丙烯酸-泊洛沙姆407共聚物的合成及其原位胶凝性质

目的制备丙烯酸和泊洛沙姆407构成的共聚物,研究其温度敏感的原位胶凝性质。方法将泊洛沙姆407溶于丙烯酸单体,引发聚合反应,产物用红外光谱和凝胶渗透色谱表征。用旋转黏度计测定共聚物水溶液的黏度随温度的变化。以维生素B12为模型药物,研究药物的释放性质。结果较低浓度的丙烯酸泊洛沙姆407共聚物水溶液具有受热原位胶凝的性质,其胶凝特征与共聚物的组成、浓度、溶液pH等有关,共聚物凝胶可延缓药物释放。结论丙烯酸泊洛沙姆407共聚物可望应用于黏膜给药的原位凝胶递药系统。     

A novel poloxamers/hyaluronic acid in situ forming hydrogel for drug delivery: Rheological, mucoadhesive and in vitro release properties

The influence of hyaluronic acid (HA) on the gelation properties of poloxamers blends has been studied with the aim of engineering thermosensitive and mucoadhesive polymeric platforms for drug delivery. The gelation temperature (T(gel)), viscoelastic properties and mucoadhesive force of the systems were investigated and optimised by means of rheological analyses. Poloxamers micellar diameter was evaluated by Photon Correlation Spectroscopy (PCS). Moreover in order to explore the feasibility of these platforms for drug delivery, the optimised systems were loaded with acyclovir and its release properties studied in vitro. By formulating poloxamers/HA platforms, at specific concentrations, it was possible to obtain a thermoreversible gel with a T(gel) close to body temperature. The addition of HA did not hamper the self assembling process of poloxamers just delaying the gelation temperature of few Celsius degrees. Furthermore, HA presence led to a strong increase of the poloxamer rheological properties thus indicating possible HA interactions with micelles through secondary bonds, such as hydrogen ones, which reinforce the gel structure. These interactions could also explain PCS results which show, in systems containing HA, aggregates with hydrodynamic diameters much higher than those of poloxamer micelles. Mucoadhesion experiments showed a rheological synergism between poloxamers/HA gels and mucin dispersion which led to a change of the flow behaviour from a quite Newtonian one of the separate solutions to a pseudoplastic one of their mixture. In vitro release experiments indicated that the optimised platform was able to prolong and control acyclovir release for more than 6h.     

透明质酸氟脲嘧啶耦合物的制备与研究

目的合成肿瘤靶向药物透明质酸氟尿嘧啶耦联物,并探讨最佳合成条件。方法①以透明质酸（HA）和5-氟尿嘧啶（5-FU）为原料,将5-FU通过4位上的氨基与HA片段上的羧基耦合,得到HA-FU耦联物,测定其产物的紫外光谱。②以HA-FU耦联产物量作为指标,考察反应试剂加入的顺序、反应温度、溶液pH等多个水平,并从中选出最佳实验条件。结果制备HA-FU耦联物的最佳条件是将5-FU滴入HA中,温度为20-30℃,pH为3～4。合成了透明质酸与5-氟尿嘧啶耦合物,呈乳白色粉末。结论通过实验研究,找到合成透明质酸氟脲嘧啶的最佳合成条件。     

硝酸毛果芸香碱温敏凝胶的研制及溶蚀性能研究

目的制备硝酸毛果芸香碱温敏凝胶,考察其载药凝胶溶蚀行为。方法以泊洛沙姆为温敏凝胶基质制备硝酸毛果芸香碱眼用凝胶,通过凝胶相变温度筛选最佳处方,采用无膜溶蚀实验研究凝胶释药特性。结果18%、19%、20%的泊洛沙姆407溶液在体温范围内发生相变形成凝胶,其pH≈7,凝胶中硝酸毛果芸香碱释放速度分别为0.462、0.393、0.294 mg.min-1。结论18%-20%泊洛沙姆407溶液适合作为眼部给药的温敏凝胶基质,凝胶中药物释放基本符合零级释放行为。     

Self-assembled amphiphilic hyaluronic acid graft copolymers for targeted release of antitumoral drug

Polymeric micelles obtained by self-assembling of amphiphilic hyaluronic acid (HA) graft copolymers have been prepared and characterized. In particular, hyaluronic acid (HA) has been grafted to polylactic acid (PLA) and polyethylenglycol chains (PEG), then the copolymers able to form micelles in aqueous medium have been chosen to entrap the antitumoral drug Doxorubicin. The critical aggregation concentration of HA-g-PLA or HA-g-PLA-g-PEG micelles has been determined by using pyrene as a fluorescent probe, whereas their shape and size have been evaluated by light scattering measurements, scanning and transmission electron microscopies. The selective cytotoxicity of drug loaded micelles toward the CD-44 over-expressing HCT-116 cells compared to receptor deficient human derm fibroblasts has been demonstrated. Pegylated micelles showed better stability and drug loading capacity and they were able to escape from macrophage phagocytosis.     

