替硝唑固体分散体的制备及其体外释放特性研究

目的:利用固体分散技术制备替硝唑固体分散体,增加替硝唑溶解度和溶出速度。方法:以聚乙二醇(PEG)为载体材料,采用溶剂-熔融法制成固体分散体,测定表观溶解度,进行体外溶出试验,并采用差示扫描量热(DSC)法鉴别药物在固体分散体中的存在状态。结果:替硝唑的溶出度和表观溶解度随PEG的比例不同而不同,且溶出度随载体用量增加而增加。固体分散体的DSC曲线中替硝唑药物的特征熔融峰消失。结论:所制得的固体分散体能明显提高替硝唑的溶出度和表观溶解度。     

塞来昔布/介孔硅SBA-15固体分散体的制备和性质研究

目的制备塞来昔布(CEL)/介孔硅SBA-15的固体分散体并进行性质研究。方法利用溶剂吸附平衡法制备CEL/SBA-15固体分散体,通过测定表观溶解度考察水溶性,通过热分析(DSC)和溶出试验考察药物溶出行为、药物存在状态及物理稳定性。结果确定了CEL/SBA-15固体分散体的制备方法。固体分散体载药量约37%,溶解度约为原料药的2倍以上,30 min内药物的累计溶出就超过90%,药物以非晶状态存在,加速试验6个月溶出和存在状态稳定。结论 CEL/SBA-15固体分散体物理稳定性良好,明显提高难溶药物的水溶性和溶出速率,改善药物的口服吸收。     

阿奇霉素固体分散体制备工艺研究

目的比较不同方法制备难溶性阿奇霉素固体分散体的体外溶出度,优化制备工艺。方法选择不同载体,并采用热熔挤出法和喷雾干燥法制备阿奇霉素固体分散体,并与气流粉碎技术制备的样品比较。采用饱和溶解度和体外累积溶出度判定不同方法所制备成品的差异。结果 2种固体分散体制备技术均能加快药物的溶出度,同时均优于气流粉碎制备的样品。结论相比热熔挤出法,采用喷雾干燥法制备的固体分散体更能显著提高药物的饱和溶解度和溶出度。     

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。     

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。     

姜黄素-聚维酮固体分散体的制备及溶出度的测定

目的:制备姜黄素－聚维酮固体分散体,改善姜黄素的溶出度.方法:应用聚乙烯吡咯烷酮(PvPk30)为载体,以溶剂法制备固体分散体,差示扫描量热法、X-射线粉末衍射进行物相鉴定,并测定溶出度.结果:姜黄素在固体分散体中可能以无定型态或分子状态存在,药物的累积溶出百分率随栽体比例增加而增加,以1:6的比例效果最好.制成固体分散体后,药物在水中的溶解度达66.28 g·L-1.结论:采用PVPk30制备的固体分散体能显著提高姜黄素的溶出度.     

瑞戈非尼固体分散体的制备及体外溶出度考察

目的采用固体分散技术提高难溶性药物瑞戈非尼的体外溶出度。方法选用聚维酮K30为载体,以溶剂法制备不同比例的瑞戈非尼固体分散体;采用紫外分光光度法测定其溶出度;采用X-射线粉末衍射法分析药物在固体分散体中的存在状态。结果瑞戈非尼固体分散体的溶出度较原料药、物理混合物均有显著提高,且载体比例越大,固体分散体溶出度越大;瑞戈非尼以无定形态分散在载体中。结论采用固体分散技术可有效提高瑞戈非尼的体外溶出度。     

喷雾干燥法制备阿司匹林固体分散体及其胶囊制备与体外特性研究

目的 制备阿司匹林固体分散体及其胶囊,提高其溶出度。方法 以聚乙烯吡咯烷酮(PVP K 30)为载体,采用喷雾干燥法制备阿司匹林固体分散体,测定溶出度,采用X-射线衍射和扫描电镜(SEM)考察药物在载体中的分散状态,测定比表面积;制备阿司匹林固体分散体胶囊,考察胶囊的体外溶出度。结果 与阿司匹林原料药、阿司匹林物理混合物相比,阿司匹林固体分散体中药物的溶出度均有显著提高,且载体比例越大,药物溶出越快,但药物和载体比例达1∶6以上时,溶出度增加不再明显。阿司匹林以无定型或分子形式高度分散在载体中,药辅比在l∶6时,阿司匹林固体分散体比阿司匹林原料药的比表面积增大3.2倍;制成固体分散体胶囊后,30 min时药物累积溶出度达99.8%。结论 该固体分散体制备工艺可行,制备的胶囊质量可控。     

