Penta-block copolymer microspheres: Impact of polymer characteristics and process parameters on protein release

Here, we aimed to develop protein loaded microspheres (MSs) using penta-block PLGA-based copolymers to obtain sustained and complete protein release. We varied MS morphology and studied the control of protein release. Lysozyme was used as a model protein and MSs were prepared using the solid-in-oil-in-water emulsion solvent extraction method. We synthesized and studied various penta-block PLGA-based copolymers. Copolymer characteristics (LA/GA ratio and molecular weight of PLGA blocks) influenced MS morphology. MS porosity was influenced by process parameters (such as solvent type, polymer concentration, emulsifying speed), whereas the aqueous volume for extraction and stabilizer did not have a significant effect. MSs of the same size, but different morphologies, exhibited different protein release behavior, with porous structures being essential for the continuous and complete release of encapsulated protein. These findings suggest strategies to engineer the morphology of MSs produced from PLGA-based multi-block copolymers to achieve appropriate release rates for a protein delivery system.     

基于pH梯度载药技术的咪喹莫特脂质体的制备工艺研究

目的 根据咪喹莫特的理化性质,利用pH梯度主动载药技术制备脂质体,考察其性状、粒径、表面电荷及体外释药特征。方法 葡聚糖凝胶滤过法测定脂质体的包封率,以包封率与成型性为主要指标筛选制备方法,考察水化液的种类、pH值、离子强度及pH梯度载药、磷脂-胆固醇比例、脂药比、维生素E用量对包封率的影响;正交试验优化咪喹莫特脂质体的处方,考察脂质体样品在0~4℃下的稳定性。结果 按处方咪喹莫特50 mg、大豆卵磷脂400 mg、胆固醇130 mg、油酸10 mg、维生素E 5 mg、柠檬酸pH 2.5缓冲液5 mL,采用薄膜分散法工艺制备脂质体样品,并进行pH梯度主动载药,pH值调至7.0。制得的咪喹莫特脂质体呈白色均匀的混悬液,脂质体微粒圆整,分散性好,粒径（347±21）nm,包封率（81.2±1.9）%,Zeta电位（-12.19±1.7）mV。结论 pH梯度主动载药技术适于咪喹莫特脂质体的制备。     

热休克转录因子-1表达与子宫内膜癌的临床特征及病理学关系

目的 探讨子宫内膜癌中热休克转录因子-1(HSF-1)蛋白的表达水平及其与患者临床病理学特征的关系.方法 选取2014年1月至2016年5月在周口市妇幼保健院收集的术后或活检经病理学证实为子宫内膜癌标本67例,既往收集的35例正常子宫内膜组织,采用免疫组化染色观察两组HSF-1蛋白的表达水平,并探讨其临床病理学意义.结果 子宫内膜癌组织标本中HSF-1蛋白阳性表达率71.64%(48/67),正常子宫内膜组织中HSF-1蛋白阳性表达率31.43%(11/35),两组阳性表达率比较差异有统计学意义(P<0.05);子宫内膜癌组织标本中HSF-1蛋白在高分化组织中阳性表达率86.96%高于中低分化组织的63.64%,浸润深度≤1/2肌层的阳性表达率87.50%高于≥1/2肌层的62.79%,淋巴结转移阴性组织中的阳性表达率为80.49%高于阳性组织的57.69%,均差异有统计学意义(P<0.05).结论 HSF-1蛋白在子宫内膜癌组织中表达水平显著升高,并且与肿瘤的组织分化程度、淋巴结转移及浸润深度有关.     

Control release of mitochondria-targeted antioxidant by injectable self-assembling peptide hydrogel ameliorated persistent mitochondrial dysfunction and inflammation after acute kidney injury

Persistent mitochondrial injury occurs after acute kidney injury (AKI) and mitochondria-targeted antioxidant Mito-2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO) (MT) has shown benefits for AKI, but its efficiency is limited by short half-life and side effect in vivo. Self-assembling peptide (SAP) hydrogel is a robust platform for drug delivery. This study aims to develop an SAP-based carrier to slow release MT for enhancing its long-term therapeutic potency on AKI. The KLD with aspartic acid (KLDD) was designed. The microstructure and in vitro release of MT was assayed. The protective role of MT-loaded SAP (SAP-MT) hydrogel on renal mitochondrial injury, tubular apoptosis, and inflammation was evaluated in mice at five days after ischemia-reperfusion injury (IRI). Our results showed that KLDD could self-assemble into cross-linked nanofiber hydrogel and it had lower release rate than free MT and KLD hydrogel. Compared to IRI and free MT mice, SAP-MT mice exerted reduced renal mitochondria-produced ROS (mtROS) and improved mitochondrial biogenesis and architecture. Consequently, SAP-MT mice showed less renal tubular cell apoptosis, kidney injury marker kidney injury molecule-1 (Kim-1) expression, lower level of pro-inflammatory factors expression, and macrophages infiltration than those of IRI and free MT mice. This study suggested that SAP-MT ameliorated IRI due to its extended mitochondrial protection role than free MT and thus improved the long-term outcomes of AKI.     

