新型的皮肤给药系统——脂质体

综述了以脂质体作为各种药物进入皮肤的载体，包括促进吸收的机制、脂质体与角质层的作用及其ＤＤＳ制剂的制备方法等．同时列出了有关的专利．     

新型局部给药系统促进创伤愈合的研究进展

目的 皮肤组织的创伤修复是临床常见的问题,对于创伤的治疗手段多种多样。方法 对近几年的相关创伤愈合文献进行整理、分析和归纳。结果 阐述了皮肤组织愈合的机制及用于创伤治疗的新型局部给药系统。结论 新型的局部给药系统具有能够增加局部药物浓度、减少不良反应、促进伤口愈合、使用方便、提高患者依从性等特点,新型的给药系统用于治疗局部创伤具有巨大的市场潜力。     

脂质体作为经皮局部给药载体的研究进展

介绍国内外脂质体作为经皮局部给药载体的研究进展,从脂质体作为经皮局部给药载体特点,脂质体局部给药机制和脂质体局部吸收影响因素等方面进行论述,为研制此类制剂提供依据.在经皮给药系统中,脂质体是一种极具前途的给药载体.     

Topical Drug Delivery from Thin Applications: Theoretical Predictions and Experimental Results

Stainless-steel templates of various thicknesses (75, 200, 800, and 1600 µm) were used to apply propylene glycol/water gels containing methyl or propyl p-aminobenzoates to silicone rubber membranes, and drug delivery was studied with the use of the Bronaugh diffusion cell under conditions in which the drug was initially in thermodynamic equilibrium with respect to the application and membrane. Theoretical diffusion profiles were generated with the use of a model which assumes that diffusional gradients exist within the application. To use the model equation, previously derived for the initial condition in which the drug is in thermodynamic equilibrium with respect to the application and membrane, drug diffusivity in both the application and the membrane and the drug's membrane/ vehicle partition coefficient were independently determined. In general, agreement between experimental and theoretical results was within 25%.     

Oleic Acid: Its Effects on Stratum Corneum in Relation to (Trans)Dermal Drug Delivery

Calorimetric studies with porcine stratum corneum (SC) have shown that the lipid phase transitions associated with the intercellular bilayers are markedly affected by treatment with oleic acid. Specifically, the transition temperatures (T _m) and cooperativity are reduced, whereas no effect was observed on the endotherm associated with keratin denaturation, suggesting that oleic acid primarily affects the SC lipids. The decrease in the lipid-associated T _m's was further correlated with the amount of oleic acid taken up by the SC. Parallel experiments with silastic implied that the uptake is dependent on the thermodynamic activity of oleic acid in the vehicle itself. The in vitro transport of Piroxicam across human and hairless mouse skin (HMS) was significantly enhanced by oleic acid, as a function of the extent of oleic acid uptake, with an attendant change in T _m. These results emphasize the role of SC lipids in percutaneous absorption. Transport also depended on the donor concentration of ionized drug suggesting that the enhanced transport mechanism cannot be accounted for solely on the principles of the classical pH-partition hypothesis. Accordingly, a model of skin permeability enhancement involving solid-fluid phase separation within the SC lipids is proposed for oleic acid, consistent with the existing phospholipid literature. In conjunction with the use of oleic acid as an enhancer, very soluble hydrophilic salts were recognized as key factors in attaining maximum delivery. Oleic acid uptake, lipid T _m, and enhanced drug flux were all found to correlate, exhibiting a bell-shaped curve as a function of the ethanol vehicle concentration. Therefore, uptake and/or DSC experiments are useful for formulating enhanced topical delivery systems.     

