化学促渗剂及其机理的探讨

目的:阐述常用化学促渗剂在透皮制剂方面的应用特点并对其促渗机理进行探讨.方法:从化学促渗剂的分类、结构、影响因数、促渗机理及近年的应用进展等方面进行综述.结果与结论:阐释了不同化学促渗剂的特点及促渗机制.应建立能动态跟踪药物透皮过程的观察方法,以便更客观、合理和深层次地认识和发挥化学促渗剂的作用.     

不同促渗剂对盐酸氨酮戊酸原位凝胶体外透皮吸收的影响

目的：研究不同透皮促渗剂对盐酸氨酮戊酸原位凝胶体外透皮吸收的影响,为筛选最佳透皮促渗剂提供实验依据。方法：采用Franz扩散池法,以离体大鼠皮肤为模型,选择3种常用透皮促渗剂月桂氮芯卓酮（azone,AZ）、丙二醇（propylene glycol,PG）、二甲亚砜（dimethyl sulfoxide,DMSO）,分别考察单一促渗剂及二元促渗剂对盐酸氨酮戊酸原位凝胶体外透皮吸收的影响。结果：含促渗剂盐酸氨酮戊酸原位凝胶体外透皮吸收显著高于未添加促渗剂盐酸氨酮戊酸原位凝胶及市售制剂;采用单一促渗剂时,1% PG促渗效果最好;采用二元促渗剂时,3% AZ+1% PG促渗效果最好;3% AZ+1% PG促渗效果优于1% PG,含促渗剂3% AZ+1% PG的盐酸氨酮戊酸原位凝胶透皮性优于市售制剂艾拉。结论：添加促渗剂的方法能够显著改善盐酸氨酮戊酸的体外透皮吸收性,3% AZ+1% PG构成的二元促渗剂用于盐酸氨酮戊酸原位凝胶促渗效果最佳;本研究为设计优良的盐酸氨酮戊酸经皮给药系统药物奠定了重要基础。     

氮酮应用研究进展

目的：介绍氮酮在制剂中的应用及研究进展，为透皮吸收制剂的开发提供一定参考。方法：查阅国内关氮酮应用的献报道，进行整理、综述。结果：氮酮单用或与其它促渗剂合用均能不同程度加快药物经皮渗透速度，提高累积渗透率。结论：氮酮在透皮吸收制剂的研制和开发中具有广阔的应用前景。     

透皮吸收制剂的研究进展

目的:综述近年来透皮吸收制剂的研究进展.方法:以国内外大量有代表性的论文为基础,进行分析、整理和归纳.结果:透皮吸收制剂在促渗方法、使用材料等方面获得了很大的发展,制剂的皮肤渗量增大,渗透速率提高,上市产品增多.结论:透皮吸收制剂具有广泛的研究和应用前景.     

纳米制剂在透皮药物递送系统中的应用研究进展

透皮药物递送系统作为一种非侵入式给药途径，与传统给药方式相比具有顺应性高、无首过效应等优势。纳米技术的应用使得透皮药物递送系统的药物选择范围进一步扩大，并提高了药物的治疗效果，形成了一种极具价值、令人期待的新型给药方式。目前常用于透皮药物递送系统的纳米制剂包括纳米乳、脂质纳米囊泡、脂质纳米粒、聚合物纳米粒、纳米晶体、溶致液晶纳米粒等。介绍了皮肤屏障和透皮递送的常用促渗方法，综述了各类应用于透皮药物递送系统的纳米制剂及其与物理促渗方法联合应用的研究进展，以期为纳米制剂在透皮递送方面的深入研究提供参考。     

涂膜剂的研究概述

透皮制剂（TDD）已成为国际制药业界竞相开发的新技术,涂膜剂是透皮制剂的一种。随着近几年透皮制剂技术的发展。涂膜剂的研究与开发也异常活跃,本文主要从涂膜剂基质、促渗剂、成膜材料、促渗技术、制备工艺及检测分析等几个方面的研究进展作一综述。     

不同种类的促渗剂对芍药苷透皮吸收的影响

目的：研究6种促渗剂对芍药苷透皮吸收的影响。方法采用Franz扩散池,生理盐水为接收介质,小鼠腹部皮肤为透皮屏障,计算不同促渗剂对芍药苷的累积渗透量Q及相关参数,并优选效果最好的促渗剂,研究其浓度对促渗效果的影响。结果试验中促渗剂对芍药苷均有不同程度的促渗作用。结论0.2%卡波姆凝胶的促渗效果最好,本实验可为芍药苷透皮吸收制剂处方的优化提供依据。     

