In vivo and in vitro anti-cancer activity of thermo-sensitive and photo-crosslinkable doxorubicin hydrogels composed of chitosan–doxorubicin conjugates

Doxorubicin was chemically conjugated to acrylated chitosan in order to obtain sustained-release profiles of doxorubicin from thermo-responsive and photo-crosslinkable hydrogels. Chitooligosaccharide was acrylated with glycidyl methacrylate and subsequently conjugated to doxorubicin via an amide linkage. A mixture of doxorubicin–chitosan conjugates, acrylated Pluronic, and doxorubicin formed physical gels at 37 °C. Photo-irradiation was subsequently performed to chemically crosslink the physical hydrogel at 37 °C. Chitooligosaccharide–doxorubicin conjugates in the doxorubicin hydrogels significantly reduced burst release of free doxorubicin from doxorubicin hydrogels compared hydrogels without the conjugates. Upon incubating doxorubicin hydrogels at 37 °C, chitosan–doxorubicin conjugates were confirmed to be degraded into more hydrophilic oligomers by reversed-phase chromatography. In vitro cytotoxicity assay using released media from doxorubicin hydrogels showed that degraded chitosan–doxorubicin had cytotoxicity comparable to free doxorubicin. Athymic nude mice bearing human lung adenocarcinoma were subjected to intra-tumoral injections of physical hydrogels. After photo-crosslinking injected hydrogels using surgical catheters, tumor sizes, body weights, and survivals were measured for 1 month. Released media from doxorubicin hydrogels exerted similar cytotoxicities to free doxorubicin, and the tumor volume was significantly reduced for 1 month compared to other samples. Thus, doxorubicin hydrogels containing doxorubicin conjugates can be employed as a novel injectable anti-cancer drug aiming to achieve sustained release of doxorubicin for several weeks against solid tumors.     

Synthesis,characterization, in vitro and in vivo evaluation of PEGylated oridonin conjugates

Oridonin (ORI), a diterpenoid compound with promising antitumor activity, was proved to possess potent antileukemia efficacies in vitro and in vivo recently. However, the development and application of ORI was limited by its poor solubility and rapid plasma clearance. The purpose of this study was to solve these problems. PEGylated oridonin linked with succinic acid (SA) as spacer moiety (PEG-SA-ORI conjugate) was synthesized. mPEG amines with four specifications of molecular weight (MW) were utilized. All polymeric conjugates showed satisfactory aqueous solubility and in vitro studies implied that the drug solubility and release features of conjugates were relevant to PEGs. The drug solubility increased more when the MW of PEG was lower, while more significant sustained-release effect was shown with higher PEG MW. Moreover, the release behaviors of conjugates showed a pH-sensitive property. In vivo pharmacokinetic studies demonstrated that the elimination half-life was prolonged in comparison with ORI solution. PEGylation could be a promising method to obtain better efficacy in the field of drug delivery system.     

In vitro cytotoxicity, in vivo biodistribution and antitumor activity of HPMA copolymer–5-fluorouracil conjugates

5-Fluorouracil (5-FU) is an antimetabolite with a broad-spectrum activity against solid tumors. However, its very short half-life in plasma circulation greatly limited the in vivo antitumor efficacy and clinical application. The current work aimed to solve this problem as well as to increase 5-FU biodistribution to tumor by covalently conjugating 5-FU to a biocompatible, non-toxic and non-immunogenic drug carrier – N-(2-hydroxypropyl) methacrylamide (HPMA) copolymer. The in vitro cytotoxicity, in vivo biodistribution and therapeutic efficacy of HPMA copolymer–5-FU conjugates (P-FU) were reported. Cytotoxicity was evaluated by using a serial of tumor cells (A549, CT-26, Hela, HepG₂ cells and 5-FU resistant HepG₂ cells). In vivo biodistribution and therapeutic efficacy were investigated in Kunming mice-bearing hepatoma 22 (H₂₂). Results indicated that P-FU could increase the cytotoxicity of 5-FU in Hela, HepG₂ and 5-FU resistant HepG₂ cells, while it decreases the cytotoxicity of 5-FU in A549 and CT-26. Both in vitro release profile in plasma and biodistribution study showed that P-FU significantly prolonged the drug plasma circulation time. P-FU also showed an over 3-fold larger area under the concentration–time curve (AUC) in tumor when compared with free drug. Therapeutic evaluation also demonstrated that the treatment with P-FU displayed stronger inhibition of the tumor growth when compared with that of control group (physiologic saline) or 5-FU group at the same dose. All the results suggested that P-FU could increase cytotoxicity of 5-FU in certain cancer cell lines, prolong 5-FU circulation time in vivo, enhance 5-FU distribution to tumor and improve therapeutic efficacy. Therefore, HPMA copolymer is a potential carrier for 5-FU for the effective treatment of cancer.     

