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.     

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.     

固体分散技术提高枸橼酸莫沙必利片溶出度的研究

目的考察固体分散技术对枸橼酸莫沙必利片的体外溶出度的影响。方法以聚维酮K30为载体制备枸橼酸莫沙必利片固体分散体,紫外分光光度法对其体外溶出度进行测定。结果聚维酮K30-枸橼酸莫沙必利比例大于2∶1(w/w)时所得枸橼酸莫沙必利片5 min累积溶出量接近100%,而市售品溶出缓慢,5 min累积溶出量约为50%,30min累积溶出量约为90%。结论采用固体分散技术制备的枸橼酸莫沙必利片能显著提高枸橼酸莫沙必利的溶出速率。     

Improvement of solubility and dissolution rate of indomethacin by solid dispersions in Gelucire 50/13 and PEG4000

The aim of this study was to prepare and characterize solid dispersions of water insoluble non-steroidal anti-inflammatory drug, indomethacin (IND), with polyethylene glycol 4000 (PEG4000) and Gelucire 50/13 (Gelu.) for enhancing the dissolution rate of the drug. The solid dispersions (SDs) were prepared by hot melting method at 1:1, 1:2 and 1:4 drug to polymer ratios. Scanning electron microscopy (SEM), X-ray powder diffractometry (XRD) and differential scanning calorimetry (DSC) were used to examine the physical state of the drug. Furthermore, the solubility and the dissolution rate of the drug in its different systems were explored. The data from the XRD showed that the drug was still detectable in its solid state in all SDs of IND–Gelu. and disappeared in case of higher ratio of IND–PEG4000. DSC thermograms showed the significant change in melting peak of the IND when prepared as SDs suggesting the change in crystallinity of IND. The highest ratio of the polymer (1:4) enhanced the drug solubility about 4-folds or 3.5-folds in case of SDs of IND–PEG or IND–Gelu., respectively. An increased dissolution rate of IND at pH 1.2 and 7.4 was observed when the drug was dispersed in these carriers in form of physical mixtures (PMs) or SDs. IND released faster from the SDs than from the pure crystalline drug or the PMs. The dissolution rate of IND from its PMs or SDs increased with an increasing amount of polymer.     

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。     

槲皮素-聚乙二醇固体分散体的研制

目的 制备槲皮素-聚乙二醇6000(PEG6000)固体分散体以提高槲皮素的水溶性。方法以PEG6000为载体,采用熔融法制备槲皮素的固体分散体,测定了槲皮素对照品、固体分散物以及机械混合物的溶解度,并通过红外光谱和紫外光谱对固体分散物进行了分析。结果槲皮素固体分散物的溶解度与槲皮素原料药和机械混合物相比有明显提高。结论槲皮素分子和载体分子之间未发生化学变化。     

Preparation,characterization, and in vitro/vivo evaluation of polymer-assisting formulation of atorvastatin calcium based on solid dispersion technique

 Due to low solubility and bioavailability, atorvastatin calcium is confronted with challenge in conceiving appropriate formulation. Solid dispersion of atorvastatin calcium was prepared through the solvent evaporation method, with Poloxamer 188 as hydrophilic carriers. This formulation was then characterized by scanning electron microscopy, differential scanning calorimetry,powder X-ray diffraction and fourier transform infrared spectroscopy. Moreover, all these studies suggested the conversion of crystalline atorvastatin calcium. In addition, the drug solubility studies as well as dissolution rates compared with bulk drug and market tablets Lipitor were also examined. Furthermore, the study investigated the pharmacokinetics after oral administration of Lipitor and solid dispersion. And the AUC0–8 h and Cmax increased after taking ATC-P188 solid dispersion orally compared with that of Lipitor. All these could be demonstrated that ATC-P188 solid dispersions would be prospective means for enhancing higher oral bioavailability of ATC.     

Revealing facts behind spray dried solid dispersion technology used for solubility enhancement

Poor solubility and bioavailability of an existing or newly synthesized drug always pose challenge in the development of efficient pharmaceutical formulation. Numerous technologies can be used to improve the solubility and among them amorphous solid dispersion based spray drying technology can be successfully useful for development of product from lab scale to commercial scale with a wide range of powder characteristics. Current review deals with the importance of spray drying technology in drug delivery, basically for solubility and bioavailability enhancement. Role of additives, selection of polymer, effect of process and formulation parameters, scale up optimization, and IVIVC have been covered to gain the interest of readers about the technology. Design of experiment (DoE) to optimize the spray drying process has been covered in the review. A lot more research work is required to evaluate spray drying as a technology for screening the right polymer for solid dispersion, especially to overcome the issue related to drug re-crystallization and to achieve a stable product both in vitro and in vivo. Based on the recent FDA recommendation, the need of the hour is also to adopt Quality by Design approach in the manufacturing process to carefully optimize the spray drying technology for its smooth transfer from lab scale to commercial scale.     