壳聚糖及其衍生物作为促渗剂在经皮给药系统中的研究进展

壳聚糖及其衍生物具有良好的生物特性,广泛应用于医药领域中。近些年,越来越多的研究发现其应用于经皮给药系统中具有一定的促渗作用,因此本文对壳聚糖及其衍生物在经皮给药系统中的透皮促渗机制、应用及前景进行综述。     

中药挥发油作为透皮吸收促进剂的研究进展

近年来,透皮吸收制剂正受到人们的普遍关注,而其中存在的一个难题就是吸收率低,难以达到有效的治疗浓度。透皮吸收促进剂的应用可以有效地解决这一难题。中药挥发油作为透皮吸收促进剂不良反应小,有促渗、治疗双重作用,因此逐渐引起了广大医药工作者的注意。就中药挥发油作促透剂的研究现状做一综述。     

非甾体抗炎药透皮给药的研究进展

目的:介绍非甾体抗炎药经皮给药的进展。方法:就常见非甾体抗炎药的透皮剂型、促渗方法和透皮模型进行综述。结果与结论:研究非甾体抗炎药经皮给药对此类药物的透皮制剂开发有重要意义。     

Transcending the skin barrier to deliver peptides and proteins using active technologies

Peptides and proteins have been investigated as promising therapeutic agents over the past decade. These macromolecules are conventionally administered by the parenteral route because oral delivery is associated with degradation in the gastrointestinal tract. Transdermal delivery presents a promising alternative route of drug delivery, avoiding pain associated with parenteral administration and degradation issues associated with oral delivery. However, the barrier properties of skin limit delivery to only small, moderately lipophilic molecules. Hence, hydrophilic macromolecules like peptides and proteins cannot passively permeate across skin. Active physical enhancement approaches such as iontophoresis electroporation, microneedles treatment, and sonophoresis have been developed to assist transdermal delivery of peptides and proteins. This review describes active physical transdermal enhancement approaches for transdermal delivery of peptides and proteins. The mechanisms associated with each technique and important parameters governing transdermal delivery of peptides and proteins are discussed in detail. Combinations of enhancement techniques for synergistic enhancement in protein and peptide delivery are also discussed.     

Nanostructured lipid carrier-based hydrogel formulations for drug delivery: A comprehensive review

The scientific literature today provides several systems that can deliver active pharmaceutical ingredients (APIs) across the skin. These include reservoir matrices, matrix diffusion-controlled devices, multiple polymer devices and multilayer matrix assemblies. Among these, nanostructured lipid carriers (NLC) have emerged as novel systems composed of physiological lipid materials suitable for topical, dermal and transdermal administration. This review focuses on the design characteristics, production and composition of semi-solid formulations containing NLC as API carriers. One of the useful semi-solid systems are hydrogels, which can be used as vehicles to provide appropriate consistency for NLC formulations to be applied onto the skin. In the present review recent developments in the field are highlighted, including examples of APIs successfully entrapped within NLC now amenable for delivery via the skin. Further innovations in NLC composition and formulation, as well as in semi-solid hydrogel assemblies, are likely to expand the number of APIs available for topical, dermal and transdermal delivery.     

Topical delivery of cyclosporin A: an in vitro study using monoolein as a penetration enhancer.

Topical delivery of cyclosporin A (CysA) is of great interest for the treatment of autoimmune skin disorders, but it is frequently ineffective due to poor drug penetration in the skin. The present study was aimed at investigating whether the presence of monoolein (a lipidic penetration enhancer) in a preparation of propylene glycol can improve CysA delivery to the skin. CysA was incorporated in a propylene glycol preparation containing 5-70% (w/w) of monoolein. The topical (to the skin) and transdermal (across the skin) delivery of CysA were evaluated in vitro using porcine ear skin mounted in a Franz diffusion cell. CysA was quantified by UV-HPLC. At 5%, monoolein increased only the transdermal delivery of CysA. At 10%, it increased both topical and transdermal delivery. When the concentration of monoolein was further increased (20-70% w/w), an interesting phenomenon was observed: the topical delivery of CysA was still elevated but its transdermal delivery was substantially reduced. It was concluded that monoolein (in propylene glycol formulations) can promote the topical delivery of CysA, with reduced transdermal delivery.     

