Dual agents loaded PLGA nanoparticles: Systematic study of particle size and drug entrapment efficiency

PLGA nanoparticles simultaneously loaded with vincristine sulfate (VCR) and quercetin (QC) were prepared via O/W emulsion solvent evaporation. Six independent processing parameters and PLGA characteristics were assessed systematically to enhance the incorporation of the dual agents with different properties (VCR and QC, hydrophilic and hydrophobic molecule, respectively) into PLGA nanoparticles and control particle size. Approaches investigated for the enhancement of drug entrapment efficiencies and the controlling of particle size included the influence of the molecular weight (MW) of PLGA and the lactide-to-glycolide (L:G) ratio of PLGA, PLGA concentration, PVA concentration, initial QC content, acetone-to-dichloromethane (A/D) volume ratio, aqueous phase pH and aqueous to organic phase (W/O) volume ratio. The nanoparticles produced by optimal formulation were submicron size (139.5+/-4.3 nm, n=3) with low polydispersity index (0.095+/-0.031, n=3). Nanoparticles observed by transmission electron microscopy (TEM) showed extremely spherical shape. The entrapment efficiencies determined by high performance liquid chromatography (HPLC) by ultracentrifuge method were 92.84+/-3.37% for VCR and 32.66+/-2.92% for QC (n=3). The drug loadings were 0.0037+/-0.0001% for VCR and 1.36+/-0.12% for QC (n=3).     

重组Exendin-4固体脂质纳米粒包封率的测定

目的 测定重组exendin-4固体脂质纳米粒(rE4-SLN)的包封率.方法 通过改变rE4-SLN水溶液的pH值、调节Zeta电位后,采用低温高速离心法分离游离rE4与rE4-SLN,采用HPLC法测定rE4-SLN的包封率.结果 rE4 2.48 ～ 99.2μg·mL-1与峰面积的线性关系良好(r=0.9999),平均回收率为100.6％,RSD=1.3％ (n =9).结论 所用方法简便、灵敏、准确,可用于rE4-SLN包封率的测定.     

盐酸氟桂利嗪固体脂质纳米粒包封率的测定

目的建立盐酸氟桂利嗪固体脂质纳米粒包封率的测定方法。方法分别采用透析法、离心法和葡聚糖凝胶法分离盐酸氟桂利嗪固体脂质纳米粒和游离药物,并计算盐酸氟桂利嗪固体脂质纳米粒的包封率。结果透析法包封率的测定结果为76．42％,RSD值为1．75％;离心法包封率为46．37％,RSD值为3．26％;葡聚糖凝胶法包封率为79．2％,RSD值为1．61％。结论通过比较三种方法的优缺点,葡聚糖凝胶法作为盐酸氟桂利嗪固体脂质纳米粒的包封率测定方法最为合适。     

左旋多巴固体脂质纳米粒的制备及包封率测定

目的:用微乳法制备左旋多巴固体脂质纳米粒(LDP-SLN),并建立包封率的测定方法。方法:通过绘制三元相图,采用微乳法制备LDP-SLN,用TEM和激光粒度仪进行了颗粒形貌和粒径分布的研究,用葡聚糖凝胶层析法分离测定包封率。对其粒径、形态、包封率等理化性质进行研究,并考察其稳定性。结果:实验制得LDP-SLN为稳定的略泛蓝色乳光的纳米混悬液,在透射电镜下显示为较为均匀的球体,激光粒度测定平均粒径为108nm,多分散系数1.153;4℃放置2个月,粒径、包封率无显著变化。包封率测定的线性范围为2～100mg·mL-1,线性良好(r=0.9999),精密度符合要求,LDP-SLN上柱洗脱后分离度和回收率均符合要求。结论:该研究中制备了物理性质较为稳定的LDP-SLN,建立了合适的包封率测定方法,并考查初步稳定性较好。     

HPLC法测定葛根总黄酮固体脂质纳米粒的载药量及包封率

目的：建立HPLC法同时测定葛根总黄酮固体脂质纳米粒中4种异黄酮类成分的包封率及载药量。方法采用RP-HPLC法,Kromasil C18（4.6mm ×250mm,5μm）色谱柱;甲醇-0.1%枸橼酸溶液为流动相梯度洗脱;流速1.0mL/min,柱温40℃,检测波长250nm。采用高速离心法分离固体脂质纳米粒中游离药物。结果3-羟基葛根素、葛根素、大豆苷和大豆苷元线性关系良好,平均回收率分别为（100.28±2.52）%、（100.26±2.33）%、（100.08±3.35）%及（100.44±3.48）%。3批次葛根总黄酮固体脂质纳米粒中3＇-羟基葛根素、葛根素、大豆苷和大豆苷元的包封率分别为（84.35±0.45）%、（86.84±0.48）%、（89.52±0.86）%及（93.80±0.50）%,其载药量分别为（10.37±0.36）%、（14.19±0.52）%、（16.79±0.34）%及（20.00±0.97）%。结论本法简单快速、结果准确可靠,可同时测定葛根总黄酮固体脂质纳米粒4种成分的载药量与包封率。     

