Enhanced intestinal lymphatic absorption of saquinavir through supersaturated self-microemulsifying drug delivery systems

The therapeutic potential of saquinavir, a specific inhibitor of human immunodeficiency virus(HIV)-1 and HIV-2 protease enzymes, has been largely limited because of a low solubility and consequnt low bioavailability. Thus, we aimed to design a supersaturated selfmicroemulsifying drug delivery system(S-SMEDDS) that can maintain a high concentration of saquinavir in gastro-intestinal fluid thorugh inhibiting the drug precipitation to enhance the lymphatic transport of saquinavir and to increase the bioavailability of saquinavir considerably. Solubilizing capacity of different oils, surfactants, and cosurfactants for saquinavir was evaluated to select optimal ingredients for preparation of SMEDDS.Through the construction of pseudo-ternary phase diagram, SMEDDS formulations were established. A polymer as a precipitation inhibitor was selected based on its viscosity and drug precipitation inhibiting capacity. The S-SMEDDS and SMEDDS designed were administered at an equal dose to rats. At predetermined time points, levels of saquinavir in lymph collected from the rats were assessed. SMEDDS prepared presented a proper selfmicroemulsification efficiency and dispersion stability. The S-SMEDDS fabricated using the SMEDDS and hydroxypropyl methyl cellulose 2910 as a precipitation inhibitor exhibited a signficantly enhanced solubilizing capacity for saquinavir. The drug concentration in a simulated intestinal fluid evaluated with the S-SMEDDS was also maintained at higher levels for prolonged time than that examined with the SMEDDS. The S-SMEDDS showed a considerably enhanced lymphatic absoprtion of saquinavir in rats compared to the SMEDDS.Therefore, the S-SMEDDS would be usefully exploited to enhance the lymphatic absorption of hydrophobic drugs that need to be targeted to the lymphatic system.

Inhibitive Effect of Cremophor RH40 or Tween 80-based Self-microemulsiflying Drug Delivery System on Cytochrome P450 3A Enzymes in Murine Hepatocytes

This study examined the effect of self-microemulsiflying drug delivery system (SMEDDS) containing Cremophor RH40 or Tween 80 at various dilutions on cytochrome P450 3A (CYP3A) enzymes in rat hepatocytes, with midazolam serving as a CYP3A substrate.The particle size and zeta potential of microemulsions were evaluated upon dilution with aqueous medium.In vitro release was detected by a dialysis method in reverse.The effects of SMEDDS at different dilutions and surfactants at different concentrations on the metabolism of MDZ were investigated in murine hepatocytes.The cytotoxicity of SMEDDS at different dilutions was measured by LDH release and MTT technique.The effects of SMEDDS on the CYP3A enzymes activity were determined by Western blotting.Our results showed that dilution had less effect on the particle size and zeta potential in the range from 1:25 to 1:500.The MDZ was completely released in 10 h.A significant decrease in the formation of 1’-OH-MDZ in rat hepatocytes was observed after treatment with both SMEDDS at dilutions ranging from 1:50 to 1:250 and Cremophor RH 40 or Tween 80 at concentrations ranging from 0.1% to 1% (w/v), with no cytotoxicity observed.A significant decrease in CYP3A protein expression was observed in cells by Western blotting in the presence of either Cremophor RH40 or Tween 80-based SMEDDS at the dilutions ranging from 1:50 to 1:250.This study suggested that the excipient inhibitor-based formulation is a potential protective platform for decreasing metabolism of sensitive drugs that are CYP3A substrates.

In vitro and in vivo evaluation of a self-microemulsifying drug delivery system for silybin

To enhance the oral absorption of the poorly water-soluble drug silybin, a self-microemulsifying drug delivery system （SMEDDS） composed of ethyl linoleate, Cremophor EL and PEG 400 for oral administration of silybin was formulated, and its physicochemical properties and bioavailability of silybin were evaluated. The in vitro release of silybin from microemulsion and dispersion of silybin from SMEDDS were significantly faster than those from the commercial silybin hard capsule, respectively. The area under the drug concentration-time curve （AUC） and the mean maximum plasma level （Cmax） of the SMEDDS were remarkably greater than those of the hard capsule after oral administration to rats. The absorption of silybin formulated in SMEDDS exhibited a 2.3-fold increase in bioavailability as compared with the hard capsule. These results demonstrated that SMESDDS might be a useful drug delivery system for the oral delivery of the poorly water-soluble drug silybin.

Effect of mesopores on solidification of sirolimus self-microemulsifying drug delivery system

To investigate the influence of mesopores towards the solidification of self-microemulsifying drug delivery system(SMEDDS), mesoporous silica nanospheres(MSNs) and Santa Barbara Amorphous-15(SBA-15) were compared. The MSNs had hydrodynamic size of 195.35 ± 5.82 nm, and pore diameter of 2.70 nm. The SBA-15 had hydrodynamic size of 2312.19 ± 106.93 nm, and pore diameter of 10.91 nm. The MSNs and SBA-15 showed similar loading efficiency of SMEDDS containing sirolimus(SRL). However,MSNs had higher drug dissolution and in vivo absorption, with relative bioavailability of 174.62%. Thus,the length of mesopores played a more important role in solidification of SMEDDS as compared with the pore diameter. This study suggests that the SMEDDS-MSNs can be a potential candidate for oral administration of hydrophobic drugs.

