Amorphous Stabilization and Dissolution Enhancement of Amorphous Ternary Solid Dispersions: Combination of Polymers Showing Drug–Polymer Interaction for Synergistic Effects

The purpose of this study was to understand the combined effect of two polymers showing drug–polymer interactions on amorphous stabilization and dissolution enhancement of indomethacin (IND) in amorphous ternary solid dispersions. The mechanism responsible for the enhanced stability and dissolution of IND in amorphous ternary systems was studied by exploring the miscibility and intermolecular interactions between IND and polymers through thermal and spectroscopic analysis. Eudragit E100 and PVP K90 at low concentrations (2.5%–40%, w/w) were used to prepare amorphous binary and ternary solid dispersions by solvent evaporation. Stability results showed that amorphous ternary solid dispersions have better stability compared with amorphous binary solid dispersions. The dissolution of IND from the ternary dispersion was substantially higher than the binary dispersions as well as amorphous drug. Melting point depression of physical mixtures reveals that the drug was miscible in both the polymers; however, greater miscibility was observed in ternary physical mixtures. The IR analysis confirmed intermolecular interactions between IND and individual polymers. These interactions were found to be intact in ternary systems. These results suggest that the combination of two polymers showing drug–polymer interaction offers synergistic enhancement in amorphous stability and dissolution in ternary solid dispersions. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 103:3511–3523, 2014     

电纺制备酮洛芬纳米纤维状固体分散体

以水难溶性药物酮洛芬为模型、聚乙烯吡咯烷酮为成纤基材,使用高压静电纺丝技术制各固体分散体.场扫描电镜观察到纳米纤维状固体分散体具有连续三维立体网状结构特征,X-射线衍射和差示扫描量热分析结果表明,药物以无定形或分子状态高度分散于聚合物基材中,傅里叶红外光谱分析结果证明,酮洛芬与聚乙烯吡咯烷酮之间能通过氢键相互作用.体外溶出结果表明,所制备的纳米纤维状固体分散体中酮洛芬能在30s内释放完全.     

Anti-plasticizing Effect of Amorphous Indomethacin Induced by Specific Intermolecular Interactions with PVA Copolymer

The mechanism of how poly(vinyl alcohol-co-acrylic acid-co-methyl methacrylate) (PVA copolymer) stabilizes an amorphous drug was investigated. Solid dispersions of PVA copolymer, poly(vinyl pyrrolidone) (PVP), and poly(vinyl pyrrolidone-co-vinyl acetate) (PVPVA) with indomethacin (IMC) were prepared. The glass transition temperature (T_g)-proportion profiles were evaluated by differential scanning calorimetry (DSC). General T_g profiles decreasing with the IMC ratio were observed for IMC–PVP and IMC–PVPVA samples. An interesting antiplasticizing effect of IMC on PVA copolymer was observed; T_g increased up to 20% IMC ratio. Further addition of IMC caused moderate reduction with positive deviation from theoretical values. Specific hydrophilic and hydrophobic interactions between IMC and PVA copolymer were revealed by infrared spectra. The indole amide of IMC played an important role in hydrogen bonding with PVA copolymer, but not with PVP and PVPVA. X-ray diffraction findings and the endotherm on DSC profiles suggested that PVA copolymer could form a semicrystalline structure and a possibility of correlation of the crystallographic nature with its low hygroscopicity was suggested. PVA copolymer was able to prevent crystallization of amorphous IMC through both low hygroscopicity and the formation of a specific intermolecular interaction compared with that with PVP and PVPVA.     

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.     

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.     

Development of spray-dried co-precipitate of amorphous celecoxib containing storage and compression stabilizers

The purpose of this study was to obtain an amorphous system with minimum unit operations that will prevent recrystallization of amorphous drugs since preparation, during processing (compression) and further storage. Amorphous celecoxib, solid dispersion (SD) of celecoxib with polyvinyl pyrrollidone (PVP) and co-precipitate with PVP and carrageenan (CAR) in different ratios were prepared by the spray drying technique and compressed into tablets. Saturation solubility and dissolution studies were performed to differentiate performance after processing. Differential scanning calorimetry and X-ray powder difraction revealed the amorphous form of celecoxib, whereas infrared spectroscopy revealed hydrogen bonding between celecoxib and PVP. The dissolution profile of the solid dispersion and co-precipitate improved compared to celecoxib and amorphous celecoxib. Amorphous celecoxib was not stable on storage whereas the solid dispersion and co-precipitate powders were stable for 3 months. Tablets of the solid dispersion of celecoxib with PVP and physical mixture with PVP and carrageenan showed better resistance to recrystallization than amorphous celecoxib during compression but recrystallized on storage. However, tablets of co-precipitate with PVP and carageenan showed no evidence of crystallinity during stability studies with comparable dissolution profiles. This extraordinary stability of spray-dried co-precipitate tablets may be attributed to the cushioning action provided by the viscoelastic polymer CAR and hydrogen bonding interaction between celecoxib and PVP. The present study demonstrates the synergistic effect of combining two types of stabilizers, PVP and CAR, on the stability of amorphous drug during compression and storage as compared to their effect when used alone.     