Study of solid lipid nanoparticles with respect to particle size distribution and drug loading

This work deals with the formulation and development of Solid Lipid Nanoparticles (SLN) using pressure homogenization technique, nimesulide being used as the model drug. Main emphasis of the work was to study the effect of individual process parameters (homogenization pressure and homogenization cycles) and formulation parameters (lipid concentration and surfactant concentration) on particle size distribution and drug loading. Particle size distribution data indicate that by optimizing the homogenization process and formulation parameters it is possible to produce SLN within a desired size range as required for carrier mediated drug targeting. Approaches to improve drug loading efficiency indicate that drug loading was higher in case of SLN prepared from glyceryl beheanate, palmitostearate and glyceryl tristearate + span 60 as compared to monoacid triglyceride (MAT) tristearate. Thermal analysis by differential scanning calorimetry of the drug loaded SLN indicates the solid nature of the lipid carrier as required for sustained drug release.     

PLGA nanoparticles simultaneously loaded with vincristine sulfate and verapamil hydrochloride: systematic study of particle size and drug entrapment efficiency

PLGA nanoparticles simultaneously loaded with vincristine sulfate (VCR) and verapamil hydrochloride (VRP) were prepared via combining O/W emulsion solvent evaporation and salting-out method. Ten independent processing parameters and two materials characteristics were assessed systematically to enhance the incorporation of the two hydrophilic low molecular weight drugs into PLGA nanoparticles and minimize nanoparticles size. Approaches investigated for the enhancement of drug entrapment efficiencies and the minimization of particle size included the influence of the molecular weight (MW) of PLGA and the lactide to glycolide (L:G) ratio of PLGA, PLGA concentration, the degrees of hydrolyzation and polymerization of PVA, PVA concentration, initial VCR and VRP content, acetone to dichloromethane volume ratio, aqueous phase pH, salt concentration of aqueous phase, aqueous to organic phase volume ratio, sonication time, sonication energy and removal rate of organic solvents. The nanoparticles produced by optimal formulation were submicron size (111.4 ± 2.35 nm, n = 3) and of low polydispersity (0.062 ± 0.023, n = 3). Nanoparticles observed by transmission electron microscopy (TEM) showed extremely spherical shape. The entrapment efficiencies determined with high performance liquid chromatogram (HPLC) by ultracentrifuge method were 55.35 ± 4.22% for VCR and 69.47 ± 5.34% for VRP, respectively (n = 3).     

Effect of particle size on oral bioavailability of darunavir-loaded solid lipid nanoparticles

The present investigation aimed to study the effect of particle size of solid lipid nanoparticles (SLNs) on oral bioavailability of darunavir. High pressure homogenisation technique was used to prepare SLNs. Three different sized SLNs loaded with darunavir were developed with mean particle sizes of around 100?nm, 200?nm and 500?nm, respectively. The in vivo pharmacokinetics in rats showed a significant increase in oral bioavailability of darunavir from all the three formulations in comparison to plain drug suspension and reference tablet. The results revealed insignificant difference between SLNs of 100 and 200?nm and these had significantly higher bioavailability in comparison to SLNs of 500?nm. However, more number of homogenisation cycles is required for obtaining 100?nm and thus we selected 200?nm as an optimum size for oral bioavailability enhancement of darunavir. The optimised SLN formulation was stable for a period of 6 months at 25?±?2?°C/60?±?5% relative humidity (RH).     

氢溴酸高乌甲素固体脂质纳米粒包封率的测定方法

目的:建立氢溴酸高乌甲素固体脂质纳米粒(LH-SLN)的包封率测定方法。方法:采用高压乳匀法制备LH-SLN,分别用透析法、超滤法分离固体脂质纳米粒和游离药物;采用HPLC法测定药物含量,并对这2种方法进行方法学考察,优选出准确度高的包封率测定方法。结果:超滤法能有效地将LH-SLN与游离药物分离。在所选色谱条件下,氢溴酸高乌甲素得到良好分离,辅料不干扰测定,氢溴酸高乌甲素在10.0~120.0mg.L-1内线性关系良好(r=0.999 9)。用此方法测定3批LH-SLN的平均包封率为53.65%,RSD为0.97%。结论:超滤法方便快捷,结果准确,更适用于LH-SLN的包封率测定。     

