Hydrogels As drug-delivery Platforms: Physicochemical Barriers and Solutions

• Berger J , ReistM, MayerJM, FeltO, GurnyR. Structure and interactions in covalently and ionically crosslinked chitosan hydrogels for biomedical applications. Eur. J. Pharm. Biopharm.57, 19–34 (2004).
   PubMed Web of Science ®Google Scholar
• Peppas NA , BuresP, LeobandungW, ChikqwaH. Hydrogels in pharmaceutical formulations. Eur. J. Pharm. Biopharm.50, 27–46 (2000).
   PubMed Web of Science ®Google Scholar
• Hoffman AS . Hydrogels for biomedical applications. Adv. Drug Deliv. Rev.43, 3–12 (2002).
   Web of Science ®Google Scholar
• Lin CC , MettersAT. Hydrogels in controlled release formulations: network design and mathematical modelling. Adv. Drug Deliv. Rev.58, 1379–1408 (2006).
   PubMed Web of Science ®Google Scholar
• Jagur-Grodzinski J . Polymeric gels and hydrogels for biomedical and pharmaceutical applications. Polym. Adv. Technol.21, 27–47 (2010).
   Web of Science ®Google Scholar
• Costa-Junior ES , Barbosa-StancioliEF, MansurAP, VasconcelosWL, MansurHS. Preparation and characterization of chitosan/poly(vinyl) alcohol chemically crosslinked blends for biomedical applications. Carbohydr. Polym.76, 472–481 (2009).
   Web of Science ®Google Scholar
• Amsden B . Solute diffusion within hydrogels: mechanisms and models. Macromolecules31, 8382–8395 (1998).
   Web of Science ®Google Scholar
• Peppas NA , MikosAG. Preparation methods and structure of hydrogels. In: Hydrogels in Medicine and Pharmacy (Volume 1). Peppas NA (Ed.). CRC Press, Boca Raton, FL, USA, 1–27 (1986).
   Google Scholar
• Anseth KS , Bownman,CN, Brannon-PeppasL. Mechanical properties of hydrogels and their experimental determination. Biomaterials17, 1647–1657 (1996).
   PubMed Web of Science ®Google Scholar
• Davis TP , HuglinMB. Effect of composition on properties of copolymeric N-vinyl-2–7 pyrrolidone /methylmethacrylate hydrogels and organogels. Polymer31, 513–519 (1990).
   Web of Science ®Google Scholar
• Vogel MK , CrossRA, BixlerHJ, GuzmanRJ. Medical uses for polyelectrolyte complexes. J. Macromol. Sci. Chem.4, 675–692 (1970).
   Web of Science ®Google Scholar
• Bhattarai N , GunnJ, ZhangM. Chitosan-based hydrogels for controlled, localized drug delivery. Adv. Drug Deliv. Rev.62, 83–99 (2010).
   PubMed Web of Science ®Google Scholar
• Drury JL , DennisRG, MooneyDJ. The tensile properties of alginate hydrogels. Biomaterials25, 3187–3199 (2004).
   PubMed Web of Science ®Google Scholar
• Jeffrey L , HinkleyA, MorgretLD, GehrkeSH. Tensile properties of two responsive hydrogels. Polymer45, 8837–8843 (2004).
   Web of Science ®Google Scholar
• Svensson A , NicklassonE, HarrahTet al. Bacterial cellulose as a potential scaffold for tissue engineering of cartilage. Biomaterials 26, 419–431(2005).
   PubMed Web of Science ®Google Scholar
• Awad HA , Quinn Wickham M, Leddy HA, Gimble JM, Guilak F. Chondrogenic differentiation of adipose-derived adult stem cells in agarose, alginate and gelatine scaffolds. Biomaterials25, 3211–3222 (2004).
   PubMed Web of Science ®Google Scholar
• Ranta-Eskola AJ . Use of the hydraulic bulge test in biaxial tensile testing. Int. J. Mech. Sci.21, 457–465 (1979).
   Web of Science ®Google Scholar
• Tsakalakos T . The bulge test: a comparison of the theory and experiment for isotropic and anisotropic films. Thin Solid Films75, 293–305 (1981).
   Web of Science ®Google Scholar
• Mirshams RA , PothapragadaRM. Correlation of nanoindentation measurements of nickel made using geometrically different indenter tips. Acta Mater.54, 1123–1134 (2006).
