Protolytic Equilibria of Sartans in Micellar Solutions of Differently Charged Surfactants
Abstract
Protolytic equilibria of irbesartan, losartan, and valsartan have been investigated in the presence and absence of differently charged anionic (sodium dodecyl sulfate), cationic (cetyltrimethylammonium bromide), and nonionic (4-octylphenol polyethoxylate and polyoxyethylene (23) lauryl ether) surfactants. Ionization constants were determined by potentiometric titration at a constant ionic strength (0.1 M NaCl) and temperature 25 degrees C. The effect of surfactants was estimated, based on a shift in apparent ionization constants (pK(a)(app)) determined in micellar solutions against the pK(a)(w) values in water. The anionic surfactant caused an increase in the pK(a)(app) values of sartans (up to 1.72 pK units), while the cationic surfactant had an opposite effect and caused a reduction in pK(a)(app) values (up to -1.44 pK units). These results point out to the fact that the ionizable groups of sartans are involved in electrostatic interactions with the charged surface of the ionic micel...les. Shift in the pKa app values in the presence of nonionic surfactants (from -0.86 to +1.30) is a consequence of the interactions of drugs with the hydrophilic palisade layer. Significant changes in the distribution profiles of the equilibrium forms (from -44% to +80%) are observed at the biopharmaceutically important pH 4.5 value and can be considered in terms of the potential influence on intestinal absorption and bioavailability.
Source:
Journal of Pharmaceutical Sciences, 2016, 105, 8, 2444-2452Publisher:
- Wiley, Hoboken
Funding / projects:
DOI: 10.1016/j.xphs.2016.06.007
ISSN: 0022-3549
PubMed: 27422089
WoS: 000381770400025
Scopus: 2-s2.0-84978929438
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Institution/Community
PharmacyTY - JOUR AU - Grujić, Maja AU - Popović, Marija AU - Popović, Gordana AU - Nikolić, Katarina AU - Agbaba, Danica PY - 2016 UR - https://farfar.pharmacy.bg.ac.rs/handle/123456789/2715 AB - Protolytic equilibria of irbesartan, losartan, and valsartan have been investigated in the presence and absence of differently charged anionic (sodium dodecyl sulfate), cationic (cetyltrimethylammonium bromide), and nonionic (4-octylphenol polyethoxylate and polyoxyethylene (23) lauryl ether) surfactants. Ionization constants were determined by potentiometric titration at a constant ionic strength (0.1 M NaCl) and temperature 25 degrees C. The effect of surfactants was estimated, based on a shift in apparent ionization constants (pK(a)(app)) determined in micellar solutions against the pK(a)(w) values in water. The anionic surfactant caused an increase in the pK(a)(app) values of sartans (up to 1.72 pK units), while the cationic surfactant had an opposite effect and caused a reduction in pK(a)(app) values (up to -1.44 pK units). These results point out to the fact that the ionizable groups of sartans are involved in electrostatic interactions with the charged surface of the ionic micelles. Shift in the pKa app values in the presence of nonionic surfactants (from -0.86 to +1.30) is a consequence of the interactions of drugs with the hydrophilic palisade layer. Significant changes in the distribution profiles of the equilibrium forms (from -44% to +80%) are observed at the biopharmaceutically important pH 4.5 value and can be considered in terms of the potential influence on intestinal absorption and bioavailability. PB - Wiley, Hoboken T2 - Journal of Pharmaceutical Sciences T1 - Protolytic Equilibria of Sartans in Micellar Solutions of Differently Charged Surfactants VL - 105 IS - 8 SP - 2444 EP - 2452 DO - 10.1016/j.xphs.2016.06.007 ER -
@article{ author = "Grujić, Maja and Popović, Marija and Popović, Gordana and Nikolić, Katarina and Agbaba, Danica", year = "2016", abstract = "Protolytic equilibria of irbesartan, losartan, and valsartan have been investigated in the presence and absence of differently charged anionic (sodium dodecyl sulfate), cationic (cetyltrimethylammonium bromide), and nonionic (4-octylphenol polyethoxylate and polyoxyethylene (23) lauryl ether) surfactants. Ionization constants were determined by potentiometric titration at a constant ionic strength (0.1 M NaCl) and temperature 25 degrees C. The effect of surfactants was estimated, based on a shift in apparent ionization constants (pK(a)(app)) determined in micellar solutions against the pK(a)(w) values in water. The anionic surfactant caused an increase in the pK(a)(app) values of sartans (up to 1.72 pK units), while the cationic surfactant had an opposite effect and caused a reduction in pK(a)(app) values (up to -1.44 pK units). These results point out to the fact that the ionizable groups of sartans are involved in electrostatic interactions with the charged surface of the ionic micelles. Shift in the pKa app values in the presence of nonionic surfactants (from -0.86 to +1.30) is a consequence of the interactions of drugs with the hydrophilic palisade layer. Significant changes in the distribution profiles of the equilibrium forms (from -44% to +80%) are observed at the biopharmaceutically important pH 4.5 value and can be considered in terms of the potential influence on intestinal absorption and bioavailability.", publisher = "Wiley, Hoboken", journal = "Journal of Pharmaceutical Sciences", title = "Protolytic Equilibria of Sartans in Micellar Solutions of Differently Charged Surfactants", volume = "105", number = "8", pages = "2444-2452", doi = "10.1016/j.xphs.2016.06.007" }
Grujić, M., Popović, M., Popović, G., Nikolić, K.,& Agbaba, D.. (2016). Protolytic Equilibria of Sartans in Micellar Solutions of Differently Charged Surfactants. in Journal of Pharmaceutical Sciences Wiley, Hoboken., 105(8), 2444-2452. https://doi.org/10.1016/j.xphs.2016.06.007
Grujić M, Popović M, Popović G, Nikolić K, Agbaba D. Protolytic Equilibria of Sartans in Micellar Solutions of Differently Charged Surfactants. in Journal of Pharmaceutical Sciences. 2016;105(8):2444-2452. doi:10.1016/j.xphs.2016.06.007 .
Grujić, Maja, Popović, Marija, Popović, Gordana, Nikolić, Katarina, Agbaba, Danica, "Protolytic Equilibria of Sartans in Micellar Solutions of Differently Charged Surfactants" in Journal of Pharmaceutical Sciences, 105, no. 8 (2016):2444-2452, https://doi.org/10.1016/j.xphs.2016.06.007 . .