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。     

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.     

Experimental and mesoscale computational dynamics studies of the relationship between solubility and release of quercetin from PEG solid dispersions

The flavonol quercetin is potentially clinically relevant for its antimicrobial, beneficial cardiovascular effects, cancer treatment amongst others. However, its successful therapeutic application is severely curtailed by its poor water solubility and poor absorption following oral administration. In this study, solid dispersions of quercetin in poly(ethylene glycol) (PEG) at various compositions demonstrated an increase in the solubility, however with time, dissolution profiles show a decrease in dissolved flavonol concentration. The mechanism by which this decrease in solubility occurs was studied experimentally as well as by computational mesocscale particle dynamics simulations. The results suggest that phase separation of the polymer and flavonol during release from the solid dispersion is responsible for the time-dependent decrease in dissolved quercetin. It is suggested that the increase in release of quercetin in a PEG solid dispersion would only be beneficial if it were administered at the site of absorption, e.g. rectal administration, to ensure absorption prior to phase separation. The solid dispersions presented here would greatly improve the pharmaceutical availability of the flavonol at the site of absorption. Computational mesoscopic modeling was successfully applied to study the solid dispersions and corroborate experimental findings.     

Novel Tanshinone II A ternary solid dispersion pellets prepared by a single-step technique: In vitro and in vivo evaluation

Novel Tanshinone II A (TA) ternary solid dispersion (tSD) pellets with the combination of polyvinylpyrrolidone and poloxamer 188 as dispersing carriers were prepared by a single-step technique. A formulation screening study showed that the addition of poloxamer 188 to binary TA-PVP system could remarkably promote the dissolution rate of TA from 60% to 100% after 60 min. Scanning electron microscopy study revealed a smooth surface and a tightly packed coating structure. Differential scanning calorimetry analysis confirmed the formation of solid dispersions. In vivo test showed that TA tSD pellets presented significantly larger AUC_0-t, which was 0.76 times more than that of binary solid dispersion (bSD) pellets, 2.87 times more than that of physical mixtures (PMs) and 5.40 times more than that of TA. C_max of TA tSD pellets also increased by 1.82-8.97-fold as that of bSD pellets, PMs and TA. TA tSD pellets generated obviously shortened T_max of (3.80 ± 0.398) h, compared to bSD pellets with (4.15 ± 0.456) h, PMs with (4.65 ± 0.226) h and TA with (5.52 ± 0.738) h. In conclusion, the addition of poloxamer 188 to pellets containing PVP-based solid dispersions could achieve complete dissolution, accelerated absorption rate and superior oral bioavailability. The fluid-bed technique becomes an alternative approach to obtain solid dispersion-coated pellets.     

共研磨法改善水飞蓟素固体分散体的溶出度

目的:通过共研磨技术改善水飞蓟素固体分散体的体外溶出度。方法:设计单因素试验考察溶出度的影响因素,如共研磨载体材料的种类及与共研磨药物的比例,研磨的时间等因素。结果:以甘露醇与PVP K30为混合亲水性载体材料,与药物的比例为1∶1∶1,研磨6 h,以pH7.4的磷酸盐缓冲溶液为溶出介质。结论:共研磨法制备水飞蓟素固体分散体能显著提高药物的体外溶出度,且制备工艺简单易行。     

Quercetin-phospholipids complex solid dispersion and quercetin solid dispersion: preparation and evaluation