   Web of Science ®Google Scholar
• De Groot CJ , Van Luyn MJA, Van Dijk-Wolthuis WNE et al.In vitro biocompatibility of biodegradable dextran-based hydrogels tested with human fibroblasts. Biomaterials22, 1197–1203 (2001).
   PubMed Web of Science ®Google Scholar
• Jatav , VS, Singh, H, Singh, SK. Recent trends on hydrogel in human body. Int. J. Res. Pharm. Biomed. Sci.2, 442–447 (2011).
   Google Scholar
• Pal K , BanthiaAK, MajumdarDK. Polymeric hydrogels: characterization and biomedical applications – a mini review. Designed Monomers Polym.12, 197–220 (2009).
   Web of Science ®Google Scholar
• Biazar E , RoveimiabZ, ShahhosseiniG, KhataminezhadM, ZafariM, MajdiA. Biocompatibility evaluation of a new hydrogel dressing based on polyvinylpyrrolidone/polyethylene glycol. J. Biomed. Biotechnol. doi:10.1155/2012/343989 (2012) (Epub ahead of print).
   PubMedGoogle Scholar
• Danielsson C , RuaultS, SimonethM, NeuenschwanderP, FreyaP. Polyesterurethane foam scaffold for smooth muscle cell tissue engineering. Biomaterials27, 1410–1415 (2006).
   PubMed Web of Science ®Google Scholar
• Sajeesh S , BouchemalK, SharmaCP, VauthierC. Surface-functionalized polymethacrylic acid based hydrogel microparticles for oral drug delivery. Eur. J. Pharm. Biopharm.74, 209–218 (2010).
   PubMed Web of Science ®Google Scholar
• Liang L , XuXD, ChenCSet al. Evaluation of the biocompability of novel peptide hydrogel in rabbit eye. J. Biomed. Mater. Res. B Appl. Biomater. 93, 324–332 (2010).
   PubMedGoogle Scholar
• Patel VR , AmjiMM. Preparation and characterization of freeze-dried chitosan and poly(ethylene oxide) hydrogels for site-specific antibiotic delivery in the stomach. Pharm. Res.13, 588–593 (1996).
   PubMed Web of Science ®Google Scholar
• Yamaguta T , MorishitaM, KavimandanNJet al. Characterisation of insulin protection properties of complexation hydrogels in gastric and intestinal enzyme fluids. J. Control Release 112, 343–349 (2006).
   PubMed Web of Science ®Google Scholar
• Alvarez-Lorenzo C , YanezF, ConcheiroA. Ocular drug delivery from molecularly-imprinted contact lenses. J. Drug Deliv. Sci. Technol.20, 237–248 (2010).
   Web of Science ®Google Scholar
• Xinming l, Yingde C, Lloyd AW et al. Uptake and release of dexamethasone phosphate from silicone hydrogel and group I, II, and IV hydrogel contact lenses. Cont. Lens Anterior Eye31, 57–64 (2008).
   PubMedGoogle Scholar
• Andrade-Vivero P , Fernandez-GabrielE, Alvarez-LorenzoC, ConcheiroA. Improving the loading and release of NSAIDs from pHEMA hydrogels by copolymerization with functionalized monomers. J. Pharm. Sci.96, 802–813 (2007).
   PubMed Web of Science ®Google Scholar
• Gulsen D , ChauhanA. Dispersion of microemulsion drops in HEMA hydrogel: a potential ophthalmic drug delivery vehicle. Int. J. Pharm.292, 95–117 (2005).
   PubMed Web of Science ®Google Scholar
• Carlfors J , EdsmanK, PertersonR, JonvingK. Rheological evaluation of Gelrite in situ gels for ophthalmic use. Eur. J. Pharm. Sci.6, 113–119 (1998).
   PubMed Web of Science ®Google Scholar
• Moriyama K , YuiN. Regulated insulin release from biodegradable dextran hydrogels containing polyethylene glycol. J. Control Release42, 237–248 (1996).
   Web of Science ®Google Scholar
• Megeed Z , CappelloJ, GhandehariH. In vitro and in vivo evaluation of recombinant silk-elastin like hydrogels for cancer gene therapy. J. Control Release94, 433–445 (2004).