Effect of drug-carrier interaction on the dissolution behavior of solid dispersion tablets

The objective of this study was to compare the dissolution behavior of tablets prepared from solid dispersions with and without drug-carrier interactions. Diazepam and nifedipine were used as model drugs. Two types of carriers were used; polyvinylpyrrolidone (PVP K12, K30 and K60) and saccharides (inulin 1.8?kDa, 4?kDa and 6.5?kDa). Solid dispersions with various drug loads were prepared by lyophilization. It was found that the drug solubility in aqueous PVP solutions was significantly increased indicating the presence of drug-carrier interaction while the drug solubility was not affected by the saccharides indicating absence of drug-carrier interaction. X-ray powder diffraction and modulated differential scanning calorimetry revealed that all solid dispersions were fully amorphous. Dissolution behavior of solid dispersion tablets based on either the PVPs or saccharides was governed by both dissolution of the carrier and drug load. It was shown that a fast drug dissolution of solid dispersions with a high drug load could be obtained with carrier that showed interaction with the drug.     

Characterization of ternary solid dispersions of itraconazole, PEG 6000, and HPMC 2910 E5

In order to reduce the crystallinity of PEG 6000, blends were prepared by spray drying and extrusion with the following polymers; PVP K25, PVPVA 64, and HPMC 2910 E5. The maximal reduction of crystallinity in PEG 6000 was obtained by co-spray drying with HPMC 2910 E5. In the next step the model drug Itraconazole was added to the blend and the resulting ternary solid dispersions were characterized. The results of this study show that the addition of PEG 6000 to the Itraconazole/HPMC 2910 E5 system leads to phase separation that in most cases gives rise to recrystallization of either PEG 6000 or Itraconazole. For all ternary dispersions containing 20% of Itraconazole the drug was highly amorphous and the dissolution was improved compared to the binary 20/80 w/w Itraconazole/HPMC 2910 E5 solid dispersion. For all ternary dispersions containing 40% of Itraconazole, the drug was partially crystalline and the dissolution was lower than the dissolution of the binary 40/60 w/w Itraconazole/HPMC 2910 E5 dispersion. These results show that provided Itraconazole is highly amorphous the addition of PEG 6000 to HPMC 2910 E5 leads to an increase in drug release.     

Preparation, characterization and in vitro dissolution of aceclofenac-loaded PVP solid dispersions prepared by spray drying or rotary evaporation method

This study was conducted to enhance dissolution rate of aceclofenac (ACF) with extremely low solubility and high permeability (BCS class II) in water using poly vinyl pyrrolidone (PVP) and sodium lauryl sulfate as carriers. Solid dispersions were prepared by spray drying method and rotary evaporation method using different ratios of ACF and polymers. The characterization of solid dispersions was evaluated by scanning electron microscopy, Fourier transformation infrared spectroscopy, differential scanning calorimetry and powder X-ray diffractometer. The dissolution behavior of solid dispersions was compared with pure ACF (API) and Airtal^® (Deawoong, Co, Korea) as control groups in simulated phosphate buffer at pH 6.8. The dissolution rate of the drug was affected by nature and amount of polymer used. The prepared solid dispersion of ACF/PVP (1:5) appeared to have the highest dissolution rate. Therefore, solid dispersion techniques of spray drying and rotary evaporation method can be successfully used for the enhancement of the dissolution rate of ACF.     

