尼美舒利固体分散体的制备及其性质考察

目的提高尼美舒利释放速率及生物利用度。方法分别以聚乙二醇(PEG)、聚乙烯吡咯烷酮(PVP k30)及泊洛沙姆188为载体,采用熔融法、溶剂法及溶剂-熔融法等制备尼美舒利固体分散体;考察载体类别及载体-药物质量比对释放的影响;配合差示扫描量热(DSC)分析与电子扫描电镜(SEM)观察考察药物在载体中的存在状态。结果尼美舒利以无定型状态存在于固体分散体中,载体类别不同、载体-药物质量比不同,药物的释放度不同。结论将尼美舒利制成固体分散体能显著增加尼美舒利的体外释放度。     

水飞蓟素-聚乙二醇6000固体分散体系的制备及其特征考察

目的制备水飞蓟素固体分散体，加快药物的溶出，并进行特征考察。方法以聚乙二醇6000(PEG6000)为材料，采用熔融法将难溶性药物水飞蓟素制成固体分散体，通过体外释药试验考察固体分散技术对水飞蓟素的增溶作用，并以X-射线粉末衍射、傅立叶变换红外光谱(FT-IR)考察水飞蓟素固体分散体的特性。结果与原药比较，固体分散体中药物的释放速率明显增大，PEG6000固体分散体系能显著加快水飞蓟素的溶出。X-射线粉末衍射分析表明，PEG6000及药物在固体分散体中的晶格点阵面间距离、衍射峰位移及其相对强度等均发生了规律性变化，FT-IR分析表明PEG6000与药物间无相互作用。结论PEG6000固体分散体系的对难溶性药物溶出和扩散的加快，与载体材料和药物的晶格参数的改变密切相关。     

硝苯地平固体分散体制备工艺的研究

目的利用固体分散技术将硝苯地平制成固体分散体,提高其体外溶出速率。方法分别以聚乙二醇6000(PEG6000)、聚乙二醇4000(PEG4000)、聚乙烯吡咯烷酮K30(PVPK30)、泊洛沙姆188(Pluronic F68)等为载体,用熔融法、溶剂法、溶剂-熔融法和喷雾干燥法制备硝苯地平固体分散体。采用差热分析法(DTA)分析药物在固体分散体中的存在状态,并进行体外溶出度试验。结果各种固体分散体均能加快药物的溶出速率,并且随着载体在固体分散体中的比例增大,溶出速率增大。DTA分析显示硝苯地平在PVPK30的固体分散体中以微细结晶存在。结论将硝苯地平制成固体分散体能显著提高硝苯地平的体外溶出速率。     

硝苯地平固体分散体制备工艺的研究

目的利用固体分散技术将硝苯地平制成固体分散体,提高其体外溶出速率。方法分别以聚乙二醇6000(PEG6000)、聚乙二醇4000(PEG4000)、聚乙烯吡咯烷酮K30(PVPK30)、泊洛沙姆188(Pluronic F68)等为载体,用熔融法、溶剂法、溶剂-熔融法和喷雾干燥法制备硝苯地平固体分散体。采用差热分析法(DTA)分析药物在固体分散体中的存在状态,并进行体外溶出度试验。结果各种固体分散体均能加快药物的溶出速率,并且随着载体在固体分散体中的比例增大,溶出速率增大。DTA分析显示硝苯地平在PVPK30的固体分散体中以微细结晶存在。结论将硝苯地平制成固体分散体能显著提高硝苯地平的体外溶出速率。     

卡维地洛固体分散体的制备及其体外溶出度的测定

目的 :制备卡维地洛固体分散体 ,提高其溶解度和溶速率。方法 :以聚乙烯吡咯烷酮 (PVP)、聚乙二醇 -6000(PEG -6000)为载体 ,以溶剂法和熔融法制备固体分散体 ,并进行体外溶出度研究。结果 :载体比例越大 ,药物溶出愈快 ;载体比例愈小 ,差异愈显著。载体为PVP所制固体分散体的体外溶出行为总体优于载体为PEG -6000的固体分散体。结论 :本试验所制卡维地洛固体分散体能加速体外溶出 ,提高生物利用度 ,可用于制备高效制剂     