N-(2-羟丙基)甲基丙烯酰胺聚合物-5-氟尿嘧啶接合物的体外释药规律、体内分布及抗肿瘤活性研究

考察本实验室合成的N-(2-羟丙基)甲基丙烯酰胺［N-(2-hydroxypropyl) methacrylamide，HPMA］聚合物-5-氟尿嘧啶(5-flurouracil，5-FU)接合物(P-FU)的体外释药、体内分布及抗肿瘤活性。以小鼠血浆为介质，考察P-FU中5-FU的释放规律；以小鼠H22肝癌实体瘤模型(皮下型)为肿瘤模型，考察接合物在荷瘤小鼠体内的分布情况、药代动力学规律及抑瘤活性。结果表明，37 ℃时P-FU在小鼠血浆中具有一定的稳定性，半衰期(t_1/2)为32.4 h。与5-FU相比，P-FU在荷瘤小鼠体内的循环时间明显延长(血浆中t_1/2为原药的166倍)，在肿瘤中的沉积量(AUC为5-FU的3.3倍)及滞留时间(t_1/2为5-FU的2.3倍)均有明显增加。体内药效学研究表明，P-FU组对荷瘤小鼠的肿瘤生长抑制率(69.09%)显著高于5-FU组(56.49%，P<0.05)，瘤块组织病理学观察结果也显示P-FU组小鼠肿瘤组织中细胞凋亡程度大于5-FU组。HPMA聚合物可被用于为5-FU构建一种新型实体瘤高分子给药系统。     

番茄红素微囊的体内外药剂学行为

目的考察番茄红素微囊的体外释放、番茄红素原料及番茄红素微囊在家犬体内的药代动力学、体外释放和体内吸收的相关性。方法用分光光度法测定释放介质中番茄红素的含量。用HPLC法测定家犬体内的番茄红素含量，数据用3P87程序处理，得到各主要药代动力学参数。体内吸收与体外释放进行点点相关。结果微囊体外释放呈肠溶性，原料及番茄红素微囊的T_1/2α分别为7.30和15.06 h；T_1/2β分别为28.10和46.76 h；T_max分别为22.32和41.03 h；AUC_0-∞分别为1.67和2.08 μg·h·L^-1。体内外相关性良好。结论微囊较原料药呈现缓释特征，体内外相关性结果表明可以根据体外释放情况预测体内的吸收。     

In vitro and in vivo reproduction toxicology of 12 monoaminergic reuptake inhibitors: Possible mechanisms of infrequent cardiovascular anomalies

The rat Whole Embryo Culture (WEC) has been used to predict the potential teratogenicity of 12 selective/mixed monoaminergic reuptake inhibitors (MRUI). WEC results were compared with in vivo animal and human epidemiological teratogenicity data. In vitro, paroxetine and the positive control retinol were the only compounds identified as a clear teratogen, but developmental morphological indicators suggestive of a teratogenic potential were observed for most other MRUIs, including fluoxetine, citalopram and venlafaxine. No clear evidence of teratogenic potential was observed for three compounds, however, all compounds assessed showed a dose-dependent general embryotoxicity.In vivo testing of nine MRUIs for teratogenicity was limited by maternal toxicity (e.g. anorexia) without showing overt embryotoxicity (e.g. implantation loss). Next to complete absence, the cardiovascular (CV) anomalies observed (mostly) in rabbits ranged from a low incidence (e.g. above historical background of 0.35%) to a clear incidence (mean 4.1%).It is suggested that observed specific malformations in vitro (e.g. branchial bars deformed, displaced or additional otic system), not noted in any (historical) controls, may be early ontogenetic indicators for infrequent CV-anomalies observed in vivo. Despite the low incidence of anomalies in vitro or in vivo, they may yet be clinically relevant as in the case of paroxetine. Possible mechanisms are discussed, e.g. perturbed neural crest cell migration.     