Comparative Study of the Skin Penetration of Protein Transduction Domains and a Conjugated Peptide

Purpose. We examined the ability of a protein transduction domain (PTD), YARA, to penetrate in the skin and carry a conjugated peptide, P20. The results with YARA were compared to those of a well-known PTD (TAT) and a control, nontransducing peptide (YKAc). The combined action of PTDs and lipid penetration enhancers was also tested.Methods. YARA, TAT, YKAc, P20, YARA-P20, and TAT-P20 were synthesized by Fmoc chemistry. Porcine ear skin mounted in a Franz diffusion cell was used to assess the topical and transdermal delivery of fluorescently tagged peptides in the presence or absence of lipid penetration enhancers (monoolein or oleic acid). The peptide concentrations in the skin (topical delivery) and receptor phase (transdermal delivery) were assessed by spectrofluorimetry. Fluorescence microscopy was used to visualize the peptides in different skin layers.Results. YARA and TAT, but not YKAc, penetrated abundantly in the skin and permeated modestly across this tissue. Monoolein and oleic acid did not enhance the topical and transdermal delivery of TAT or YARA but increased the topical delivery of YKAc. Importantly, YARA and TAT carried a conjugated peptide, P20, into the skin, but the transdermal delivery was very small. Fluorescence microscopy confirmed that free and conjugated PTDs reached viable layers of the skin.Conclusions. YARA and TAT penetrate in the porcine ear skin in vitro and carry a conjugated model peptide, P20, with them. Thus, the use of PTDs can be a useful strategy to increase topical delivery of peptides for treatment of cutaneous diseases.     

Drug crystallization – implications for topical and transdermal delivery

ABSTRACT

Introduction: Crystallization of actives in skin following topical application was suggested by studies in the 1950s and 1960s but is poorly understood. In contrast, the problem of crystallization of actives on skin and in transdermal formulations has been known for many years.

Areas covered: With respect to crystallization in skin, this review describes early reports of a skin ‘reservoir’ and possible reasons underlying its genesis. Techniques to study crystallization on and in skin and in transdermal patches are outlined. The role of the vehicle in skin delivery is emphasised. Studies which have investigated permeation from crystalline particles are described. Approaches to limit crystallization of actives are discussed. Using supersaturation and antinuclean polymers, control of crystal size is possible; controlled release from crystals is also employed in transdermal patches.

Expert Opinion: Drug crystallization has significant implications for topical and transdermal delivery. Approaches have been developed to counteract the issue for transdermal patches but crystallization in and on the skin for other formulations remains unresolved. Greater knowledge of residence time of excipients and their interaction with skin at the molecular level is critical in order to address the problem. This will lay the foundations for better design of topical/transdermal formulations.     

Polymeric and lipid-based materials for topical nanoparticle delivery systems

The delivery of drugs and cosmetic actives to the skin by nanoparticle formulations has a number of advantages over conventional formulations. Nanoparticle formulations offer protection of incorporated active compounds against chemical degradation, more flexibility in modulating the release of the compound, the use of well-tolerated excipients, and feasibility of large scale production. The materials used in the nanoparticle synthesis and formulation can influence product stability, active ingredient properties and delivery to the intended site of action. This review describes the characteristics and application of various polymeric and lipid materials in the preparation of nanoparticles for topical and transdermal drug delivery.     

Enhancement of transdermal delivery of progesterone using medium-chain mono and diglycerides as skin penetration enhancers

We evaluated whether medium-chain mono and diglycerides (MCG) can be utilized to optimize the transdermal delivery of progesterone (PGT). MCG was studied at 10–70% (w/w) in propylene glycol (a polar solvent) or Myvacet oil (nonpolar solvent); PGT was used at 1% (w/w). The topical (to the skin) and transdermal (across the skin) delivery of PGT were evaluated in vitro using porcine ear skin. When incorporated in propylene glycol, MCG at 10% enhanced the topical and transdermal delivery of PGT by 2.5- and 7-fold, respectively. At 20–50%, topical delivery was further enhanced while transdermal delivery gradually returned towards baseline. At 70%, MCG enhanced neither the delivery to viable skin nor the transdermal delivery of PGT. Similar concentration-dependent effects were observed when MCG was incorporated in Myvacet oil, but their magnitudes were 2- to 3-fold smaller. The relative safety of MCG was assessed in cultured fibroblasts and compared to propylene glycol (regarded as safe) and sodium lauryl sulfate (moderate-to-severe irritant). Both MCG and propylene glycol were substantially less cytotoxic than sodium lauryl sulfate. We conclude that formulations containing 10% MCG in propylene glycol may be a simple and safe method to improve the transdermal delivery of progesterone and promote its use in hormone replacement therapy.     