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。     

联苯双酯固体分散体处方及体外性质评价

目的应用不同亲水性载体材料制备联苯双酯固体分散体,提高联苯双酯体外溶出。方法应用溶解度参数法初步筛选载体材料,采用热熔挤出法制备联苯双酯固体分散体,采用差示扫描量热法、X射线粉末衍射法和傅立叶变换红外光谱法对所制备的固体分散体进行表征。对固体分散体进行溶出度测定,以体外累积溶出度为主要指标,分别考察不同载体、不同载药量对固体分散体中联苯双酯溶出度的影响。结果应用不同亲水性载体材料制备的固体分散体均可提高联苯双酯溶出度,其中以Soluplus对联苯双酯溶出度的提高最为显著,累积溶出度可达到90%左右。优选Soluplus为固体分散体载体材料,并且当载药量为20%时,溶出度最高。结论应用载体材料Soluplus制备固体分散体可以显著提高联苯双酯溶出度。载体材料的性质及载药量的高低都会影响固体分散体中药物的溶出度。     

Physicochemical Characterization and Dissolution Study of Solid Dispersions of Lovastatin with Polyethylene Glycol 4000 and Polyvinylpyrrolidone K30

Solid dispersions in water-soluble carriers have attracted considerable interest as a means of improving the dissolution rate, and hence possibly bioavailability, of a range of hydrophobic drugs. The aim of the present study was to improve the solubility and dissolution rate of a poorly water-soluble drug, Lovastatin, by a solid dispersion technique. Solid dispersions were prepared by using polyethylene glycol 4000 (PEG 4000) and polyvinylpyrrolidone K30 (PVP K30) in different drug-to‐carrier ratios. Dispersions with PEG 4000 were prepared by fusion-cooling and solvent evaporation, whereas dispersions containing PVP K30 were prepared by solvent evaporation technique. These new formulations were characterized in the liquid state by phase solubility studies and in the solid state by differential scanning calorimetry, X-ray powder diffraction, and FT-IR spectroscopy. The aqueous solubility of Lovastatin was favored by the presence of both polymers. The negative values of the Gibbs free energy and enthalpy of transfer explained the spontaneous transfer from pure water to the aqueous polymer environment. Solid-state characterization indicated Lovastatin was present as amorphous material and entrapped in polymer matrix. In contrast to the very slow dissolution rate of pure Lovastatin, the dispersion of the drug in the polymers considerably enhanced the dissolution rate. This can be attributed to improved wettability and dispersibility, as well as decrease of the crystalline and increase of the amorphous fraction of the drug. Solid dispersion prepared with PVP showed the highest improvement in wettability and dissolution rate of Lovastatin. Even physical mixture of Lovastatin prepared with both polymers also showed better dissolution profile than that of pure Lovastatin. Tablets containing solid dispersion prepared with PEG and PVP showed significant improvement in the release profile of Lovastatin compared with tablets containing Lovastatin without PEG or PVP.     

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.     