过饱和自微乳释药系统的研究进展

过饱和自微乳是指在原有的自微乳处方中,加入过饱和促进剂而形成的一种释药系统。处于过饱和状态下的微乳,能明显抑制药物的结晶,延长药物的过饱和状态,从而增加药物的溶解度,降低原有自微乳处方中表面活性剂的用量。本文介绍了过饱和自微乳释药系统的处方组成、吸收机制,以及在药物制剂方面的应用。

尼莫地平过饱和自微乳的研制

目的制备尼莫地平过饱和自微乳化给药系统(NMP S-SMEDDS),并对其体外特性进行考察。方法以平均粒径、平均电位、乳化时间为评价指标,通过星点设计-效应面优化法优化自微乳化给药系统(SMEDDS)处方;以PVPK30为促饱和物质,制备NMP S-SMEDDS,并通过考察PVPK30用量对SSMEDDS体外溶出行为的影响,筛选PVPK30的适用量。结果 SMEDDS的最优处方为油酸乙酯∶吐温-80∶Transcutol P=17.25∶49.16∶44.76(质量比);以PVPK30质量分数为2%,尼莫地平质量分数为2.5%制备得到的NMP S-SMEDDS的粒径为(33.41±0.48)nm,Zeta电位为(-9.62±1.49)mV,60 min的体外溶出度达90.4%,比市售尼莫地平片的溶出度明显提高。结论 NMP S-SMEDDS可提高尼莫地平的体外溶出度。

紫杉醇超饱和自微乳化给药系统的制备及大鼠体内药动学研究

目的:制备紫杉醇超饱和自微乳化给药系统(supersaturatable self-microemulsifying drug delivery system,S-SMEDDS),并对其在大鼠体内的药动学进行研究。方法:采用伪三元相图的方法,优化紫杉醇自微乳化给药系统(SMEDDS)的处方。18只大鼠随机分为3组,分别灌胃给予10 mg/kg紫杉醇溶液、SMEDDS和S-SMEDDS,测定紫杉醇的血药浓度c、max、AUC和tmax,计算相对生物利用度。结果:确定紫杉醇SMEDDS最优处方为:油相∶表面活性剂∶助表面活性剂=50∶33∶17。油相为Lauroglycol FCC∶橄榄油(2∶1),表面活性剂为Cremophor EL∶吐温-80(1∶1),助表面活性剂为PEG-400。S-SMEDDS在此处方基础上添加5%羟丙基甲基纤维素。稀释对制剂的粒径无显著影响。SMEDDS和S-SMEDDS的粒径分别为(92.7±47.7)和(93.6±36.8)nm,粒径分布呈高斯分布。SMEDDS和S-SMEDDS的cmax和AUC显著高于溶液剂,tmax<溶液剂,生物利用度分别为333.9%和719.3%。结论:紫杉醇S-SMEDDS的口服吸收强于溶液剂和SMEDDS。

白藜芦醇过饱和自微乳的制备和溶出率研究

目的:研究白藜芦醇过饱和自微乳的处方组成,制备白藜芦醇过饱和自微乳。方法:通过测定白藜芦醇溶解度,以及伪三元相图的考察,筛选油相、乳化剂、助乳化剂和促过饱和物质,制备白藜芦醇自微乳;考察白藜芦醇过饱和自微乳与白藜芦醇原料药在0.1mol/L HCL溶液和p H6.8的磷酸盐缓冲液中溶出率。结果:筛选并优化出白藜芦醇过饱和自微乳的最佳处方为MCT:聚氧乙烯氢化蓖麻油:异丙醇=45:30:25,促过饱和物质的最优含量为1.5%。结论:该方法制备的白藜芦醇过饱和自微澄清、均一、稳定、溶出良好,提高了白藜芦醇的溶出率。

Enhancement of solubility and therapeutic potential of poorly soluble lovastatin by SMEDDS formulation adsorbed on directly compressed spray dried magnesium aluminometasilicate liquid loadable tablets: A study in diet induced hyperlipidemic rabbits

The aim of present study was to formulate and evaluate a self-microemulsifying drug delivery systems(SMEDDS)containing lovastatin and to further explore the ability of porous Neusilin■ US2 tablet as a solid carrier for SMEDDS.SMEDDS formulations of varying proportions of peceol,cremophor RH 40 and transcutol-P were selected and subjected to invitro evaluation,including dispersibility studies,droplet size,zeta potential measurement and release studies.The results indicated that the drug release profile of lovastatin from SMEDDS formulations was statistically significantly higher(p-value<0.05)than the plain lovastatin powder.Thermodynamic stability studies also confirmed the stability of the prepared SMEDDS formulations.The optimized formulation,which consists of 12% of peceol,44% of cremophor RH 40,and 44% of transcutol-P was loaded into directly compressed liquid loadable tablet of Neusilin■ US2 by simple adsorption method.In order to determine the ability of Neusilin®US2 as a suitable carrier pharmacodynamics study were also carried out in healthy diet induced hyperlipidemic rabbits.Animals were administered with both liquid SMEDDS and solid SMEDDS as well.From the results obtained,Neusilin■ was found to be a suitable carrier for SMEDDS and was equally effective in reducing the elevated lipid profile.In conclusion,liquid loadable tablet(LLT)is predicted to be a promising technique to deliver a liquid formulation in solid state.