甲氨蝶呤-聚乙二醇偶联物的合成及其体外抗肿瘤活性

为了改善甲氨蝶呤的溶解性能和生物学性能，本工作在合成甲氨蝶呤-聚乙二醇偶联物的基础上，考察了该偶联物的溶解性和体外抗肿瘤活性。通过采用微波催化与化学催化相结合的方法，制备了新型甲氨蝶呤-聚乙二醇偶联物，其结构得到了紫外、红外和核磁共振谱的确证。测定了偶联物在水中的溶解度及其在辛醇/水中的分配系数，测得偶联物的水溶性和脂溶性均有明显增加，在纯水中的溶解度提高了128倍，分配系数提高了近5倍。以小鼠L1210白血病细胞作为研究对象，测定该偶联物的体外抗肿瘤活性，结果表明，偶联物的抗肿瘤活性与甲氨蝶呤基本接近。与文献相比，该甲氨蝶呤的聚乙二醇修饰方法具有快捷、方便的特点。     

抗体偶联药物及其体内外代谢的研究进展

抗体偶联药物（ADC）是由单克隆抗体和细胞毒性有效载荷通过连接子偶联而成,结合了单克隆抗体的高特异性靶向能力和细胞毒活性小分子高效杀伤作用的优点,实现了对癌细胞的精准高效清除,已成为抗癌药物研发的热点之一。自2000年美国食品药品监督管理局（FDA）批准第一个ADC药物吉妥珠单抗（Mylotarg）以来,迄今全球已有14个ADC药物获批上市。这类新型的抗癌药物正引领癌症靶向治疗的新时代。基于ADC药物的构建核心和抗肿瘤作用机制,对ADC药物的体内外代谢的研究进展进行综述,以期从代谢角度为ADC药物的设计、开发、临床前药理、毒理及后续研究提供参考。     

甘草次酸修饰马钱子碱纳米给药系统的体内外肝靶向性评价

目的 制备甘草次酸（GA）修饰的马钱子碱（B）-聚乙二醇-二硫代二丙酸-单硬脂酸甘油酯（PSG）纳米粒（NPs）（B-GPSG-NPs）并评价其体内外肝靶向性。方法 采用溶剂乳化超声法制备B-GPSG-NPs和B-PSG-NPs,于透射电镜下观察其外观形态,测定其粒径、多分散性指数（PDI）、Zeta电位、包封率、载药量等理化性质。建立检测心、肝、脾、肺、肾、脑组织中马钱子碱含量的高效液相色谱法。将雌雄各半的小鼠90只随机分为3组：马钱子碱组、B-PSG-NPs组、B-GPSG-NPs组,禁食不禁水12h后,尾iv相应溶液（以马钱子碱计10mg·kg^-1）,分别于给药后10、30、60、120、180min取各组织进行HPLC检测,计算相对摄取率（Re）和靶向效率（Te）,以评价给药系统的体内靶向性。制备载异硫氰基荧光素（FITC）的FITC-B-PSG-NPs、FITC-B-GPSG-NPs,FITC、空白PSG载体制成的纳米粒（PSG-NPs）、空白GPSG载体制成的纳米粒（GPSG-NPs）以及含马钱子碱质量浓度分别为500、250、125μg·mL^-1的FITC-B-PSG-NPs和FITC-B-GPSG-NPs与CBRH-7919肝癌细胞共培养24h,荧光显微镜下观察CBRH-7919细胞对各受试物的摄取情况,以评价给药系统的体外靶向性。结果 B-GPSG-NPs的粒径为（98.91±3.62）nm,呈正态分布;PDI值为（0.221±0.006）,Zeta电位为-（19.63±0.40）mV,包封率为（78.37±1.83）%,载药量为（2.86±0.05）%;B-PSG-NPs与B-GPSG-NPs组肝脏的Re分别为1.49和1.72,明显高于其他组织;马钱子碱组肾脏Te最高,脑Te最低,而B-PSG-NPs和B-GPSG-NPs组肝脏中马钱子碱的Te明显高于其他各组织;CBRH-7919细胞摄取B-GPSG-NPs效率明显高于B-PSG-NPs,并表现出剂量相关性。结论 制备的BGPSG-NPs在体内外均表现出良好的肝靶向效应,且优于无GA修饰的B-PSG-NPs。     

