Hydrogel-Based lontotherapeutic Delivery Devices for Transdermal Delivery of Peptide/Protein Drugs

Hydrogels were synthesized as the drug reservoir matrix for peptide-based pharmaceuticals, and the iontophoretic release and transdermal delivery of three model peptides, insulin, calcitonin, and vasopressin, from these hydrogel-based iontotherapeutic devices were investigated. The swelling behavior of polyacrylamide-type hydrogel as a function of its monomer and cross-linker concentration was studied, and a hydrogel with minimal swelling was synthesized. The release of peptides from the hydrogel matrix was found to follow a Q vs t ^1/2 relationship under passive diffusion conditions, which shifted to a Q vs t relationship under iontophoresis-facilitated transport. The release flux (dQ/dt) of peptides was observed to decline when the electric current was turned off and was resumed when the current was turned on, thus allowing for modulation of drug release by varying the application parameters of iontophoresis-facilitated transport. The permeability coefficients for these peptides across the hairless rat skin were evaluated using the hydrogel formulations prepared from polyacrylamide, p-HEMA, and carbopol. A rank order of vasopressin > calcitonin > insulin was obtained in accordance with the order of molecular size.     

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。     

可溶性聚合物微针用于药物经皮递送的研究进展

目的： 了解国内外对于可溶性聚合物微针这一新型药物递送系统的研究进展，并对其优势及存在的问题进行分析，对发展前景进行展望。方法： 通过文献调研，总结可溶性聚合物微针的材料及功能，分析可溶性微针所解决的临床用药问题，以及各微针基质材料所具有的优势与面临的挑战。结果： 本文以临床不同的用药需求为视角进行分类，介绍了聚合物材料在可溶性微针递药系统中的应用，并对其优势及面临的挑战进行总结，对发展前景进行展望。结论： 目前对于可溶性聚合物微针的研究已取得了令人瞩目的进展。然而，为实现临床转化，可溶性聚合物微针递药系统的载药能力、安全性等方面仍然需要进一步的研究。     

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.     

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).     

多肽、蛋白质药物鼻腔给药系统的研究进展

随着生物技术和遗传工程的发展，多肽与蛋白质类药物的种类及数量日益增多，临床应用越来越广泛，相应的制剂学研究也日益受到重视。常见的多肽和蛋白质类药物如血管紧张素Ⅱ抑制剂、心房肽激素、脑啡肽、人生长激素（hGH）、免疫调节系统药物如集落刺激因子、代谢调节系统药物如胰岛素等，     

蛋白质和多肽类药物口服给药研究进展

蛋白质和多肽类药物具有良好的选择性和生物活性,已成为治疗众多疾病的首选药物。由于胃肠道内酶的降解作用以及肠道粘膜的低通透性,蛋白质和多肽类药物口服生物利用度极低,其常规给药一直以注射为主。为了使蛋白质和多肽类药物能够广泛应用于临床,研究人员对蛋白质和多肽类药物口服给药系统做了大量研究。目前用于提高蛋白质和多肽类药物口服生物利用度的方法主要有微粒给药系统、内源性细胞转运系统、应用酶抑制剂和黏附给药系统等。文章就这些方法在蛋白质和多肽类药物口服给药中的应用进行了综述。     

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。     

Fabrication of Rapidly Separable Microneedles for Transdermal Delivery of Metformin on Diabetic Rats

In this work, the rapidly separable microneedles (MNs) consisted of needle-tips and supporting bases have been fabricated by a step-by-step coating method. Poly (vinyl alcohol) (PVA) have been used to prepare the needle-tips of MNs in which they are capped on the solvable supporting bases consisted of sodium bicarbonate, poly (vinyl pyrolidone) (PVP), and tartaric acid (TA) (NaHCO₃/PVP/TA). After insertion into the skin, the needle-tips can be separated rapidly from the patches within 90 s due to the generation of air bubbles in the supporting bases by the reaction between NaHCO₃ and TA after absorption of tissue fluid, leading to the needle-tips remaining in the skin tissue. Metformin, a hypoglycemic drug, encapsulated in the needle-tips of MNs can be released due to swelling and decomposition of PVA by the absorption of tissue fluid. To investigate the pharmacological effect via transdermal delivery route, metformin-loaded MNs are applied on the diabetic SD rats induced by streptozotocin (STZ). They exhibit a longer hypoglycemic effect in vivo than that of subcutaneous injection. These results indicated the as-fabricated rapidly separable MNs present a promising platform for transdermal delivery of drugs against diabetic patients.     

纳米粒作为肽类和蛋白质类药物的载体

用纳米粒作为肽类和蛋白质药物的载体可以有效地克服肽类和蛋白质类药物在体内稳定性差、吸收不佳、半衰期短等缺陷，从而显著地增强疗效。本文从制备方法、体内吸收、药效学等三方面对近年来这一领域的研究进展进行综述，并介绍了最新的研究动向。     

Fabrication of Dissolving Polymer Microneedles for Controlled Drug Encapsulation and Delivery: Bubble and Pedestal Microneedle Designs

Dissolving microneedle patches offer promise as a simple, minimally invasive method of drug and vaccine delivery to the skin that avoids the need for hypodermic needles. However, it can be difficult to control the amount and localization of drug within microneedles. In this study, we developed novel microneedle designs to improve control of drug encapsulation and delivery using dissolving microneedles by (i) localizing drug in the microneedle tip, (ii) increasing the amount of drug loaded in microneedles while minimizing wastage, and (iii) inserting microneedles more fully into the skin. Localization of our model drug, sulforhodamine B in the microneedle tip by either casting a highly concentrated polymer solution as the needle matrix or incorporating an air bubble at the base of the microneedle achieved approximately 80% delivery within 10 min compared to 20% delivery achieved by the microneedles encapsulating nonlocalized drug. As another approach, a pedestal was introduced to elevate each microneedle for more complete insertion into the skin and to increase its drug loading capacity by threefold from 0.018 to 0.053 μL per needle. Altogether, these novel microneedle designs provide a new set of tools to fabricate dissolving polymer microneedles with improved control over drug encapsulation, loading, and delivery.     