   PubMed Web of Science ®Google Scholar
• Quick D , AnsethK. DNA delivery from photocrosslinked PEG hydrogels: encapsulation efficiency, release profiles, and DNA quality. J. Control Release96, 341–351 (2004).
   PubMed Web of Science ®Google Scholar
• Lei P , PadmashaliRM, AndreadisST. Cell-controlled and spatially arrayed gene delivery from fibrin hydrogels. Biomaterials30, 3790–3799 (2009).
   PubMed Web of Science ®Google Scholar
• Wieland JA , Houchin-RayTL, SheaLD. Non-viral vector delivery from PEG hyaluronic acid hydrogels. J. Control Release120, 233–241 (2007).
   PubMed Web of Science ®Google Scholar
• Lei Y , HuwanS, Sharif-KashaniP, ChenY, KavehpourP, SeguraT. Incorporation of active DNA/cationic polymer polyplexes into hydrogel scaffolds. Biomaterials31, 9106–9116 (2010).
   PubMed Web of Science ®Google Scholar
• Nguyen KT , WestJL. Photopolymerizable hydrogels for tissue engineering applications. Biomaterials23, 4307–4314 (2002).
   PubMed Web of Science ®Google Scholar
• Mann BK , BobinAS, TsaiAT, SchmedienRH, WestJL. Smooth muscle cell growth in photopolymerized hydrogels with cell adhesive and proteolytically degradable domains: synthetic ECM analogs for tissue engineering. Biomaterials22, 30–45 (2001).
   Google Scholar
• Ferreira P , CoelhoJFJ, Dos Santos KSCR, Ferreira EI, Gil MH. Thermal characterization of chitosan-grafted membranes to be used as wound dressings J. Carbohydr. Chem.25, 233–251 (2006).
   Web of Science ®Google Scholar
• West JL , HubbellJA. Separation of the arterial wall from blood contact using hydrogel barriers reduces intimal thickening after balloon injury in the rat: the roles of hydrogel medial and luminal factors in arterial healing. Proc. Natl Acad. Sci.93, 13188–13193 (1996).
   PubMed Web of Science ®Google Scholar
• Hoare TR , KohaneDS. Hydrogels in drug delivery: progress and challenges. Polymer49, 1993–2007 (2008).
   Web of Science ®Google Scholar
• Long D , Van Luyen D. Chitosan-carboxymethylcellulose hydrogel as supports for cell immobilization. J. Macromol. Sci. Pure Appl. Chem. A33, 1875–1884 (1996).
   Web of Science ®Google Scholar
• Tsao TC , ChangCH, LinYYet al. Antibacterial activity and biocompatibility of a chitosan–c-poly(glutamic acid) polyelectrolyte complex hydrogel. Carbohydr. Res. 345, 1774–1780 (2010).
   PubMed Web of Science ®Google Scholar
• Shaha HK , ConkiebJA, TaitRC, JohsonaJR, WisonaCG. A novel biodegradable and reversible polyelectrolyte platform for topical-colonic delivery of pentosan polysulphate. Int. J. Pharm.404, 124–132 (2011).
   PubMedGoogle Scholar
• Chellat F , TabrizianM, DumitriuSet al. In vitro and in vivo biocompatibility of chitosan–xanthanpolyionic complex. J. Biomed. Mater. Res.51, 107–116 (2000).
   PubMed Web of Science ®Google Scholar
• Sakiyama T , TakataH, KikuchiM, NakanishiK. Polyelectrolyte complex gel with high pH-sensitivity prepared from dextran sulphate and chitosan. J. Appl. Polym. Sci.73, 2227–2233 (1999).
   Web of Science ®Google Scholar
• Feng X , PeltonR. Carboxymethyl cellulose: polyvinylamine complex hydrogel swelling. Macromolecules40, 1624–1630 (2007).
   Web of Science ®Google Scholar
• Piyakulawat P , PraphairaksitN, ChantarasiriN, MuangsinN. Preparation and evaluation of chitosan/carrageenan beads for controlled release of sodium diclofenac. AAPS Pharm. Sci. Tech.8(4), E97 (2007).
   PubMed Web of Science ®Google Scholar
• Beauchamp RO , St Clair MB, Fennell TR, Clarke DO, Morgan KT. A critical review of the toxicology of glutaraldehyde. Crit. Rev. Toxicol.22, 143–174 (1992).