In vitro and in vivo evaluation of tegaserod maleate pH-dependent tablets

The purpose of this study was to prepare tegaserod maleate (TM) pH-dependent tablets and evaluate their advantages as a sustained release delivery system. TM, insoluble in water and unstable in gastric milieu, was formulated into pH-dependent tablets coated with combinations of two methacrylic acid copolymers – Eudragit^® L100 and Eudragit^® S100. The influence of core tablet compositions, polymer combination ratios and coating levels on the in vitro release rate of TM from coated tablets was investigated. The optimum formulation was evaluated for in vitro release rate and in vivo bioavailability study on beagle dogs. In addition, physico-chemical properties of the drug, including solubility at different pH and temperatures, and dissociation constant were determined. The results showed that no drug was released in 0.1 mol/L hydrochloric acid within 2 h, and about 90% of the drug was released in the pH 6.8 phosphate buffer within 12 h in a sustained manner. The pharmacokinetic investigation showed that TM pH-dependent tablets exhibited a sustained plasma concentration, a lag time of approximately 2.3 h and a relative bioavailability of 159% compared to plain tablets. A close correlation existed between the in vitro release rate of the pH-dependent system and its in vivo absorption percentage. The results of the present study have demonstrated that the pH-dependent tablet system is a promising vehicle for preventing rapid hydrolysis in gastric milieu and improving oral bioavailability of TM for the treatment of irritable bowel syndrome.     

精氨酸水溶液复溶的多西他赛聚合物胶束的体外药效学及体内分布

目的：考察精氨酸复溶的多西他赛胶束的体外药效及体内分布情况。方法：用CCK-8法考察多西他赛胶束和多西他赛注射液对肿瘤细胞的增殖抑制作用。以荧光染料DIR标记多西他赛聚合物胶束,通过活体成像系统比较精氨酸水溶液复溶组,生理盐水复溶组和多西他赛注射液组的荧光分布。结果：多西他赛胶束组IC₅₀值明显比多西他赛注射液组高。精氨酸复溶的多西他赛胶束组肿瘤部位荧光强度比生理盐水复溶组和多西他赛注射液组都强。结论：精氨酸复溶的多西他赛胶束肿瘤靶向性更强且在肿瘤部位的停留时间更长,但其体外抗肿瘤活性有待提高。     

Improvement of physicochemical and biopharmaceutical properties of theophylline by poly(ethylene glycol) conjugates

In the present paper two theophylline esters with poly (ethylene glycol) (PEG) and methoxy poly (ethylene glycol) (mPEG) were prepared. Quantitative yields of the pure products were obtained. Unlike the free drug, the drug-polymer conjugates are freely water-soluble at room temperature. In vitro release experiments in aqueous buffer demonstrate that both conjugates are stable in buffer of pH 7.4 and 1.2. In vivo release studies after oral administration of theophylline conjugates demonstrate a good release of parent drug.     

