Special Issue "Colloidal Drug Carrier Systems"
A special issue of Pharmaceutics (ISSN 1999-4923).
Deadline for manuscript submissions: closed (30 April 2011)
Prof. Dr. Dr. h.c. Reinhard Neubert
Biopharmacy Group, Pharmaceutics and Biopharmaceutics Division, Institute of Pharmacy, Martin-Luther-University Halle-Wittenberg, Wolfgang-Langenbeck-Str. 4, D-06120 Halle/Saale, Germany
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Interests: drug transport; dermal drug delivery; colloidal drug carrier systems; biosensors based on quartz microbalance; drug analysis based on capillary electrophoresis and HPLC-mass spectrometry; food-drug interactions; molecular structure of the stratum corneum lipids
Modern colloidal drug carriers (CDCs) are called in the literature mostly microemulsions (MEs). These systems form spontaneously combining appropriate amounts of a lipophilic and a hydrophilic ingredient, as well as a surfactant and a co-surfactant.
The formation of a ME is accompanied by a significant increase in the interfacial area A. The required very low interfacial tension cannot be realized by only one surfactant. The additionally used cosurfactant penetrates the amphiphilic interfacial layer and increases its curvature and fluidity.1,2
Basically two types of MEs are differentiated: bicontinuous ones and MEs with droplet like structure. The droplet structures are forming depending on the major compounds water-in-oil (w/o) and oil-in-water (o/w) MEs having colloidal phases in the range of 10 – 100 nm.
The term “ME” itself is sometimes used in a misleading way. On the one hand, various homogeneous surfactant-containing solutions were named like this and on the other hand, the expression itself implies emulsion-like properties with droplet sizes in the submicron-range. In the future, therefore, the term colloidal drug carrier (CDC) should be used. This concept covers also other colloidal structures such as solubilized micellar systems are also covered by the term CDC. Some authors use the term “swollen micelles” to describe droplet like MEs.
Due to their special features, CDCs such as MEs offer a lot of advantages for pharmaceutical use, such as ease of preparation, long term stability, high solubilization capacity for hydrophilic and lipophilic drugs, and improved drug delivery. The latter provides a wide range of possible applications.
Most interesting is the application of CDCs:
i) to improve the bioavailability of extremely lipophilic low molecular drugs and modern biopharmaceuticals such as peptides, proteins as well as RNA and DNA derivatives and
ii) to develop new ways of drug delivery such as transdermal, parenteral and ocular drug delivery.
Prof. Dr. Reinhard Neubert
1 De Gennes, P.G.; Taupin, C. Microemulsions and the flexibility of oil/water interfaces. J. Phys. Chem. 1982, 86, 2294-2304.
2 Attwood, D. Microemulsions. In Colloidal drug delivery systems, Drugs and the Pharmaceutical Sciences; Kreuter, J., ed.; Marcel Dekker: New York, NY, USA, 1994; Volume 66.
- colloidal carrier systems
- drug delivery
- low molecular drugs
- biopharmaceuticals (peptides, proteins, DNA and RNA derivatives)