Calcium condensed cell penetrating peptide complexes offer highly efficient, low toxicity gene silencing

The development of short-interfering RNA (siRNA) offers new strategies for manipulating specific genes responsible for pathological disorders. Myriad cationic polymer and lipid formulations have been explored, but an effective, non-toxic carrier remains a major barrier to clinical translation. Among the emerging candidates for siRNA carriers are cell penetrating peptides (CPPs), which can traverse the plasma membrane and facilitate the intracellular delivery of siRNA. Previously, a highly efficient and non-cytotoxic means of gene delivery was designed by complexing plasmid DNA with CPPs, then condensing with calcium. Here, the CPP TAT and a longer, 'double' TAT (dTAT) were investigated as potential carriers for siRNA. Various N/P ratios and calcium concentrations were used to optimize siRNA complexes in vitro. Upon addition of calcium, 'loose' siRNA/CPP complexes were condensed into small nanoparticles. Knockdown of luciferase expression in the human epithelial lung cell line A549-luc-C8 was high (up to 93%) with no evidence of cytotoxicity. Selected formulations of the dTAT complexes were dosed intravenously up to 1000 mg/kg with minimal toxicity. Biodistribution studies revealed high levels of gene knockdown in the lung and muscle tissue suggesting these simple vectors may offer a translatable approach to siRNA delivery.     

Topical delivery of acyclovir and ketoconazole

Abstract

Context: Viral and fungal cutaneous manifestations are regularly encountered in immunocompromised human immunodeficiency virus/acquired immunodeficiency syndrome individuals and can be treated by drugs such as acyclovir and ketoconazole, respectively.

Objective: The aim of this study was to determine whether the novel Pheroid? delivery system improved the transdermal delivery and/or dermal delivery of acyclovir and ketoconazole when incorporated into semi-solid formulations.

Materials and methods: Semi-solid products (creams and emulgels) containing these drug compounds were formulated, either with or without (control) the Pheroid? delivery system. The stability of the formulated semi-solid products was examined over a period of six months and included the assay of the actives, pH, viscosity, mass loss and particle size observation. Vertical Franz cell diffusion studies and tape stripping methods were used to determine the in vitro, stratum corneum (SC)-epidermis and epidermis-dermis delivery of these formulations.

Results and discussion: Stability tests showed that none of the formulations were completely stable. Acyclovir showed a biphasic character during the in vitro skin diffusion studies for all the tested formulations. The Pheroid? cream enhanced the transdermal, SC-epidermis and epidermis–dermis delivery of acyclovir the most. The average amount of ketoconazole diffused over 12?h showed improved delivery of ketoconazole, with the Pheroid? emulgel exhibiting the best transdermal and epidermis–dermis delivery.

Conclusion: The Pheroid? formulae increased transdermal penetration as well as delivery to the dermal and epidermal skin layers. The Pheroid? emulgel and the Pheroid? cream increased the topical delivery of ketoconazole and acyclovir, respectively.     

Biomaterials as novel penetration enhancers for transdermal and dermal drug delivery systems

Abstract

The highly organized structure of the stratum corneum provides an effective barrier to the drug delivery into or across the skin. To overcome this barrier function, penetration enhancers are always used in the transdermal and dermal drug delivery systems. However, the conventional chemical enhancers are often limited by their inability to delivery large and hydrophilic molecules, and few to date have been routinely incorporated into the transdermal formulations due to their incompatibility and local irritation issues. Therefore, there has been a search for the compounds that exhibit broad enhancing activity for more drugs without producing much irritation. More recently, the use of biomaterials has emerged as a novel method to increase the skin permeability. In this paper, we present an overview of the investigations on the feasibility and application of biomaterials as penetration enhancers for transdermal or dermal drug delivery systems.