纳米晶提高难溶性药物溶出及生物利用度的研究进展

目的综述了纳米晶在提高难溶性药物溶解度、加快药物溶出速度及提高药物口服生物利用度方面的研究进展。方法查阅相关文献31篇,对纳米晶提高难溶性药物溶出及生物利用度的机制、制备方法、物理稳定性及其在提高难溶性药物口服生物利用度方面的应用进行归纳总结。结果纳米晶可通过多种作用机制,有效提高难溶性药物的溶出及口服生物利用度,易于工业化生产。结论纳米晶在提高难溶性药物溶出及生物利用度方面具有广阔的应用前景。     

难溶性药物的制剂增溶技术及应用

目的：综述难溶性药物增溶和提高生物利用度的制剂技术及应用。方法：查阅国内外相关文献进行总结、归纳。结果：难溶性药物随着制剂技术的改进及新剂型的应用,可通过环糊精包合或复合、固体分散体、微粉化、加增溶剂或助溶剂、成盐处理等多种途径来提高药物的溶出速率和生物利用度。结论：随着药学领域中新制剂技术的发展、新材料的应用,难溶性药物的吸收差、生物利用度低这一限制已逐渐被克服,难溶性药物也可获得较好的吸收和生物利用度。     

自微乳化释药系统与液固压缩技术在难溶性中药制剂中的联合应用

药物的难溶性严重影响药物的生物利用度,也严重影响药物制成各类制剂。如何增加中药难溶性成分的溶解度,改善其生物利用度,一直是药剂学研究的重要内容。对于难溶性药物来说,药物只有处于溶解状态下,才能表现出较好的溶出和生物利用度。自微乳化释药系统和液固压缩技术均有很好的增溶作用,而且液固压缩技术使药物以无定形或分子状态给药,两者联合应用,可以显著提高药物的溶出度和生物利用度,为中药增溶领域提供一种新的思路与方法。     

纳米混悬剂粒径稳定性及其控制策略

纳米混悬荆具有高溶出速率、高饱和溶解度和黏膜吸附性等特点,可有效提高难溶性药物的生物利用度.本文主要综述纳米混悬剂制备方法及其粒径控制策略,分析难溶性药物制剂开发技术.     

固体分散体在提高难溶性药物口服生物利用度中的应用

固体分散体在提高难溶性药物溶出度和口服生物利用度中的应用引起了药学工作者的关注,本文综述了固体分散体常用载体、常用的溶剂、提高难溶性药物溶出速率的机制和制备方法以及其他替代的方法,以期将难溶性药物制备为固体分散体提供参考。     

安体舒通固态分散体的研究

难溶于水的药物,由于服后在胃肠液中溶解度小,溶出速度慢,吸收缓慢且不完全而影响疗效的发挥。药物溶出速度与其表面积是直接成比例的,故减小药物粒子就可增加溶出速度,从而在体内就有较快的吸收和较高的生物利用度。近代,基于药物粒子大小与溶出速度及吸收速度关系而发展起来的固态分散法,是解决难溶性药物体内吸收问题的一项新技术。它是将难溶性药物和一种生理上惰性、易溶于水的固体载体以熔融、溶剂或溶剂-熔融相结合的方法制成的药物在固体载体中的高度分散体系。服用后,载体溶解并使药物以分子状态释出,从而具有比原来快得多的溶出速度和生物利用度。近年来,国内已用此法改善一些药物的吸收,取得成效。     

非晶固体分散体技术的研究现状

提高药物的溶解度和生物利用度是制剂研究的重要挑战.非晶固体分散体(ASD)能极大增加药物的溶解度和溶出速度,从而改善其生物利用度,被广泛用于难溶性药物的递送.ASD的成功必须满足两点要求:良好的物理稳定性以及良好的溶出以获得较高的生物利用度.本文主要综述ASD的制备方法,表征技术,物理稳定性以及制剂设计理论,以期为AS...     