利巴韦林温度-离子敏感型鼻用原位凝胶喷雾剂的制备及体外性质考察

目的制备具有适宜临界相变温度和临界相变阳离子强度,及适宜的喷雾粒度、使用方便、缓慢释放药物的温度-离子敏感复合型鼻用原位凝胶。方法以临界相变温度、临界相变阳离子强度、喷雾粒度为考察指标筛选温敏及离子敏材料的用量,制备利巴韦林温度-离子敏感复合型原位凝胶。以透析袋法评价该复合凝胶的凝胶外排水量、溶蚀速率、体外释放度,并以断裂距离为指标评价凝胶的黏膜黏附力。结果以质量分数为0.3%的去乙酰化结冷胶和质量分数为18.0%的泊洛沙姆407制备的温度-离子敏感复合型原位凝胶,临界相变温度为32.6℃,临界相变阳离子强度为93.4 mmol.kg-1,喷雾粒度为68.0μm,凝胶外排水质量分数为(13.8±0.8)%,溶蚀速度常数为1×10-4min-1,断裂距离为(1.60±0.06)mm。该混合凝胶具有良好的体外缓释特征。结论该复合型原位凝胶剂适宜作为水溶性药物的鼻用缓释载体。     

地塞米松磷酸钠温度敏感原位凝胶的特性研究

本文以泊罗沙姆PluronicF127为温度敏感原位凝胶材料，考察了PluronicF127与PluronicF68不同浓度处方对地塞米松磷酸钠温度敏感原位凝胶的胶凝温度、相转变温度、凝胶强度、稳态黏度、溶蚀和药物释放行为等特性的影响。采用试管倒转法测定胶凝温度；旋转流变仪测定相转变温度、弹性模量、稳态黏度等流变学参数；无膜溶出法测定凝胶的溶蚀行为；HPLC测定地塞米松磷酸钠的释放度。结果表明，随着处方中F127浓度的增高，凝胶的胶凝温度和相转变温度降低，黏度和弹性模量增加，溶蚀速率和药物释放速率减慢；而处方中F68对凝胶特性的影响与F127相反。温度敏感原位凝胶在低温时为牛顿流体，黏度很小；随着温度升高，黏度增大；当增至相转变温度附近，表现出典型的假塑性流体特征；药物释放速率受控于凝胶溶蚀速率，二者遵循零级动力学方程。处方中含F127 22.5% / F68 2.5%的地塞米松磷酸钠温度敏感原位凝胶的性质与临床治疗要求基本吻合，有望在临床中获得应用。     

Chitosan in situ gelation for improved drug loading and retention in poloxamer 407 gels

A method for the in situ gelation of poloxamers and the mucoadhesive polymer chitosan has been developed by exploiting the tendency of poloxamer solution to form gel at physiological temperatures and of chitosan (CT) to form ionotropic gel structures in the presence of sodium tripolyphosphate (TPP). Novel poloxamer gels containing CT-TPP complex formed in situ during the administration were prepared by mixing poloxamer-CT and poloxamer-TPP solutions in double syringes. The micellization and gelation of poloxamer 407 in the presence of chitosan and/or TPP were studied using differential scanning calorimetry and tube inversion; both additives were found to reduce the critical micellization temperature and critical gelation temperature of poloxamer aqueous solution. The poloxamer gels containing CT-TPP complex formed in situ were found to exhibit reduced dissolution rate and superior release characteristics with three different drugs--metoprolol, doxycycline and flufenamic acid. Furthermore, by varying the compositions of the two solutions independently, it is possible to control the pH in a way to suit the solubilization of a drug as well as the specific environment of a particular application site. By varying the concentrations of chitosan, TPP and poloxamer, the delivery system can be fine-tuned to afford gels with specific properties, ranging from nanoparticle suspensions to semisolid gels. These in situ gels have the potential to increase the utility of thermo-reversible poloxamers in drug delivery.     