酮洛芬-聚乙烯吡咯烷酮固体分散物的制备及其体外溶出度的研究

目的提高难溶性药物酮洛芬体外溶出速度。方法以聚乙烯吡咯烷酮(PVPK30)为载体,制备药物与载体不同比例的固体分散物及物理混合物,采用X射线衍射和红外吸收方法,比较二者及药物的结晶形态,并进行体外药物溶出度的测定。结果固体分散物体外溶出速率明显高于物理混合物及酮洛芬原料的体外溶出速度,且随载体比例增加而增大。固体分散物的X射线衍射及红外吸收图谱确定了酮洛芬以无定形态分散在载体中,放置6个月后,固体分散物X射线衍射图谱没有明显变化。结论药物与载体以合适比例制备的固体分散物可以明显提高药物体外溶出速度。     

Solid dispersion of carbamazepine in PVP K30 by conventional solvent evaporation and supercritical methods

This study compares the physicochemical properties of carbamazepine (CBZ) solid dispersions prepared by either a conventional solvent evaporation versus a supercritical fluid process. Solid dispersions of carbamazepine in polyvinylpyrrolidone (PVP) K30 with either Gelucire 44/14 or Vitamin E TPGS, NF (d-alpha-tocopheryl polyethylene glycol 1000 succinate) were prepared and characterized by intrinsic dissolution, differential scanning calorimetry, powder X-ray diffraction and Fourier transform infrared spectroscopy. CBZ/PVP K30 and CBZ/PVP K30/TPGS solid dispersions showed increased dissolution rate. The best intrinsic dissolution rate (IDR) was obtained for supercritically processed CBZ/PVP K30 that was four-fold higher than pure CBZ. Thermograms of various solid dispersions did not show the melting peak of CBZ, indicating that CBZ was in amorphous form inside the carrier system. This was further confirmed by X-ray diffraction studies. Infrared spectroscopic studies showed interaction between CBZ and PVP K30 in solid dispersions. The amorphous state of CBZ coupled with presence of interaction between drug and PVP K30 suggests fewer, if any, stability problems. Because the supercritical-based process produced solid dispersions with IDR better than conventional solid dispersions augmented with amphiphilic carriers, stability issues associated with lipid carriers do not apply, which, in turn, implies easier scale up under current Good Manufacturing Practice for this technique.     

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.     

Preparation, dissolution and characterization of albendazole solid dispersions

In this study, solid dispersion systems of the sparingly water soluble drug, albendazole (ABZ), were mixed with varying concentrations of polyvinylpyrrolidone (PVP K 12) in an attempt to improve the solubility and dissolution rate of ABZ. Physical characteristics were investigated by Powder X-ray diffraction. As expected, the albendazole dissolution rate, expressed as the dissolution efficiency, and also the solubility coefficient were increased when albendazole was mixed with PVP. An increase in the concentration of the polymer in the solid dispersion produced an increase in both parameters. The powder X-ray diffraction patterns showed that the solid dispersion presented an amorphous form of albendazole in this coprecipitate system.     

阿瑞匹坦三元超饱和固体分散体的制备及性能考察

目的：为了提高难溶性药物阿瑞匹坦(Aprepitant,APR)的溶解度,解决其酸中溶出、碱中结晶沉淀的问题,选择不同功能的聚合物载体,采用热熔挤出技术制备三元固体分散体,并对其进行性能考察;方法：采用溶剂-熔融法制备二元固体分散体,以溶出度和溶出速度为指标,筛选具有增溶功能的载体材料。通过介质转移法考察各聚合物在不同浓度的药物溶液中的抑晶性能,筛选出最佳的沉淀抑制剂。确定药载比,将APR、溶出促进剂及沉淀抑制剂以不同比例混合,采用热熔挤出技术制备三元固体分散体,以溶出度和抑晶时间为指标,优选出三元固体分散体处方。经XRD确认药物在载体中的存在状态,考察该三元固体分散体在模拟肠液中的动态溶解度和加速条件下的物理稳定性。结果：亲水性聚合物PVP K30制备的二元固体分散体溶出速度快,增溶效果佳,肠溶性聚合物HPMCAS显示出优越的抑晶作用,延长了APR的过饱和点,质量比为1:1:3(APR:PVP K30:HPMCAS)的三元固体分散体在酸中迅速完全释放(120min溶出95%),相对于原料药显著提高了溶出度和溶出速率,当介质pH转为6.8后,三元固体分散体完全释放并在6h内维持溶液处于高过饱和的稳定状态,药物以无定形形式存在于载体基质中,同时能在加速条件下保持至少三个月的无定形状态。结论：基于不同聚合物的理化特性,本研究制备的三元固体分散体通过协调溶出速率和结晶抑制效果,不仅显著提高APR的溶解度,并能解决APR在胃中溶出、肠中沉淀析晶的问题,具有良好的溶出特性。     

