Lipophilicity of vinpocetine and related compounds characterized by reversed-phase thin-layer chromatography

Mazák, Károly; Vámos, J; Nemes, András; Rácz, Anita; Noszál, Béla

doi:10.1016/s0021-9673(03)00617-4

Cited by 32 publications

(16 citation statements)

References 20 publications

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“…This can be explained by the relatively high lipophilicity of the ligand (Log P = 3.56; Mazák et al, 2003). This value is higher than the "optimal lipophilicity value of PET radioligands" (Halldin et al, 2001, but still lower than that of PK11195 (cLog P = 5.1, Log D = 3.7-3.97 (Zhang et al, 2007;Fujimura et al, 2010).…”

Section: Youngmentioning

confidence: 95%

Age and disease related changes in the translocator protein (TSPO) system in the human brain: Positron emission tomography measurements with [11C]vinpocetine

et al. 2011

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Section: Youngmentioning

confidence: 95%

Age and disease related changes in the translocator protein (TSPO) system in the human brain: Positron emission tomography measurements with [11C]vinpocetine

et al. 2011

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“…The distribution coefficients were calculated from the absorbance of the molecules before and after partitioning at several octanol/water phase ratios . 1.0 · 10 −3 m solutions of the drug molecules were prepared using octanol‐saturated water.…”

Section: Methodsmentioning

confidence: 99%

“…The distribution coefficients were calculated from the absorbance of the molecules before and after partitioning at several octanol/water phase ratios. [35] 1.0 Á 10 À3 M solutions of the drug molecules were prepared using octanol-saturated water. For the pH control glycine or phosphate buffers, and standardized HCl and NaOH solutions were used with an ionic strength of 0.15M.…”

Section: Partition Coefficient Measurements By the Stir-flask Methodsmentioning

confidence: 99%

Passive Membrane Penetration of the Serotonin Precursor 5‐Hydroxytryptophan is Controlled by Its Zwitterion

Mazák

Noszál

2017

Chemistry & Biodiversity

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Species-specific partition coefficients in the octanol/water system were determined for the neurotransmitter serotonin (5-HT) and its precursor 5-hydroxytryptophan (5-HTP). The pH-independent partition coefficients (p) of the individual microspecies were determined by combination of experimentally measured distribution constants and a custom-tailored evaluation method, using highly similar auxiliary compounds. Experimental microscopic partition coefficients for triprotic molecules have only been reported before for thyroxine and its derivatives. The parabolic pH-distribution profile of 5-HT shows the dominance of the lipophilic non-charged microspecies, with a log p of 0.66. However, the most lipophilic non-charged form of 5-HTP, with a log p of 0.31, has no significant contribution to the distribution coefficient at any pH value. Instead, the less lipophilic zwitterionic protonation isomer dominates the distribution in the pH range 2.10 - 11.11. Although the non-charged microspecies of 5-HTP is 151 times more lipophilic than its zwitterionic protonation isomer, the overwhelming dominance of the zwitterionic form ensures that its contribution to the overall lipophilicity exceeds 1320 times that of the non-charged one. This fact is another counter-example of the widespread belief that passive diffusion into lipophilic media is predominated by the non-charged species. The lipophilicity profile of 5-HT and 5-HTP is depicted in terms of species-specific lipophilicities.

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“…Only one of the two enantiomers generally retains therapeutic activity, while in some instances the other one may be toxic. NMR Lisinopril (Sakamoto and Ishi, 1993) Anandamide (Chen et al, 2005) Peptic ulcer drug (Watts, 1999) TLC Vinpocetine (Mazák et al, 2003) Betamethasone (Vukušić, 1982) Nifedipine (Patravale et al, 2000) Timolol ( This technique uses a chiral stationary phase and the separation is based on the difference in the strength of the interactions. The stationary phase must be chosen in such a way to interact only with one of the two enantiomers.…”

Section: Acid Dissociation Constantmentioning

confidence: 99%

Recent application of analytical methods to phase I and phase II drugs development: a review

Locatelli

Governatori

Carlucci

et al. 2011

Biomedical Chromatography

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Drug development is a time-consuming and costly process. It is usually divided into four phases, although it is not always possible to draw a sharp line between the various stages. In phase I and II there are many molecules investigate and it is necessary to analyze all of them in a short period of time, with lower costs, and with high-throughput assay. During phase I relevant chemical-physical parameters like the acid dissociation constant, lipophilicity, solubility and stability must be analyzed. Classic techniques such as 'shake-flask' can be used, but instrumental analytical methods such as HPLC may be helpful to improve and enhance the productivity and reproducibility of the results. During phase II the activity of a drug and factors that may have an influence on it, like metabolic profile and transformations, impurities and plasma biding proteins, must be considered. In this field, recent hyphenated analytical methods, such as LC-MS/MS, GC-MS/MS or more complex couplings, can provide more complete information. The aim of this review is to report the processes required for the validation of drug efficacy with reference to the description of 'classic' and modern techniques used.

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Lipophilicity of vinpocetine and related compounds characterized by reversed-phase thin-layer chromatography

Cited by 32 publications

References 20 publications

Age and disease related changes in the translocator protein (TSPO) system in the human brain: Positron emission tomography measurements with [11C]vinpocetine

Age and disease related changes in the translocator protein (TSPO) system in the human brain: Positron emission tomography measurements with [11C]vinpocetine

Passive Membrane Penetration of the Serotonin Precursor 5‐Hydroxytryptophan is Controlled by Its Zwitterion

Recent application of analytical methods to phase I and phase II drugs development: a review

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