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allows the production of several functional cellulose-materials, among them an ion-exchange fibre.
With the same process, they succeeded to develop a PCM fibre (see chapter 2.4.5.1) [198].
Hollow fibres, microencapsulated fibres, microparticles and nanofibres
A group at the University of Tehran Medical Sciences investigates hollow fibres drug delivery systems
in which the fibre wall is a permeable membrane. The fibre itself is filled with a liquid drug or a drug
solution. Therefore there is still a distinct separation in fibres and drugs.
Another method to incorporate drugs into fibres is to suspend or dissolve a drug into a polymer
solution used to produce fibres. A research group in Baltimore, U.S., works on producing drug-loaded
Chitosan-alginate fibres from interfacial polyelectrolyte complexation. The drug, namely
dexamethasone, can be trapped into the fibres as the two polyelectrolytes formed a complex at the
solution interface and were mechanically drawn into a fibre. These fibres are supposed to have high
encapsulation efficiency and sustained release of charged molecules. In this case the driving force for
drug release is diffusion [199].
Another technology to produce textile structures containing drugs is electrospinning, which is very
promising. In general, the smaller the dimensions of the drug and the coating material required to
encapsulate the drug, the better the drug to be absorbed by the human body. Drug delivery with
polymer nanofibres is based on the principle the dissolution rate of a particular drug increases with
increasing surface area of both the drug and its carrier.
A joint research group of different departments of the Commonwealth University in Richmond, U.S.,
produced electrospun fibre mats out of poly(lactic acid) (PLA), poly(ethylene-co-vinyl acetate) (PEVA)
and from a 50:50 blend of the two, containing an antibiotic. They found out that electrospun PEVA and
blended mats gave a smooth drug release over five days [200].
Electrospun poly(L-lactic acid) fibre mats are further examined by a research group at the Chinese
Academy of Sciences. They try to improve the drug release by reducing the diameter of the fibre with
the help of anionic, cationic and non-ionic surfactants. They further studied the encapsulation of
lipophilic and hydrophilic drugs inside the fibre mats and their release kinetics [201, 202].
Another team researches on heparin incorporated into electrospun PCL fibre mats for controlled drug
release for vascular injuries.
Lonwave (hollow, PES+ceramic micro-particles) from KURARAY is an infrared radiating fibre.
2.6.4.2 Patents published
126