Self-Emulsifying Drug Delivery Systems: Formulation and Biopharmaceutic Evaluation of an Investigational Lipophilic Compound

Self-emulsifying drug delivery systems (SEDDSs) represent a possible alternative to traditional oral formulations of lipophilic compounds. In the present study, a lipophilic compound, WIN 54954, was formulated in a medium chain triglyceride oil/nonionic surfactant mixture which exhibited self-emulsification under conditions of gentle agitation in an aqueous medium. The efficiency of emulsifi-cation was studied using a laser diffraction sizer to determine particle size distributions of the resultant emulsions. An optimized formulation which consisted of 25% (w/w) surfactant, 40% (w/w) oil, and 35% (w/w) WIN 54954 emulsified rapidly with gentle agitation in 0.1 N HCl (37°C), producing dispersions with mean droplet diameters of less than 3 µm. The self-emulsifying preparation was compared to a polyethylene glycol 600 (PEG 600) solution formulation by administering each as prefilled soft gelatin capsules to fasted beagle dogs in a parallel crossover study. Pharmacokinetic parameters were determined and the absolute bioavailability of the drug was calculated by comparison to an i.v. injection. The SEDDS improved the reproducibility of the plasma profile in terms of the maximum plasma concentration (C _max) and the time to reach the maximum concentration (t _max). There was no significant difference in the absolute bioavailability of WIN 54954 from either the SEDDS or the PEG formulations.     

壳聚糖在新型给药系统中的应用

综述壳聚糖的物理化学和生物特性及在基因转染和不同给药系统中的应用研究近况。壳聚糖作为新型药用辅料,已受到越来越多的关注,对其应用的开发和研究已渗透到药剂学的多个领域。壳聚糖用作非病毒基因载体,也已成为近年来的研究热点之一。它也被广泛研究应用于眼部、鼻腔、口腔、胃内、小肠和结肠等靶向给药载体。     

Topical delivery for the treatment of psoriasis

Importance of the field: Psoriasis is one of the most common human skin diseases. Topical therapy forms the cornerstone in the management of mild-to-moderate psoriasis. Topical therapies are also used as adjunctive to systemic therapy in moderate and severe forms of the disease.

Areas covered in this review: In this review, an overview of psoriasis pathogenesis, new topical medications for psoriasis, new targets and molecules, combination topical therapies and combination of topical and phototherapy is provided. Over the past decade several efficacious and acceptable treatment options have emerged from the age-old therapies. The development of sophisticated formulation options has led to an enhancement in the rate and extent of drug delivery across the skin, increasing therapeutic value and improving patient compliance.

What the reader will gain: Readers will learn about monotherapy and combination topical products as well as new topical drug delivery technology to achieve optimal clinical outcomes. This review will highlight the need to generate more dermal pharmacokinetic data for better understanding of the impact of formulation change on skin pharmacokinetics to help design improved topical drug delivery systems.

Take home message: New topical formulations have the potential to achieve better efficacy with improved safety profile.     

Topical Delivery of a Model Phenolic Drug: Alkyloxycarbonyl Prodrugs of Acetaminophen

PURPOSE: To determine whether the delivery of a phenolic parent drug by its alkyloxycarbonyl (AOC) prodrugs through hairless mouse skin would show similar dependencies on water and lipid solubilities that similar prodrugs of more polar heterocyclic amide and imide parent drugs have shown. METHODS: Flux through hairless mouse skin from suspensions in isopropyl myristate (J(MIPM)), solubilities in IPM (S(IPM)) and water (S(AQ)), and partition coefficients between isopropyl myristate (IPM) and pH 4.0 buffer (K(IPM:4.0)) were measured for two series of AOC derivatives of acetaminophen (APAP); their solubilities in pH 4.0 buffer (S4.0) were estimated from S(IPM)/K(IPM:4.0). Log J(MIPM) values were calculated from the n = 43 coefficients for the parameters in the transformed Potts-Guy (Roberts-Sloan) equation, and the average error of prediction (delta log J'(IPM)) was calculated. The J(MIPM), S(IPM), S4.0, and molecular weight (MW) data for this series and two other series were combined with the n = 43 database to give a n = 61 database, and new best fit coefficients were determined for the Roberts-Sloan equation: log J(MIPM) = x + y log S(IPM) + (1 - y) log S4.0 - z MW. RESULTS: All of the 4-AOC-APAP derivatives underperformed based on their predicted log J(MIPM) (delta log J'(MIPM) = 0.275 +/- 0.147 log units) and, although the two more water soluble members of this more lipid soluble series were more effective than APAP, they were only marginally so: <2 times. Addition of three new series to the n = 43 database for the Roberts-Sloan equation did not substantially change the coefficients to the parameters: x, y, z, and r2 = -0.322, 0.530, 0.00337 and 0.92, respectively. CONCLUSIONS: The topical delivery of a model phenolic drug by its AOC prodrugs through hairless mouse skin from IPM shows the same dependence on S(IPM), S4.0, and MW as the delivery of polar heterocycles by their similar prodrugs.     

