Determination of Critical Micelle Concentration of Lipopolymers and Other Amphiphiles:  Comparison of Sound Velocity and Fluorescent Measurements

Priev, Aba; Zalipsky, Samuel; Cohen, Rivka; Barenholz, Yechezkel

doi:10.1021/la0110085

Cited by 78 publications

(58 citation statements)

References 22 publications

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“…To support the above hypothesis, the critical micelle concentration (CMC) of Cremophor EL, which is reported at 0.039 mM, equivalent to around 0.0098% (w/v) in water at 25°C, should be considered (27). The concentration of Cremophor EL within the experimental range is therefore well above the CMC of the nanoemulsion upon 1,000 times dilution during droplet size analysis.…”

Section: Discussionmentioning

confidence: 99%

“…Although there is substantial difference between hydrogen bonding environments in crystal form and aqueous solution state, the captioned value suffices to yield a reasonable estimation in the molecular size of Cremophor EL. By comparison of the space filling models between SDS and Cremophor EL (27), the length of Cremophor EL is 4.6 nm approximately, and its polar head group region is about 3.0 nm (Fig. 3a).…”

Section: Discussionmentioning

confidence: 99%

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Formulation Development and Bioavailability Evaluation of a Self-Nanoemulsified Drug Delivery System of Oleanolic Acid

Xi¹,

et al. 2009

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Abstract. This study aims to formulate and evaluate bioavailability of a self-nanoemulsified drug delivery system (SNEDDS) of a poorly water-soluble herbal active component oleanolic acid (OA) for oral delivery. Solubility of OA under different systems was determined for excipient selection purpose. Four formulations, where OA was fixed at the concentration of 20 mg/g, were prepared utilizing Sefsol 218 as oil phase, Cremophor EL and Labrasol as primary surfactants, and Transcutol P as cosurfactant. Pseudoternary phase diagrams were constructed to identify self-emulsification regions for the rational design of SNEDDS formulations. Sefsol 218 was found to provide the highest solubility among all medium-chained oils screened. Efficient self-emulsification was observed for the systems composing of Cremophor EL and Labrasol. The surfactant to cosurfactant ratio greatly affected the droplet size of the nanoemulsion. Based on the outcomes in dissolution profiles, stability data, and particle size profiles, three optimized formulations were selected: Sefsol 218/Cremophor EL/Labrasol (50:25:25, w/w), Sefsol 218/Cremophor EL/Labrasol/Transcutol P (50:20:20:10, w/w), and Sefsol 218/Cremophor EL/Labrasol/Transcutol P (50:17.5:17.5:15, w/w). Based on the conventional dissolution method, a remarkable increase in dissolution was observed for the SNEDDS when compared with the commercial tablet. The oral absorption of OA from SNEDDS showed a 2.4-fold increase in relative bioavailability compared with that of the tablet (p<0.05), and an increased mean retention time of OA in rat plasma was also observed compared with that of the tablet (p<0.01). These results suggest the potential use of SNEDDS to improve dissolution and oral bioavailability for poorly water-soluble triterpenoids such as OA.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Formulation Development and Bioavailability Evaluation of a Self-Nanoemulsified Drug Delivery System of Oleanolic Acid

Xi¹,

et al. 2009

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“…17 Only the oleyl-modified derivatives were found to enhance transfection appreciably. We used 1,6-diphenyl-1,3,5-hexatriene (DPH) in order to demonstrate the difference in state of self-association (micelle formation) 18 between D-SPM and olely-modified D-SPM (ODS-20%, where 20% of e-NH 2 of D-SPM is covalently attached to the oleyl moiety). DPH fluoresces only when present in a hydrophobic environment, 19 and therefore it can be used successfully to determine the critical micellar concentration (CMC).…”

Section: Effect Of Serum On Transfection Efficiencymentioning

confidence: 99%

“…Therefore, it can be used to detect the presence of such lipidic assemblies, as well as to determine CAC or CMC, as described elsewhere. 18 The mole ratio of polymers' e-NH 2 or DOTAP to DPH was kept constant (400:1). Fluorescence intensities of samples with and without DPH were read using excitation and emission wavelengths of 360 and 430 nm, respectively, slits of 5 nm, and the net fluorescence intensity (corrected for …”

Section: Determination Of Cmcmentioning

confidence: 99%

Novel dextran–spermine conjugates as transfecting agents: comparing water-soluble and micellar polymers

et al. 2004

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Recently, a novel cationic polymer, dextran-spermine (D-SPM) was developed for gene delivery. An efficient transfection was obtained using this polycation for a variety of genes and cell lines in serum-free or serum-poor medium. However, transfection using the water-soluble D-SPMbased polyplexes decreased with increasing serum concentration in cell culture in a concentration-dependent manner, reaching 95% inhibition at 50% serum in the cell growth medium. In order to overcome this obstacle, oleyl derivatives of D-SPM (which form micelles in aqueous phase) were synthesized at 1, 10, and 20 mol% of oleyl moiety to polymer e-NH 2 to form N-oleyl-D-SPM (ODS). Polyplexes based on ODS transfected well in medium containing 50% serum. Comparison with polyplexes based on well-established polymers (branched and linear polyethyleneimine) and with DOTAP/Cholesterol lipoplexes showed that regarding b-galactosidase transgene expression level and cytotoxicity in tissue culture, the D-SPM and ODS compare well with the above polyplexes and lipoplexes. Intracellular trafficking using FITC-labeled ODS and Rhodamine-labeled pGeneGrip plasmid cloned with hBMP2 monitored by confocal microscopy revealed that during the transfection process the fluorescent-labeled polymer concentrates in the Golgi apparatus and around the nucleus, while the cell cytoplasm was free of fluorescent particles, suggesting that the polyplexes move in the cell toward the nucleus by vesicular transport through the cytoplasm and not by a random diffusion. We found that the plasmids penetrate the cell nucleus without the polymer. Preliminary results in zebra fish and mice demonstrate the potential of ODS to serve as an efficient nonviral vector for in vivo transfection. Gene Therapy (2005) 12, 494-503.

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“…O módulo de compressão em função da pressão de superfície para a amostra AE-PEG9 (massa molar média ~681 g·mol -1 ) foi avaliado variando arbitrariamente a massa molar média do composto em uma faixa (Priev et al, 2002). A tabela 3 apresenta os dados estimados da CAC associados aos quatro ésteres graxos de PEG.…”

Section: Filmes De Langmuir Dos éSteres De Polietilenoglicolunclassified

Filmes De Langmuir De Ésteres De Polietilenoglicol Derivados De Ácidos Graxos

COLLAZOS¹

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Determination of Critical Micelle Concentration of Lipopolymers and Other Amphiphiles: Comparison of Sound Velocity and Fluorescent Measurements

Cited by 78 publications

References 22 publications

Formulation Development and Bioavailability Evaluation of a Self-Nanoemulsified Drug Delivery System of Oleanolic Acid

Formulation Development and Bioavailability Evaluation of a Self-Nanoemulsified Drug Delivery System of Oleanolic Acid

Novel dextran–spermine conjugates as transfecting agents: comparing water-soluble and micellar polymers

Filmes De Langmuir De Ésteres De Polietilenoglicol Derivados De Ácidos Graxos

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