Determination of pKa values of alendronate sodium in aqueous solution by piecewise linear regression based on acid-base potentiometric titration

Ke, Jing; Dou, Hanfei; Zhang, Ximin; Uhagaze, Dushimabararezi Serge; Ding, Xuan; Dong, Yuming

doi:10.1016/j.jpha.2016.07.001

Cited by 35 publications

(30 citation statements)

References 24 publications

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“…Figure 2 c shows that the zeta potential of all samples was negative at pH 7.4, owing to the presence of the negatively charged HA and Ce6 [ 50 , 51 ]. Especially, (ALN)@dHA-Ce6, (ALN/cRGD)@HDOC-Ce6 NP, and (ALN/cRGD)@dHA-Ce6 have a very reduced zeta potential value owing to the presence of rich phosphoryl groups of ALN [ 52 , 53 ].…”

Section: Resultsmentioning

confidence: 99%

Alendronate/cRGD-Decorated Ultrafine Hyaluronate Dot Targeting Bone Metastasis

et al. 2020

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In this study, we report the hyaluronate dot (dHA) with multiligand targeting ability and a photosensitizing antitumor model drug for treating metastatic bone tumors. Here, the dHA was chemically conjugated with alendronate (ALN, as a specific ligand to bone), cyclic arginine-glycine-aspartic acid (cRGD, as a specific ligand to tumor integrin αvβ3), and photosensitizing chlorin e6 (Ce6, for photodynamic tumor therapy), denoted as (ALN/cRGD)@dHA-Ce6. These dots thus prepared (≈10 nm in diameter) enabled extensive cellular interactions such as hyaluronate (HA)-mediated CD44 receptor binding, ALN-mediated bone targeting, and cRGD-mediated tumor integrin αvβ3 binding, thus improving their tumor targeting efficiency, especially for metastasized MDA-MB-231 tumors. As a result, these dots improved the tumor targeting efficiency and tumor cell permeability in a metastatic in vivo tumor model. Indeed, we demonstrated that (ALN/cRGD)@dHA-Ce6 considerably increased photodynamic tumor ablation, the extent of which is superior to that of the tumor ablation of dot systems with single or double ligands. These results indicate that dHA with multiligand can provide an effective treatment strategy for metastatic bone tumors.

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Section: Resultsmentioning

confidence: 99%

Alendronate/cRGD-Decorated Ultrafine Hyaluronate Dot Targeting Bone Metastasis

et al. 2020

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“…Several techniques 4 have been used for pKa determinations such as potentiometric titration 5 , 6 , UV-Vis spectroscopy 7 , 8 , reverse-phase high performance liquid chromatography 9 , and capillary electrophoresis 10 . UV-Vis spectroscopy takes advantage over other techniques since it is accurate, precise, reproducible and cost-effective using only micromolar concentrations of samples.…”

Section: Introductionmentioning

confidence: 99%

A pH-induced conformational switch in a tyrosine kinase inhibitor identified by electronic spectroscopy and quantum chemical calculations

Khattab

Wang

Clayton

2017

Sci Rep

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Tyrosine kinase inhibitors (TKIs) are a major class of drug utilised in the clinic. During transit to their cognate kinases, TKIs will encounter different pH environments that could have a major influence on TKI structure. To address this, we report UV-Vis spectroscopic and computational studies of the TKI, AG1478, as a function of pH. The electronic absorption spectrum of AG1478 shifted by 10 nm (from 342 nm to 332 nm) from acid to neutral pH and split into two peaks (at 334 nm and 345 nm) in highly alkaline conditions. From these transitions, the pKa value was calculated as 5.58 ± 0.01. To compute structures and spectra, time-dependent density functional theory (TD-DFT) calculations were performed along with conductor-like polarizable continuum model (CPCM) to account for implicit solvent effect. On the basis of the theoretical spectra, we could assign the AG1478 experimental spectrum at acidic pH to a mixture of two twisted conformers (71% AG1478 protonated at quinazolyl nitrogen N(1) and 29% AG1478 protonated at quinazolyl nitrogen N(3)) and at neutral pH to the neutral planar conformer. The AG1478 absorption spectrum (pH 13.3) was fitted to a mixture of neutral (70%) and NH-deprotonated species (30%). These studies reveal a pH-induced conformational transition in a TKI.

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“…The dissociation constant of 4‐ClMA was determined by an acid–base potentiometric titration method using a pHS‐25 pH meter equipped with an E‐201‐C combined glass electrode (Leici) . The pH electrode was calibrated by buffer solutions with pH of 4.00 and pH of 6.86, respectively, before use.…”

Section: Methodsmentioning

confidence: 99%

“…This procedure was repeated one time. The dissociation constant was calculated by the average value of two experiments according to the method reported in the literature …”

Section: Methodsmentioning

confidence: 99%

Enantioselective resolution of 4‐chloromandelic acid by liquid–liquid extraction using 2‐chloro‐N‐carbobenzyloxy‐L‐amino acid

Lü

Cai

et al. 2017

Chirality

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A liquid-liquid extraction resolution of 4-chloro-mandelic acid (4-ClMA) was studied by using 2-chloro-N-carbobenzyloxy-L-amino acid (2-Cl-Z-AA) as a chiral extractant. Important factors affecting the extraction efficiency were investigated, including the type of chiral extractant, pH value of aqueous phase, initial concentration of chiral extractant in organic phase, initial concentration of 4-ClMA in aqueous phase, and resolution temperature. It was observed that the concentration of (R)-4-ClMA was much higher than that of (S)-4-ClMA in organic phase due to a higher stability of the complex formed between (R)-4-ClMA and 2-Cl-Z-AA. A separation factor (α) of 3.05 was obtained at 0.02 mol/L 2-Cl-Z-Valine dissolved in dichloromethane, pH of 2.0, concentration of 4-ClMA of 0.11 mmol/Land T of 296.7K.

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Determination of pKa values of alendronate sodium in aqueous solution by piecewise linear regression based on acid-base potentiometric titration

Cited by 35 publications

References 24 publications

Alendronate/cRGD-Decorated Ultrafine Hyaluronate Dot Targeting Bone Metastasis

Alendronate/cRGD-Decorated Ultrafine Hyaluronate Dot Targeting Bone Metastasis

A pH-induced conformational switch in a tyrosine kinase inhibitor identified by electronic spectroscopy and quantum chemical calculations

Enantioselective resolution of 4‐chloromandelic acid by liquid–liquid extraction using 2‐chloro‐N‐carbobenzyloxy‐L‐amino acid

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