The thermodynamic dissociation constants of the anticancer drugs camptothecine, 7-ethyl-10-hydroxycamptothecine, 10-hydroxycamptothecine and 7-ethylcamptothecine by the least-squares nonlinear regression of multiwavelength spectrophotometric pH-titration data

Meloun, Milan; Bordovská, Sylva; Vrána, Aleš

doi:10.1016/j.aca.2006.11.049

Cited by 47 publications

(58 citation statements)

References 25 publications

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“…Lachema Brno) were not further purified. The preparation of other solutions from analytical reagent-grade chemicals has been described previously [37][38][39][40].…”

Section: Methodsmentioning

confidence: 99%

“…The apparatus used and the pH-spectrophotometric titration procedure described in [37][38][39][40] were applied. The microscale pH-titrimetric method generally decreases the amount of drug sample required but the duration of experiment is as long as that of a conventional titration.…”

Section: Apparatus and Procedurementioning

confidence: 99%

“…The computation scheme for the determination of the protonation constants of the multicomponent system is taken from Meloun et al, cf. [1, page 226] and the five steps are described elsewhere [37][38][39][40][44][45][46][47][48]: (1) instrumental error of absorbance measurements, s inst (A), (2) experimental design, (3) number of light-absorbing species with a factor analysis, (4) choice of computational strategy of the nonlinear regression, (5) diagnostics indicating a correct chemical (protonation) model: when a minimization process terminates, some curve-fitting diagnostics are examined to determine whether the results should be accepted: the physical meaning of parametric estimates, the physical meaning of the species concentrations, the goodness-offit test of spectra calculated, and the deconvolution of the experimental spectra set.…”

Section: Apparatus and Procedurementioning

confidence: 99%

“…The procedure for the determination of the mixed protonation/dissociation constants has been described previously [37][38][39][40]. The details of the computer data treatment are collected in the Supporting Information.…”

Section: Introductionmentioning

confidence: 99%

“…, m, may be examined by a goodness-of-fit test, cf. a previous tutorial [37][38][39][40]. Repeatability and reproducibility (R&R) are critical factors closely related to precision and accuracy.…”

Section: Introductionmentioning

confidence: 99%

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The Thermodynamic Dissociation Constants of Clotrimazole, Terbinafine HCL, Acetylsalicylic Acid, Salicylic Acid, and Galanthamine by the Nonlinear Regression of Multiwavelength Spectrophotometric pH-Titration Data

2010

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The mixed dissociation constants of five drugs-clotrimazole, terbinafine HCl, acetylsalicylic acid, salicylic acid, and galanthamineat various ionic strengths I and at temperatures of 25 • C and 37 • C were determined with the use of multiwavelength and multivariate treatments of spectral data SPECFIT/32 nonlinear regression analysis and INDICES factor analysis. The factor analysis in the INDICES program predicts the number of components, when the data quality is high and the instrumental error is known. The thermodynamic dissociation constant pK T a was estimated by nonlinear regression of {pK a, I} data at 25 • C and 37 • C: for clotrimazole pK T a,1 = 4.38(1) and 4.16(3); for terbinafine HCl pK T a,1 = 4.19(3) and 4.12(5); for acetylsalicylic acid pK T a,1 = 3.49(25) and 3.41(15); for salicylic acid pK T a,1 = 3.01(1) and 3.00(1) and for galanthamine pK T a,1 = 8.21(1) and 7.99(2) where in brackets the standard deviation is in the last significant digits. Goodness-of-fit tests for various regression diagnostics enabled the reliability of the parameter estimates found to be proven. Pharma Algorithms predicts pK a being based on the structural formulae of drug compounds.

