可溶微针在经皮药物递送领域的研究进展

可溶微针是一种极具潜力的新型透皮给药技术,它具有药物递送可控性、可调节性以及自我给药的便捷性等特点,在生物医学领域具有广阔的应用前景。综述微针技术的研究进展,包括微针分类、常用材料和制备方法,重点介绍了可溶微针在小分子、多肽、蛋白和核酸等药物递送领域的研究进展,系统讨论了可溶微针在生物医学领域的发展前景,以期为更精准智能的可溶微针经皮递药系统的研发提供参考。     

可溶性微针的研究进展

微针是一种新型经皮给药技术,具有无痛高效递送药物、良好的患者依从性以及便于自主给药等优势。较其他类型的微针而言,可溶性微针具有制备成本低、载药量大、应用范围广、无尖锐废弃物残留、易于控制药物释放等优点。综述可溶性微针的基质和制备方法、质量评价及其在药物递送、免疫接种等多个领域的应用,探讨可溶性微针发展中存在的问题并展望其未来的研究方向,为进一步开发、应用可溶性微针提供参考。     

马钱子碱双层聚合物可溶性微针的制备及其在不同载药方式下的体外经皮渗透性研究

目的:制备马钱子碱(Bru)双层聚合物可溶性微针,并考察其在不同载药方式下的体外经皮渗透特性。方法:以微针揭膜难易程度、阵列完整性、气泡量、针型、针尖硬度、背衬韧性等为考察指标分别筛选微针的针尖材料和背衬材料,并以微针形态为考察指标筛选基质溶胀方法和干燥方法,然后采用两步法制备双层聚合物可溶性微针,并进行表征和安全性评价。通过Franz扩散池法考察针尖载药、背衬载药、全载药Bru双层聚合物可溶性微针的体外经皮渗透特性,绘制体外透皮曲线并计算累积渗透量(Q)和累积渗透率。结果:优选的双层聚合物可溶性微针的制备工艺为以硫酸软骨素-聚乙烯吡咯烷酮K30(1∶1,m/m)作为针尖材料,15%聚乙烯醇作为背衬材料,在4℃冰箱静置1 h进行基质溶胀,干燥器室温干燥24 h。所制微针阵列完整,机械性能良好,能成功刺穿铝箔和大鼠皮肤,微针处理后皮肤在6 h内即可恢复到原来的状态。体外透皮试验结果显示,微针递药可大大提高Bru的经皮累积渗透量,针尖材料可在10 min内溶解并释放药物;针尖载药微针在8 h内基本释放完全,Q_{8 h}为102.185μg/cm²,累...     

眼用微针药物递送系统研究进展

由于眼睛特殊的生理结构,眼部疾病(包括眼前段和眼后段)的治疗一直是充满挑战的。传统的给药方式,如局部给药和全身给药,生物利用度低,难以达到治疗效果。临床常用的眼部注射给药,虽可克服生物膜屏障,但一系列严重的不良反应使患者的耐受性差。微针,是一种微创无痛且具有穿透性的给药方式,可将药物递送至眼前段和眼后段,在眼部疾病的应用中受到了广泛的关注。目前,用于眼部药物递送的微针主要有涂布微针、中空微针和可溶微针3类,本文分别概述了3类眼用微针的代表性研究,分析各类微针的特点,为微针在眼部药物递送中的扩大应用提供参考。     

高分子聚合物用于siRNA递送系统的研究进展

小干扰RNA（siRNA）具有沉默互补的目标信使RNA（mRNA）从而抑制疾病相关基因表达的作用。因其高效性及特异性,siRNA具有作为基因药物的巨大潜力,但其在体内易受到血管屏障、内涵体及RNA酶等因素的影响,从而难以发挥药效。因此,设计高效的能够负载siRNA的纳米载体以使其富集至靶标是目前siRNA药物研发的重要任务,高分子聚合物纳米载体是目前研究热点之一。本文就高分子聚合物纳米载体实现siRNA药物递送的研究进展进行综述。     

