自乳化释药系统的体外评价

目的 探讨自乳化释药系统的体外评价方法。方法 通过测定自乳化时间、乳化后乳剂粒径的大小及模型药物的体外溶出行为对自乳化释药系统进行体外评价。结果 优选出的自乳化处方10min内已基本乳化完全，乳化后乳剂粒子大小大多数在3μm左右，以吲哚美辛和尼莫地平为模型药物制备出自乳化释药系统，体外溶出结果表明：与混悬液相比，两种药物的体外溶出显提高。结论 自乳化释药系统能够提高难溶性药物的体外溶出。     

维生素E烟酸酯自乳化制剂处方研究

目的研究维生素E烟酸酯(简称VEN)自乳化制剂,探求其最佳处方配比。方法通过溶解度实验、正交筛选和假三角相图的绘制,以形成自乳化区域的大小、溶出度和所得乳滴粒径的大小为指标,对VEN自乳化制剂中的油相、乳化剂及助乳化剂的组成、用量进行筛选,找出最佳的搭配和处方配比。结果在VEN自乳化制剂处方中,以油酸乙酯为油相,聚氧乙烯蓖麻油(EL20)为乳化剂,乙二醇单乙基醚(transcutol)为助乳化剂时,可以获得较好的乳化效果。结论VEN自乳化制剂的最佳处方比例为m(VEN)∶m(油酸乙酯)∶m(EL20)∶m(transcuto1)=1∶0.75∶1.35∶0.9。     

In vitro and in vivo correlation for lipid-based formulations: Current status and future perspectives

Lipid-based formulations (LBFs) have demonstrated a great potential in enhancing the oral absorption of poorly water-soluble drugs. However, construction of in vitro and in vivo correlations (IVIVCs) for LBFs is quite challenging, owing to a complex in vivo processing of these formulations. In this paper, we start with a brief introduction on the gastrointestinal digestion of lipid/LBFs and its relation to enhanced oral drug absorption; based on the concept of IVIVCs, the current status of in vitro models to establish IVIVCs for LBFs is reviewed, while future perspectives in this field are discussed. In vitro tests, which facilitate the understanding and prediction of the in vivo performance of solid dosage forms, frequently fail to mimic the in vivo processing of LBFs, leading to inconsistent results. In vitro digestion models, which more closely simulate gastrointestinal physiology, are a more promising option. Despite some successes in IVIVC modeling, the accuracy and consistency of these models are yet to be validated, particularly for human data. A reliable IVIVC model can not only reduce the risk, time, and cost of formulation development but can also contribute to the formulation design and optimization, thus promoting the clinical translation of LBFs.     

Quantitative Prediction of Oral Bioavailability of a Lipophilic Antineoplastic Drug Bexarotene Administered in Lipidic Formulation Using a Combined In Vitro Lipolysis/Microsomal Metabolism Approach

For performance assessment of the lipid-based drug delivery systems (LBDDSs), in vitro lipolysis is commonly applied because traditional dissolution tests do not reflect the complicated in vivo micellar formation and solubilization processes. Much of previous research on in vitro lipolysis has mostly focused on rank-ordering formulations for their predicted performances. In this study, we have incorporated in vitro lipolysis with microsomal stability to quantitatively predict the oral bioavailability of a lipophilic antineoplastic drug bexarotene (BEX) administered in LBDDS. Two types of LBDDS were applied: lipid solution and lipid suspension. The predicted oral bioavailability values of BEX from linking in vitro lipolysis with microsomal stability for lipid solution and lipid suspension were 34.2 ± 1.6% and 36.2 ± 2.6%, respectively, whereas the in vivo oral bioavailability of BEX was tested as 31.5 ± 13.4% and 31.4 ± 5.2%, respectively. The predicted oral bioavailability corresponded well with the oral bioavailability for both formulations, demonstrating that the combination of in vitro lipolysis and microsomal stability can quantitatively predict oral bioavailability of BEX. In vivo intestinal lymphatic uptake was also assessed for the formulations and resulted in <1% of the dose, which confirmed that liver microsomal stability was necessary for correct prediction of the bioavailability.     