   PubMed Web of Science ®Google Scholar
• Murata-Kamiya N , KamiyaH, KajiH, KasaiH. Mutational specificity of glyoxal, a product of DNA oxidation, in the lacI gene of wild-type Escherichia coli. Mutat. Res.377, 255–262 (1997).
   PubMed Web of Science ®Google Scholar
• Mi FL , TanYC, LiangHF, SungHW. In vivo biocompatibility and degradability of a novel injectable-chitosan-based implant. Biomaterials23, 181–191 (2002).
   PubMed Web of Science ®Google Scholar
• Ying L , SunJA, JiangGQ, JiaZ, DingFX. In vitro evaluation of lysozyme-loaded microspheres in thermosensitive methylcellulose-based hydrogel. J. Chem. Eng.15, 566–572 (2007).
   Google Scholar
• Ito T , YenY, HighleyCB, BellasE, BenitezCA, KohaneDS. The prevention of peritoneal adhesions by in situ cross-linking hydrogels of hyaluronic acid and cellulose derivatives. Biomaterials28, 975–985 (2007).
   PubMed Web of Science ®Google Scholar
• Mastekova R , ChalupovaZ, SklubalovaZ. Stimuli sensitive hydrogels in controlled and sustained drug delivery. Micina39, 19–24 (2003).
   Google Scholar
• Katchalsky A , MichaeliI. Polyelectrolyte gels in salt solution. J Polym. Sci.15, 69–86 (1955).
   Web of Science ®Google Scholar
• Qiu Y , ParkK. Environment-sensitive hydrogels for drug delivery. Adv. Drug Deliv. Rev.53, 321–339 (2001).
   PubMed Web of Science ®Google Scholar
• Kim B , LimSH, RyooW. Preparation and characterization of pH-sensitive anionic hydrogel microparticles for oral protein-delivery applications. J. Biomater. Sci. Polym. Ed.20, 427–436 (2009).
   PubMed Web of Science ®Google Scholar
• Mahkam M . New interpolymers as hydrogels for oral protein delivery application. J. Drug. Target17(1), 29–35 (2009).
   PubMed Web of Science ®Google Scholar
• Nho YC , ParkSE, KimHI, HwangTS. Oral delivery of insulin using pH-sensitive hydrogels based on polyvinyl alcohol grafted with acrylic acid/methacrylic acid by radiation. Nucl. Instrum. Methods Phys. Res. B236, 283–288 (2005).
   Web of Science ®Google Scholar
• Mundargi RC , RangaswamyR, AminabhaviTM. Poly(N-vinylcaproloactam-co-methacrylic acid) hydrogel microparticles for oral insulin delivery. J. Microencapsul.28, 384–394 (2011).
   PubMed Web of Science ®Google Scholar
• Gupta KM , BarnesSR, TangaroRAet al. Temperature and pH sensitive hydrogels: an approach towards smart semen-triggered vaginal microbicidal vehicles. J. Pharm. Sci. 96, 670–681 (2007).
   PubMed Web of Science ®Google Scholar
• Chang JY , OhYK, ChoiHG, KimYB, KimCK. Rheological evaluation of thermosensitive and mucoadhesive vaginal gels in physiological conditions. Int. J. Pharm.241, 155–163 (2002).
   PubMed Web of Science ®Google Scholar
• Kohori F , YokoyamaM, SakaiK, OkanoT. Process design for efficient and controlled drug incorporation into polymeric micelle carrier systems. J. Control. Release7, 155–163 (2002).
   Google Scholar
• Chen PC , KohaneDS, ParkYJ, BartletRH, LangerR, YangC. Injectable microparticle-gel system for prolonged and localized lidocaine release. II. In vivo anesthetic effects. J. Biomed. Mater. Res. A70, 459–466 (2004).
   PubMedGoogle Scholar
• Whiting CJ , VoiceAM, OmstedPD, McLeishTCB. Shear modulus of polyelectrolyte gels under electric field. J. Phys. Condens. Mater.13, 1381–1393 (2001).
   Web of Science ®Google Scholar
• Ramanathan S , BlockLH. The use of chitosan gels as matrices for electrically-modulated drug delivery. J. Control. Release70, 109–123 (2001).
   PubMed Web of Science ®Google Scholar
• Kim SJ , YoonSG, LeeYM, KimSI. Electrical sensitive behaviour of poly(vinyl alchohol)/poly (diallyldimethylammonium chloride) IPN hydrogel. Sens. ActuatorsB88, 286–291 (2003).
