Partition and distribution coefficients of aryloxypropanolamine β-adrenoceptor antagonists

Recanatini, Maurizio

doi:10.1111/j.2042-7158.1992.tb14369.x

Cited by 12 publications

(5 citation statements)

References 15 publications

(13 reference statements)

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“…Indeed a diff(log P N-Z ) of approximately 6 units is expected in the absence of any internal neutralization, starting from the mere estimate that the monocharged species are each at least 3 log P units less lipophilic than the uncharged one. 47 When partial charge neutralization occurs, some polarity is lost, and diff(log P N-Z ) is expected to decrease with increasing charge neutralization.…”

Section: Zwitterions With a Large K Zmentioning

confidence: 99%

“…A diff (log P N-Z ) of 2.2 was found, suggesting that the two opposite charges in the zwitterion undergo partial neutralization as a result of an internal ionic bond made possible by a folded conformation. Indeed a diff (log P N-Z ) of approximately 6 units is expected in the absence of any internal neutralization, starting from the mere estimate that the monocharged species are each at least 3 log P units less lipophilic than the uncharged one . When partial charge neutralization occurs, some polarity is lost, and diff (log P N-Z ) is expected to decrease with increasing charge neutralization.…”

Section: Zwitterions With a Large K Zmentioning

confidence: 99%

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Lipophilicity Profiles of Ampholytes

et al. 1997

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ContentsI. Introduction 3385 A. Significance of Amphoteric Drugs and Biomolecules 3385 B. Partitioning of Amphoteric Drugs: Zwitterions Compared to Ordinary Ampholytes 3386 II. Theoretical Background 3386 A. Acid−Base Equilibria 3386 1. Ordinary Ampholytes 3386 2. Zwitterionic Ampholytes: Microdissociation Equilibria and Micro-pK a 3387 3. Zwitterionic Ampholytes Having a Large Value of K Z 3388 B. Partitioning of Zwitterions 3389 1. General Assumptions for Ionizable Solutes 3389 2. General Assumptions for Zwitterionic Ampholytes 3389 3. Zwitterions Having a Large Value of K Z 3391 III. Relevant Techniques 3391 A. Experimental Techniques 3391 1. Measurements of pK a Values 3391 2. Investigation of Microdissociation Equilibria: Assignment of Micro-pK a and K Z 3391 3. Measurement of Lipophilicity Profiles 3392 B. Computational Techniques 3392 1. Two-Dimensional Fragmental Systems 3392 2. Calculation of Virtual log P Values 3392 IV. Lipophilicity Profiles of Zwitterionic Ampholytes 3392 A. Bell-Shaped Distribution Profiles 3392 1. Zwitterions with a Small K Z 3392 2. Zwitterions with a Large K Z 3394 B. U-Shaped Distribution Profiles 3396 C. Counterion Effects on the Partitioning of Cations and Anions 3397 V. Conclusions 3397 A. Physicochemical Outlook 3397 B. Pharmacokinetic Relevance 3397 VI. Acknowledgments 3398 VII. Glossary 3398 VIII. References 3399

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Section: Zwitterions With a Large K Zmentioning

confidence: 99%

Section: Zwitterions With a Large K Zmentioning

confidence: 99%

Lipophilicity Profiles of Ampholytes

et al. 1997

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“…(6) indicates that in MOPS buffer there is a greater difference in the establishment of homo-energetics of the systems. This means, the solvophobic effect [22] of MOPS is useful for the evaluation of physicochemical parameters in terms of solvent strength.…”

Section: Resultsmentioning

confidence: 95%

The role of ion pairing in the chromatographic study of propranolol analogues

et al. 2001

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SummaryThe partition coefficients, log Papp RPLC, for a series of propranolol analogues have been determined by reversed phase high performance liquid chromatography. The hydrochloride salts and free base log Papp RPLC show that charged and uncharged species can partition into the reversed phase. An extrathermodynamic relationship was found for log Papp RPLC measured in I',,vo different column stationary phases, C8 and PMOS, suggesting that the same set of compounds experience a similar trend in these elution systems. The importance of using phosphate and/or MOPS buffer is due to the fact that the latter can avoid ion-pairing partitioning, but the former does play the same role for PMOS column when the free base is considered.

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“…The log D o/w -pH profiles for each of the model compounds have been calculated fitting Eq. 17 to the log D o/w values determined at different values of pH taken from the literature [32][33][34][35][36][37]. The log D o/w values compiled have been determined using the reference shake-flask, and the pH-metric titration methods.…”

Section: Log D O/w Estimation Of Ionized Basic Compoundsmentioning

confidence: 99%

“…15. The log D o/w from the literature [32][33][34][35][36][37] and the estimated values are summarized in Table 4. The ionization degree Table 4 for bases neutral or fully ionized ( Figure 3A) or partially ionized, from 1 to 99 % ( Figure 3B).…”

Section: Log D O/w Estimation Of Ionized Basic Compoundsmentioning

confidence: 99%

Estimation of the octanol-water distribution coefficient of basic compounds by a cationic microemulsion electrokinetic chromatography system

et al. 2020

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The octanol-water partition coefficient (Po/w), or the octanol-water distribution coefficient (Do/w) for ionized compounds, is a key parameter in the drug development process. In a previous work, this parameter was estimated through the retention factor measurements in a sodium dodecyl sulfate (SDS) - microemulsion electrokinetic chromatography (MEEKC) system for acidic compounds. Nonetheless, when ionized basic compounds were analyzed, undesirable ion pairs were formed with the anionic surfactant and avoided a good estimation of log Do/w. For this reason, an alternative MEEKC system based on a cationic surfactant has been evaluated to estimate Po/w or Do/w of neutral compounds and ionized bases. To this end, it has been characterized through the solvation parameter model (SPM) and compared to the octanol-water partition system. Results pointed out that both systems show a similar partition behavior. Hence, the log Po/w of a set of neutral compounds has been successfully correlated against the logarithm of the retention factor (log k) determined in this MEEKC system. Then, the log Do/w of 6 model bases have been estimated at different pH values and they have been compared to data from the literature, determined by the reference shake-flask and potentiometric methods. Good agreement has been observed between the literature and the estimated values when the base is neutral or partially ionized (up to 99 % of ionization).

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Partition and distribution coefficients of aryloxypropanolamine β-adrenoceptor antagonists

Cited by 12 publications

References 15 publications

Lipophilicity Profiles of Ampholytes

Lipophilicity Profiles of Ampholytes

The role of ion pairing in the chromatographic study of propranolol analogues

Estimation of the octanol-water distribution coefficient of basic compounds by a cationic microemulsion electrokinetic chromatography system

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