星点设计法优化布南色林-泊洛沙姆温敏水凝胶处方及含量测定

目的 优化泊洛沙姆温敏水凝胶体系负载布南色林,并对凝胶中布南色林含量进行测定.方法 采用直接混合法配备含药温敏水凝胶体系,倒置小管法测定胶凝温度(Tgel).以Tgel为因变量,25％泊洛沙姆407体积(X1)、50％泊洛沙姆188体积(X2)和1％布南色林药物混悬液(X3)为考察因素,通过星点设计法优化制剂处方.采用...     

安乃近原位凝胶的制备及体外评价

目的 制备安乃近原位凝胶,延长安乃近在体内的作用时间.方法 以泊洛沙姆407(P407)和泊洛沙姆188(P188)作为载体材料,采用冷溶法制备安乃近原位凝胶,考察P407和P188的含量、亚硫酸氢钠及安乃近浓度对胶凝温度的影响,并用透析袋法考察凝胶的体外释药情况.结果 当P407浓度为23％、P188浓度为6％、亚硫酸氢钠的浓度为0.2％时,所制得的安乃近原位凝胶注射剂的胶凝温度合适,为35.3℃时,该凝胶在1h内的平均体外累积释放率为40.57％,较安乃近水溶液同时间内的累积释放率低50.39％.结论 安乃近原位凝胶的温敏性明显,其胶凝温度适合体内给药;安乃近原位凝胶对安乃近药物的释放显示出了明显的缓释效应,可以进一步用于临床.     

Synthesis and in vitro evaluation of thiolated hyaluronic acid for mucoadhesive drug delivery

It was the aim of this study to synthesize and characterize a novel hyaluronic acid-cysteine ethyl ester (HA-Cys) conjugate providing improved mucoadhesive properties and a significantly lowered biodegradation rate. Mediated by carbodiimide and N-hydroxysuccinimide, L-cysteine ethyl ester hydrochloride was covalently attached to hyaluronic acid (HA, hyaluronan) via the formation of an amide bond. The adhesive properties of HA-Cys conjugates were evaluated in vitro on a freshly excised porcine mucosa via the rotating cylinder method. The cohesive properties of the resulting conjugates were evaluated by oxidation experiments. Biodegradability studies were carried out by viscosity measurements and spectrophotometric assays. Release studies were performed with fluorescein isothiocyanate-dextrans (FD) as model compounds. The obtained conjugate displayed 201.3+/-18.7 micromol immobilized free thiol groups and 85.7+/-22.3 micromol disulfide bonds per gram polymer. Results from the rotating cylinder method showed more than 6.5-fold increase in the adhesion time of HA-Cys versus unmodified HA. In aqueous solutions, the obtained conjugate demonstrated improved cohesive properties. The hydrolysis degree of HA-Cys was lower compared with the corresponding unmodified HA in the framework of viscosity experiments. In addition, the cross-linking process via disulfide bonds additionally reduced the rate of degradation of the new derivative. Cumulative release studies out of matrix tablets comprising HA-Cys and the model compound FD demonstrated a sustained drug release for more than 12h due to in situ formation of inter- and intramolecular disulfide bonds in the thiomer matrix. According to the results of the present study, this novel thiolated polymer seems to represent a promising multifunctional excipient for the development of various drug delivery systems.     

Preparation and characterization of HA–PEG–PCL intelligent core–corona nanoparticles for delivery of doxorubicin