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.     

Ocular Membrane Permeability of Hydrophilic Drugs for Ocular Peptide Delivery

The purpose of this study is to investigate the ocular membrane permeability and the permeation mechanism of hydrophilic drugs such as thyrotropin-releasing hormone (TRH), p-nitrophenyl β-cellopentaoside (PNP) and luteinizing hormone-releasing hormone (LHRH). The penetration of hydrophilic drugs was measured across the isolated corneal and conjunctival membranes of albino rabbits using a two-chamber diffusion glass cell. The corneal permeabilities of hydrophilic drugs were much lower than those of beta blockers reported previously. The corneal penetration of TRH was the highest among the hydrophilic drugs studied. Scraping the corneal epithelium increased the penetration of hydrophilic drugs. Conjunctival membranes showed higher permeability to hydrophilic drugs compared with corneal membranes. The permeability of drugs was also analysed by Fick's equation. The partition parameter and diffusion parameter of TRH, PNP and LHRH in the cornea were lower than those in scraped cornea and conjunctiva. In addition to the data of fluorescein isothiocyanate-dextran reported previously, the permeability coefficient of hydrophilic drugs through the cornea, scraped cornea and conjunctiva correlated with molecular weight of the drugs. The diffusion parameters of hydrophilic drugs decreased with an increase of molecular weight for all ocular membranes. The extent of dependency of partition parameters on the molecular weights of drugs varied according to the ocular membrane. These results indicate that ocular membranes are sufficiently different in permeation character and mechanism to control the extent and pathway for ocular absorption of hydrophilic drugs.     

Chitosan as a Novel Nasal Delivery System for Peptide Drugs

A nasal solution formulation of the cationic material chitosan was shown to greatly enhance the absorption of insulin across the nasal mucosa of rat and sheep. The absorption promoting effect was concentration dependent with the optimal efficacy obtained for concentrations higher than 0.2% and 0.5% in rats and sheep, respectively. The absorption promoting effect was reversible with time in a pulse-chase study. Histological examination of the nasal mucosa of rats exposed to a chitosan solution for 60 minutes showed little change.     

多肽类药物的口服吸收及其剂型研究

根据国外有关文献，分析了多肽类药物口服生物利用度低的原因，包括胃肠道黏膜的低渗透性、胃酸和各种消化酶的降解作用及首过效应等，并介绍从结构修饰、处方和剂型设计三方面提高多肽口服生物利用度的方法。     

胶原蛋白作为蛋白类药物载体系统的应用

近几年来有效的蛋白类药物载体系统一直是药剂学领域研究的热点,为了延长蛋白类药物的疗效,人们对许多材料作为蛋白类药物载体系统进行了研究.胶原蛋白作为众多候选材料之一,目前有凝胶、膜、海绵等制剂以及近几年才出现的供皮下注射的微条.该文对胶原蛋白在蛋白类药物载体系统中的应用进行了介绍.     

蛋白和多肽药物的透粘膜吸收

随着蛋白和多肽药物的增多，其非注射给药剂型的研究受到了越来越多的重视，本文综述了国外对鼻腔、口腔、口服、直肠和阴道几种主要透粘膜吸收给药途径的研究。蛋白和多肽药物的透粘膜给药剂型的研究推进了蛋白和多肽药物的临床应用。     

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。     

Polymer Coated Polymeric (PCP) Microneedles for Controlled Delivery of Drugs (Dermal and Intravitreal)

Microneedles are used to deliver drugs topically across the skin and mucous membranes. Dissolvable microneedles are made using soluble polymers, which disintegrates in the tissue and release the entire payload instantaneously including the polymer construct. Often, a slow release of drug into the tissue is desirable to overcome the severity of side effects at the site of administration as well as systemic adverse effects. In addition, controlled release of active pharmaceutical ingredient (API) only (not the excipients) is safe and effective particularly when the drug delivery is intended to sensitive organs like the eye. In this project, the feasibility of fabricating polymer coated polymeric (PCP) microneedles to achieve a gradual release of only the active ingredient from the device was investigated. The potential application of such PCP microneedles in the dermal and intravitreal drug delivery was also explored using animal tissue models. The PCP microneedles were found to be intact even after prolonged contact with the release medium. The time at which 50% (T50%) of dextran (10 K) was released in case of microneedles prepared using 20% of core polymer (PVP-K30) was about 15 min versus less than 5 min in the case of uncoated microneedles. Whereas when the core polymer concentration was increased to 50%, the T_50% was increased to 90 min. The rate of release depended on the polymer molecular weight grade. The rate of drug release was not influenced by the total amount of concentration of dextran. The PCP microneedles of lidocaine hydrochloride could constantly release the drug for up to 9 h in the skin tissue. Likewise, the PCP microneedles infused voriconazole, intravitreally for 6 h.