固体分散技术提高黄芩提取物溶出度的研究

目的：通过制备固体分散体，提高黄芩提取物的溶出度。方法：采用熔融法和溶剂法，制备聚乙二醇4000（PEG4000），聚乙二醇6000（PEG6000），聚乙烯吡咯烷酮K30（PVPK30）3种载体材料及不同比例条件下的固体分散体。通过比较原药材、固体分散体、机械混合物的溶出性能，从而确定制备的最佳方法和最佳比例。结果：不同载体不同比例的固体分散体均能提高药物的溶出度，且载体比例越大，药物的溶出越快，3种载体的增溶效果依次为PVPK30〉PEG4000〉PEG6000。结论：以PVP为载体，采用溶剂法所制备的药物/载体比例为1：6的固体分散体能显著提高黄芩提取物的溶出速率。     

氨苯砜固体分散体的制备与溶出度测定

目的制备氨苯砜固体分散体，增大氨苯砜溶出度。 方法以聚乙二醇6000(PEG 6000)为载体，采用熔融法，按照不同比例制备固体分散体，并进行体外溶出度研究。结果体外溶出实验表明分散体的溶出速率明显快于原料药及物理混合物，且载体比例越大，药物溶出越快。结论将氨苯砜制备成固体分散体，可以增大其溶出度，有利于提高其剂型的生物利用度。     

硝酸异山梨酯固体分散体的制备及其体外溶出特性研究

目的采用固体分散技术,提高硝酸异山梨酯在水中的溶解度和体外溶出速率.方法以聚乙二醇6000(PEG6000)为载体,熔融法制备硝酸异山梨酯的固体分散体.考察其体外特性,并采用X-射线粉末衍射、差示扫描量热法(DSC)和红外光谱法鉴别药物在固体分散体中的存在状态.结果固体分散体能加快药物的溶出速率,最佳比例为1∶7.硝酸异山梨酯在PEG6000的固体分散体中以微细结晶存在.结论硝酸异山梨酯-PEG6000(1∶7)固体分散体增加硝酸异山梨酯溶出度的效果显著.     

洛伐他汀固体分散体的制备及体外溶出特性比较

目的：利用固体分散技术制备洛伐他汀固体分散体，增加其溶出速率。方法：以不同比例的聚乙烯吡咯烷酮（PVPk-30）、聚乙二醇6000（PEG6000）为载体，采用溶剂法和熔融法制成洛伐他汀固体分散体，测定其溶出速率，并采用差示扫描量热（DSC）法、显微照相技术鉴别药物在固体分散体中的存在状态。结果：两种固体分散体均能提高洛伐他汀溶出速率，在药物载体比例大于1：5时效果较好；洛伐他汀固体分散体中晶型消失，分散在载体中。载体为PVPK30所制固体分散体的溶出速率总体优于载体PEG6000。结论：固体分散体能加速洛伐他汀溶出速率。     

固体分散体技术提高新抗癫痫药生物利用度

目的用固体分散体技术提高难溶性新抗癫痫药——Q808生物利用度。方法以PEG为载体,以不同比例不同方法制备Q808固体分散体,并考察它们的溶解度、溶出速率及Caco-2细胞透过性。结果经优化条件后制备的Q808固体分散体能提高原料药的溶解度、溶出速率及Caco-2细胞透过性。结论以PEG6000(1∶30)为载体,采用溶解蒸发法制备Q808固体分散体能显著改善其生物利用度。     

Dissolution-modulating mechanism of alkalizers and polymers in a nanoemulsifying solid dispersion containing ionizable and poorly water-soluble drug