The objective of the present study was to synthesize core–corona nanoparticles of doxorubicin (DOX) using hyaluronic acid–polyethyleneglycol–polycaprolactone (HA–PEG–PCL) copolymer for tumor targeting. Targeting efficiency of HA–PEG–PCL nanoparticles was compared with non-HA-containing nanoparticles (methoxy poly ethylene glycol (MPEG)–PCL). The copolymers were chemically synthesized and characterized by IR and NMR spectroscopies. The nanoparticles were characterized for shape and morphology by transmission electron microscopy, particle size, percentage of drug entrapment, and in vitro drug release profile. Differential scanning calorimetry and X-ray diffraction studies were also performed to appraise the crystalline or amorphous nature of DOX inside the polymer matrix. Formulations were prepared using different DOX:polymer ratios (1:1–1:3 w/w) and the optimum formulation with the drug:polymer ratio of 1:1 showed the mean particle size of 95 ± 5 nm and entrapment efficiency of 95.56% in the case of HA–PEG–PCL nanoparticles, while the values were 115 nm and 95.50%, respectively, in the case of MPEG–PCL nanoparticles. The HA–PEG–PCL nanoparticles could release DOX for up to 17 days, whereas the MPEG–PCL nanoparticles could release it for up to 14 days. The hemolytic toxicity and hematological studies confirmed that both DOX-loaded HA–PEG–PCL and MPEG–PCL nanoparticles were safe and suitable for sustained and targeted drug delivery. The tissue distribution study and tumor growth inhibition were performed after intravenous injection of nanoparticles in Ehrlich ascites tumor (EAT)-bearing mice. The nanoparticles of HA–PEG–PCL copolymer accomplishes efficient delivery of DOX in EAT tumor when compared with the MPEG–PCL nanoparticles by the process of receptor-mediated endocytosis, as well as enhanced permeability and retention effect.     

眼用维生素A棕榈酸酯阳离子脂质体-原位凝胶的研制及体外释药研究

目的：以维生素A棕榈酸酯（VAP）为模型,制备眼用阳离子脂质体-原位凝胶系统,并对其体外释药行为进行考察。方法：采用薄膜分散法制备VAP脂质体,根据胶凝温度筛选泊洛沙姆407的最佳处方浓度,采用无膜溶出模型对该制剂的体外释放行为进行考察。结果：透射电镜显示VAP脂质体-原位凝胶（VAPL—ISG）粒径分布均匀,经N-三甲基壳聚糖（TMC）包衣后Zeta电位〉40mV,泊洛沙姆407的最佳浓度为25％,VAPL—ISG中药物释放和凝胶溶蚀均呈现良好的零级释放特征。结论：VAPL—ISG具有阳离子脂质体和原位凝胶的优势,延缓了药物释放,为下一步研究其延长角膜滞留时间打下基础。     

Thermosensitive and mucoadhesive in situ gel based on poloxamer as new carrier for rectal administration of nimesulide

Poloxamer 407 has excellent thermo-sensitive gelling properties. Nevertheless, these gels possess inadequate poor bioadhesiveness and high permeability to water, which limited its' application as a thermoresponsive matrix. The main aim of the present investigation was to develop thermosensitive and mucoadhesive rectal in situ gel of nimesulide (NM) by using mucoadhesive polymers such as sodium alginate (Alg-Na) and HPMC. These gels were prepared by addition of mucoadhesive polymers (0.5%) to the formulations of thermosensitive gelling solution containing poloxamer 407 (18%) and nimesulide (2.0%). Polyethylene glycol (PEG) was used to modify gelation temperature and drug release properties. The gelation temperature and drug release rate of the prepared in situ gels were evaluated. Gelation temperature was significantly increased with incorporation of nimesulide (2.0%) in the poloxamer solution, while the addition of the mucoadhesive polymers played a reverse role on gelation temperature. The addition of PEG polymers increased the gelation temperature and the drug release rate. Among the formulations examined, the poloxamer 407/nimesulide/sodium alginate/PEG 4000 (18/2.0/0.5/1.2%) exhibited the appropriate gelation temperature, acceptable drug release rate and rectal retention at the administration site. Furthermore, the micrographic results showed that in situ gel, given at the dose of 20mg/kg, was safe for no mucosa irritation. In addition, it resulted in significantly higher initial serum concentrations, C(max) and AUC of NM compared to the solid suppository.     

氯霉素温敏型眼用原位凝胶的研制

目的制备氯霉素泊洛沙姆眼用原位温敏型凝胶并建立其质量控制方法。方法以泊洛沙姆P407和P188为温敏材料,通过测定溶液-凝胶相转变温度优化处方;采用紫外分光光度法测定氯霉素含量。结果氯霉素温敏型原位凝胶的胶凝温度随P407浓度增大而降低,随P188浓度增加先升高后降低,模拟泪液的稀释可使胶凝温度升高,建立了泪液稀释后相变温度与泊洛沙姆浓度的拟合方程,经Design-Expert软件优化出的氯霉素温敏型原位凝胶最佳处方为25%P407和4.19%P188;优化处方在29.5℃时为自由流动的液体,泪液稀释后在34.6℃能够发生相变形成凝胶。结论该眼用温敏凝胶符合眼部应用要求,体现出良好的应用前景。     