Development of Novel Peptides for Mitochondrial Drug Delivery: Amino Acids Featuring Delocalized Lipophilic Cations

Purpose  

To create a new class of mitochondria-penetrating peptides (MPPs) that would facilitate drug delivery into the organelle through the inclusion of delocalized lipophilic cations (DLCs) in the peptide sequence.     

眼表局部给药的屏障及克服屏障的方法研究进展

眼部结构的复杂性使药物经眼表局部给药的生物利用度极低。基于纳米制剂的新型眼部药物递送系统,因其更易克服眼部给药屏障,使得药物经眼表局部给药后有效递送至眼组织内成为可能。介绍了眼表局部给药后药物递送至眼内需克服的屏障,总结了克服给药屏障的重要方法及眼用新剂型的临床进展,并对眼表局部给药系统的前景进行了展望,以期为眼部疾病的治疗提供新思路。     

皮肤科局部用药新载体的研究进展

近年来,随着皮肤病发病率的增加,传统剂型在治疗皮肤病中存在的药物稳定性差、透皮效率和皮肤保留量低等问题也逐渐凸显出来,因此需要药学人员研究、开发皮肤科局部用药的新载体。本文通过对近几年相关文献的查阅、分析、归纳和总结,综述了当前皮肤科局部用药新型载体的种类、特点及应用。     

微乳作为皮肤局部用药载体的研究进展

微乳是目前药剂学研究的热点,通过皮肤给药以达到局部或全身治疗目的的1种给药载体。综述近年来国内外对微乳作为皮肤局部用药载体的作用机制、影响因素、评价方法以及临床应用等方面的研究进展。     

Preparation of Various Solid-Lipid Beads for Drug Delivery of Enrofloxacin

Solid-lipid beads were prepared to retard the release rate of enrofloxacin and to mask its bitter taste using carrageenan or sodium alginate as a shell material and either cacao butter or Witepsol W-35 as a solid lipid core. Sodium alginate was a better shell material than carrageenan and the highest loading efficiency was obtained using 2% sodium alginate. The alginate beads had a spherical morphology and a sturdy shell structure. The enrofloxacin release rate at room temperature was greatly reduced. Solid-lipid beads have the potential to mask the bitter taste of enrofloxacin and extend its release rate.     

Hybrid Nanostructured Films for Topical Administration of Simvastatin as Coadjuvant Treatment of Melanoma

This work aims at (1) assessing the potential of repurposing simvastatin (SV) to support the most common therapies against melanoma and (2) developing an innovative topical adhesive film, composed by chitosan-coated nanostructured lipid carriers (Ch-NLC) used as drug vehicle. A factorial design approach was employed as the basis for the formulation development. Optimized Ch-NLC displayed a particle size of 108 ± 1 nm, a polydispersity index of 0.226, a zeta potential of 17.0 ± 0.6 mV, as well as an entrapment efficiency of 99.86 ± 0.08%, and SV loading of 14.99 ± 0.01%. The performance of SV-Ch-NLC films was assessed in terms of release, permeation, and adhesion, as critical quality attributes. Cutaneous tolerability and in vitro cytotoxicity studies were performed to warrant film safety and drug effectiveness, respectively. The topical films provided a sustained release kinetic profile of SV and were classified as nonirritant systems. The encapsulation of SV increased cytotoxicity in melanoma cells. The key role of squalene as nanostructuring agent of the lipid nanoparticle matrix and as permeation enhancer was highlighted, suggesting its key action for potentiating skin permeation and uptake into melanoma cells. Topical SV-Ch-NLC films are thus able to provide an in situ extended drug delivery and useful as coadjuvant treatment of melanoma skin lesions.     