Study on dissolution and absorption of four dosage forms of isosorbide mononitrate: Level A in vitro–in vivo correlation

The objective of the present study was to develop a novel in vitro system to simulate the process of dissolution and permeation of oral solid dosage forms in vivo, and to establish a correlation between in vitro permeation and in vivo absorption that could predict the bioavailability (BA) and bioequivalence (BE) of congeneric products. The in vitro dissolution and absorption kinetics of four dosage forms of isosorbide mononitrate (ISMN) were evaluated by the USP basket/paddle system and drug dissolution/absorption simulating system (DDASS). The corresponding pharmacokinetic study was performed in beagle dogs. A comparative study was carried out between the classical and the novel method to estimate the effectiveness of the modified DDASS in simulating the course of dissolution and absorption in vivo. Indeed, the correlation coefficients of in vitro dissolution and in vivo absorption obtained from DDASS and dogs were higher. Moreover, a higher level A in vitro–in vivo correlation (IVIVC) between DDASS permeation and dog absorption was established, with correlation coefficients of 0.9968, 0.9872, 0.9921, and 0.9728. The DDASS method was more accurate at modeling the process of dissolution and absorption in vivo for both immediate-release (IR) and sustained-release (SR) dosage forms of ISMN.     

PEG-metronidazole conjugates: synthesis, in vitro and in vivo properties

Metronidazole (MTZ), a drug used for the treatment of protozoal infections caused by protozoa and anaerobic microorganisms, was conjugated to linear or branched poly(ethylene glycol) of 5,000, 10,000 and 20,000 Da. An ester linkage between polymer and drug was used in the coupling to yield a polymeric prodrug. The modification allowed overcoming the known MTZ solubility problem leading us to obtain a bioconjugate more suitable for parental administration. The conjugates of various molecular weight polymers have been tested in vitro toward chemical degradation and digestive enzymes. It was found that molecular weight and shape of PEG is critical for the prodrugs stability. Good resistance in the stomach acidic media was found and a slow release of the drug in the large intestinal fluid may take place. In vivo studies carried out following i.v. or s.c. administration to mice revealed improved pharmacokinetics properties upon conjugation.     

In vitro and in vivo antioxidant properties of different fractions of Moringa oleifera leaves

The antioxidant potency of different fractions of Moringa oleifera leaves were investigated by employing various established in vitro systems, such as β-Carotene bleaching, reducing power, DPPH/superoxide/hydroxyl radical scavenging, ferrous ion chelation and lipid peroxidation. On the basis of in vitro antioxidant properties polyphenolic fraction of M. oleifera leaves (MOEF) was chosen as the potent fraction and used for the DNA nicking and in vivo antioxidant properties. MOEF shows concentration dependent protection of oxidative DNA damage induced by HO and also found to inhibit the toxicity produced by CCl₄ administration as seen from the decreased lipid peroxides (LPO) and increased glutathione (GSH) levels. Among the antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT) levels were restored to almost normal levels compared to CCl₄ intoxicated rats. The HPLC analysis indicated the presence of phenolic acids (gallic, chlorogenic, ellagic and ferulic acid) and flavonoids (kaempferol, quercetin and rutin). Thus, it may be concluded that the MOEF possess high phenolic content and potent antioxidant properties, which may be mediated through direct trapping of the free radicals and also through metal chelation.     

In vitro/in vivo phototoxic risk assessments of griseofulvin based on photobiochemical and pharmacokinetic behaviors

The present investigation aims to establish efficacious screening strategy to clarify the phototoxic potential of pharmaceutical substances and its possible pathways by characterizing both photobiochemical properties and pharmacokinetic profiles. Photochemical behavior of griseofulvin, as model compounds, was evaluated by reactive oxygen species (ROS) assay, and the photogenotoxic potential was also assessed by DNA binding assay, DNA photocleavage assay, and atomic force microscopy. Pharmacokinetic (PK) study was also carried out after dermal and oral administration of griseofulvin in rats. ROS assay suggested the phototoxic potential of griseofulvin via type II photochemical pathways, and the photogenotoxic risk of griseofulvin was also proposed as evidenced by high affinity toward DNA and potent DNA photocleaving activity. PK profiling and in vivo phototoxicity testing demonstrated that a highly concentrated griseofulvin in the skin might cause phototoxic skin reactions in rats, whereas oral administration of griseofulvin in single dosing regimen (20 mg/kg) resulted in 10³-fold less skin deposition than phototoxic skin concentration of griseofulvin. Upon these findings, the phototoxic potential of griseofulvin might not be severe at least in a single oral dosing regimen, whereas it might be phototoxic in dermal administration. The combination use of photobiochemical and pharmacokinetic data would be valuable to provide reliable prediction on phototoxic risk and possible toxic pathways of new drug entities in the early stage of drug discovery.     