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“…Lachema Brno) were not further purified. The preparation of other solutions from analytical reagent-grade chemicals has been described previously [37][38][39][40].…”

Section: Methodsmentioning

confidence: 99%

Section: Apparatus and Procedurementioning

confidence: 99%

Section: Apparatus and Procedurementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

The Thermodynamic Dissociation Constants of Clotrimazole, Terbinafine HCL, Acetylsalicylic Acid, Salicylic Acid, and Galanthamine by the Nonlinear Regression of Multiwavelength Spectrophotometric pH-Titration Data

2010

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Characterization and quantification of 10‐hydroxycamptothecine in Camptotheca acuminate and its medicinal preparation by liquid chromatography–ion trap mass spectrometry

Chen

Pan

Xiong

et al. 2013

Biomedical Chromatography

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A rapid and sensitive method for the identification and quantification of 10-hydroxycamptothecine (HCPT) in Camptotheca acuminata Decne is described. The HCPT standard solution was directly infused into the ion trap mass spectrometers (IT/MS) for collecting the MS(n) spectra. The electrospray ionization (ESI) mass spectral fragmentation pathway of HCPT was proposed and the ESI-MS(n) fragmentation behavior of HCPT was deduced in detail. The major fragment ions of HCPT were confirmed by MS(n) in both negative ion and positive ion mode. The possible main cleavage pathway of fragment ions was studied. Quantification of HCPT was assigned in negative-ion mode at a product ion at m/z 363 → 319 by LC-MS. The LC-MS method was validated for linearity, sensitivity, accuracy and precision, and then used to determine the content of the HCPT. Lastly, the LC-MS method was successfully applied to determine HCPT in real samples of Camptotheca acuminate Decne and its medicinal preparation in the first time.

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Simultaneous determination of camptothecin and 10‐hydroxycamptothecine in the Camptotheca acuminate, its medicinal preparation and in rat plasma by liquid chromatography with fluorescence detection

Chen

et al. 2015

Biomedical Chromatography

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Camptotheca acuminata Decne is an important medicinal plant that contains various cytotoxic alkaloids, such as camptothecine (CPT) and 10-hydroxycamptothecine (HCPT). A rapid and sensitive liquid chromatography with fluorescence detection (LC-FLD) method for the quantification of CPT and HCPT is described. The separation was carried out on a DL-Cl8 column (4.6 × 150 mm, 5 µm), with the mobile phase of acetonitrile-sodium dihydrogen phosphate buffer (10 mm) using an gradient elution at the flow rate of 0.6 mL/min. The LC-FLD method was validated for linearity, sensitivity, accuracy and precision, and then used to determine the content of the above components. The lower detection limits of CPT and HCPT were 0.4 and 0.1 ng/mL, respectively. The precision was <1.58% and the mean recovery of the analytes was 96.0-98.6%. The LC-FLD method was successfully applied to determine CPT and HCPT in real samples including C. acuminate, HCPT injection and rat plasma.

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The thermodynamic dissociation constants of the anticancer drugs camptothecine, 7-ethyl-10-hydroxycamptothecine, 10-hydroxycamptothecine and 7-ethylcamptothecine by the least-squares nonlinear regression of multiwavelength spectrophotometric pH-titration data

Cited by 47 publications

References 25 publications

The Thermodynamic Dissociation Constants of Clotrimazole, Terbinafine HCL, Acetylsalicylic Acid, Salicylic Acid, and Galanthamine by the Nonlinear Regression of Multiwavelength Spectrophotometric pH-Titration Data

The Thermodynamic Dissociation Constants of Clotrimazole, Terbinafine HCL, Acetylsalicylic Acid, Salicylic Acid, and Galanthamine by the Nonlinear Regression of Multiwavelength Spectrophotometric pH-Titration Data

Characterization and quantification of 10‐hydroxycamptothecine in Camptotheca acuminate and its medicinal preparation by liquid chromatography–ion trap mass spectrometry

Simultaneous determination of camptothecin and 10‐hydroxycamptothecine in the Camptotheca acuminate, its medicinal preparation and in rat plasma by liquid chromatography with fluorescence detection

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