Table 2.
Examples of application of polymers sensitive to stimuli in drug delivery systems (Kim et al., 2009, Priya et al., 2014).
| Stimulus | Polymer | Application |
|---|---|---|
| Temperature | Poly(N-isopropylacrylamide) | Hydrogel, doxorubicin release |
| Ultrasound | Polyanhydride, polyglycolide, polylactide poly(hydroxyethyl methacrylate-co-N,N′-dimethylaminoethyl methacrylate) | Ultrasound-enhanced biodegradation |
| Ultrasound-enhanced drug release rate | ||
| Magnetic field | Poly(ethylene-co-vinylacetate) | Prompted BSA release from matrix magnetic field |
| Oxidation | PEG-b-poly(propylene sulphide)-b-PEG | Oxidation-sensitive polymer vesicle disintegration |
| Light | Poly(N,N-dimethylacrylamide-co-4-phenyl-azophenyl acrylate) | Photo-sensitive active site-gating of streptavidin |
| Poly(N,N-dimethyl acrylamide-co-4-phnyl-azophenyl acrylamide) | ||
| Electricity | Poly(ethylenediamine-co-1,10-bis(chloro-carbonyl)decane) polyethyloxazoline/poly(methacrylate) | Electric-sensitive capsule |
| Electrically erodible matrix for insulin delivery | ||
| Mechanical stress | Dihydrazide-crosslinked polyguluronate poly(methyl methacrylate)/poly(vinyl alcohol) or/cellulose ether | Pressure-sensitive hydrogel |
| Pressure-sensitive adhesive | ||
| pH | Poly(acrylic acid)-g-PEG | Oral insulin delivery |
| PEG-b-poly(L-histidine) | Doxorubicin release | |
| Poly(n-isopropylacrylamide-co-propylacrylic acid-co-butylacrylate) alginate and chemically modified carboxymethyl chitosan | Fibroblast growth factor: improvement of angiogenesis, providing the advantage of acidic microenvironment of ischaemic myocardium | |
| Protein drug for oral delivery: protecting the drug from the harsh acidity of stomach with potential release in the intestine | ||
| Ionic strength | Poly(NIPAAm-co-benzo-18-crown[6]-acrylamide) | Ba2+-sensitive membrane pore |
| Enzymes | aPEG-peptide linker-doxorubicin | Doxorubicin release by lysosomal enzyme-mediated peptide degradation |
| aPoly(N-(2-hydroxypropyl)methacrylamide)-peptide linker-doxorubicin | ||
| Biomolecules | PEO-b-poly(2-glucosyloxyethyl acrylate) | Glucose-sensitive micelle for insulin delivery |
| Thiolate PEG-b-poly(L-lysine) | Glutathione-sensitive micelle for anti-sense DNA delivery | |
| bPoly(RCOOH-co-butyl acrylate-co-pyridyl disulphide acrylate) | ||
| Glutathione- and pH-sensitive copolymers for oligodeoxynucleotide delivery |
a
Peptide linker = GFLG.
b
R = –CH3, –CH2CH3, or –CH2CH2CH3.