We investigated the dissolution-modulating mechanism of alkalizers and polymers in nanoemulsifying Gelucire 44/14 (GUC)-based solid dispersions (SDs) for controlled release. Aceclofenac (AFC), an ionizable and poorly water-soluble drug, was chosen because of its extremely low solubility at low pH. Nanoemulsifying SD systems containing alkalizers and/or polymers were prepared by the melting method. Drug crystallinity, microenvironmental pH (pH_M), dissolution rate, and droplet size in the media from nanoemulsifying SD were then characterized. Ternary SD containing alkalizers, mainly Na₂CO₃ and NaHCO₃, enhanced the initial release rate of AFC in simulated gastric fluid (pH 1.2), but resulted in spring-like precipitation. However, adding a secondary polymer, Poloxamer 407, prevented precipitation in the quaternary SD system. Poloxamer 407 and alkalizer (Na₂CO₃) facilitated nanoemulsion formation (80-140 nm) with a smaller droplet size in a medium of pH 1.2 as visualized by TEM. The surface and inner pH_M were also modulated by the alkalizers, but not by the polymers. The drug’s crystalline structure was further changed to partially or almost amorphous form by the alkalizers and polymers in SD as characterized by instrumental analysis. The synergistic effects of alkalizers and secondary polymers in SD on reduction of drug crystallinity and modulation of pH_M via molecular interactions could modulate dissolution rates of ionizable and poorly water-soluble model drug without spring-like precipitation by providing more favorable nanoemulsion-forming environment.     

Enhanced dissolution and oral bioavailability of valsartan solid dispersions prepared by a freeze-drying technique using hydrophilic polymers

This study aimed to improve the dissolution rate and oral bioavailability of valsartan (VAL), a poorly soluble drug using solid dispersions (SDs). The SDs were prepared by a freeze-drying technique with polyethylene glycol 6000 (PEG6000) and hydroxypropylmethylcellulose (HPMC 100KV) as hydrophilic polymers, sodium hydroxide (NaOH) as an alkalizer, and poloxamer 188 as a surfactant without using any organic solvents. In vitro dissolution rate and physicochemical properties of the SDs were characterized using the USP paddle method, differential scanning calorimetry (DSC), X-ray diffractometry (XRD) and Fourier transform-infrared (FT-IR) spectroscopy, respectively. In addition, the oral bioavailability of SDs in rats was evaluated by using VAL (pure drug) as a reference. The dissolution rates of the SDs were significantly improved at pH 1.2 and pH 6.8 compared to those of the pure drug. The results from DSC, XRD showed that VAL was molecularly dispersed in the SDs as an amorphous form. The FT-IR results suggested that intermolecular hydrogen bonding had formed between VAL and its carriers. The SDs exhibited significantly higher values of AUC_0–24?h and C_max in comparison with the pure drug. In conclusion, hydrophilic polymer-based SDs prepared by a freeze-drying technique can be a promising method to enhance dissolution rate and oral bioavailability of VAL.     

A comparative study on the effects of amphiphilic and hydrophilic polymers on the release profiles of a poorly water-soluble drug

