Tetronic micellization, gelation and drug solubilization: Influence of pH and ionic strength

Alvarez‐Lorenzo, Carmen; González-López, Jaime; Fernandez-Tarrio, Marta; Sandez-Macho, Isabel

doi:10.1016/j.ejpb.2006.10.010

Cited by 100 publications

(85 citation statements)

References 40 publications

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“…Some authors have studied the effect of pH on the associative behavior of several Tetronics. 8,[29][30][31] . With the aim of studying the behavior of Tetronic 90R4 solutions as a function of pH and/or ionic strength, dynamic light scattering was used.…”

Section: Resultsmentioning

confidence: 99%

Phase Behavior of Reverse Poloxamers and Poloxamines in Water

Larrañeta

Isasi

2013

Langmuir

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ABSTRACT:The phase behavior of two types of poly(ethylene oxide)/ poly(propylene oxide) (PEO/PPO) copolymers in aqueous solutions was studied by light scattering, viscometry and infrared spectroscopy. Both the reverse poloxamer (Pluronic 10R5) and the star type poloxamine (Tetronic 90R4) have practically the same PEO/PPO ratio with their hydrophobic blocks (PPO) located in the outer part. The temperature-composition phase diagrams show that both 10R5 and 90R4 tend to form aggregates in water. Up to four different phases can be detected in the case of Tetronic 90R4 for each temperature: unimers, random networks, micellar networks and macrophase separation. Viscometric and infrared measurements complemented the results obtained by light scattering and visual inspection.

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Section: Resultsmentioning

confidence: 99%

Phase Behavior of Reverse Poloxamers and Poloxamines in Water

Larrañeta

Isasi

2013

Langmuir

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“…The dependence of the conformation and hydrophilicity of the Tetronic T904 unimers and micelles on CMC has been shown by Alvarez-Lorenzo and others [152]. For Tetronic at pH < 5.8, the diprotonated form predominates over the nonprotonated one.…”

Section: Properties and Characterization Of Micellesmentioning

confidence: 95%

Polymeric micelles: authoritative aspects for drug delivery

Kulthe

Choudhari

Inamdar

et al. 2012

Designed Monomers and Polymers

187

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“…Using the values of N for poloxamine micelles in HCl 10 mM previously reported [21], the binding constant K would be much larger for T904 (49 260) compared with that of T908 (21 001), T1107 (16 439) and T1307 (25 482), owing to the fact that each micelle of T904 is formed by a greater number of unimers (14) than those of T908 (7), T1107 (4) and T1307 (5). It is probably because the N values are still larger in NaCl 0.9 per cent than in HCl 10 mM because of a lower degree of protonation of the ethylendiamine group [43], but the trend in the K values should be quite similar. Mixed micelles did not show a synergistic solubilization as previously shown with efavirenz [27], but improved the physical stability of the system with respect to ETOXloaded T904 single micelles.…”

Section: Ethoxzolamide Solubilizationmentioning

confidence: 99%

Single and mixed poloxamine micelles as nanocarriers for solubilization and sustained release of ethoxzolamide for topical glaucoma therapy

Ribeiro

Sosnik

Chiappetta

et al. 2012

J. R. Soc. Interface.

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Polymeric micelles of single and mixed poloxamines (Tetronic) were evaluated regarding their ability to host the antiglaucoma agent ethoxzolamide (ETOX) for topical ocular application. Three highly hydrophilic varieties of poloxamine (T908, T1107 and T1307) and a medium hydrophilic variety (T904), possessing a similar number of propylene oxide units but different contents in ethylene oxide, were chosen for the study. The critical micellar concentration and the cloud point of mixed micelles in 0.9 per cent NaCl were slightly greater than the values predicted from the additive rule, suggesting that the co-micellization is hindered. Micellar size ranged between 17 and 120 nm and it was not altered after the loading of ETOX (2.7-11.5 mg drug g -1 poloxamine). Drug solubilization ability ranked in the order: T904 (50-fold increase in the apparent solubility) . T1107 ffi T1307 . T908. Mixed micelles showed an intermediate capability to host ETOX but a greater physical stability, maintaining almost 100 per cent drug solubilized after 28 days. Furthermore, the different structural features of poloxamines and their combination in mixed micelles enabled the tuning of drug release profiles, sustaining the release in the 1-5 days range. These findings together with promising hen's egg test-chorioallantoic membrane biocompatibility tests make poloxamine micelles promising nanocarriers for carbonic anhydrase inhibitors in the treatment of glaucoma.

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Tetronic micellization, gelation and drug solubilization: Influence of pH and ionic strength

Cited by 100 publications

References 40 publications

Phase Behavior of Reverse Poloxamers and Poloxamines in Water

Phase Behavior of Reverse Poloxamers and Poloxamines in Water

Polymeric micelles: authoritative aspects for drug delivery

Single and mixed poloxamine micelles as nanocarriers for solubilization and sustained release of ethoxzolamide for topical glaucoma therapy

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