Size of Bile Salt Micelles: Techniques, Problems and Results

Kratohvil, J. P.

doi:10.1002/hep.1840040816

Cited by 40 publications

(21 citation statements)

References 31 publications

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“…To this end a BS concentration of 5610 26 M was found to be detectable and subsequently used as the sample concentration throughout. Also, it is known that BS form aggregates above a certain concentration [45][46][47], the CMC. It is necessary to ensure that micelles do not form in the ACE experiments.…”

Section: Ace Proceduresmentioning

confidence: 99%

Complexation of tauro‐ and glyco‐conjugated bile salts with three neutral β‐CDs studied by ACE

et al. 2007

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Complexation of the bile salts (BS) taurocholate, tauro-beta-muricholate, taurodeoxycholate, taurochenodeoxycholate, glycocholate, glycodeoxycholate, and glycochenodeoxycholate common in rat, dog, and man with natural beta-CD and the chemically modified beta-CDs 2-hydroxypropyl-beta-CD and 2-O-methyl-beta-CD was studied using mobility shift ACE. The CDs were selected due to their frequent use in preformulation and drug formulation as oral excipients for the solubilization of drug substances with low aqueous solubility. ACE was demonstrated to be a feasible and efficient technique for investigation of the interactions between BS and beta-CDs. All the investigated BS possessed affinity for the three CDs with stability constants ranging from 2x10(3) to 4x10(5) M(-) (1). The requirements and assumptions related to the use of ACE for estimating high affinity stability constants were discussed. The extent and pattern of hydroxylation significantly influenced the affinity of the glyco- and tauro-conjugated BS toward the beta-CDs (chenodeoxycholates >> deoxycholates > cholates) whereas the nature of the beta-CD derivatization and BS conjugation played a minor role only. The results indicate that displacement of drug substances from beta-CD inclusion complexes is likely to occur in the small intestine where BS are present potentially influencing drug bioavailability.

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Section: Ace Proceduresmentioning

confidence: 99%

Complexation of tauro‐ and glyco‐conjugated bile salts with three neutral β‐CDs studied by ACE

et al. 2007

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“…Next to the other species, for each W, one species with odd aggregation number (r = 3 for W = 0.100 and r = 5 for W = 0.500 and 0.800 mol dm -3 ) is present. At W = 0.800 mol dm -3 , r assumes the values: 2,8,12,16,24.…”

Section: Discussionmentioning

confidence: 99%

“…The bigger aggregates can be represented by Na m' [Na 4 (Col) 8 ] n' , while the species Na 8 (Col) 12 could be considered as a transition from dimer to octamer, if it is written in the form Na 2 [Na(Col) 2 ] 2 [Na 4 (Col) 8 In conclusion a peculiarity of the sodium salts of bile acid not conjugated, i.e. NaDC and NaCol, as respect to their conjugated, i.e.…”

Section: Discussionmentioning

confidence: 99%

“…were studied by many researchers. [4][5][6][7][8][9][10][11][12][13][14][15][16] The results obtained from e.m.f. measurements, carried out as a function of hydrogen ions, reagents and ionic medium 17 concentrations on aqueous sodium salt solution of dihydroxycholanic acids (deoxycholate = NaDC 18 , glycodeoxycholate = NaGDC 19 and taurodeoxycholate = NaTDC 20 ), were explained by assuming the presence of several species with different odd high aggregation numbers and also formed with the uptake of protons.…”

Section: Introductionmentioning

confidence: 99%

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Composition of Sodium Cholate Micellar Solutions

Bottari¹,

Buonfigli²,

Festa³

2005

Annali di Chimica

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To study the composition of sodium cholate solutions, an investigation was carried out at 25 degrees C and in N(CH3)4Cl, as a constant ionic medium, at three different concentrations (W = 0.100; 0.500 and 0.800 mol dm(-3)). Electromotive force measurements of three different galvanic cells, the first involving a glass electrode for hydrogen ions, the second an electrode for sodium ions and the third a lead amalgam electrode, were performed. Independently, lead (II) cholate solubility measurements in the presence of sodium ions were performed, as well. The experimental results obtained from both approaches were explained by assuming the formation of aggregates in cholate and sodium of different composition depending on W and on the cholate concentration. The maximum aggregation found number for cholate was 24 and even aggregation numbers were markedly predominant. Only two species with odd aggregation number were found, but at a low percentage. The assumed species and the relative constants were compared with those found for the other sodium salt of cholanic acids.

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“…Compact Formula "core + link" formula Na 3 (GC) 2 (GDC) 3 { Na(GC) 2 Na(GDC) 3 } Na 10 (GC) 4 (GDC) 9 { [Na(GC) 2 ] 2 [Na(GDC) 3 ] 3 } Na 5 Na 19 (GC) 8 (GDC) 18 { [Na(GC) 2 ] 4 [Na(GDC) 3 ] 6 } Na 9 Na 28 (GC) 8 The species and the relative constants collected in Table 1 were used to calculate the percentage of each species as function of the GDC -or the GC -aggregation number, N -and N' -, respectively. Fig.…”

Section: Data Obtained At W = 0750 Mol Dm -3mentioning

confidence: 99%

Composition of Aqueous Solutions Containing Sodium Glycocholate and Glycodeoxycholate

Bottari

Festa

2005

Annali di Chimica

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Composition and existence range of aggregates formed by sodium glycocholate and glycodeoxycholate contemporary present in aqueous micellar and premicellar solutions were investigated. Solubility measurements of lead (II) glycocholate and glycodeoxycholate give analytical concentration of lead (II) and glycocholate and glycodeoxycholate, respectively. Electromotive force measurements provide the free concentration of hydrogen, sodium and lead (II) ions. Experimental data obtained at 25 degrees C and at three different concentrations of N(CH3)4Cl, used as a constant ionic medium, can be explained by assuming the presence of aggregates of different composition depending on the reagent and ionic medium concentrations. Next to two species containing only glycocholate or glycodeoxycholate, the presence of aggregates formed with the contemporary participation of both bile anions in different ratios was assumed. Species with the hydrogen ion participation are not present in appreciable quantity in the investigated concentration range. As expected, the size of aggregates increases by increasing reagent and ionic medium concentration. Most of the species can be explained with a "core + link" mechanism, where all the glycocholate aggregation numbers are even, while those of glycodeoxycholate are always multiple of three. Analogy and difference with aggregates formed by the two bile anions separately are discussed.

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Size of Bile Salt Micelles: Techniques, Problems and Results

Cited by 40 publications

References 31 publications

Complexation of tauro‐ and glyco‐conjugated bile salts with three neutral β‐CDs studied by ACE

Complexation of tauro‐ and glyco‐conjugated bile salts with three neutral β‐CDs studied by ACE

Composition of Sodium Cholate Micellar Solutions

Composition of Aqueous Solutions Containing Sodium Glycocholate and Glycodeoxycholate

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