PHPMA

Methoxy poly(ethyleneglycol) (mPEG) was the most frequently used semitelechelic polymer for over 2 decades. It has been successfully used for the modification of various proteins, biomedical surfaces and hydrophobic anticancer drugs (for reviews see References [3,9,10]. Recently, a number of new semitelechelic (ST) polymers, such as ST-poly(A -isopropylacry-lamide) (ST-PNIPAAM) [11-15], ST-poly(4-acryloylmorpholine) (ST-PAcM) [16], ST-poly(A-vinylpyrrolidone) (ST-PVP) [17], and ST-poly[A-(2-hydroxypropyl)methacrylamide] (ST-PHPMA) [18-21] have been prepared and shown to be effective in the modification of proteins or biomedical surfaces. 

Figure 2 MALDI-TOF mass spectrum of a ST-PHPMA-COOCH3. Peak series a represent polymer chains with initiator (IBN) end groups peak series b represent polymer chains with methyl ester end groups.

Figure 3 The MALDI-TOF mass spectrum of the chymotrypsin conjugate with a ST-PHPMA-NHNH2 fraction = 1,400). The peaks 1, 2, and 3 are the double-charged, single-charged conjugate, and single-charged double conjugate aggregate, respectively.

It seems that a maximum of about 10 ST-PHPMA chains can be attached to 1 CT molecule. The conjugation degree was lower than that of the chy-motrypsin conjugates with PEG-SC (succinimidyl carbonate of mPEG up to 14 chains per one CT molecule) [20,33]. This might be attributed to the solution stmcture difference between the two polymers. PHPMA has a random coil stmcture in aqueous solution, whereas PEG possesses a more extended one. The coiled PHPMA may cover more of the enzyme surface, and the steric effect may prevent more PHPMA macromolecules from attaching to the enzyme. 

The modification of the nanospheres with ST HPMA polymers significantly changed the surface structure and property of the nanospheres, which resulted in substantial changes in the biorecogiuzability and biodistribution of the nanospheres. The biocompatibility of HPMA polymers bodes well for the future application of ST PHPMA in the modification of biomedical surfaces. 

Wu T, Mei Y, Xu C, Byrd HCM, Beers KL (2005) Block copolymer PEO-b-PHPMA synthesis using controlled radical polymerization on a chip. Macromol Rapid Commun 26 1037... 

Poly [V-(2-hy droxy propy 1)-methacrylamide]-b-poly (trimethy lam-moniomethy 1 methacrylate chloride) (PHPMA-b-PTMAEM) Block copolymer, quaternary ammonium salt In vitro transfection (Wolfert etal., 1996)... 

Wolfert et al. (1996) examined the transfection and cytotoxicity of poly (V-2-hydroxypropyl methacrylamide)-/>-poly(trimethylaminoethyl methacrylate) (PHPMA-PTMAEM), an amino methacrylate... 

Figure 11.2 Structure of pHPMA-based polymer-drug conjugates.

The effect of reactive plasma and its distance form the PE film surface has also been studied in detail [138]. The surface of polyethylene films was modified with various water-soluble polymers [(poly[2-(methacryloy-loxy)ethyl phosphorylcholine] (PMPC), poly[2-(glucosyloxy)ethyl methacrylate] (PGEMA), poly(N-isopropylacrylamide) (PNIPAAm) and poly[N-(2-hy-droxypropyl) methacrylamide] (PHPMA)] using Ar plasma-post polymerisation technique [139]. Here, the reactive sites were generated on the PE surface under the influence of argon plasma. These reactive sites on the surface were then utilised to covalently anchor the functional monomers as shown in Scheme 11. 

Poly(N-(2-hydroxypropyl)methaciylamide) (pHPMA) has been investigated as a soluble macromolecular carrier system, using doxorubicin as the active drag (Figure 5.5). 

Kissel, M., Peschke, P, Subr, V., Ulbrich, K., Strunz, A. M., Kuehnlein, R., Debus, J., Friedrich, E. Detection and cellular localisation of the synthetic soluble macromolecular drug carrier pHPMA. Eur. J. Nucl. Med. Mol. Imaging 2002, 29(8), 1055-1062. 

PELLys PGEA PGEMA Phe, F PHPMA PIAA PIC PMMA PNIPAM PS Poly(A -[2-(2-(methoxyethoxy)ethoxy)]acetyl-L-lysine) Poly(2-(P-D-glucopyranosyloxy)ethyl acrylate) Poly(2-glucosyloxyethyl methacrylate) Phenylalanine Poly(A-(2-hydroxypropyl)methacrylamide) Polyisocyanodipeptide Polyion complex Poly(methyl methacrylate) Pol v (/V-i s o p r o p y 1 aery 1 am idc) Polystyrene Radius of gyration Hydrodynamic radius... 

PhPMA, The Pursuit of High Performance through Research and Development Understanding Pharmaceutical Research and Development Cost Drivers, Accenture, Editor, Washington, D.C., 1, 2007. 

IR analysis after treatment with signal enhancing reagents can also be useful. For example, the presence of carboxylic acid impurities in PHEMA and PHPMA was confirmed by IR analysis after exposure to sulfur tetrafluoride gas, (a useful technique if the 1600-1700 cm-1 region is cluttered with extraneous absorbances) converting carboxylic adds to the corresponding fluoride which absorbs at about 1825 cm -1 (80,81). The acidic impurity was confirmed in both HEMA and HPMA as MAA by GC-MS. The original content of MAA in... 

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