Mechanisms of dissolution of frusemide/PVP solid dispersions

With a discriminating intrinsic dissolution apparatus the dissolution rates and profiles of frusemide-polyvinylpyrrolidone (PVP) mix and solid dispersion systems (10–100% w/w frusemide) have been examined together with scanning electron photomicrographs (SEM) of the dissolution surfaces of compressed discs before and after dissolution. Solid dispersion systems exhibited higher dissolution rates than corresponding mixes and untreated frusemide. The peak intrinsic dissolution rate, found for both mix and dispersion systems containing 40% w/w frusemide, was attributed to a balance of two opposing factors. In mix systems a dissolution-promoting effect of soluble complex formation with PVP is balanced by a viscosity-related retarding effect of increasing PVP content in the diffusion layer. In dispersion systems a large dissolution-promoting effect of the X-ray amorphous state of the drug at the 40% drug level produces a highly supersaturated diffusion layer demonstrated in time/solubility profiles which is also balanced by the increasing PVP content in the diffusion layer. These findings were further supported by the observed dependence of the dissolution rate on the molecular weight and related solution viscosity of the PVP used to form the X-ray amorphous solid dispersion and mechanical mix, in high polymer content systems. In addition, a filming effect over dissolved compact faces shown by SEM, when the drug level was 40% w/w or less was attributed to a PVP layer covering the dissolving face and the change from a crystalline drug-controlled dissolution mechanism to a polymer controlled system.     

Investigation of drug–polymer interaction in solid dispersions by vapour sorption methods

The objective of this study was to investigate the effect of different polymeric carriers in solid dispersions with an active pharmaceutical ingredient (API) on their water vapour sorption equilibria and the influence of the API–polymer interactions on the dissolution rate of the API. X-ray diffraction, scanning electron microscopy (SEM), moisture sorption analysis, infrared (IR) spectroscopy and dissolution tests were performed on various API–polymer systems (Valsartan as API with Soluplus, PVP and Eudragit polymers) after production of amorphous solid dispersions by spray drying. The interactions between the API and polymer molecules caused the water sorption isotherms of solid dispersions to deviate from those of ideal mixtures. The moisture sorption isotherms were lower in comparison with the isotherms of physical mixtures in all combinations with Soluplus and PVP. In contrast, the moisture sorption isotherms of solid dispersions containing Eudragit were significantly higher than the corresponding physical mixtures. The nature of the API–polymer interaction was explained by shifts in the characteristic bands of the IR spectra of the solid dispersions compared to the pure components. A correlation between the dissolution rate and the water sorption properties of the API–polymer systems has been established.     

The Influence of Drug Physical State on the Dissolution Enhancement of Solid Dispersions Prepared Via Hot-Melt Extrusion: A Case Study Using Olanzapine

In this study, we examine the relationship between the physical structure and dissolution behavior of olanzapine (OLZ) prepared via hot-melt extrusion in three polymers [polyvinylpyrrolidone (PVP) K30, polyvinylpyrrolidone-co-vinyl acetate (PVPVA) 6:4, and Soluplus® (SLP)]. In particular, we examine whether full amorphicity is necessary to achieve a favorable dissolution profile. Drug–polymer miscibility was estimated using melting point depression and Hansen solubility parameters. Solid dispersions were characterized using differential scanning calorimetry, X-ray powder diffraction, and scanning electron microscopy. All the polymers were found to be miscible with OLZ in a decreasing order of PVP>PVPVA>SLP. At a lower extrusion temperature (160°C), PVP generated fully amorphous dispersions with OLZ, whereas the formulations with PVPVA and SLP contained 14%–16% crystalline OLZ. Increasing the extrusion temperature to 180°C allowed the preparation of fully amorphous systems with PVPVA and SLP. Despite these differences, the dissolution rates of these preparations were comparable, with PVP showing a lower release rate despite being fully amorphous. These findings suggested that, at least in the particular case of OLZ, the absence of crystalline material may not be critical to the dissolution performance. We suggest alternative key factors determining dissolution, particularly the dissolution behavior of the polymers themselves. © 2014 The Authors. Journal of Pharmaceutical Sciences published by Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 103:1214–1223, 2014     