日夜两用生长激素微针贴片的制备及体外评价

目的 制备日夜两用生长激素微针贴片,模拟人体生理状态下内源性生长激素分泌的昼夜差异,实现生长激素给药时间和用量的优化,同时有效减轻皮下注射给药疼痛感,提高患者使用依从性。方法 采用铸模法制备微针贴片,通过光学显微镜和扫描电子显微镜观察微针表面形貌。经体外释放试验确定含生长激素微针制备的最佳工艺条件,包括优化紫外交联时间和交联剂含量。通过微针力学强度测试和体外透皮试验验证微针贴片有效穿透皮肤的可行性,通过圆二色光谱测定药物的稳定性。通过调试负载不同剂量生长激素制备日用和夜用微针贴片。结果 在显微镜下观察到微针排列整齐,针体完整、尖锐,微针在药物释放前后形貌无明显差异。工艺优化结果表明,当紫外交联时间为7 min,交联剂用量为1.5%时,微针贴片可以有效穿透离体大鼠皮肤,同时实现了生长激素在12 h内稳定释放,且微针释放出的蛋白药物构象无明显变化。通过在针体中负载不同剂量生长激素,制备了日用和夜用生长激素微针贴片。结论 本研究制备的微针能够顺应在生理状态下生长激素分泌的日夜差异,实现了适宜时间释放适量生长激素的目标,未来可进一步优化微针药物负载量以满足不同患者的实际使用需求,以期实现个体化治疗。     

不锈钢微针经皮给药的研究

目的：将不锈钢微针阵列应用于经皮给药。考察离体大鼠皮肤经不同针形微针预处理相同时间、相同针形微针预处理不同时间后，模型药物鬼臼毒素经大鼠皮肤的透皮能力。方法：微针预处理大鼠皮肤后，用改进的Franz扩散池研究鬼臼毒素对皮肤的透皮速率。高效液相色谱法测定鬼臼毒素的含量。结果：皮肤经微针预处理后进行鬼臼毒素透皮，其透皮速率比未经微针处理时有明显提高。三角形微针、梯形微针、矛形微针对鬼臼毒素的促渗能力依次增强；三者所引起的鬼臼毒素在皮肤中的滞留量有显著差异。同种针形微针预处理皮肤时间越长，鬼臼毒素的透皮速率越大；但微针预处理时间对皮肤中的药物滞留量无显著影响。结论：微针用于药物经皮给药时，微针针形、微针的预处理时间对药物的经皮渗透具有重要影响。     

微针经皮给药应用的新进展

微针有助于改善患者的用药依从性,提高药物的生物利用度.近年来,微针在疫苗接种、蛋白质和多肽给药、DNA给药、皮肤美容、眼科用药、局部麻醉、微量取样等领域均有应用.微针在胰岛素给药和局部麻醉中的研究已进入临床试验阶段,在皮肤美容、疫苗接种和蛋白质给药方面已有上市产品.     

Polymer Microneedles for Controlled-Release Drug Delivery

Purpose As an alternative to hypodermic injection or implantation of controlled-release systems, this study designed and evaluated biodegradable polymer microneedles that encapsulate drug for controlled release in skin and are suitable for self-administration by patients. Methods Arrays of microneedles were fabricated out of poly-lactide-co-glycolide using a mold-based technique to encapsulate model drugs—calcein and bovine serum albumin (BSA)—either as a single encapsulation within the needle matrix or as a double encapsulation, by first encapsulating the drug within carboxymethylcellulose or poly-l-lactide microparticles and then encapsulating drug-loaded microparticles within needles. Results By measuring failure force over a range of conditions, poly-lactide-co-glycolide microneedles were shown to exhibit sufficient mechanical strength to insert into human skin. Microneedles were also shown to encapsulate drug at mass fractions up to 10% and to release encapsulated compounds within human cadaver skin. In vitro release of calcein and BSA from three different encapsulation formulations was measured over time and was shown to be controlled by the encapsulation method to achieve release kinetics ranging from hours to months. Release was modeled using the Higuchi equation with good agreement (r² ≥ 0.90). After microneedle fabrication at elevated temperature, up to 90% of encapsulated BSA remained in its native state, as determined by measuring effects on primary, secondary, and tertiary protein structure. Conclusions Biodegradable polymer microneedles can encapsulate drug to provide controlled-release delivery in skin for hours to months.     

