Block copolymer self-assembly in selective solvents: theory of solubilization in spherical micelles

Nagarajan, Ramaswamy; Ganesh, K. N.

doi:10.1021/ma00201a029

Cited by 173 publications

(166 citation statements)

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“…As shown in Table 1, the CAC values decrease with increasing molar content of PEO 10 -C 16 residues linked to the DEX backbone. These results are consistent with recent evidence, suggesting that the increase in the length of a hydrophobic residue for a given length of a hydrophilic polymer chain causes noticeable decrease in CAC value and increase in micelle stability [78].…”

Section: Physicochemical Characteristics Of Polymeric Micellessupporting

confidence: 93%

“…In solutions of the copolymer of concentration higher than the CAC, micelles and single chains coexist. This definition is used commonly to describe polymeric micelles, in analogy with the CMC of surfactant micelles, although the mechanism of micellization may not be the same for amphiphilic polymers and surfactants [78,79]. A delivery system is subject to "sink conditions" or severe dilution in the GI fluid upon oral administration.…”

Section: Physicochemical Characteristics Of Polymeric Micellesmentioning

confidence: 99%

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Polymeric micelles for oral drug delivery: Why and how

Francis

Cristea

Winnik

2004

Pure and Applied Chemistry

168

100

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Abstract:The oral delivery of drugs is regarded as the optimal means for achieving therapeutic effects owing to increased patient compliance. Unfortunately, the oral delivery route is beset with problems such as gastrointestinal (GI) destruction of labile molecules, low levels of macromolecular absorption, etc. To reduce the impact of digestive enzymes and to ensure the absorption of bioactive agents in an unaltered form, molecules may be incorporated into microparticulate carriers. Many approaches to achieve the oral absorption of a wide variety of drugs are currently under investigation. Among the different polymer-based drug delivery systems, polymeric micelles represent a promising delivery vehicle especially intended for poorly water-soluble pharmaceutical active ingredients in order to improve their oral bioavailability. Recent findings of a dextran-based polymeric micelle study for solubilization of a highly lipophilic drug, cyclosporin A (CsA), will be discussed.

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Section: Physicochemical Characteristics Of Polymeric Micellessupporting

confidence: 93%

Section: Physicochemical Characteristics Of Polymeric Micellesmentioning

confidence: 99%

Polymeric micelles for oral drug delivery: Why and how

Francis

Cristea

Winnik

2004

Pure and Applied Chemistry

168

100

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“…[41,42] Some of the theoretical treatments on the micellation process show that the coronal block can also exert a strong influence on the micellar characteristics, especially when the solvent is very good for the outer block. [43] This indicates the possibility of obtaining differently sized micelles by simply changing solvents. We found that under suitable experimental conditions the typical dimensions of the ensuing arrays of micelles are also strongly dependent on the deposition conditions, which in turn form a convenient handle for tuning.…”

Section: Full Papermentioning

confidence: 95%

Tuning the Dimensions and Periodicities of Nanostructures Starting from the Same Polystyrene‐block‐poly(2‐vinylpyridine) Diblock Copolymer

Krishnamoorthy

Pugin

Brugger

et al. 2006

Adv Funct Materials

102

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The controlled tuning of the characteristic dimensions of two‐dimensional arrays of block‐copolymer reverse micelles deposited on silicon surfaces is demonstrated. The polymer used is polystyrene‐block‐poly(2‐vinylpyridine) (91 500‐b‐105 000 g mol–1). Reverse micelles of this polymer with different aggregation numbers have been obtained from different solvents. The periodicity of the micellar array can be systematically varied by changing copolymer concentration, spin‐coating speeds, and by using solvent mixtures. The profound influence of humidity on the micellar film structure and the tuning of the film topography through control of humidity are presented. Light scattering, atomic force microscopy, scanning electron microscopy, transmission electron microscopy, and X‐ray photoelectron spectroscopy were used for characterization. As possible applications, replication of micellar array topography with polydimethylsiloxane and post‐loading of the micelles to form iron oxide nanoparticle arrays are presented.

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“…(16,17) The drug loading efficiency of the nanoparticles is also governed by a number of critical parameters, particularly the chemical affinity of the loaded drug for the nanoparticle core. (18)(19)(20) We have recently reported on the design and synthesis of an unique ABA-type amphiphilic triblock copolymers that self-assemble into nanospheres at low critical aggregation concentration. (21-23) The A-blocks of these copolymers are composed of poly(ethylene glycol) PEG and the B-blocks are composed of polyarylate oligomers of desaminotyrosyl-tyrosine alkyl esters (DTR) and non-toxic diacids (Scheme 1).…”

Section: Introduction Backgroundmentioning

confidence: 99%

Nanospheric Chemotherapeutic and Chemoprotective Agents

Sheihet¹

2008

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Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing this collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. REPORT DATE (DD-MM-YYYY) ABSTRACTPurpose: Investigate the delivery of camptothecin in the presence of vitamin D3 with triblock copolymer-derived nanospheres that will increase the solubility of both of the drugs and provide protection to the camptothecin's lactone ring, resulting in its increased bioavailability to breast cancer cells. To date we have done the evaluation of two nanosphere formulations containing short alkyl pendent chain (DTB-SA/5K, Butyl) and/or benzyl ring (DTBn-SA/5K) Drug-binding efficiency of these nanospheres was evaluated for a constant quantity of the nanospheres with varying concentrations of the CPT and/or VD3. HPLC methods were developed and validated for quantitative determination of CPT and VD3 in the copolymer systems. To elucidate the synergistic effect of vitamin D3 on increasing the binding efficiency of CPT, different CPT to VD3 feed ratio were investigated. Results: The binding efficiency of VD3 in the presence of CPT. VD3 binding efficiency is not affected by the presence of the camptothecin, but is strongly affected by the nanospheres composition. Work was delayed by contract difficulties at Rutgers, but is now underway. SUBJECT TERMSNo subject terms were provided. I would like to bring to your attention that although this research project was awarded in August 2006 the actual award document was not issued until after April 2007. As a consequence, the actual research has begun just 3 month ago. We also applied for a one-year no-cost extension of funding that was accepted only on August 13, 2007. Thus, the below report is a summary of preliminary data obtained within 3.5 month of a research work. Introduction BackgroundSelf-assembling nanospheres offer a promising route to the delivery of pharmaceuticals that have poor bioavailability by improving the drugs' stability, circulation times in the body, and permeability through cell membranes, while reducing their toxicities.(1) Many drugs, including anti-tumor agents, anti-depressants and statins, are lipophilic and therefore require a solubilization process to enable their parenteral delivery. (2) Of the many alternative approac...

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Block copolymer self-assembly in selective solvents: theory of solubilization in spherical micelles

Cited by 173 publications

References 10 publications

Polymeric micelles for oral drug delivery: Why and how

Polymeric micelles for oral drug delivery: Why and how

Tuning the Dimensions and Periodicities of Nanostructures Starting from the Same Polystyrene‐block‐poly(2‐vinylpyridine) Diblock Copolymer

Nanospheric Chemotherapeutic and Chemoprotective Agents

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