This paper reports the use of two crystalline polymers, an amphiphilic Pluronic® F-127 (PF-127) and a hydrophilic poly(ethylene glycol) (PEG6000) as drug delivery carriers for improving the drug release of a poorly water-soluble drug, fenofibrate (FEN), via micelle formation and formation of a solid dispersion (SD). In 10% PF-127 (aq.), FEN showed an equilibrium solubility of ca. 0.6?mg/mL, due to micelle formation. In contrast, in 10% PEG6000 (aq.), FEN only exhibited an equilibrium solubility of 0.0037?mg/mL. FEN-loaded micelles in PF-127 were prepared by direct dissolution and membrane dialysis. Both methods only yielded a highest drug loading (DL) of 0.5%. SDs of FEN in PF-127 and PEG6000, at DLs of 5–80%, were prepared by solvent evaporation. In-vitro dissolution testing showed that both micelles and SDs significantly improved FEN’s release rate. The SDs of FEN in PF-127 showed significantly faster release than crystalline FEN, when the DL was as high as 50%, whereas SDs of PEG6000 showed similar enhancement in the release rate when the DL was not more than 20%. The DSC thermograms of SDs of PF-127 exhibited a single phase transition peak at ca. 55–57?°C when the DL was not more than 50%, whereas those in PEG6000 exhibited a similar peak at ca. 61–63?°C when the DL was not more than 35%. When the DL exceeded 50% for SDs of PF-127 and 35% for SDs of PEG6000, DSC thermograms showed two melting peaks for the carrier polymer and FEN, respectively. FT-IR studies revealed that PF-127 has a stronger hydrophobic–hydrophobic interaction with FEN than PEG6000. It is likely that both dispersion and micelle formation contributed to the stronger effect of PF-127 on enhancing the release rate of FEN in its SDs.     

Enhanced dissolution and systemic availability of albendazole formulated as solid dispersions

Solid dispersions (SDs) containing the anthelmintic compound albendazole (ABZ) and either Pluronic 188 (P 188) or polyethylene glycol 6000 (PEG 6000) as hydrophilic carriers were formulated. Drug–polymers interactions in solid state were investigated using different techniques.

Only a 4% of total ABZ was dissolved at 5 min post-incubation, reaching dissolution rates of 32.8% (PEG 6000) and 69.4% (P 188) in SDs. In this way, P 188 was substantially more efficient as ABZ dissolution promoter in comparison to PEG 6000, especially at the initial stages of the dissolution processes (<30 min).

An increased systemic availability (p < 0.001) was obtained when ABZ was administered as ABZ-P 188 SDs, with a 50% enhancement in systemic exposure (AUC values) compared to treatment with an ABZ suspension. Consistently, the Cmax increased 130% (p < 0.001) following treatment with P 188 based SD ABZ formulation. For the ABZ-PEG 6000 SD formulation, the favorable effect on ABZ systemic availability did not reached statistical significance compared to the control group.

The study reported here showed the utility of pharmacokinetic assays performed on mice as a model for preliminary drug formulation screening studies.     

Effect of solubilizing and microemulsifying excipients in polyethylene glycol 6000 solid dispersion on enhanced dissolution and bioavailability of ketoconazole

Polyethylene glycol (PEG) 6000-based solid dispersions (SDs), by incorporating various pharmaceutical excipients or microemulsion systems, were prepared using a fusion method, to compare the dissolution rates and bioavailabilities in rats. The amorphous structure of the drug in SDs was also characterized by powder X-ray diffractometry (XRD) and differential scanning calorimetry (DSC). The ketoconazole (KT), as an antifungal agent, was selected as a model drug. The dissolution rate of KT increased when solubilizing excipients were incorporated into the PEG-based SDs. When hydrophilic and lipophilic excipients were combined and incorporated into PEG-based SDs, a remarkable enhancement of the dissolution rate was observed. The PEG-based SDs, incorporating a self microemulsifying drug delivery system (SMEDDS) or microemulsion (ME), were also useful at improving the dissolution rate by forming a microemulsion or dispersible particles within the aqueous medium. However, due to the limited solubilization capacity, these PEG-based SDs showed dissolution rates, below 50% in this study, under sink conditions. The PEG-based SD, with no pharmaceutical excipients incorporated, increased the maximum plasma concentration (Cmax) and area under the plasma concentration curve (AUC(0-6h)) two-fold compared to the drug only. The bioavailability was more pronounced in the cases of solubilizing and microemulsifying PEG-based SDs. The thermograms of the PEG-based SDs showed the characteristic peak of the carrier matrix around 60 degrees C, without a drug peak, indicating that the drug had changed into an amorphous structure. The diffraction pattern of the pure drug showed the drug to be highly crystalline in nature, as indicated by numerous distinctive peaks. The lack of the numerous distinctive peaks of the drug in the PEG-based SDs demonstrated that a high concentration of the drug molecules was dissolved in the solid-state carrier matrix of the amorphous structure. The utilization of oils, fatty acid and surfactant, or their mixtures, in PEG-based SD could be a useful tool to enhance the dissolution and bioavailability of poorly water-soluble drugs by forming solubilizing and microemulsifying systems when exposed to gastrointestinal fluid.     

