Pluronic® block copolymers

Figure 9.3. Characterization of mesoporous Ti02 films templated by Pluronics block copolymers using diverse characterization techniques XRD pattern (a), transmission electron microscope (TEM) image (b), dark-field TEM image (c), and isotherms of Kr adsorption (d).The Pluronic-templated Ti02 films were calcined at 400°C (solid points) and 600°C (open points). The films were prepared according to Alberius et al. (Ref. 14).

Seeballuck F, Ashford MB, O Driscoll CM (2003) The effects of Pluronic block copolymers and Cremophor EL on intestinal lipoprotein processing and the potential link with P-glycoprotein in Caco-2 cells. Pharm Res 20 1085-1092... 

Batrakova E, Lee S, Li S, Venne A, Alakhov V, Kabanov A. Fundamental relationships between the composition of Pluronic block copolymers and their hypersensitization effect in MDR cancer cells. Pharm Res 1999 16 1373-1379. 

Sakai T, Alexandridis P (2004) Single-step synthesis and stabilization of metal nanoparticles in aqueous Pluronic block copolymer solutions at ambient temperature. Langmuir 20 8426-8430... 

Polyethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) (Pluronic) block copolymer is a very efficient reducing agent and nanoparticle stabilizer. Au NPs of about 10 nm can be stabilized with PEO-PPO-PEO block copolymer solutions in water and at room temperature and using HAuC14 as precursor. The formation of gold nanoparticles is controlled by the overall molecular weight and relative block length of the block copolymer [118]. 

Batrakova, E., H. Han, V. Y. Alakhov, D. W. Miller, and A. V. Kabanov. 1998. Effects of pluronic block copolymers on drug absorption in Caco-2 cell monolayRSharm. Res15 850-855. 

Croy, S. R. andG. S. Kwon. 2004. The effects of Pluronic block copolymers on the aggregation state of nystatin. J. Control. Rel.95 161-171. 

Alakhov, V., etal., Pluronic block copolymers and Pluronic poly(acrylic acid) microgels in oral delivery of megestrol acetatd, Pharm. Pharmacol., 56, 1233, 2004. 

Recently, a new class of inhibitors (nonionic polymer surfactants) was identified as promising agents for drug formulations. These compounds are two- or three-block copolymers arranged in a linear ABA or AB structure. The A block is a hydrophilic polyethylene oxide) chain. The B block can be a hydrophobic lipid (in copolymers BRIJs, MYRJs, Tritons, Tweens, and Chremophor) or a poly(propylene oxide) chain (in copolymers Pluronics [BASF Corp., N.J., USA] and CRL-1606). Pluronic block copolymers with various numbers of hydrophilic EO (,n) and hydrophobic PO (in) units are characterized by distinct hydrophilic-lipophilic balance (HLB). Due to their amphiphilic character these copolymers display surfactant properties including ability to interact with hydrophobic surfaces and biological membranes. In aqueous solutions with concentrations above the CMC, these copolymers self-assemble into micelles. 

FIGURE 28.4 Schematic illustration twofold effects of Pluronic block copolymer on Pgp drug efflux system. Inhibition of Pgp activity is due to a combination of two cellular pathways depletion of ATP levels and membrane fluidization in the cells. 

Kabanov, A., E. Batrakova, and V. Alakhov. 2002. Pluronic block copolymers as novel polymer therapeutics for drug and gene delivery. J Control Release 82 189. 

Miller, D., et al. 1997. Interactions of Pluronic block copolymers with brain microvessel endothelial cells Evidence of two potential pathways for drug absorption. Bioconjug Chem 8 649. 

Batrakova, E., et al. 2003. Optimal structure requirements for pluronic block copolymers in modifying P-glycoprotein drug efflux transporter activity in bovine brain microvessel endothelial cells. J Pharmacol Exp Ther 304 845. 

Miller, D., E. Batrakova, and A. Kabanov. 1999. Inhibition of multidrug resistance-associated protein (MRP) functional activity with pluronic block copolymers. Pharm Res 16 396. 

Batrakova, E.V., et al. 2001. Mechanism of sensitization of MDR cancer cells by Pluronic block copolymers Selective energy depletion. Br J Cancer 85 1987. 

Kabanov, A.V., E.V. Batrakova, and V.Y. Alakhov. 2003. An essential relationship between ATP depletion and chemosensitizing activity of Pluronic block copolymers. J Control Release 91 75. 

Kabanov, A. Y., E.V. Batrakova, and D.W. Miller. 2003. Pluronic block copolymers as modulators of drug efflux transporter activity in the blood-brain barrier. Adv Drug Deliv Rev 55 151. 

P123 P3HT P3(ODAP)HT P3TOPA trade name for a Pluronic block copolymer poly (3 -hexyl thiophene) poly(3-(6-oxy-2,4-diaminopyrimidine)hexylthiophene) poly(3-(3 -thienyloxy)propyltrimethylammonium)... 

Figure 47.3. Schematic illustrating twofold effects of Pluronic block copolymers witli intemiediate lipophilicity on Pgp and MRPs drag efflux system. Tliese effects include (a) decrease in membrane viscosity ( fluidization ) resulting in inliibition of Pgp and MRPs ATPase activity, and (b) ATP depletion in BMVEC. Extremely lipo-pliilic or hydi ophilic Plui onic block copolymers do not cross tire cel-lulai membranes and do not cause energy depletion in tire cells.

Describe the effects of Pluronic block copolymers on di ug efflux transporters in the BBB. 

Kabanov AV, Badakova EV, Alakliov VY (2003b) An essendal rela-donship between ATP depledon and chemosensidzing acdvity of Pluronic block copolymers. J Condol Release 91 75-83. 

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