Transdermal Delivery of Sumatriptan Succinate Using Iontophoresis and Dissolving Microneedles

This study focuses on the in vitro transdermal transport of sumatriptan succinate using combined iontophoresis and dissolving polymeric microneedle arrays. Permeation experiments were performed to evaluate the effects of formulation parameters on drug release from polyvinylpyrrolidone systems under mild electrical current (≤500 μA/cm²). The preparations consisted of hydrophilic, positively charged molecules encapsulated in a water-soluble and biocompatible polymeric material. Current densities of 100, 300, and 500 μA/cm² were applied during a 6-h period using silver/silver chloride electrodes. The circular array consisted of 600 needles and occupied a 0.785 cm² area. Tests, carried out with Franz diffusion cells and skin of Göttingen minipigs, showed that small decreases in the polymer concentration led to negligible lag times and marked increases in the cumulative amount of drug permeated in 6 h (Q_6h) and in the flux (J_ss). At 500 μA/cm², Q_6h and J_ss nearly doubled for a microneedle loaded with 5% (w/w) sumatriptan and 20% (w/w) PVP (lag time = 0 min; Q_6h = 2888 μg/cm²; J_ss = 490 μg/cm²/h) relative to a system loaded with 5% (w/w) drug and 30% (w/w) PVP (lag time = 36 min; Q_6h = 1437 μg/cm²; J_ss = 266 μg/cm²/h).     

Dissolving Microneedles Loaded With Etonogestrel Microcrystal Particles for Intradermal Sustained Delivery

The study design is that lipophilic drug was encapsulated within dissolving microneedles (DMNs) for sustained-release delivery over 1 week. Etonogestrel (ENG), the progestogen used in hormonal contraceptives, was loaded in 2-layered DMNs in the form of microcrystal particles (MPs). In vitro release study indicated that ENG in the MP form could sustain drug release compared to noncrystal form. Hydroxypropyl methylcellulose and polyvinyl alcohol were used to prepare the fast dissolving needle tips and flexible back layer, respectively. The mechanical strength of microneedles was not affected even with the drug-loading efficiency of 50.0% in needle tips. The penetration depth of DMNs in skin, observed using a confocal laser scanning microscope, was approximately 280 μm. The tips of DMNs could be dissolved in rat skin within 1 h with a drug delivery efficiency of 63.8 ± 2.0%. The pharmacokinetic study of DMN treatment in rats showed that the plasma levels of ENG were a dose-dependent profile and were much steadier than intradermal (ID) injections. There was no statistical difference between bioavailability of ENG treated with DMNs or ID injections (p >0.05). Therefore, the novel DMNs loaded with drug MP provided a potential minimally invasive route for ID sustained delivery of lipophilic drug.     

微针经皮给药技术

微针是介于皮下注射和透皮贴剂之间的一种给药方式,利用在皮肤角质层产生的微小孔道来显著增加药物的经皮吸收。综述微针经皮给药技术的研究进展,介绍制造微针的材料和方法、微针的给药方式及其在经皮给药系统中的应用。     

Characterization of Solid Maltose Microneedles and their Use for Transdermal Delivery