Characterization and stability of solid dispersions based on PEG/polymer blends

Solid dispersions were prepared by a melting method from the water-insoluble model drugs carbamazepine and nifedipine and polyethylene glycol 1500 (PEG 1500) or 1:1 mixtures of PEG 1500 and the polymers polyvinylpyrrolidone (PVP 30, PVP 12), polyvinylpyrrolidone-co-vinylacetate (PVPVA) and Eudragit EPO (Eudragit) in order to combine advantages of the different carrier polymers (recrystallization inhibition, processability and stability). The solid dispersions were characterized by dissolution, powder X-ray diffractometry and microscopy directly after preparation and after storage for 3 and 6 months at 25 °C/0% relative humidity (RH) or 3 months at 40 °C/75% RH. More than 80% drugs were released from all solid dispersions within 20 min. The dissolution rate of carbamazepine decreased in the order of PEG 1500 > PEG 1500/Eudragit > PEG 1500/PVP 30 > PEG 1500/PVPVA > PEG 1500/PVP 12. The dissolution rank order was not directly correlated to the amorphous/crystalline state of the drugs, but rather to the properties of the PEG 1500/polymer compositions. Nifedipine was released in the order of PEG 1500 > PEG 1500/PVPVA > PEG 1500/PVP 30 > PEG 1500/PVP 12 > PEG 1500/Eudragit. Amorphous nifedipine was present in all PEG 1500/polymer dispersions except in pure PEG 1500 solid dispersion. The significant increase in dissolution rate of PEG 1500 solid dispersions was due to the reduced crystallinity of the drug and the excellent solubilisation properties of PEG 1500. After 6 months storage at 25 °C/0% RH, the solid dispersions released both drugs in the order PEG 1500/PVPVA > PEG 1500/PVP 30 > PEG 1500/PVP 12 > PEG 1500/Eudragit > PEG 1500. The stabilized amorphous state of the drug resulted in stable dissolution profiles of PEG 1500/PVPVA, PEG 1500/PVP 30 and PEG 1500/PVP 12 when compared to the PEG 1500 solid dispersions, which contained a higher amount of crystalline drug. The solid dispersions with PEG 1500/PVPVA or PEG 1500/PVP stored for 3 months at 40 °C/75% RH showed phase separation due to the hygroscopic properties of the polymers. The influence of 10% (w/w) of the solubilisers polyoxyl 40 hydrogenated castor oil (Cremophor), macrogol-15-hydroxystearate (Solutol) and fatty alcohol alkoxylate (Pluronic) on the dissolution rate and the physical state of the drug was significant.     

阿司匹林固体分散体及其胶囊的制备与体外溶出度研究

目的:制备阿司匹林固体分散体及其胶囊,并研究其体外溶出度。方法:以聚乙烯吡咯烷酮为载体,采用喷雾干燥法制备阿司匹林固体分散体,比较阿司匹林原料药、阿司匹林与载体不同比例的物理混合物和固体分散体的溶出度;采用X-射线衍射和扫描电镜考察药物在载体中的分散状态,测定比表面积;考察阿司匹林固体分散体胶囊的体外溶出度。结果:与阿司匹林原料药、阿司匹林物理混合物比较,阿司匹林固体分散体中药物的溶出度均有提高,且载体比例越大,药物溶出越快,但药物-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;药物-载体在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。     

Intraorally fast-dissolving particles of a poorly soluble drug: Preparation and in vitro characterization

In this study, the dissolution rate of a poorly soluble drug, perphenazine (PPZ) was improved by a solid dispersion technique to permit its usage in intraoral formulations. Dissolution of PPZ (4 mg) in a small liquid volume (3 ml, pH 6.8) within one minute was set as the objective. PVP K30 and PEG 8000 were selected for carriers according to the solubility parameter approach and their 5/1, 1/5 and 1/20 mixtures with PPZ (PPZ/polymer w/w) were prepared by freeze-drying from 0.1 N HCl solutions. The dissolution rate of PPZ was improved with all drug/polymer mixture ratios compared to crystalline or micronized PPZ. A major dissolution rate improvement was seen with 1/5 PPZ/PEG formulation, i.e. PPZ was dissolved completely within one minute. SAXS, DSC and XRPD measurements indicated that solid solutions of amorphous PPZ in amorphous PVP or in partly amorphous PEG were formed. DSC and FTIR studies suggested that PPZ dihydrochloride salt was formed and hydrogen bonding was occurred between PPZ and the polymers. It was concluded that molecular mixing together with salt formation promoted the dissolution of PPZ, especially in the case of the 1/5 PPZ/PEG dispersion, making it a promising candidate for use in intraoral formulations.