Development and Characterization of Cinnamon Leaf Oil Nanocream for Topical Application

Cinnamon leaf oil contains a high percentage of eugenol and has antimicrobial, antioxidant and antiinflammatory properties. However, the undiluted oil can cause irritation to the skin. Therefore, the aims of this study were to develop and evaluate cinnamon leaf oil nanocream using palm oil. Nanocream base was prepared using different ratios of oil, surfactants and water. The surfactant used were mixture of Tween 80:Carbitol or Tween 80:Span 65 at different hydrophile-lipophile balance values. The pseudoternary phase diagrams were constructed to identify the nanocream base areas and the results showed that the nanocream bases using Span 65 as co-surfactant produced bigger cream area. Fifteen formulations using mixtures of Tween 80:Span 65 were further evaluated for accelerated stability test, droplet size, zeta potential, rheological properties and apparent viscosity. The nanocream base which had an average droplet size of 219 nm and had plastic flow with thixotropic behavior was selected for incorporation of 2% cinnamon leaf oil. The nanocream containing cinnamon leaf oil had the average size of 286 nm and good rheological characteristics. The in vitro release study demonstrated that eugenol as the main constituent of cinnamon leaf oil was released for about 81% in 10 h. The short-term stability study conducted for 6 months showed that the cinnamon leaf oil nanocream was stable at a temperature of 25° and thus, cinnamon leaf oil nanocream is a promising natural based preparation to be used for topical application.     

Beads of Acryloylated Polyaminoacidic Matrices Containing 5-Fluorouracil for Drug Delivery

Spherical polymeric microparticles have been prepared by a reverse phase suspension polymerization technique. The starting polymer was α, β-poly(N-2-hydroxyethyl)-DL-aspartamide (PHEA), partially derivatized with glycidylmethacrylate (GMA). PHEA-GMA copolymer (PHG) was crosslinked in the presence of N,N'-dimethylacrylamide (DMAA) or N,N'-ethylenebisacrylamide (EBA). 5-fluorouracil was incorporated into PHG-DMAA or PHG-EBA beads both during and after the crosslinking process. Swelling studies revealed a high affinity toward aqueous medium, influenced by the presence of 5-fluorouracil. The in vitro release study showed that the release rate depends on the chemical structure of the beads and the procedure adopted to incorporate 5-fluorouracil into the microparticles.     

Optimizing Metrics for the Assessment of Bioequivalence Between Topical Drug Products

PURPOSE: Stratum corneum tape stripping post-application of a drug product followed by analysis of the active agent in this tissue layer is an approach being seriously considered for the comparative assessment of topical bioavailability. Key issues revolve around how best to perform this experiment and interpret the data. METHODS: Using previously published results from a comparative study of three 0.025% tretinoin gel products, alternative data analysis approaches are presented that may render the technique more accessible to the evaluation of new and generic topical dosage forms. RESULTS: For the tretinoin gel study, the conclusions for bioequivalence from measurements of drug levels at only one uptake and one clearance time were the same as those from the original study, which required measurements at eight different treatment times. Furthermore, comparisons of drug levels at one uptake and one clearance time discriminated differences in bioequivalence for clearance and uptake, which had previously been missed. Half-life estimates, derived from time course data of drug clearance, can be related to lag time for drug penetration through the SC. CONCLUSIONS: This new data analysis demonstrates that comparative bioequivalence might be assessed more easily.