Purpose To characterize solid maltose microneedles and assess their ability to increase transdermal drug delivery. Materials and Methods Microneedles and microchannels were characterized using methylene blue staining and scanning electron microscopy. Diffusion pattern of calcein was observed using confocal scanning laser microscopy. Transepidermal water loss (TEWL) measurements were made to study the skin barrier recovery after treatment. Uniformity in calcein uptake by the pores was characterized and percutaneous penetration of nicardipine hydrochloride (NH) was studied in vitro and in vivo across hairless rat skin. Results Microneedles were measured to be 508.46 ± 9.32 μm long with a radius of curvature of 3 μm at the tip. They penetrated the skin while creating microchannels measuring about 55.42 ± 8.66 μm in diameter. Microchannels were visualized by methylene blue staining. Pretreatment with microneedles resulted in the migration of calcein into the microchannels. TEWL increased after pretreatment and uptake of calcein by the pores was uniform as measured by the pore permeability index values. NH in vitro transport across skin increased significantly after pretreatment (flux 7.05 μg/cm²/h) as compared to the untreated skin (flux 1.72 μg/cm²/h) and the enhanced delivery was also demonstrated in vivo in hairless rats. Conclusion Maltose microneedles were characterized and shown to create microchannels in the skin, which were also characterized and shown to improve the transdermal delivery of NH.     

Rapidly Dissolving Microneedle Patches for Transdermal Iron Replenishment Therapy

The prevalence of iron deficiency anemia (IDA) is predominant in women and children especially in developing countries. The disorder affects cognitive functions and physical activity. Although oral iron supplementation and parenteral therapy remains the preferred choice of treatment, gastric side effects and risk of iron overload decreases adherence to therapy. Transdermal route is an established approach, which circumvents the side effects associated with conventional therapy. In this project, an attempt was made to investigate the use of rapidly dissolving microneedles loaded with ferric pyrophosphate (FPP) as a potential therapeutic approach for management of IDA. Microneedle array patches were made using the micromolding technique and tested in vitro using rat skin to check the duration required for dissolution/disappearance of needles. The ability of FPP-loaded microneedles to replenish iron was investigated in anemic rats. Rats were fed iron-deficient diet for 5 weeks to induce IDA following which microneedle treatment was initiated. Recovery of rats from anemic state was monitored by measuring hematological and biochemical parameters. Results from in vivo study displayed significant improvements in hemoglobin and serum iron levels after 2-week treatment with FPP-loaded microneedles. The study effectively demonstrated the potential of microneedle-mediated iron replenishment for treatment of IDA.     

Transdermal Delivery of Insulin Using Microneedles in Vivo

PURPOSE: The purpose of this study was to design and fabricate arrays of solid microneedles and insert them into the skin of diabetic hairless rats for transdermal delivery of insulin to lower blood glucose level. METHODS: Arrays containing 105 microneedles were laser-cut from stainless steel metal sheets and inserted into the skin of anesthetized hairless rats with streptozotocin-induced diabetes. During and after microneedle treatment, an insulin solution (100 or 500 U/ml) was placed in contact with the skin for 4 h. Microneedles were removed 10 s, 10 min, or 4 h after initiating transdermal insulin delivery. Blood glucose levels were measured electrochemically every 30 min. Plasma insulin concentration was determined by radioimmunoassay at the end of most experiments. RESULTS: Arrays of microneedles were fabricated and demonstrated to insert fully into hairless rat skin in vivo. Microneedles increased skin permeability to insulin, which rapidly and steadily reduced blood glucose levels to an extent similar to 0.05-0.5 U insulin injected subcutaneously. Plasma insulin concentrations were directly measured to be 0.5-7.4 ng/ml. Higher donor solution insulin concentration, shorter insertion time, and fewer repeated insertions resulted in larger drops in blood glucose level and larger plasma insulin concentrations. CONCLUSIONS: Solid metal microneedles are capable of increasing transdermal insulin delivery and lowering blood glucose levels by as much as 80% in diabetic hairless rats in vivo.     

电致孔技术在透皮给药中的应用

电致孔可显著提高药物的经皮吸收,有望用于多肽和蛋白质类生物大分子药物的透皮给药.本文对电致孔法的透皮促渗机制、影响因素以及安全性进行了讨论,并介绍了有关实验装置及其在透皮给药中的应用.