Construction and application of biotin–poloxamer conjugate micelles for chemotherapeutics

Biotin was conjugated on poloxamer to prepare biotin–poloxamer (BP) conjugate micelles for chemotherapeutics. Epirubicin (EPI) was encapsulated in BP micelles. The EPI-loaded BP micelles were characterized in terms of size, ζ-potential, morphology, drug loading, drug encapsulation and drug release. Marrow leukemic HL-60 cells were used for evaluating the in vitro cytotoxicity of EPI-loaded BP micelles. Nude mice were axillainoculated subcutaneously HL-60 cells to establish tumour model for investigating the inhibition effects of EPI-loaded BP micelles. From the results, the sizes of these nanoparticles were about 100?nm. Fluorescence microscope observation supported the enhanced cellular uptake of the micelles. The order of the inhibition on tumour volume growth was: EPI-loaded BP micelles >EPI-loaded MATP micelles >EPI-loaded poloxamer micelles >EPI. BP micelles showed significant antitumour activity and low toxicity, compared with the non-targeted micelles. With the advantage of EPR effect and tumour-targeting potential, BP conjugate micelles might be developed as a new system for chemotherapeutics.     

Microneedles containing cross-linked hyaluronic acid particulates for control of degradation and swelling behaviour after administration into skin

Microneedles (MN) containing cross-linked hyaluronic acid (X-linked HA) particulates were prepared to control the degradation and swelling behaviour after transdermal drug delivery. The X-linked HA particulates were prepared by cross-linking HA chains and then passing the particulates through a sieve. Then, microneedles were prepared by micromolding method. The rheological properties of X-linked HA were studied. The penetration success rate, mechanical failure and dissolution rate of microneedles containing only hyaluronic acid (HA MN) and microneedles containing X-linked HA were compared. The delivery of fluorescein into the skin with X-linked HA MN was also observed using a confocal microscope. The size of the pulverised particulates in water ranged between 29 and 82?μm in diameter. The HA MN and X-linked HA MN were 270?μm in length. X-linked HA MN with fluorescein was inserted to a depth of 90% of the microneedle length successfully. There was no decrease in the penetration success rate for MN with up to 20% content of X-linked HA particulates. X-linked HA MN with up to 20% of particulate content did not change the dissolution time. Delay in degradation of HA, sustained drug release, and swelling behaviour of the skin layer can be obtained by X-linked HA MN.     

温敏在体凝胶给药系统的研究与应用

综述N-异丙基丙烯酰胺类聚合物、聚氧乙烯-聚氧丙烯共聚物、聚氧乙烯-聚乳酸羟基乙酸共聚物和多糖类衍生物等温敏聚合物的性质、特点、胶凝机制及在温敏在体凝胶给药系统中的应用进展。温敏在体凝胶作为一种智能水凝胶,可用作药物缓、控释和靶向输送的有效载体。     

CD44-tropic polymeric nanocarrier for breast cancer targeted rapamycin chemotherapy

In contrast with the conventional targeting of nanoparticles to cancer cells with antibody or peptide conjugates, a hyaluronic acid (HA) matrix nanoparticle with intrinsic-CD44-tropism was developed to deliver rapamycin for localized CD44-positive breast cancer treatment. Rapamycin was chemically conjugated to the particle surface via a novel sustained-release linker, 3-amino-4-methoxy-benzoic acid. The release of the drug from the HA nanoparticle was improved by 42-fold compared to HA-temsirolimus in buffered saline. In CD44-positive MDA-MB-468 cells, using HA as drug delivery carrier, the cell viability was significantly decreased compared to free rapamycin and CD44-blocked controls. Rat pharmacokinetics showed that the area under the curve of HA nanoparticle formulation was 2.96-fold greater than that of the free drug, and the concomitant total body clearance was 8.82-fold slower. Moreover, in immunocompetent BALB/c mice bearing CD44-positive 4T1.2neu breast cancer, the rapamycin-loaded HA particles significantly improved animal survival, suppressed tumor growth and reduced the prevalence of lung metastasis.From the Clinical EditorThis study demonstrates increased efficiency of rapamycin delivery and consequential treatment effects in a breast cancer model by hyaluronic acid - L-rapamycin conjugates with intrinsic tropism for CD44-positive cells.