壳聚糖纳米粒作为基因载体的研究:粒径对转染效率的影响

研究粒径对壳聚糖(chitosan，CS)纳米粒介导的转染效率的影响。通过调整CS溶液加入质粒基因(plasmid DNA，pDNA)溶液的速度和涡旋时间制备250，580和1 300 nm粒径pDNA/CS纳米粒，研究粒径对CS介导的细胞转染效率的影响。为深入探讨粒径对转染效率的影响，考察了3种粒径pDNA/CS纳米粒的药剂学性质，对抗核酸酶作用和细胞对纳米粒的吸附和摄取行为。结果表明：本文制备的3种粒径纳米粒的药剂学性质和凝聚pDNA的能力等特性基本无差别，均能有效保护pDNA免受核酸酶降解；在HEK293细胞中的转染效率无显著差异；与细胞共孵育4 h，流式细胞仪测定的三者细胞摄取率与摄取量相似；荧光显微图像显示3种粒径纳米粒均以小聚集体形式吸附于细胞表面，激光扫描共聚焦显微图像显示直径约为2 μm小聚集体较易被细胞内吞入胞。因此粒径在250～1 300 nm中对壳聚糖纳米粒介导的细胞转染率基本无影响。     

RP—HPLC法测定醋柳黄酮固体脂质纳米粒的含量及包封率

目的:建立 HPLC 法测定醋柳黄酮固体脂质纳米粒(TFH-SLN)含量及包封率的方法。方法:采用 Diamonsil~(TM)(钻石)ODS 柱(4.6 mm×250 mm,5 μm);流动相为甲醇-0.02 mol·L~(-1)磷酸溶液(52∶48);柱温35℃;流速为0.8 mL·min~(-1);紫外检测波长为370 nm;采用超速离心法分离测定 TFH-SLN 中的游离药物。结果:在本色谱条件下醋柳黄酮中异鼠李素和槲皮素与辅料及溶剂峰能够达到有效分离,异鼠李素及槲皮素均在16～56μg·mL~(-1)范围内线性关系良好,相关系数分别为0.9992及0.9994(n=5),回收率在98.0%～102.0%之间。结论:测定方法简便、准确、可靠,灵敏度高,可作为质量控制方法。     

Impact of particle size and pH on protein corona formation of solid lipid nanoparticles: A proof-of-concept study

When nanoparticles were introduced into the biological media, the protein corona would be formed, which endowed the nanoparticles with new bio-identities. Thus, controlling protein corona formation is critical to in vivo therapeutic effect. Controlling the particle size is the most feasible method during design, and the influence of media pH which varies with disease condition is quite important. The impact of particle size and pH on bovine serum albumin (BSA) corona formation of solid lipid nanoparticles (SLNs) was studied here. The BSA corona formation of SLNs with increasing particle size (120–480 nm) in pH 6.0 and 7.4 was investigated. Multiple techniques were employed for visualization study, conformational structure study and mechanism study, etc. “BSA corona-caused aggregation” of SLN2‒3 was revealed in pH 6.0 while the dispersed state of SLNs was maintained in pH 7.4, which significantly affected the secondary structure of BSA and cell uptake of SLNs. The main interaction was driven by van der Waals force plus hydrogen bonding in pH 7.4, while by electrostatic attraction in pH 6.0, and size-dependent adsorption was confirmed. This study provides a systematic insight to the understanding of protein corona formation of SLNs.KEY WORDS: Protein corona, Solid lipid nanoparticles, BSA corona-Caused aggregation, Nanoparticle-protein interaction, Size effect, Cell uptake, Medium pH, Conformational structure     

Haloperidol-loaded PLGA nanoparticles: systematic study of particle size and drug content

We have produced haloperidol-loaded PLGA/PLA nanoparticles by using two emulsification-solvent evaporation methods: homogenization and sonication. We have established how five independent processing parameters and two materials characteristics control the particle size and drug content. The interdependencies between processing and materials parameters and the subsequent nanoparticle characteristics are discussed in terms of underlying scientific principles that are broadly applicable to the production of drug-loaded polymer nanoparticles. This level of understanding should quicken the pace of designing protocols for making new drug-PLGA nanoparticles. It was determined that the particle size of haloperidol-loaded PLGA/PLA nanoparticles is effectively controlled by the amount of shear stress transferred from the energy source to the organic phase, which is strongly correlated to the following parameters: type of applied energy, aqueous phase volume, and polymer concentration in the organic solvent. The drug content of these nanoparticles is controlled by reducing the diffusion of the drug from the organic to the aqueous phase during the solvent evaporation stage of the preparation and by increasing the drug-polymer interactions. The following significantly inhibit drug diffusion: large particle size, higher polymer concentration and polymer molecular weight, and reducing the drug solubility in the aqueous phase by adjusting the pH. Specific drug-polymer interactions are engineered by optimizing the lactide to glycolide ratio (L:G ratio) and including specific polymer end groups. When optimized, the drug-loaded PLGA/PLA nanoparticles contain as much as 2.5% haloperidol.     

