility and dissolution at 2 h were 34.2- and 12.7-fold higher than the crude powder. The type of emulsifying excipient used had a significant influence on the dissolution of the emulsified solid dispersion. The dissolution of the emulsified solid dispersion prepared by the solvent-melting method or the solvent method was higher than the melting method. There were no apparent differences among the dissolution media utilized. The status of the drug in the emulsified solid dispersion was observed in an amorphous or a molecular dispersion state by differential thermal analysis and powder Xray diffraction. In conclusion, the incorporation of emulsifying pharmaceutical excipients and HPMC with polymers into a solid dispersion could be a new and useful tool to greatly increase the solubility and dissolution of poorly water-soluble drugs.     

穿心莲内酯聚丙烯酸树脂Ⅱ固体分散体的制备及表征

目的：研究无定形聚合物聚丙烯酸树脂Ⅱ（Eudragit Ⅱ）制备的穿心莲内酯固体分散体的优良性质,为固体分散体的载体选择提供参考依据。方法：以无定形聚合物Eudragit Ⅱ为载体材料,按穿心莲内酯-载体质量比为1：3,采用喷雾干燥法制备穿心莲内酯固体分散体,并用傅里叶变换红外光谱（FTIR）、热重分析（TG）、X-射线衍射（XRD）、差示扫描量热（DSC）、扫描电镜（SEM）、比表面积、粒径和溶出度测定穿心莲内酯固体分散体的理化性质及溶出行为。结果：FTIR光谱和TG分析说明在穿心莲内酯固体分散体和物理混合物中穿心莲内酯与Eudragit Ⅱ之间都存在分子间相互作用,其中穿心莲固体分散体具有更好的热稳定性;DSC和XRD分析说明无定形载体Eudragit Ⅱ制备的固体分散体中穿心莲内酯主要以无定形形式存在;SEM显示,固体分散体中穿心莲内酯由块状晶体形态变为了不规则的圆形形态;同时与物理混合物相比,穿心莲内酯固体分散体具有更大的比表面积、更大的孔体积和更小的粒径等粉体学性质;溶出实验表明穿心莲内酯固体分散体具有增大溶出的优势,效果明显。结论：以无定形载体Eudragit Ⅱ制备的穿心莲内酯固体分散体具有优良的理化性质,同时比表面积大,孔体积大的特征更有利于水分子的进入,从而有效地增大穿心莲内酯的溶出速率。     

Raman and thermal analysis of indomethacin/PVP solid dispersion enteric microparticles

Indomethacin (IMC) and three types of poly-(vinylpyrrolidone) (PVP 12PF, PVP K30 and PVP K90) were studied in the form of solid dispersion, prepared with the solvent evaporation method, by spectroscopic (Raman, FT-IR, X-ray diffraction), thermal (differential scanning calorimetry, thermogravimetry, hot-stage microscopy), fractal and image analysis. Raman and FT-IR micro-spectroscopy indicated the occurrence of drug/polymer interaction and the presence of an amorphous form of IMC, as also resulting from X-ray diffractometry. Hot-stage microscopy suggested that the interaction between IMC and the polymer occurring on heating of a physical mixture, is common to other acidic compounds and causes a depression of the temperature of the appearance of a molten phase. Co-evaporated particles were coated by spray-congealing process with molten stearic acid for gastroprotection, but also for stabilization of the amorphous structure of the drug: the final particles were spherically shaped. Dissolution tests carried out on the final microparticles showed that the coating with stearic acid prevents IMC release at acidic pH and also protects against recovery of the IMC crystallinity, at least after 9 months of aging: the extent and mode of the release, before and after aging, overlap perfectly. The test revealed a notable improvement of the drug release rate from the solid dispersion at suitable pH, with respect to pure IMC. The comparison of the present solid dispersion with IMC/PVP (surface) solid dispersion obtained by freeze-drying of an aqueous suspension, where IMC maintained its crystalline state, revealed that there was no difference concerning the release rate, but suggested a superior quality of this last process as a mean of improving IMC availability for the easiness of preparation and stability, due to the absence of the amorphous state of the drug, as a possible instability source of the system. Finally, the coating with stearic acid is discussed as a determining process for the practical application of solid dispersions.     

Preparation and characterization of spray-dried valsartan-loaded Eudragit® E PO solid dispersion microparticles

The purpose of this study was to develop the immediate release stomach-specific spray-dried formulation of valsartan (VAL) using Eudragit^® E PO (EPO) as the carrier for enhancing dissolution rate in a gastric environment. Enhanced solubility and dissolution in gastric pH was achieved by formulating the solid dispersion using a spray drying technique. Different combinations of drug–polymer–surfactant were dissolved in 10% ethanol solution and spray-dried in order to obtain solid dispersion microparticles. Use of the VAL–EPO solid dispersion microparticles resulted in significant improvement of the dissolution rate of the drug at pH 1.2 and pH 4.0, compared to the free drug powder and the commercial product. A hard gelatin capsule was filled with the VAL–EPO solid dispersion powder prior to the dissolution test. The increased dissolution of VAL from solid dispersion microparticles in gastric pH was attributed to the effect of EPO and most importantly the transformation of crystalline drugs to amorphous solid dispersion powder, which was clearly shown by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and powder X-ray diffraction (P-XRD) studies. Thus, VAL, a potential antihypertensive drug in the form of a solid dispersion microparticulate powder, can be effectively delivered in the immediate release dosage form for stomach-specific drug delivery.     