Zero-order release and bioavailability enhancement of poorly water soluble Vinpocetine from self-nanoemulsifying osmotic pump tablet

Abstract

Solid self-nanoemulsifying (S-SNEDDS) asymmetrically coated osmotic tablets of the poorly water-soluble drug Vinpocetine (VNP) were designed. The aim was to control the release of VNP by the osmotic technology taking advantage of the solubility and bioavailability-enhancing capacity of S-SNEDDS. Liquid SNEDDS loaded with 2.5?mg VNP composed of Maisine? 35-1, Transcutol^® HP, and Cremophor^® EL was adsorbed on the solid carrier Aeroperl^®. S-SNEDDS was mixed with the osmotic tablet excipients (sodium chloride, Avicel^®, HPMC-K4M, PVP-K30, and Lubripharm^®), then directly compressed to form the core tablet. The tablets were dip coated and mechanically drilled. A 3²*2¹ full factorial design was adopted. The independent variables were: type of coating material (X₁), concentration of coating solution (X₂), and number of drills (X₃). The dependent variables included % release at 2?h (Y₁), at 4?h (Y₂), and at 8?h (Y₃). The in vivo performance of the optimum formula was assessed in rabbits. Zero-order VNP release was obtained by the single drilled 1.5% Opadry^® CA coated osmotic tablets and twofold increase in VNP bioavailability was achieved. The combination of SNEDDS and osmotic pump tablet system was successful in enhancing the solubility and absorption of VNP as well as controlling its release.     

Renewable poly(δ-decalactone) based block copolymer micelles as drug delivery vehicle: in vitro and in vivo evaluation

Polymers from natural resources are attracting much attention in various fields including drug delivery as green alternatives to fossil fuel based polymers. In this quest, novel block copolymers based on renewable poly(δ-decalactone) (PDL) were evaluated for their drug delivery capabilities and compared with a fossil fuel based polymer i.e. methoxy-poly(ethylene glycol)-b-poly(ε-caprolactone) (mPEG-b-PCL). Using curcumin as a hydrophobic drug model, micelles of PDL block copolymers with different orientation i.e. AB (mPEG-b-PDL), ABA (PDL-b-PEG-b-PDL), ABC (mPEG-b-PDL-b-poly(pentadecalactone) and (mPEG-b-PCL) were prepared by nanoprecipitation method. The size, drug loading and curcumin stability studies results indicated that mPEG-b-PDL micelles was comparable to its counterpart mPEG-b-PCL micelles towards improved delivery of curcumin. Therefore, mixed micelles using these two copolymers were also evaluated to see any change in size, loading and drug release. Drug release studies proposed that sustained release can be obtained using poly(pentadecalactone) as crystalline core whereas rapid release can be achieved using amorphous PDL core. Further, mPEG-b-PDL micelles were found to be non-haemolytic, up to the concentration of 40?mg/mL. In vivo toxicity studies on rats advised low-toxic behaviour of these micelles up to 400?mg/kg dose, as evident by histopathological and biochemical analysis. In summary, it is anticipated that mPEG-b-PDL block copolymer micelles could serve as a renewable alternative for mPEG-b-PCL copolymers in drug delivery applications.     

苦参碱结肠靶向微丸的制备及体外释放性能评价

目的:优选苦参碱结肠靶向微丸的制备工艺。方法:采用挤出-滚圆法制备苦参碱载药丸芯,利用流化床包衣技术对苦参碱载药丸芯进行包衣,并进行体外释放度的考察。结果:苦参碱载药丸芯的优化处方工艺为:苦参碱10g,微晶纤维素40g,羧甲基纤维素钠0.5g,纯化水46mL。其包衣微丸外层衣尤特奇L30D-55增重20%,内层衣尤特奇EPO增重30%。体外释放度实验表明,苦参碱包衣微丸在模拟的胃液中基本不释放,在pH 5.0磷酸缓冲液中较快释放,在pH 6.8磷酸缓冲液中则释放缓慢。结论:苦参碱载药丸芯处方工艺简单稳定。苦参碱包衣微丸结肠靶向性较好,同时模拟实验提示在结肠pH发生明显下降时苦参碱结肠靶向微丸仍具有结肠靶向性。     

Box-Behnken响应面法优化去氧氟尿苷缓释片处方及其体外释放机制研究

目的 响应面法优化去氧氟尿苷骨架片处方,并进行体外释放机制研究。方法 以羟丙甲纤维素(HPMC K4M)为骨架材料,结合其他辅料混合均匀,以直接压片法制备去氧氟尿苷骨架缓释片。通过Box-Behnken响应面法(Box-Behnken design-response surface methodology, BBD-RSM)对处方进行优化,研究优化处方的体外释药规律,并进行数学模型拟合。结果 优化处方的去氧氟尿苷骨架缓释片体外释放性能良好,可持续释药24h,药物释放符合Ritger-peppas模型。结论 通过BBD-RSM建立的模型可用于去氧氟尿苷骨架缓释片的处方优化,优化处方达到去氧氟尿苷缓释骨架片设计要求。