From: Richard Prankerd (richard.prankerd$##$pharmacy.uq.edu.au)
Date: Tue Mar 30 1999 - 20:35:20 EST
Orglist - interested readers:
The literature lists a large number of pKa values for propranolol, of which
the following is a selection:
9.53±0.01 (t = 25°C; I = 0.15): pH-metric log P 10. Determination o=
f
liposomal membrane-water partition coefficients of ionizable drugs, Avdeef
A, Box KJ, Comer JEA, Hibbert C, Tam KY, Pharm. Res., 15(2) 209-215 (1998)
9.32: Zaagsma and Nauta, J.Med.Chem., 17, 507-13, 1974
9.23 (t = 35°C): Schoenwald and Huang, J.Pharm. Sci., 72, 1266-72, 1983
9.72 (t = 23°C): Ionization constants by curve-fitting: Determination of
partition and distribution coefficients of acids and bases and their ions,
Clarke, F.H. and Cahoon, N.M., J. Pharm. Sci., 76(8) 1987, 611-620
9.51 (t = 25): Irwin-WJ; Belaid-KA, Drug delivery by ion exchange. Part 2.
Physicochemical properties of ester prodrugs of propranolol,
Drug-Dev-Ind-Pharm; 1987; 13(9-11); 2033-2045
9.43 (t = 22°C; I = 0.5): The synthesis, hydrolysis kinetics and
lipophilicity of O-acyl esters of propranolol, Quigley, J.M., Jordan,
C.G.M. and Timoney, R.F., IntJPharm, 101, 1994, 145-163
9.7 (t = 37°C): Kramer-SD; Wunderli-Allenspach-H, pH-dependence in the
partitioning behavior of (RS)-(3H)propranolol between MDCK cell lipid
vesicles and buffer, Pharm-Res (Pharmaceutical-Research); 1996; 13(Dec);
1851-1855
These values are taken from a very large compilation (more than 1100
entries) of pKa values that I am preparing for publication. You will note
that the pKa value is significantly dependent on both temperature and ionic
strength. Given the disparity in some of these results (e.g., both Kramer
et al and Clarke and Cahoon give about 9.7 for t = 37 and t = 23,
respectively, while others give quite different results at these
temperatures), the original publications will need to be checked (I have
not yet completed this task) to validate results for the purpose and
conditions that an end user may require.
Regards
Richard
>
>
>A colleague asked me to post this question.
>Does anybody know (or have access to) the experimental pKa of propranolol ?
>
>Please answer directly to rui.viegas$##$dq.fct.unl.pt
>
pKa of propranolol
>------------------------------
>
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