自微乳释药系统研究进展

简要介绍了自微乳释药系统的组成、体外释药研究方法及自微乳新型制剂的研究进展。自微乳新型制剂主要包括固体自微乳、过饱和自微乳和正电荷自微乳,新型自微乳制剂可以弥补其不足,更好地发挥自微乳固有特点。

多西他赛固体过饱和自乳化释药系统的制备及体外特性

目的:制备多西他赛固体过饱和自乳化释药系统(DTX-S-sSEDDS),并对其体外特性进行评价。方法:比较了不同的多西他赛自乳化释药系统在理化性质和体外溶出度方面的差异。结果:采用2.5%羟丙基甲基纤维素(HPMC K100)为促过饱和物质,乳糖为固体载体,喷雾干燥法制备获得的多西他赛固体过饱和自乳化释药系统(DTX-S-sSEDDS1),与常规自乳化制剂(DTX-SEDDS2)相比,DTX-S-sSEDDS1处方中自乳化油辅料用量减少2/5,经水分散后的粒径(106.12nm)仍小于DTX-SEDDS2的粒径(119.84nm);水中2h累积溶出百分率(90.96%)显著大于DTX-SEDDS2(76.77%),是原料药(2.87%)的约32倍。结论:所制备的多西他赛固体过饱和自微乳化释药系统(DTX-S-sSEDDS)在减少自乳化辅料用量的同时,可大大提高药物DTX的溶解性和溶出度,为进一步研发安全性和稳定性好的多西他赛自乳化新制剂提供了理论和实验依据。

长春西汀固体过饱和自乳化释药系统的研制

目的:制备长春西汀(VIN)固体过饱和自乳化释药系统(VIN-S-sSEDDS),并对其体内、外特性进行研究。方法:以羟丙基甲基纤维素(HPMC)为促过饱和物质、右旋糖苷-40为固体载体,采用喷雾干燥法制备VIN-S-sSEDDS。以常规长春西汀自乳化释药系统(VIN-SEDDS)为对照,比较二者在粒径、体外溶出度和大鼠灌胃给药后体内生物利用度上的不同。结果:与VIN-SEDDS比较,VIN-S-sSEDDS粒径降低(65.12 nm vs.58.78 nm)、累积溶出百分率(2 h)增加(58.2%vs.88.7%)、大鼠体内相对生物利用度增加(1.63 vs.2.30)。结论:所制备的VIN-S-sSEDDS可提高VIN的溶出度和生物利用度,比常规自乳化制剂更具有优势。

依托泊苷过饱和自微乳化释药系统的制备工艺及质量评价研究

目的制备依托泊苷(etoposide,VP-16)过饱和自微乳化释药系统(supersaturatable self-microemulsifying drug delivery system,S-SMEDDS),增加难溶性药物VP-16的溶解度,并对其进行质量评价,为提高其生物利用度提供科学依据。方法对VP-16 S-SMEDDS的处方及制备工艺进行研究,从不同油相、表面活性剂的配伍情况以及不同助表面活性剂伪三元相图中微乳区域的大小,确定自微乳化浓缩液的基本处方组成;以VP-16的溶解度和析晶情况为考察指标进行处方优化,筛选适宜的促过饱和物质和最佳处方载药量;进行VP-16 S-SMEDDS的制备工艺研究,以自微乳化速率为指标,考察制备工艺对过饱和自微乳液自乳化能力的影响,并对VP-16 S-SMEDDS进行理化性质、溶出度、稳定性的考察。结果确定最优处方为聚氧乙烯氢化蓖麻油(RH40)-聚乙二醇400(PEG 400)-辛酸葵酸三甘油酯(GTCC)-聚乙烯吡咯烷酮K30(PVP K30)(20∶20∶10∶1),其中药物用量为2%。最佳工艺条件为37℃,20 r/min磁力搅拌20 min。VP-16 S-SMEDDS的平均粒径为(82.7±3.3)nm,粒径分布较集中,3批VP-16 S-SMEDDS中VP-16的平均质量分数为19.98 mg/g;溶出实验结果表明,在60 min时累积溶出率接近100%。稳定性研究的结果表明,高温与光照均影响VP-16 S-SMEDDS的稳定性与自微乳化能力,而冷热循环对其无影响,初步稳定性实验结果显示VP-16 S-SMEDDS的稳定性良好。结论优化处方的VP-16 S-SMEDDS能显著增加VP-16的溶解度,且质量稳定,可进一步提高VP-16的生物利用度。