   Google Scholar
• Liu TY , HuSH, LiuKH, LiuDM, ChenSY. Preparation and characterization of smart magnetic hydrogels and its use for drug release. J. Magn. Magn. Mater.304, 397–399 (2006).
   Google Scholar
• Sutter M , SiepmannJ, HenninkWE, JiskootW. Recombinant gelatin hydrogels for the sustained release of proteins. J. Control. Release119(3), 301–312 (2007).
   PubMed Web of Science ®Google Scholar
• Nuttleman CR , TripodiMC, AnsethKS. Dexamethasone-functionalized gels induce osteogenic differentiation of encapsulated hMSCs. J. Biomed. Mater. Res. A76(1), 183–195 (2006).
   PubMedGoogle Scholar
• Bouhadir K H, Kruger GM, Lee KY, Mooney DJ. Sustained and controlled release of daunomycin from cross-linked poly(aldehyde guluronate) hydrogels. J. Pharm. Sci.89(7), 910–919 (2000).
   PubMed Web of Science ®Google Scholar
• Schoenmakers RG , van de Wetering P, Elbert DL, Hubbell JA. The effect of the linker on the hydrolysis rate of drug-linked ester bonds. J. Control. Release95, 291–300 (2004).
   PubMed Web of Science ®Google Scholar
• Slaughter BV , KhurshidSS, FisherOZ, KhademhosseiniA, PeppasNA. Hydrogels in regenerative medicine. Adv. Mater.21, 3307–3729 9 (2009).
   PubMed Web of Science ®Google Scholar
• Zhang J , PeppasNA. Molecular interactions in poly (methacrylic acid)/poly (N-isopropyl acrylamide) interpenetrating polymer networks. J. Appl. Polym. Sci.82, 1077–1082 (2001).
   Web of Science ®Google Scholar
• Wang W , WangA. Synthesis and swelling properties of pH-sensitive semi-IPN superabsorbent hydrogels based on sodium alginate-g-poly(sodium acrylate) and polyvinylpyrrolidone. Carbohydr. Polym.80, 1028–1036 (2010).
   Web of Science ®Google Scholar
• Lee WF , ChenYJ. Studies on preparation and swelling properties of the N-isopropylacrylamide/chitosan semi-IPN and IPN hydrogels. J. Appl. Polym. Sci.82, 2487–2496 (2001).
   Web of Science ®Google Scholar
• Na K , BaeYH. Self-assembled hydrogel nanoparticles responsive to tumor extracellular pH from pullulan derivative/ sulphonamide conjugate: characterization, aggregation and adriamycin release in vitro. Pharm. Res.19, 681–688 (2004).
   Web of Science ®Google Scholar
• Yeo YQ , YangFL, HuFQ, DuYZ, YuanH, YuHY. Core-modified chitosan based polymeric micelles for controlled release of doxorubicin. Int. J. Pharm.352, 294–301 (2008).
   PubMedGoogle Scholar
• Bae JW , GoDH, ParkKD, LeeSJ. Thermosensitive chitosan as an injectable carrier for local drug delivery. Macromol. Res.14, 461–465 (2006).
   Web of Science ®Google Scholar
• Rahmani-Neishaboor E , JacksonJ, BurtH, GhaharyA. Composite hydrogel formulations of Stratifin to control MMP-1 expression in dermal fibroblasts. Pharm. Res.26(8), 2002–2014 (2009).
   PubMed Web of Science ®Google Scholar
• Weng L , LeHC, LinJ, GolzarianJ. Doxorubicin loading and eluting characteristics of bioresorbable hydrogel microspheres: in vitro study. Int. J. Pharm.409, 185–193 (2011).
   PubMed Web of Science ®Google Scholar
• Collier JH , HuBH, RubertiJWet al. Thermally and photochemically triggered self-assembly of peptide hydrogels. J. Am. Chem. Soc. 123, 9463–9464 (2001).
   PubMed Web of Science ®Google Scholar
• Liang L , YangJ, LiQet al. A novel targeting drug delivery system based on self-assembled peptide hydrogel. J. Biomater. Nanobiotechnol. 2, 622–625 (2011).