难溶性药物口服吸收体内外相关性的研究进展

体内外相关性(in vitro-in vivo correlation,IVIVC)是将药物剂型体外的释药情况与其体内相应的应答关联起来,用数学模型描述药物体外性质(药物溶出的速率或程度)与体内特性(血药浓度或药物吸收量)的关系.它是体外溶出度和体内生物利用度参数的函数.研究某个药物制剂的体内外相关性的目的,在于建立一个可以说明生物利用度的体外质量标准和用作制剂批量生产时的质控指标.水难溶性药物制剂是中国药典规定需要进行生物利用度和溶出度测定的药物类型之一.药物的生物利用度试验操作过程较溶出度试验复杂,在实际工作中,对于具有良好体内外相关性的药物,通过测定体外溶出度来预测难溶性药物的体内生物利用度,进而筛选制剂处方和控制其质量具有重要的意义.一个制剂的改变需要进行一系列生物利用度实验,以证明新制剂与旧制剂具有生物等效性.这过程需要耗费大量的时间和金钱.而具有良好体内外相关性的药物,能很好预测体内释药特征,可以申请豁免生物等效性研究,不仅节约时间,还降低成本.影响药物体内外相关性的因素很多,主要包括体外溶出度研究,体内生物利用度试验研究和拟合模型的数学方法这3个方面.     

纳米技术在口服难溶性药物的研究进展

据报道,有〉70%的化学合成药物存在难溶性问题[1],约40%的新化学实体（NCEs）因其难溶性而无法进入临床试验,使其应用受到很大程度的限制[2]。口服给药不仅方便且患者顺应性高,是新药首选的给药途径之一。但对于生物药剂学分类系统中的第Ⅱ类药物（即穿膜性好,但溶解度低而言,因在胃肠道中溶解度低或溶出速率慢,可能导致口服生物利用度低。因此,解决因药物难溶性引起的口服低吸收问题,可提高这类药物的口服生物利用度。解决药物难溶性主要有两条途径：①提高溶解度,增加药物溶出：提高难溶性药物溶解度或溶出速率的常用方法有成盐、改变药物晶型、使用增溶剂或减小粒径等;②应用纳米给药系统,将药物包入载体内部,使药物以载药传递体形式被肠道吸收。     

难溶性药物固体分散体研究新进展

如何改善难溶性药物溶出度和口服生物利用度,业已成为药剂学研究的重点,而将其制成固体分散体,作为一种行之有效的改善方法,备受关注.综述近年来用于制备难溶性药物固体分散体的新型载体材料和新技术的研究进展.     

Dry elixir formulations of dexibuprofen for controlled release and enhanced oral bioavailability

The objective of this study was to achieve an optimal formulation of dexibuprofen dry elixir (DDE) for the improvement of dissolution rate and bioavailability. To control the release rate of dexibuprofen, Eudragit(?) RS was employed on the surface of DDE resulting in coated dexibuprofen dry elixir (CDDE). Physicochemical properties of DDE and CDDE such as particle size, SEM, DSC, and contents of dexibuprofen and ethanol were characterized. Pharmacokinetic parameters of dexibuprofen were evaluated in the rats after oral administration. The DDE and CDDE were spherical particles of 12 and 19 μm, respectively. The dexibuprofen and ethanol contents in the DDE were dependent on the amount of dextrin and maintained for 90 days. The dissolution rate and bioavailability of dexibuprofen loaded in dry elixir were increased compared with those of dexibuprofen powder. Moreover, coating DDE with Eudragit(?) RS retarded the dissolution rate of dexibuprofen from DDE without reducing the bioavailability. Our results suggest that CDDE may be potential oral dosage forms to control the release and to improve the bioavailability of poorly water-soluble dexibuprofen.     