Pharmacokinetic aspects and in vitro–in vivo correlation potential for lipid-based formulations

Lipid-based formulations have been an attractive choice among novel drug delivery systems for enhancing the solubility and bioavailability of poorly soluble drugs due to their ability to keep the drug in solubilized state in the gastrointestinal tract. These formulations offer multiple advantages such as reduction in food effect and inter-individual variability, ease of preparation, and the possibility of manufacturing using common excipients available in the market. Despite these advantages, very few products are available in the present market, perhaps due to limited knowledge in the in vitro tests (for prediction of in vivo fate) and lack of understanding of the mechanisms behind pharmacokinetic and biopharmaceutical aspects of lipid formulations after oral administration. The current review aims to provide a detailed understanding of the in vivo processing steps involved after oral administration of lipid formulations, their pharmacokinetic aspects and in vitro in vivo correlation (IVIVC) perspectives. Various pharmacokinetic and biopharmaceutical aspects such as formulation dispersion and lipid digestion, bioavailability enhancement mechanisms, impact of excipients on efflux transporters, and lymphatic transport are discussed with examples. In addition, various IVIVC approaches towards predicting in vivo data from in vitro dispersion/precipitation, in vitro lipolysis and ex vivo permeation studies are also discussed in detail with help of case studies.KEY WORDS: Pharmacokinetics, Lipolysis, IVIVC, Efflux transporters, Lymphatic delivery, Food effectAbbreviations: ADME, absorption/distribution/metabolism/elimination; AUC, area under the curve; BCS, biopharmaceutics classification system; BDDCS, biopharmaceutics drug disposition classification system; CACO, human epithelial colorectal adenocarcinoma cells; C_max, maximum plasma concentration; CMC, critical micellar concentration; CYP, cytochrome; DDS, drug delivery systems; FaSSGF, fasted-state simulated gastric fluid; FaSSIF, fasted-state simulated intestinal fluid; FeSSIF, fed-state simulated intestinal fluid; GIT, gastrointestinal tract; IVIVC, in vitro in vivo correlation; LCT, long chain triglyceride; LFCS, lipid formulation classification system; log P, n-octanol/water partition coefficient; MCT, medium chain triglyceride; MDCK, Madin–Darby canine kidney cells; NCE, new chemical entity; P-app, apparent permeability; P-gp, permeability glycoprotein; SCT, short chain triglyceride; SEDDS, self-emulsifying drug delivery system; SIF, simulated intestinal fluid; SMEDDS, self-microemulsifying drug delivery system; SNEDDS, self-nanoemulsifying drug delivery system; Vit E, vitamin E     

HPLC法测定比格犬血浆中的辛伐他汀及辛伐他汀羟基酸

目的:建立血浆中辛伐他汀及其主要代谢活性成分辛伐他汀羟基酸的含量测定方法。方法:以洛伐他汀为内标物质,流动相采用甲醇-水-冰醋酸(74:26:0.5),检测波长为238nm,流速为1.0mL·min~(-1)。血浆样品采用乙腈沉淀蛋白处理。并测定了10只比格犬单剂量口服辛伐他汀自乳化胶囊和市售片后的血药浓度。结果:血浆中内源性物质对辛伐他汀及辛伐他汀羟基酸的测定无干扰;最低检出限辛伐他汀为0.5ng·mL~(-1),辛伐他汀羟基酸为0.75ng·mL~(-1);辛伐他汀羟基酸在2～100ng·mL~(-1)浓度范围内线性关系良好,r=0.9989,辛伐他汀在1～50ng·mL~(-1)浓度范围内线性关系良好,r=0.9993;绝对回收率为79.68%～95.3%,方法回收率为89.1%～95.3%;日内精密度 RSD≤2.9%、日间精密度 RSD≤4.6%。结论:本方法处理简单,无干扰,灵敏度高,适合测定生物样本中的辛伐他汀及辛伐他汀羟基酸。     