Unexpected Performance of Physical Mixtures over Solid Dispersions on the Dissolution Behavior of Benznidazole from Tablets

This work investigated the feasibility of developing benznidazole (BZL) tablets, allowing fast, reproducible, and complete drug dissolution, by compressing BZL-Polyethylene Glycol (PEG) 6000 physical mixtures (PMs) and solid dispersions (SDs). SDs were prepared by the solvent evaporation method at different drug:polymer ratios (w/w). BZL-PEG 6000 formulations were characterized by X-ray diffraction (XRD), scanning electron microscopy, and dissolution studies. The preparation of SD-based BZL tablets by the wet granulation method was carried out and the influence of pregelatinized starch (PS) and starch (S) on the disintegration time and drug dissolution rate was analyzed. SDs showed a significant improvement in the release profile of BZL as compared with the pure drug. As demonstrated by XRD, the crystalline character of BZL remained almost unaltered in both PMs and SDs. BZL release from the PEG 6000 tablets increased by the presence of PS instead S. Unexpectedly, the BZL release from tablets containing PMs was almost equal as compared with the BZL release from tablets containing SDs. In conclusion, the results suggest that PEG 6000 and PS are suitable additives for the development of BZL tablets with enhanced dissolution behavior through the preparation of ordinary PMs, instead the laborious SDs. © 2013 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 102:1016–1023, 2013     

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.     

Improvement of solubility,dissolution and stability profile of artemether solid dispersions and self emulsified solid dispersions by solvent evaporation method

Abstract

The purpose of this study was to investigate changes in the water solubility of artemether; a poorly soluble drug used for the treatment of malaria. Different solid dispersions (SDs) of artemether were prepared using artemether and polyethylene glycol 6000 at ratio 12:88 (Group 1), self-emulsified solid dispersions (SESDs) containing artemether, polyethylene glycol 6000, cremophor-A-25, olive oil, hydroxypropylmethylcellulose and transcutol in the ratio 12:75:5:4:2:2, respectively (Group 2). SESDs were also prepared by substituting cremophor-A-25 in Group 2 with poloxamer 188 (noted as Group 3). Each of these preparations was formulated using physical mixing and the solvent evaporation method. Aqueous solubility of artemether improved 11-, 95- and 102-fold, while dissolution (in simulated gastric fluid) increased 3-, 13- and 14-fold, for formulation groups 1, 2 and 3, respectively. X-ray diffraction patterns of SDs indicated a decrease in peak intensities at 10° implying reduced artemether crystallinity. Scanning electron micrographs invariably revealed embedment of artemether by various excipients and a glassy appearance for solvent evaporated mixtures for all three formulation Groups. Our findings indicate improved hydrophilic interactions for drug particles yield greater solubility and dissolution in the following order for artemether formulating methods: solvent evaporation mixtures?>?physical mixtures?>?pure artemether.     

杨梅素固体分散体的制备以及体外溶出试验

目的运用固体分散技术制备杨梅素固体分散体并提高其体外溶出速率。方法选用PEG6000和PVPK30为载体,采用溶剂法和溶剂-熔融法制备杨梅素固体分散体,采用紫外分光光度法进行含量测定,并进行溶解度、体外溶出试验。结果两种载体的固体分散体均能增加药物的溶解度和溶出速率,杨梅素在载体中以高度分散状态存在。结论以PVPK30为载体的杨梅素固体分散体体外溶解度和溶出速率明显提高。杨梅素固体分散体能显著提高杨梅素的溶出速率。     

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.