   Google Scholar
• Ozbas B , KretsingerJ, RajagopalK, SchneiderJP, PochanDJ. Salt-triggered peptide folding and consequent self-assembly into hydrogels with tunable modulus. Macromolecules37, 7331–7337 (2004).
   Web of Science ®Google Scholar
• Pochan DJ , SchneiderJP, KretsingerJ, OzbasB, RajagopalK, HainesL. Thermally reversible hydrogels via intramolecular folding and consequent self-assembly of a de novo designed peptide. J. Am. Chem. Soc.125, 11802–11803 (2003).
   PubMed Web of Science ®Google Scholar
• Schneider JP , PochanDJ, OzbasB, RajagopalK, PakstisL, KretsingerJ. Responsive hydrogels from the intermolecular folding and self-assembly of a designed peptide. J. Am. Chem. Soc.124, 15030–15037 (2002).
   PubMed Web of Science ®Google Scholar
• Chung HJ , ParkTG. Self-assembled and nanostructured hydrogels for drug delivery and tissue engineering. Nano Today4, 429–437 (2009).
   Web of Science ®Google Scholar
• Atunbas A , LeeSJ, RajaasekaranSA, SchneiderJP, PochanDJ. Encapsulation of curcumin in self-assembling peptide hydrogels as injectable drug delivery vehicles. Biomaterials32, 5906–5914 (2011).
   PubMed Web of Science ®Google Scholar
• Silva GA , CzeislerC, NieceKLet al. Selective differentiation of neural progenitor cells by high-epitope density nanofibers. Science 303, 1352–1355 (2004).
   PubMed Web of Science ®Google Scholar
• Vemula PK , CruikshankGA, KarpJM, JohnG. Self-assembled prodrugs: an enzymatically triggered drug-delivery platform. Biomaterials30, 383–393 (2009).
   PubMed Web of Science ®Google Scholar
• Oh JK , DrumrightR, SiegwartD, MatyjaszewskiK. The development of microgels/nanogels for drug delivery applications. Prog. Polym. Sci.33, 448–477 (2008).
   Web of Science ®Google Scholar
• Kim Y , ThapaM, HuaDH, ChangKO. Biodegradable nanogels for oral delivery of interferon for norovirus infection. Antiviral Res.89, 165–173 (2011).
   PubMed Web of Science ®Google Scholar
• Sahiner N , GodbeyWT, McPhersonGL, JohnVT. Novel nanogels as drug delivery systems for poorly soluble anticancer drugs. Coll. Polym. Sci.284, 1121–1129 (2006).
   Web of Science ®Google Scholar
• Chen Y , ZhengX, QianH, MaoZ, DingD, JiangX. Hollow core-porous shell structure poly(acrylic acid) nanogels with a super high capacity of drug loading. Appl. Mater. Interfaces2, 3532–3538 (2010).
   PubMed Web of Science ®Google Scholar
• Kuckling D , VoCD, WohlrabSE. Preparation of nanogels with temperature-responsive core and pH-responsive arms by photo-crosslinking. Langmuir18, 4263–4269 (2002).
   Web of Science ®Google Scholar
• Bhuchar N , SunaseeR, IshiharaKet al. Degradable thermoresponsive nanogels for protein encapsulation and controlled release. Bioconj. Chem. 23, 75–83 (2012).
   PubMed Web of Science ®Google Scholar
• Ryu JH , JiwpanichS, ChackoR, BickertonS, ThaymuanavaS. Surface-functionalizable polymer nanogels with facile hydrophobic guest encapsulation capabilities. J. Am. Chem. Soc.132, 8246–8247 (2010).
   PubMed Web of Science ®Google Scholar
• Cai C , Bakowsky,U, RyttingE, SchaperAK, KisselT. Charged nanoparticles as protein delivery systems: a feasibility study using lysozyme as model protein. Eur. J. Pharm. Biopharm.69, 31–42 (2008).
   PubMed Web of Science ®Google Scholar
• Smith MH , SouthAM, GauldingJC, LyonLA. Monitoring the erosion of hydrolytically-degradable nanogels via multi angle light scattering coupled to asymmetrical flow field-flow fractionation. Anal. Chem.82, 523–530 (2010).
   PubMed Web of Science ®Google Scholar

Patent

• Nagai T, Machida Y, Suzuki Y, Ikura H: US4226848 (1980).
   Google Scholar