Quercetin (QUE) has many beneficial biological activities and pharmacological actions in vitro. However, its oral bioavailability in vivo was very poor due to poor solubility, and severely restricted its clinical applications. In this study, we preparedquercetin solid dispersion (QUE-SD) and quercetin phospholipids complex solid dispersion (QUE-PC-SD) by a solvent evaporationmethod to improve the absorption of QUE in vivo. The results of XRD of QUE-SD and QUE-PC-SD showed that QUE was dispersed homogeneously in an amorphous or molecular state in QUE-SD and QUE-PC-SD, which could contribute to improve the solubility and dissolution of QUE. The solubility of QUE-SD and QUE-PC-SD was enhanced from (4.03±0.02) μg/mL to (26.91±0.06) μg/mL and (30.65±0.06) μg/mL, respectively. The solubility of QUE-PC-SD was higher than that of QUE-SD.In vitro dissolution study, it was showed that the maximum dissolution of QUE (9.57%) from the QUE-SD and QUE-PC-SD was enhanced to 93.81% and 94.16%, respectively. The results of pharmacokinetic experiment indicated that the QUE-SD and QUE-PC-SD exhibited considerable enhancement in the oral bioavailability. The relative bioavailability of QUE-SD and QUE-PC-SD compared with QUE were 149.49% and 198.32%, respectively. In addition, the relative bioavailability of QUE-PC-SD was also higher than that of QUE-SD. Therefore, in regard to drugs with poor solubility and low permeation, an active constituent-PC-SD system could result to a better absorption and higher bioavailability.     

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。     

醋酸棉酚——PVP固体分散体研究及体外杀精子活性的观察

本文对溶剂法制备醋酸棉酚—PVP固体分散体作了改进。以二氯甲烷为溶剂在45℃常压下完成,结果与Waller方法一致,并具有更大的安全性。经溶出实验筛选确定以1∶7醋酸棉酚—PVP配比可比Waller等人的1∶4配比提高药物溶出速率8倍,不同比例的固体分散体释药曲线均服从Q—t^1/2规律,且速度常数随固体分散体中PVP比例增加而线性递增。利用X射线衍射和¹HNMR研究了固体分散机制,认为是形成了间充型固体溶液,且PVP与醋酸棉酚之间有氢键结合。1∶7棉酚—PVP抑动精子实验结果表明10^-3M(0.052%)时20秒钟可抑制全部精子的向前运动。棉酚和醋酸棉酚结果一致,无统计学差异。PVP与生理盐水结果一致,表明PVP本身无抑制精子运动作用。     

Dissolution improvement of RS-8359 by the solid dispersion prepared by the solvent method

Study on dissolution improvement of a water-insoluble compound, RS-8359 ((±)-4-(4-cyanoanilino)-5,6-dihydro-7-hydroxy-7H-cyclopenta[d]pyrimidine) was carried out. A hydrochloric acid salt of RS-8359 had much higher solubility than its free form. However, the free form separated out of a neutral buffer solution instantaneously once the salt form was dissolved. We found that the dissolution properties were greatly improved by preparing a solid dispersion of the salt form with a water-soluble polymer mainly because the dissolved water-soluble polymer included in the solid dispersion retarded the precipitation rate of the free form. The crystallinity of the salt form in the solid dispersion did not affect the dissolution properties greatly. Furthermore, the importance of microenvironmental pH in the solid dispersion was suggested by a significant increase in the maximum concentration of RS-8359 in the dissolution process of the solid dispersion as compared with the case that the simple salt form was dissolved in the buffer solution that included the water-soluble polymer.     

反相高效液相色谱法测定紫杉醇固体分散体中紫杉醇的含量（英文）

目的优化和确定反相高压液相色谱法测定紫杉醇固体分散体中紫杉醇的含量。方法色谱柱为Phenomenex ODS 3,流动相为甲醇-乙腈-水（40：30：30）,流速为1mL·min^-1,柱温为40°C,检测波长为227nm,内标物为炔诺酮。结果在4～40μg·mL^-1度范围内,紫杉醇浓度与紫杉醇/炔诺酮峰面积比之间具有良好的线性关系,r=0.9999。加样回收率为98.42%,RSD为1.19%。结论方法准确、可靠,不但可以用于测定紫杉醇在固体分散体中的含量,也可用于紫杉醇固体分散体溶出度的检查。     

氟比洛芬聚丙烯酸树脂RL/RS固体分散体的制备

目的制备氟比洛芬固体分散体并考察其体外释药特性。方法以氟比洛芬为主药,分别以聚丙烯酸树脂Eudragit RL、RS及RL/RS混合物为载体,卵磷脂为乳化剂,以溶剂法制备固体分散体。以体外溶出半衰期t1/2为指标,优选固体分散体的最佳制备方法。结果氟比洛芬固体分散体的最佳处方比例为:药物∶载体=1∶9,RL∶RS=2∶1,卵磷脂浓度为0.2%。固体分散体体外溶出测定采用小杯法,测定波长为247 nm,分别采用紫外分光光度法和差示扫描热量法进行定量、定性分析。结论制备所得氟比洛芬固体分散体体外溶出缓慢、平稳、完全,达到提高生物利用度、12 h给药1次的缓释设计目的,可进一步制成其他剂型。