Application of dry elixir system to oriental traditional medicine: Taste masking of peonjahwan by coated dry elixir

Peonjahwan, an oriental traditional medicine composed of crude herbal drugs and animal tissues is bitter and poorly water-soluble. To mask the bitterness of peonjahwan and enhance the release of bilirubin, one of the crude active ingredients of peonjahwan, peonja dry elixir (PDE), was prepared using a spray-dryer after extracting the crude materials in ethanol-water solution. Coated peonja dry elixir (CPDE) was then prepared by coating the PDE with Eudragit acrylic resin. Panel assessed bitterness and release test of bilirubin from PDE and CPDE were carried out and compared with peonjahwan alone. PDE was found to have little effect upon the reduction of the bitterness of peonjahwan. However, the bitterness of CPDE was found to reduce to 1/4 of that of peonjahwan due to the encapsulation of crude active ingredients by the dextrin and Eudragit shell (P<0.05). The release rate of bilirubin from PDE and CPDE for 60 min increased about 3.5- and 2.5- fold, respectively, compared to peonjahwan at pH 1.2. It is concluded that CPDE, which masked the bitterness of peonjahwan and enhanced the release of bilirubin, is a preferable delivery system for peonjahwan.     

A comparative study of the utility of two superdisintegrants in microcrystalline cellulose pellets prepared by extrusion-spheronization.

This study evaluated the utility of including superdisintegrants (croscarmellose sodium or sodium starch glycolate) in microcrystalline cellulose extrusion-spheronization pellets as a means of increasing the dissolution rate of poorly water-soluble drugs. The model drug was hydrochlorothiazide, with water or water/ethanol as wetting agent for pellet preparation. Neither disintegrant had significant effects on pellet morphology, flow properties or mechanical resistance. Neither disintegrant caused disintegration of the pellet in drug dissolution medium. Nevertheless, the disintegrants afforded a modest increase in drug dissolution rate, attributable to the observed increase in pellet micropore volume. Drug dissolution rate was slightly higher in pellets prepared with sodium starch glycolate, probably because of this disintegrant's higher swelling capacity.     

Encapsulation of ethanol by spray drying technique: effects of sodium lauryl sulfate.

Microcapsules composed of ethanol, water and dextrin as a water-soluble polymer can be used to encapsulate poorly water-soluble drugs by spray drying technique. For the encapsulation of a high dose of poorly water-soluble drugs, large amounts of ethanol and consequently large quantities of dextrin are needed for the dissolution of drug and the encapsulation of ethanol, respectively. In order to increase the ethanol content with the decreased amount of dextrin, sodium lauryl sulfate (SLS) was employed in the preparation of microcapsules without drug by a spray drying method. Phase diagrams were prepared to determine the region of microcapsule formation with a three-component system of ethanol, dextrin and water. The homogeneous phase indicated in the phase diagram was used to prepare the alcoholic microcapsules since this phase was not separated rapidly and not too viscous to be spray-dried. Interestingly, SLS at concentrations below 2% remarkably increased both the ethanol content and the encapsulation efficiency of ethanol. The maximum ethanol content and encapsulation efficiency were observed with 0.5-1% of SLS (35.4 and 67.6%, respectively). Furthermore, the increase by SLS was more pronounced at the low dextrin/water ratios than at the high dextrin/water ratios. In particular, the ethanol content and the encapsulation efficiency with the dextrin/ethanol/water ratio of 0.4/1/1, which had relatively small amounts of dextrin, were about ten times higher in the presence of SLS than those without SLS. In conclusion, this study shows that small amounts of SLS can increase the ethanol content and the encapsulation efficiency of ethanol, and allow the reduction in the amount of dextrin required to encapsulate ethanol in the preparation of microcapsules. These findings suggest that the use of SLS may permit the effective encapsulation of high dose of water-insoluble drug into microcapsules.     