Comparison of surface modification and solid dispersion techniques for drug dissolution

Surface modification and solid dispersion formulations using hydrophilic excipients can significantly alter the dissolution behaviour of hydrophobic drug materials. The effect of these techniques used individually and in combination on the dissolution properties of the hydrophobic drug, phenylbutazone (PB), are compared. PB was treated with a poloxamer, Synperonic((R)) F127 by an adsorption method. Solid dispersions (10 and 20% w/w) were prepared with untreated PB or PB previously modified with Synperonic((R)) F127 (PBT) in molten F127. Dissolution tests of capsule formulations of PB, PBT and solid dispersion formulations, in pH 6.4 buffer at 37+/-0.5 degrees C demonstrated that after 140 min, release of PB was 16.7%, but 71.4% from the solid dispersion, whereas from the PBT formulation 85.6% was released. The Synperonic((R)) F127 content of PBT was only 0.05% of that in the solid dispersion formulation which suggests that it is the nature of the drug polymer contact rather than the amount of polymer which is more critical in influencing dissolution behaviour. Comparison of PBT and the 10% w/w solid dispersion of PBT in F127 showed similar amounts of drug in solution after 140 min. However there was a significantly higher release rate for PBT. Both formulation techniques offer significant improvements in drug release over untreated PB, and a combination of techniques changes the rate but not the extent of release in comparison with the surface modification technique alone.     

Evaluation of the USP dissolution test method A for enteric-coated articles by planar laser-induced fluorescence

The USP drug release standard for delayed-release articles method A was evaluated using planar laser-induced fluorescence (PLIF). Prior authors have suggested that high pH “hot spots” could develop during the buffer medium addition of the method A enteric test. Additionally, previous studies have shown heterogeneous flow patterns and low-shear regions in the USP Apparatus II dissolution vessel, which may result in poor mixing of the buffer and acid media during the pH neutralization step of the method A enteric test. In this study, PLIF was used to evaluate the mixing patterns and evolution of pH neutralization during the buffer medium addition with rhodamine-B dye and the pH-sensitive dye fluorescein, respectively. Additionally, a comparison of the methods A and B enteric tests was performed with enteric-coated tablets containing rhodamine-B in the film so as to image the dissolution rate of the coating polymer with PLIF in order to determine if rapid buffer addition for the method A procedure accelerates the rate of film coat dissolution. Rapid addition of the 250 mL of buffer medium over 5 s to the 750 mL of acidic medium shows efficient mixing and pH neutralization due to the generation of large-scale stirring and enhanced turbulence resulting from the descending buffer medium. Slow addition near the paddle shaft over 5 min showed segregation in the recirculating region around the paddle shaft. In contrast, slow addition near the vessel wall introduces the medium into fluid outside of the recirculation region and enables transport over the entire vessel. Enteric-coated tablets tested according to method A with rapid medium addition and method B enteric tests performed identically, indicating no difference in polymer dissolution rate between the two tests. From the results of the PLIF imaging studies with rhodamine-B, fluorescein, and enteric-coated tablets, it was seen that “hot spots” affecting the dissolution performance of enteric dosage forms are not generated during the neutralization step of the method A enteric test namely when the media is added rapidly or outside of the recirculating region that surrounds the paddle shaft.     

Characterization and dissolution behavior of nifedipine and phosphatidylcholine binary systems

Physicochemical properties and the dissolution behavior of binary systems of nifedipine (NIF) and dipalmitoylphosphatidylcholine (DPPC) or dimyristoylphosphatidylcholine (DMPC) as physical mixtures, solid dispersions and ground mixtures at 9:1 w/w were investigated. The drug and formulations were characterized by powder X-ray diffraction, Fourier transform infrared spectroscopy (FTIR) and differential thermal analysis (DTA). The dissolution and solubility of NIF was increased in the order physical mixture < solid dispersion < ground mixture. The powder X-ray diffraction patterns and FTIR spectra indicated absence of major crystalline or molecular changes of NIF or the PCs. The fraction of NIF dissolved after 1 h was approximately 30 and 34% from NIF/DMPC and NIF/DPPC ground mixtures, respectively, and the dissolution was only slightly reduced from NIF/DPPC, 9.75:0.25 w/w systems. The crystal lattice parameter, c, of DPPC and DMPC in the solid dispersion was longer than that of PC alone but each was considered to be in an amorphous state in the ground mixture because of the absence of an X-ray diffraction peak. Full-width at half-maximum (half width) of the X-ray diffraction peak of NIF in the ground mixture was greater than NIF in the physical mixture or solid dispersion, suggesting that the lattice distortion of NIF crystals was increased by grinding. Thermal analysis confirmed the crystalline state of DPPC and DMPC in the physical mixture and the solid dispersion but an amorphous state in the ground mixture. Thus, an increase in lattice distortion of NIF crystals due to grinding and an amorphous state of DPPC or DMPC in the ground mixtures are considered mainly responsible for the larger increase in dissolution rate and extent of dissolution of NIF after 1 h compared to the solid dispersion formulation.