Cells of different tissues for in vitro and in vivo studies in toxicology: Compilation of isolation methods

An advantage of using freshly isolated intact cells of different organs in toxicology is that they reflect more closely the in vivo situation than do long-term cultures. In vitro, primary cells provide the possibility of determining cell-specific xenobiotic metabolism, in the absence of artificial extracellular activation systems, which may result in cytotoxic and genotoxic effects. After in vivo exposure of animals to xenobiotics, isolated primary cells can be studied to elucidate toxicokinetic effects. In the review presented here, selected methods are described for isolating cells with high viability from pig liver and avian embryonic liver, and from the nasal cavity, lungs, kidneys, gastro-intestinal tract, urinary bladder, testes and thymus of the rat. Two techniques for preparing rat lymphocytes are also described. Cell isolation may be initiated with an in situ perfusion to clear the organ of blood. Steps to loosen cell-to-cell contacts and to digest the intercellular connective material may then follow. Also, in situ digestion may be performed, as described for the epithelial cells from different mucosal tissues. Following initial digestion, a single-cell suspension is prepared by tissue mincing and a second digestive step with proteolytic enzymes. Frequently used digestive enzymes are collagenase (types I, IV and P; from Clostridium histolyticum), trypsin and proteinase K. Follow-up filtration is usually required to remove undigested material. The quantities and viabilities of the harvested cells vary with the organ of choice and the procedure used; the values obtained are stated.     

Nanoparticulate delivery system for insulin: Design, characterization and in vitro/in vivo bioactivity

Insulin-loaded alginate–dextran nanospheres were prepared by nanoemulsion dispersion followed by triggered in situ gelation. Nanospheres were characterized for mean size and distribution by laser diffraction spectroscopy and for shape by transmission electron microscopy. Insulin encapsulation efficiency and in vitro release were determined by Bradford protein assay and bioactivity determined in vitro using a newly developed Western blot immunoassay and in vivo using Wistar diabetic rats. Nanospheres ranged from 267 nm to 2.76 μm in diameter and demonstrated a unimodal size distribution. Insulin encapsulation efficiency was 82.5%. Alginate–dextran particles suppressed insulin release in acidic media and promoted a sustained release at near neutral conditions. Nanoencapsulated insulin was bioactive, demonstrated through both in vivo and in vitro bioassays     

水飞蓟素磷脂复合物微孔渗透泵控释片比格犬体内药动学及体内外相关性研究

目的 评价水飞蓟素磷脂复合物微孔渗透泵(SM-PC MPOP)控释片的体外释药特性、比格犬体内药动学及其体内外相关性。方法 释放介质为pH7.5的磷酸盐缓冲液(添加0.5%十二烷基硫酸钠),以高效液相色谱法(HPLC)检测SM-PC MPOP的体外释放特征。用6只比格犬进行双周期交叉对照实验,按照30 mg/kg的剂量给药。HPLC法测定比格犬血浆内水飞蓟素的主要成分水飞蓟宾的质量浓度,应用药动学软件进行数据分析。结果 SM-PC MPOP在12 h累积释放度超过85%。药动学研究情况表明,受试制剂(SM-PC MPOP)和参比制剂(市售水飞蓟素胶囊)在比格犬体内的主要药动学参数：T_max分别为(3.2±0.4)、(0.9±0.1)h,C_max分别为(0.298 6±0.068 9)、(0.629 9±0.076 5)μg/ml,AUC_0→24分别为(2.996 8±0.583 3)、(2.268 9±0.432 8) h·μg/ml,SM-PC-MPOP对市售水飞蓟素胶囊的相对生物利用度为(162.21±30.82)%...