Efficient polymer nanoparticle-mediated delivery of gene editing reagents into human hematopoietic stem and progenitor cells

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载紫杉醇的大黄酸偶联物纳米胶束的制备及初步评价

目的制备载紫杉醇的D-α-生育酚聚乙二醇1000琥珀酸酯(D-α-tocopheryl polyethylene glycol 1000 succinate,TPGS)修饰的羧甲基壳聚糖-大黄酸偶联物(PTX/TPGS-CR)纳米胶束,并对其进行初步评价。方法采用透析法,以载药量、包封率及粒径为指标,通过单因素考察优化PTX/TPGS-CR纳米胶束的制备工艺并进行验证。以溶血实验及血管刺激性实验初步考察PTX/TPGS-CR纳米胶束的安全性。四甲基偶氮唑盐微量酶反应比色法(MTT)法考察PTX/TPGS-CR纳米胶束对Hela细胞的毒性。通过激光扫描共聚焦显微镜定性和流式细胞仪定量考察Hela细胞对PTX/TPGS-CR纳米胶束的摄取情况。结果制备工艺优化后制得的PTX/TPGS-CR纳米胶束粒径为(197.3±4.4)nm,PDI为(0.131±0.021),电位为(-31.8±0.5)mV,载药量为(48.20±3.03)%,包封率为(87.26±4.91)%。溶血实验结果表明,其溶血率低于1.71%;血管静脉注射无明显刺激性。其对Hela细胞的杀伤作用具有浓度和时间依赖性,能被Hela细胞高效摄取。结论PTX/TPGS-CR纳米胶束载药量和包封率高,安全性好,其体外抗肿瘤活性稍优于Taxol?。     

An update on polymer-lipid hybrid systems for improving oral drug delivery

Introduction: A promising approach that has recently emerged to overcome the complex biobarriers and interrelated challenges associated with oral drug absorption is to combine the benefits of polymeric and lipid-based nanocarriers within one hybrid system. This multifaceted formulation strategy has given rise to a plethora of polymer-lipid hybrid (PLH) systems with varying nanostructures and biological activities, all of which have demonstrated the ability to improve the biopharmaceutical performance of a wide range of challenging therapeutics.

Areas covered: The multitude of polymers that can be combined with lipids to exert a synergistic effect for oral drug delivery have been identified, reviewed and critically evaluated. Specific focus is attributed to preclinical studies performed within the past 5 years that have elucidated the role and mechanism of the polymer phase in altering the oral absorption of encapsulated therapeutics.

Expert opinion: The potential of PLH systems has been clearly identified; however, improved understanding of the structure–activity relationship between PLH systems and oral absorption is fundamental for translating this promising delivery approach into a clinically relevant formulation. Advancing research within this field to identify optimal polymer, lipid combinations and engineering conditions for specific therapeutics are therefore encouraged.     

Biofilm formation by ST17 and ST19 strains of Streptococcus agalactiae

Bacterial biofilms are an important virulence factor with a vital role in evasion from the host immune system, colonization and infection. The aim of the present study was to evaluate in vitro the effects of three environmental factors (H⁺, glucose and human plasma) in biofilm formation, by carrier and invasive Streptococcus agalactiae strains of ST17 and ST19 sequence types, including DNase producers and non-producers. Bacteria ability to assemble biofilms was classified based on crystal violet assay. Biofilm formation was also monitored by scanning electron microscopy. Depending on the growth medium used, each bacterial isolate could fit in different biofilm production categories. Our data showed that optimal conditions for S. agalactiae biofilm assembly were reached after 48 h incubation at pH 7.6 in the presence of glucose and inactivated human plasma. In the presence of inactivated human plasma, the biofilm biomass of ST19 strains experienced a higher increase than ST17 strains. The composition of the extracellular polymeric matrix of the three strongest biofilm producers (all from ST17) was accessed by enzymatic digestion of mature biofilms and proteins were shown to be the predominant component. The detailed identification of the extracellular protein components should contribute to the development of new therapeutic strategies to fight S. agalactiae infections.     

Hypocholesterolaemic mechanism of bitter melon aqueous extracts via inhibition of pancreatic cholesterol esterase and reduction of cholesterol micellar solubility

This study investigated the hypocholesterolaemic effects of bitter melon aqueous extracts (BMAE) in vitro, the inhibitory effects of BMAE on pancreatic cholesterol esterase (CEase) and incorporation of cholesterol into micelles were investigated. BMAE decreased the in vitro micellar solubility of cholesterol in a dose-dependent manner. The conformation of CEase was investigated by means of circular dichroism (CD) and fluorescence. The result revealed the decrease of α-helix contents, increase of β-sheet and exposure of aromatic amino acid residuals. The incorporation of cholesterol into micelles was inhibited by BMAE. A complex was observed by transmission electron microscopy (TEM), which indicated interaction between cholesterol and BMAE. The result revealed that BMAE can play a role in decreased intestinal cholesterol absorption via inhibition of CEase, and of micelle formation.     