A novel application of α-glucosyl hesperidin for nanoparticle formation of active pharmaceutical ingredients by dry grinding

The effectiveness of α-glucosyl hesperidin (Hsp-G) as a novel grinding aid for the preparation of drug nanoparticles by dry grinding was investigated. Poorly water-soluble drugs and Hsp-G were mixed at a weight ratio of 1/5 and ground for 60 min by a vibrational ball mill. It was evident that all poorly water-soluble drugs used in this study formed nanoparticles after the ground mixtures were dispersed into distilled water. The dissolution profile of glibenclamide from the ground mixtures of glibenclamide/Hsp-G showed dramatic improvement from that of untreated drug crystals. Administration of the ground mixture of glibenclamide/Hsp-G to rats resulted in a significantly higher rate of decrease in blood glucose levels than that of untreated glibenclamide. The area above the time-curve of plasma-glucose concentrations using the ground mixture of glibenclamide/Hsp-G was 6-fold higher than that using untreated glibenclamide. The improved dissolution rate due to nanoparticle formation of glibenclamide, induced by co-grinding with Hsp-G, was responsible for this improvement.     

Comparison of electrospun and extruded Soluplus®-based solid dosage forms of improved dissolution

Electrospinning (ES) and extrusion of a poorly water-soluble active pharmaceutical ingredient were used to improve its dissolution, which is a major challenge in the field of pharmaceutical technology. Spironolactone was applied as model drug and recently developed polyvinyl caprolactame-polyvinyl acetate-polyethylene glycol graft copolymer (Soluplus?) was used as carrier matrix and solubilizer. ES of the polymer matrix from ethanol solution was optimized at first without spironolactone and then the cosolution of the drug and the carrier was used for forming electrospun fibers. It resulted in real solid solution due to its very efficient amorphization effect. On the contrary, a low amount of crystalline spironolactone appeared in the extrudates according to Raman microscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive spectrometry (EDS). Raman microspectrometry had the lowest detection limit of spironolactone crystals compared with XRD and differential scanning calorimetry. Both ES and extrusion techniques resulted in significantly improved dissolution. Electrospun ultrafine fibers increased the dissolution more effectively, owing to the formed solid solution and huge surface. The developed continuous technologies demonstrate great potential to tackle the challenge of inadequate dissolution of poorly water-soluble drugs in several cases.     

Retarded dissolution of ibuprofen in gelatin microcapsule by cross-linking with glutaradehyde

Ibuprofen-loaded gelatin microcapsule, a solid form of microcapsules simultaneously containing ethanol and ibuprofen in water-soluble gelatin shell was previously reported to improve the dissolution of drug. In this study, to retard the initial high dissolution of ibuprofen from gelatin microcapsule, the ibuprofen-loaded cross-linked gelatin microcapsule was prepared by treating an ibuprofen-loaded gelatin microcapsule with glutaraldehyde and its dissolution was evaluated compared to ibuprofen powder and gelatin microcapsule. The ibuprofen-loaded cross-linked microcapsule treated with glutaraldehyde for 10 and 60 sec gave significantly higher dissolution rates than did ibuprofen powder. Furthermore, the dissolution rate of ibuprofen from the cross-linked microcapsule treated for 10 sec was similar to that from gelatin microcapsule. However, the dissolution rate of ibuprofen from the cross-linked microcapsule treated for 60 sec decreased significantly compared to gelatin microcapsule, suggesting that the treatment of gelatin microcapsule with glutaraldehyde for 60 sec could cross-link the gelatin microcapsule. Furthermore, the cross-linking of gelatin microcapsule markedly retarded the release rate of ibuprofen in pH 1.2 simulated gastric fluid compared to gelatin microcapsule. However, the cross-linking of gelatin microcapsule with glutaraldehyde hardly changed the size of gelatin microcapsules, ethanol and ibuprofen contents encapsulated in gelatin microcapsule. Thus, the ibuprofen-loaded cross-linked gelatin microcapsule could retard the initial high dissolution of poorly water-soluble ibuprofen.     