胰岛素固体脂质纳米粒的制备及其包封率的测定

目的 制备胰岛素固体脂质纳米粒(Ins-SLNs),考察其理化性质,并建立测定包封率的方法.方法 通过复乳/溶剂扩散法制备Ins-SLNs,考察其形态、粒径分布、Zeta电位;通过改变pH,调节Zeta电位后,采用冷冻高速离心分离纳米粒与游离Ins的方法,测定Ins-SLNs的包封率.结果 复乳法制备的Ins-SLNs在扫描电镜下均呈球形,分布均匀,平均粒径为114.7±4.68 nm,Zeta电位为-54.36±2.04 mV;包封率测定方法的线性范围为1.047～100.47μg·ml-1,平均回收率为98.37%,RSD=1.02%;测得3批Ins-SLNs样品的平均包封率为97.78%.结论 所用制备工艺简单,制得的纳米粒包封率较高;包封率的测定方法方便、灵敏、准确.     

固体脂质纳米粒和纳米结构脂质载体在药物传递中的研究进展

基于固体脂质的纳米粒（Solid lipid - based nanoparticles,SLBNs）作为新型药物传递系统比常规的药物传递系统存在优势。通常,基于固体脂质的纳米粒可以分成两种形态,即固体脂质纳米粒（ Solid lipid nanoparticles, SLNs）和纳米结构脂质载体（Nanostructured lipid carriers,NLCs）。但固体脂质纳米粒与纳米结构脂质载体在基质的组成上不同,本文就基于固体脂质的纳米粒的制备技术、表征方法及应用的最新研究进展进行总结,为基于固体脂质的纳米粒进一步研究提供参考依据。     

奥沙利铂纳米结构脂质载体中主药含量及包封率测定

目的:建立奥沙利铂纳米结构脂质载体(oxaliplatin-loaded nanostuctured lipid carriers,OP-NLC)包封率和含量的测定方法。方法:分别采用葡聚糖凝胶色谱法和超滤法分离OP-NLC中游离药物,高效液相色谱法测定包封率及药物含量。结果:超滤法测得药物包封率略高于葡聚糖凝胶色谱法,平均药物回收率和平均加样回收率分别为(99.3±0.6)%和(99.1±2.2)%。OP-NLC平均包封率为(74.2±1.8)%,药物含量为(0.76±0.03)mg·mL-1。结论:超滤法操作简便、准确,可以用于OP-NLC含量和包封率的测定。     

Characterization of new topical ketoprofen formulations prepared by drug entrapment in solid lipid matrices

This paper describes the evaluation of a new pharmaceutical formulation based on ketoprofen entrapment in a solid lipid particle (SLP) matrix. The drug-SLP samples, which were elaborated using a processing technology based on supercritical CO(2) , consisted of a model of a controlled-release system for topical applications. Some of the samples contained silanized TiO(2) as an additional ingredient to increase the interaction between drug and lipid matrix. The study of the sample features relied on reversed-phase high-performance liquid chromatography with a C(18) column and ultraviolet spectroscopic detection at 266 nm. Characterization assays comprised the determination of the overall amount of ketoprofen in the samples, the assessment of the release-permeation kinetic profiles, and the evaluation of impurities and decomposition products. The release and permeation of encapsulated ketoprofen were assayed at 32°C and pH 6.8 by using a static diffusion cell. Results showed a sustained drug delivery for at least 24 h. Besides, no degradation species were detected throughout the release-permeation processes, which indicated that the stability of the drug in the SLP system was preserved.     

聚结过滤法测定β-榄香烯固体脂质纳米粒的包封率

目的建立聚结过滤法测定β-榄香烯固体脂质纳米粒(SLN)的包封率。方法先以体积分数为36%的乙醇水溶液溶解SLN制剂中的游离药物,然后用氯化钠水溶液聚结SLN并过微孔滤膜,以HPLC法测定滤液中β-榄香烯含量,计算包封率。结果该方法可将游离药物与SLN分开,平均回收率为97.4%,测得的β-榄香烯SLN的包封率为96.0%。结论使用聚结过滤法可准确、快速地分离出游离β-榄香烯,可用于该制剂包封率的测定。     

黄芩素固体脂质纳米粒包封率测定及体外释放度考察

目的测定黄芩素固体脂质纳米粒的包封率,并考察其体外释放规律。方法溶剂扩散法制备脂质纳米粒,高速离心法分离纳米粒和游离药物,HPLC法测定包封率并考察其体外释放规律。结果测得纳米粒的平均包封率为60.73%,其体外释放规律符合H iguch i动力学方程。结论黄芩素固体脂质纳米粒有较高的包封率,在体外具有良好的缓释作用。