Acid-base equilibria in homogeneous and heterogeneous systems of two antihistaminics, loratadine and desloratadine were studied spectrophotometrically in Britton-Robinson's buffer at 25 degrees C. Acidity constant of loratadine was found to be pK(a) 5.25 and those of desloratadine pK(a1) 4.41 and pK(a2) 9.97. The values of intrinsic solubilities of loratadine and desloratadine were 8.65 x 10(-6) M and 3.82 x 10(-4) M, respectively. Based on the pK(a) values and intrinsic solubilities, solubility curves of these two drugs as a function of pH were calculated. The effects of anionic, cationic and non-ionic surfactants applied in the concentration exceeding critical micelle concentration (cmc) on acid-base properties of loratadine and desloratadine, as well as on intrinsic solubility of loratadine were also examined. The results revealed a shift of pK(a) values in micellar media comparing to the values obtained in water. These shifts (Delta pK(a)) ranged from -2.24 to +1.24.
TY - JOUR
AU - Popović, Gordana
AU - Čakar, Mira
AU - Agbaba, Danica
PY - 2009
UR - http://farfar.pharmacy.bg.ac.rs/handle/123456789/1234
AB - Acid-base equilibria in homogeneous and heterogeneous systems of two antihistaminics, loratadine and desloratadine were studied spectrophotometrically in Britton-Robinson's buffer at 25 degrees C. Acidity constant of loratadine was found to be pK(a) 5.25 and those of desloratadine pK(a1) 4.41 and pK(a2) 9.97. The values of intrinsic solubilities of loratadine and desloratadine were 8.65 x 10(-6) M and 3.82 x 10(-4) M, respectively. Based on the pK(a) values and intrinsic solubilities, solubility curves of these two drugs as a function of pH were calculated. The effects of anionic, cationic and non-ionic surfactants applied in the concentration exceeding critical micelle concentration (cmc) on acid-base properties of loratadine and desloratadine, as well as on intrinsic solubility of loratadine were also examined. The results revealed a shift of pK(a) values in micellar media comparing to the values obtained in water. These shifts (Delta pK(a)) ranged from -2.24 to +1.24.
PB - Pergamon-Elsevier Science Ltd, Oxford
T2 - Journal of Pharmaceutical and Biomedical Analysis
T1 - Acid-base equilibria and solubility of loratadine and desloratadine in water and micellar media
VL - 49
IS - 1
SP - 42
EP - 47
DO - 10.1016/j.jpba.2008.09.043
ER -
@article{
author = "Popović, Gordana and Čakar, Mira and Agbaba, Danica",
year = "2009",
url = "http://farfar.pharmacy.bg.ac.rs/handle/123456789/1234",
abstract = "Acid-base equilibria in homogeneous and heterogeneous systems of two antihistaminics, loratadine and desloratadine were studied spectrophotometrically in Britton-Robinson's buffer at 25 degrees C. Acidity constant of loratadine was found to be pK(a) 5.25 and those of desloratadine pK(a1) 4.41 and pK(a2) 9.97. The values of intrinsic solubilities of loratadine and desloratadine were 8.65 x 10(-6) M and 3.82 x 10(-4) M, respectively. Based on the pK(a) values and intrinsic solubilities, solubility curves of these two drugs as a function of pH were calculated. The effects of anionic, cationic and non-ionic surfactants applied in the concentration exceeding critical micelle concentration (cmc) on acid-base properties of loratadine and desloratadine, as well as on intrinsic solubility of loratadine were also examined. The results revealed a shift of pK(a) values in micellar media comparing to the values obtained in water. These shifts (Delta pK(a)) ranged from -2.24 to +1.24.",
publisher = "Pergamon-Elsevier Science Ltd, Oxford",
journal = "Journal of Pharmaceutical and Biomedical Analysis",
title = "Acid-base equilibria and solubility of loratadine and desloratadine in water and micellar media",
volume = "49",
number = "1",
pages = "42-47",
doi = "10.1016/j.jpba.2008.09.043"
}
Popović, G., Čakar, M.,& Agbaba, D. (2009). Acid-base equilibria and solubility of loratadine and desloratadine in water and micellar media.
Journal of Pharmaceutical and Biomedical Analysis
Pergamon-Elsevier Science Ltd, Oxford., 49(1), 42-47.
https://doi.org/10.1016/j.jpba.2008.09.043
Popović G, Čakar M, Agbaba D. Acid-base equilibria and solubility of loratadine and desloratadine in water and micellar media. Journal of Pharmaceutical and Biomedical Analysis. 2009;49(1):42-47
Popović Gordana, Čakar Mira, Agbaba Danica, "Acid-base equilibria and solubility of loratadine and desloratadine in water and micellar media" Journal of Pharmaceutical and Biomedical Analysis, 49, no. 1 (2009):42-47,
https://doi.org/10.1016/j.jpba.2008.09.043 .