Dehydroascorbic Acid and pGPMA Dual Modified pH-Sensitive Polymeric Micelles for Target Treatment of Liver Cancer

In clinical therapy, the poor prognosis of hepatocellular carcinoma (HCC) is mainly attributed to the failure of chemotherapeutical agents to accumulate in tumor as well as lack of potency of tumor penetration. In this work, we developed actively tumor-targeting micelles with pH-sensitive linker as a novel nanocarrier for HCC therapy. These micelles comprised biodegradable poly(ethylene glycol)-poly(aspartate) polymers, in which paclitaxel can be covalently conjugated to pAsp via an acid-labile acetal bond to form pH-responsive structures. In vitro drug release studies showed that these structures were stable in physiological condition, whereas collapsed once internalized into cells due to the mildly acidic environment in endo/lysosomes, resulting in facilitated intracellular paclitaxel release. In addition, dehydroascorbic acid and guanidinopropyl methacrylamide polymers were decorated on the surface of micelles to achieve specific tumor accumulation and tumor penetration. Cellular uptake and in vivo imaging studies proved that these micelles had remarkable targeting property toward hepatocarcinoma cells and tumor. Enhanced anti-HCC efficacy of the micelles was also confirmed both in vitro and in vivo. Therefore, this micellar system may be a potential platform of chemotherapeutics delivery for HCC therapy.     

Impact of Superdisintegrants and Film Thickness on Disintegration Time of Strip Films Loaded With Poorly Water-Soluble Drug Microparticles

Although strip films are a promising platform for delivery of poorly water-soluble drug particles via slurry casting, the effect of critical material attributes, for example, superdisintegrants (SDIs) on critical quality attributes, including film disintegration time (DT), remains underexplored. A 2-level factorial design is considered to examine the impact of the SDI type (sodium starch glycolate and croscarmellose sodium), their amount, and film thickness. SDIs were used with hydroxypropyl methylcellulose (E15LV) and glycerin solutions along with viscosity matching. Fenofibrate, a model poorly water-soluble drug, was micronized and surface modified via fluid energy milling. Significant decreases in film DT, measured using 3 different methods, were observed due to the addition of SDIs. Percentage reduction in DT was a strong function of SDI amount, and thinner films disintegrated faster. Films with either higher SDI concentrations (>9%) or films under 80 μm, exhibited fast DT (<180 s, European Pharmacopeia). All thin films (50-60 μm) exhibited immediate release (>80% in 10 min). All films achieved good content uniformity, except for those with the lowest amount of SDI, attributed to insufficient viscosity and thickness nonuniformity due to the SDI. Finally, all films achieved adequate mechanical properties, notwithstanding minor negative impact of SDIs.     

Amphotericin B-Loaded Poly(lactic-co-glycolic acid) Nanofibers: An Alternative Therapy Scheme for Local Treatment of Vulvovaginal Candidiasis

Vulvovaginal candidiasis is an inflammation localized in the vulvovaginal area. It is mostly caused by Candida albicans. Its treatment is based on the systemic and local administration of antifungal drugs. However, this conventional therapy can fail owing to the resistance of the Candida species and noncompliance of patients. Amphotericin B-loaded poly(lactic-co-glycolic acid) nanofibers are single-use, antifungal, controlled drug delivery systems, and represent an alternative therapeutic scheme for the local treatment of vulvovaginal candidiasis. Nanofibers were characterized by analytical techniques and with an in vitro drug delivery study. In vitro and in vivo fungicidal activity of amphotericin B released from nanofibers was evaluated using the agar diffusion method and an experimental murine model of vulvovaginal candidiasis, respectively. Analytical techniques showed that amphotericin B was physically mixed in the polymeric nanofibers. Nanofibers controlled the delivery of therapeutic doses of amphotericin B for 8 consecutive days, providing effective in vitro antifungal activity and eliminated the in vivo vaginal fungal burden after 3 days of treatment and with only one local application. Amphotericin B-loaded poly(lactic-co-glycolic acid) nanofibers could be potentially applied as an alternative strategy for the local treatment of vulvovaginal candidiasis without inducing fungal resistance, yet ensuring patient compliance.     

Development of a docetaxel micellar formulation using poly(ethylene glycol)–polylactide–poly(ethylene glycol) (PEG–PLA–PEG) with successful reconstitution for tumor targeted drug delivery

Docetaxel (DTX)-loaded polymeric micelles (DTBM) were formulated using the triblock copolymer, poly(ethylene glycol)–polylactide–poly(ethylene glycol) (PEG–PLA–PEG), to comprehensively study their pharmaceutical application as anticancer nanomedicine. DTBM showed a stable formulation of anticancer nanomedicine that could be reconstituted after lyophilization (DTBM-R) in the presence of PEG 2000 and D-mannitol (Man) as surfactant and protectant, respectively. DTBM-R showed a particle size less than 150?nm and greater than 90% of DTX recovery after reconstitution. The robustly formed micelles might minimize systemic toxicity due to their sustained drug release and also maximize antitumor efficacy through increased accumulation and release of DTX from the micelles. From the pharmaceutical development point of view, DTBM-R showing successful reconstitution could be considered as a potent nanomedicine for tumor treatment.