Budesonide Nanoparticle Agglomerates as Dry Powder Aerosols With Rapid Dissolution

: Nanoparticle technology represents an attractive approach for formulating poorly water-soluble pulmonary medicines. Unfortunately, nanoparticle suspensions used in nebulizers or metered dose inhalers often suffer from physical instability in the form of uncontrolled agglomeration or Ostwald ripening. In addition, processing such suspensions into dry powders can yield broad particle size distributions. To address these encumbrances, a controlled nanoparticle flocculation process has been developed. Nanosuspensions of the poorly water-soluble drug budesonide were prepared by dissolving the drug in organic solvent containing surfactants followed by rapid solvent extraction in water. Different surfactants were employed to control the size and surface charge of the precipitated nanoparticles. Nanosuspensions were flocculated using leucine and lyophilized. Selected budesonide nanoparticle suspensions exhibited an average particle size ranging from ~ 160 to 230 nm, high yield and high drug content. Flocculated nanosuspensions produced micron-sized agglomerates. Freeze-drying the nanoparticle agglomerates yielded dry powders with desirable aerodynamic properties for inhalation therapy. In addition, the dissolution rates of dried nanoparticle agglomerate formulations were significantly faster than that of stock budesonide. The results of this study suggest that nanoparticle agglomerates possess the microstructure desired for lung deposition and the nanostructure to facilitate rapid dissolution of poorly water-soluble drugs.     

A compaction process to enhance dissolution of poorly water-soluble drugs using hydroxypropyl methylcellulose

The purpose of this study was to develop a technique to enhance the dissolution rate of poorly water-soluble drugs with hydroxypropyl methylcellulose (HPMC) without the use of solvent or heat addition. Three poorly water-soluble drugs, naproxen, nifedipine, and carbamazepine, were studied with low-viscosity HPMC USP Type 2208 (K3LV), HPMC USP Type 2910 (E3LV and E5LV), and methylcellulose. Polymer and drug were dry-blended, compressed into slugs on a tablet press or into ribbons on a roller compactor, and then milled into a granular powder. Dissolution testing of the milled powder was performed on USP Apparatus II, 100 rpm, 900 ml deionized water, 37 degrees C. Drug distribution vs. particle size was also studied. The compaction processes enhanced drug dissolution relative to drug alone and also relative to corresponding loosely mixed physical mixtures. The roller compaction and slugging methods produced comparable dissolution enhancement. The mechanism for dissolution enhancement is believed to be a microenvironment HPMC surfactant effect facilitated by keeping the HPMC and drug particles in close proximity during drug dissolution. The compaction methods in this study may provide a lower cost, quicker, readily scalable alternative for formulating poorly water-soluble drugs.     

Effect of biocompatible polymers on the physicochemical and dissolution properties of fenofibrate in nanoparticle system

This study aimed to evaluate the effect of biocompatible polymers on the physicochemical and dissolution properties of poorly water-soluble drugs in nanoparticle systems. Four types of nanoparticles containing poorly water-soluble fenofibrate were prepared using solvent evaporation technique with different biocompatible polymers such as polyvinylpyrrolidone (PVP), hydroxypropylmethyl cellulose (HPMC), carbopol and ethylcellulose. Their physicochemical properties were investigated using scanning electron microscopy, differential scanning calorimetry, and powder X-ray diffraction. The solubility and dissolution of nanoparticle-entrapped fenofibrate were compared with those of free drug powder. Biocompatible polymers affected the morphology and sizes of fenofibrate nanoparticles. PVP or carbopol-based nanoparticles showed spherical appearance, whereas HPMC or ethylcellulose-based nanoparticles formed aggregates with irregular shape. The particle sizes increased in the order of the nanoparticle prepared with carbopol ≤ PVP < HPMC < ethylcellulose. The size of PVP-based nanoparticles did not significantly differ from that of carbopol-based nanoparticles, showing the mean sizes of ca. 10 μm. As compared to free drug powder, the solubility and dissolution of the drug in nanoparticles increased in the order of PVP > HPMC > carbopol > ethylcellulose. The enhanced solubility and dissolution of poorly water-soluble fenofibrate via nanoparticle system did not depend on particle size but on crystallinity. In conclusion, in nanoparticle development of poorly water-soluble drugs such as fenofibrate, the nature of biocompatible polymers plays an important role in the physicochemical and dissolution of poorly water-soluble drugs in the nanoparticles.