Liposomes — microscopic phospholipid bubbles with a bilayered membrane structure — have received a lot of attention during the past 30 years as pharmaceutical carriers of great potential. More recently, many new developments have been seen in the area of liposomal drugs — from clinically approved products to new experimental applications, with gene delivery and cancer therapy still being the principal areas of interest. For further successful development of this field, promising trends must be identified and exploited, albeit with a clear understanding of the limitations of these approaches.

Recent advances with liposomes as pharmaceutical carriers.

Liposomal drug delivery systems: from concept to clinical applications.

Poly(ethylene glycol) (PEG) is the most used polymer and also the gold standard for stealth polymers in the emerging field of polymer-based drug delivery. The properties that account for the overwhelming use of PEG in biomedical applications are outlined in this Review. The first approved PEGylated products have already been on the market for 20 years. A vast amount of clinical experience has since been gained with this polymer--not only benefits, but possible side effects and complications have also been found. The areas that might need consideration and more intensive and careful examination can be divided into the following categories: hypersensitivity, unexpected changes in pharmacokinetic behavior, toxic side products, and an antagonism arising from the easy degradation of the polymer under mechanical stress as a result of its ether structure and its non-biodegradability, as well as the resulting possible accumulation in the body. These possible side effects will be discussed in this Review and alternative polymers will be evaluated.

Poly(ethylene glycol) in Drug Delivery: Pros and Cons as Well as Potential Alternatives

PLGA-based nanoparticles: An overview of biomedical applications

Transdermal drug delivery has made an important contribution to medical practice, but has yet to fully achieve its potential as an alternative to oral delivery and hypodermic injections. First-generation transdermal delivery systems have continued their steady increase in clinical use for delivery of small, lipophilic, low-dose drugs. Second-generation delivery systems using chemical enhancers, noncavitational ultrasound and iontophoresis have also resulted in clinical products; the ability of iontophoresis to control delivery rates in real time provides added functionality. Third-generation delivery systems target their effects to skin's barrier layer of stratum corneum using microneedles, thermal ablation, microdermabrasion, electroporation and cavitational ultrasound. Microneedles and thermal ablation are currently progressing through clinical trials for delivery of macromolecules and vaccines, such as insulin, parathyroid hormone and influenza vaccine. Using these novel second- and third-generation enhancement strategies, transdermal delivery is poised to significantly increase its impact on medicine.

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Transdermal drug delivery

The use of a staggered herringbone micromixer for the preparation of rigid liposomal formulations allows efficient encapsulation of antigen and adjuvant.

/pdf/erratum-to-culture-of-reconstructed-epidermis-in-a-defined-3otbgeyrp1.pdf

Erratum to: Culture of reconstructed epidermis in a defined medium at 33° C shows a delayed epidermal maturation, prolonged lifespan and improved stratum corneum (By Susan Gibbs, Jana Vicanová, Joke Bouwstra, Dingena Valstar, Johanna Kempenaar, Maria Ponec, In: Arch Dermatol Res (1997) 289 : 585–595)

P258 interactions of bile salts with non-ionic surfactant vesicles

The primary function of the skin is to act as a barrier against unwanted influences from the environment. The barrier function of the skin is located in the superficial of the skin, the stratum corneum. The stratum corneum consists of dead cells filled with keratin and water, which are embedded in lipid regions. The lipid regions are the only continuous structure in the stratum corneum. For this reason the lipid regions are considered to be very important for the barrier function. The main lipid classes are ceramides, cholesterol and free fatty acids. In this paper the lipid organisation in human stratum corneum is reviewed. In addition, the role the various lipid classes play in the lipid organisation will be discussed using mixtures prepared from either native human ceramides or synthetic ceramides. Finally a model, referred to as the stratum corneum substitute, is described in which the lipid organisation, composition and barrier function can be examined.

Joke A. Bouwstra

Papers

The use of a staggered herringbone micromixer for the preparation of rigid liposomal formulations allows efficient encapsulation of antigen and adjuvant.

P258 interactions of bile salts with non-ionic surfactant vesicles

The Lipid Organisation in Human Stratum Corneum and Model Systems~!2009-09-01~!2009-12-10~!2010-04-23~!

P50 Subzero thermal analysis of human stratum corneum