Biomacromolecules polymers

The described bioaffinity separations demonstrate that polyacrylamide spacers aid the selective binding of highly complex and delicate biomacromolecules and their associates. Moreover, these solutes remain biologically active after desorption probably due to the high inertness and flexibility of the surrounding polymer chains fixed on the solid support. The unbound parts of serum usually show no loss of the activities of their constituents. Thus we evaluate the surface of inorganic supports coated with chemisorbed iV-hydroxyethyl polyacrylamide and its derivatives as being biocompatible. 

Puskas, J.E. and Chen, Y. Biomedical application of commercial polymers and novel polyisobutylene-based thermoplastic elastomers for soft tissue replacement. Biomacromolecules, 5, 1141, 2004 GAK-GV, 7, 455 8, 526, 2004 (German). 

Loschonsky S, Shroff K, Worz A et al (2008) Surface-attached pdmaa-grgdsp hybrid polymer monolayers that promote the adhesion of living cells. Biomacromolecules 9 543-552... 

Farmer RS, Kiick KL (2005) Conformational behavior of chemically reactive alanine-rich repetitive protein polymers. Biomacromolecules 6 1531-1539... 

Senaratne, W., Andruzzi, L. and Ober, C. K. (2005) Self-assembled monolayers and polymer brushes in biotechnology Current applications and future perspectives. Biomacromolecules, 6, 2427-2448. 

Watanabe J, Eriguchi T, Ishihara K (2002) Stereocomplex formation by enantiomeric poly (lactic acid) graft-type phospholipid polymers for tissue engineering. Biomacromolecules 3 1109-1114... 

Watanabe J, Ishihara K (2005) Cell engineering biointerface focusing on cytocompatibility using phospholipid polymer with an isomeric oligo(lactic acid) segment. Biomacromolecules 6 1797-1802... 

Nam KW, Watanabe J, Ishihara K (2002) Characterization of the spontaneously forming hydrogels composed of water-soluble phospholipid polymers. Biomacromolecules 3 100-105... 

Berglin M, Delage L, Potin P, Vilter H, Elwing H (2004) Enzymatic cross-linking of a phenolic polymer extracted from the marine algaFucus serratus. Biomacromolecules 5 2376-2383... 

Stjemdahl A, Wistrand AF, Albertsson A-C (2007) Industrial utilization of tin-initiated resorbable polymers synthesis on a large scale with a low amount of initiator residue. Biomacromolecules 8 937-940... 

Feng CL, Zhang Z, Forch R, Knoll W, Vancso GJ, Schonherr H. (2005) Reactive thin polymer films as platforms for the immobilization of biomolecules. Biomacromolecules 6, 3243-51. 

Drevon GF, RusseU AJ (2000) Irreversible immobilization of diisopropylfluorophosphatase in polyurethane polymers. Biomacromolecules l(4) 571-576... 

The classification of polymers for oral drug delivery can be done by using various means. To make this discipline readily accessible to the novice reader, the hydro-phobic-hydrophilic nature of the polymer was chosen to group polymers since the mechanism of biomacromolecule release from most hydrophobic polymeric devices is similar the mechanism of release from most hydrophilic polymeric devices also have similar mechanisms. Hydrophobic polymers are described first, followed by hydrophilic polymers. 

Hydrophobic polymers are often used to deliver biomacromolecules regardless of the route of administration. The rapid transit time of approximately 8 hours limits the time of a device in the gastrointestinal (GI) system, consequently the mechanisms possible for oral drug release are limited. The predominant method of release from hydrophobic polymers has been degradation, or biodegradation, of a polymeric matrix by hydrolysis (Figure 11.1). In fact, all of the hydrophobic polymers described in this chapter for use as oral protein or peptide delivery are hydrolytically unstable. 

An alternative hydrophobic microparticulate dosage form can be produced using poly(alkyl cyanoacrylates) also referred to as simply poly(cyanoacrylates) (PCAs) (Table 11.3). Poly(cyanoacrylates) are a class of addition polymers that undergo polymerization under mild conditions, and even upon the addition of water or ethanol. Poly(cyanoacrylates) have been widely investigated for delivery of biomacromolecules. Due to their properties, cyanoacrylates can easily be formed into two types of particles spheres (Couvreur et al. 1982) or capsules (Al-Khouri Fallouh et al. 1986), both of which can be used to deliver biomacromolecules. The most used of the poly(cyanoacrylates) is poly (isobutyl cyanoacrylate) (PBCA). The reason... 

The degradation rate can be controlled using acidic and basic excipients acidic excipients increase the degradation rates and facilitate a zero-order release rate over a 2-week period (Sparer et al. 1984). Basic additives increase the degradation time of the polymers and create a polymer that degrades specifically at the surface (Heller 1985). By careful choice of the excipient added, the degradation rate can be closely controlled. No experiments have shown the use of these polymers with proteins or peptides. This is not, however, indicative of the fact that these polymers are not compatible with proteins or peptides, but they are probably not the most appropriate polymeric carrier for oral delivery of biomacromolecules. 

Hydrophilic polymers are currently undergoing investigation for improving the transport of biomacromolecules across the intestinal walls. Hydrophilic polymers have been shown to protect proteins and peptides from proteolysis. Multiple methods utilize the properties of polymers to protect biomacromolecules without removing them from the aqueous environment of the intestines. 

Polymers that are protease inhibitors and polymer-inhibitor conjugates are now widely investigated for their ability to protect proteins and peptides from proteolytic degradation. These molecules are effective in the immediate area surrounding the delivery device, so the effects on proteins that have diffused far from the delivery device are limited. Due to the fact that bioadhesives were used as the conjugating polymer, the delivery device may adhere to the intestinal lining. If this does happen, the diffusional distance of the protein from the device to the intestinal wall will be quite short. One barrier that the protease inhibitors do not affect is the cellular barrier. Biomacromolecules must still find a method to enter the cells or be taken up by phagocytosis. 

---