Improvement of the dissolution kinetics of SR 33557 by means of solid dispersions containing PEG 6000

Solid dispersions of SR 33557 in preparations containing from 30 to 80% w/w polyethylene glycol 6000 (PEG 6000) were prepared by the fusion method. The solubility of the drug substance either alone or in solid dispersions was determined in pH 1.2 and 4.5 media (extraction fluid NFXII, without enzyme). A large increase in the solubility was noted from the 80% w/w PEG preparation. A wettability study performed by measuring the contact angle on tablets of either drug substance or PEG 6000, or solid dispersions, revealed a minimal contact angle for the 80% w/w PEG 6000 solid dispersion (eutectic composition of SR 33557/PEG 6000 phase diagram). Dissolution kinetic analysis performed at pH 1.2 on all solid dispersions, on the physical mixtures containing 70 and 80% w/w PEG 6000, and on SR 33557 alone, showed a maximum release rate (100%) for the solid dispersions containing 70 and 80% w/w PEG 6000. The dissolution rate of the physical mixtures was faster than that of the drug substance alone but remained, however, lower than that of the solid dispersions, at the same composition. It was also observed that the dissolution rate, at pH 1.2 and 4.5, of the 70% w/w PEG 6000 solid dispersion was practically pH independent, which was not the case for the drug substance alone. The latter solid dispersion showed a slowing down of the dissolution kinetics after 3 months storage at 50°C whereas no change in the dissolution rate was observed following storage for 12 months at 25°C.     

Physicochemical characterization and dissolution study of solid dispersions of Lovastatin with polyethylene glycol 4000 and polyvinylpyrrolidone K30

Solid dispersions in water-soluble carriers have attracted considerable interest as a means of improving the dissolution rate, and hence possibly bioavailability, of a range of hydrophobic drugs. The aim of the present study was to improve the solubility and dissolution rate of a poorly water-soluble drug, Lovastatin, by a solid dispersion technique. Solid dispersions were prepared by using polyethylene glycol 4000 (PEG 4000) and polyvinylpyrrolidone K30 (PVP K30) in different drug-to-carrier ratios. Dispersions with PEG 4000 were prepared by fusion-cooling and solvent evaporation, whereas dispersions containing PVP K30 were prepared by solvent evaporation technique. These new formulations were characterized in the liquid state by phase solubility studies and in the solid state by differential scanning calorimetry, X-ray powder diffraction, and FT-IR spectroscopy. The aqueous solubility of Lovastatin was favored by the presence of both polymers. The negative values of the Gibbs free energy and enthalpy of transfer explained the spontaneous transfer from pure water to the aqueous polymer environment. Solid-state characterization indicated Lovastatin was present as amorphous material and entrapped in polymer matrix. In contrast to the very slow dissolution rate of pure Lovastatin, the dispersion of the drug in the polymers considerably enhanced the dissolution rate. This can be attributed to improved wettability and dispersibility, as well as decrease of the crystalline and increase of the amorphous fraction of the drug. Solid dispersion prepared with PVP showed the highest improvement in wettability and dissolution rate of Lovastatin. Even physical mixture of Lovastatin prepared with both polymers also showed better dissolution profile than that of pure Lovastatin. Tablets containing solid dispersion prepared with PEG and PVP showed significant improvement in the release profile Lovastatin compared with tablets containing Lovastatin without PEG or PVP.     

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.     

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.     

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.     

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.     

Effect of physiochemical variables on phase solubility and dissolution behavior of indomethacin solid dispersion system

To study the influence of temperature and pH on solubility and dissolution behavior of indomethacin solid dispersions were prepared using several classes of hydrophilic carriers. Investigations on dissolution of indomethacin in binary system are reported earlier. However the phase solubility and dissolution behavior at different pH and temperature left void. The present investigation includes: phase solubility study at various pH; preparation of solid dispersion by solvent evaporation, melting and kneading method; characterization of various blends by dissolution study, and solid state studies to ensure interaction of drug with carrier. The binding between drug and carriers (PVP K30, βCD and PEG) was explained by thermodynamic parameters as calculated from phase solubility study. Indomethacin in association with PVP K30 showed very high apparent binding constant (Ka) and Gibb’s free energy change (?G) in comparison to other blends. The ternary system (drug:βCD:PVP K30, 1:5:1) showed better dissolution of about 80.97 and 99 % at pH 7.2 after 5 and 30 min respectively. At higher proportion of carrier (1:9) in binary solid dispersion of drug and PVP K30, drug dissolution was 96.23 and 97.85 % after 5 and 30 min respectively. This raised solubility of indomethacin would be helpful in designing a dosage form.