辛伐他汀自乳化胶囊的体内外评价

目的研究辛伐他汀自乳化胶囊的自乳化能力及在Beagle犬体内的药动学.方法以总体液平衡反向透析法考察自乳化胶囊与市售片的体外释药过程;通过测定不同时间的粒子的散射光强度来评价自乳化速度,光学显微镜下考察乳化后形成的乳滴的大小和分布;采用HPLC法测定Beagle犬血浆药物浓度,并与市售片比较考察自乳化胶囊的体内药动学.结果溶出度结果显示辛伐他汀自乳化胶囊比市售片溶出快、浓度高.辛伐他汀自乳化胶囊在10 min内已基本乳化完全,光学显微镜下检视,乳化后乳滴粒子大多数在2μm以下.药动学测定结果表明与市售片比较,自乳化胶囊血药浓度达峰时间提前[Tmax(1.62±0.15)vs(2.65±0.42)h,P＜0.05],最高血药浓度增大[Cmax(44.28±6.29)vs(12.43±2.51)ng·mL-1,P＜0.05],相对生物利用度为市售片剂的216.8%.结论自乳化胶囊可以显著提高辛伐他汀的体外溶出和体内吸收.     

自乳化微乳对9-硝基喜树碱内酯型的保护效应

 目的制备9-硝基喜树碱(9-nitrocamptothecin,9-NC)自乳化微乳(自微乳),并考察其对9-NC内酯型的体内外保护效应。方法以油酸乙酯为油相,Cremophor EL或Tween 80为乳化剂,PEG-400和无水乙醇为助乳化剂,制得2种9-NC自微乳。以9-NC溶液剂为对照,考察自微乳对9-NC内酯型结构的体内外保护效应。结果分别以Cremophor EL和Tween 80为乳化剂的自乳化油(油相-乳化剂-助乳化剂=20∶40∶40)在稀释倍数为20倍的水相中均可自发形成O/W型微乳液(9-NCME-C或9-NCME-T),粒径分别为(30.2±4.6)和(21.8±4.2)nm,Zeta电位分别为-(2.9±0.7)和-(8.1±0.9)mV,且具有良好的物理稳定性。与溶液剂(9-NCSol)相比,微乳能显著降低内酯型水解开环转变为羧酸盐型的速度,有利于提高体内9-NC活性结构(内酯型)的比例。大鼠静脉注射微乳(9-NCME-C和9-NCME-T)和溶液剂(9-NCSol)后血浆中内酯型9-NC的AUC_0-∞分别为23072.24,20676.33和8954.97μg·min·L_-1。结论自微乳对9-NC内酯型具有显著的体内外保护效应。     

伊曲康唑自乳化释药系统的处方研究

 目的研究伊曲康唑自乳化给药系统(ITZ-SEDDS)的处方工艺。方法通过溶解度实验?处方配伍和伪三相图的绘制,以自乳化时间?色泽和粒径的大小为指标,筛选油相、表面活性剂、助表面活性剂的最佳搭配和处方配比。并对ITZ-SEDDS的理化性质和体外溶出度进行了测定。结果伊曲康唑自乳化最终优化处方为:Maisine 35-1-Cremophor EL-Transcutol P=25∶30∶45。ITZ-SEDDS的粒径为162.5 nm,自乳化时间<1 min,ITZ-SEDDS在人工肠液中2 h累积溶出百分率为90.9%,是原药(0.52%)的174.8倍,市售胶囊(10.1%)的9.0倍。结论所制备的ITZ-SEDDS达到了设计要求,为ITZ的新制剂开发提供了实验依据。     

自乳化制剂的研究进展

本文综述了近年来自微乳化给药系统(SMEDDS)的研究进展,对自微乳化给药系统的处方优化、质量评价和新型表面活性剂的使用进行了探讨,并对自乳化制剂(SEDDS)在中药新制剂的形成与实际应用进行了展望。