Circular Dichroism Spectroscopy: A Facile Approach for Quantitative Analysis of Captopril and Study of Its Degradation

Rahman, Nafisur; Khan, Shakeel

doi:10.1021/acsomega.8b03384

Cited by 25 publications

(16 citation statements)

References 41 publications

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“… 55 The minima at 186 and 222 nm are influenced by the aforementioned amide backbone electronic transitions as well as the n → π* transition of the carboxylate group and the n → σ* transition of the amino group of the proline moiety ( Scheme 1 b). 51 , 54 , 55 In contrast to the case of captopril, there is no evidence for a concentration-dependent red shift in the CD spectra for lisinopril in Figure 5 b.…”

Section: Resultsmentioning

confidence: 77%

“…The CD data reported in the literature for 1.3 × 10 –3 wt % captopril 53 and for 1.8 × 10 –3 wt % captopril 54 in water display a negative peak at 210 or 208 nm, close to 203 nm reported in Figure 5 a, which was ascribed to the contributions from the n → π* transition of the carboxylate group and from the n → σ* transition of the amino group of the proline moiety ( Scheme 1 a). 54 − 56 Peaks in this range are also affected by backbone amide π–π* and n−π* transitions. 56 , 57 The CD spectra indicate that captopril does not form any organized secondary structure under the conditions studied.…”

Section: Resultsmentioning

confidence: 95%

“…51,52 The CD spectra for captopril are characterized by a pronounced minimum at 203 nm (Figure 5a). The CD data reported in the literature for 1.3 × 10 −3 wt % captopril 53 and for 1.8 × 10 −3 wt % captopril 54 in water display a negative peak at 210 or 208 nm, close to 203 nm reported in Figure 5a, which was ascribed to the contributions from the n → π* transition of the carboxylate group and from the n → σ* transition of the amino group of the proline moiety (Scheme 1a). 54−56 Peaks in this range are also affected by backbone amide π−π* and n−π* transitions.…”

Section: ■ Experimental Sectionmentioning

confidence: 97%

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Self-Assembly of Angiotensin-Converting Enzyme Inhibitors Captopril and Lisinopril and Their Crystal Structures

et al. 2021

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The peptide angiotensin-converting enzyme inhibitors captopril and lisinopril are unexpectedly shown to exhibit critical aggregation concentration (CAC) behavior through measurements of surface tension, electrical conductivity, and dye probe fluorescence. These three measurements provide similar values for the CAC, and there is also evidence from circular dichroism spectroscopy for a possible conformational change in the peptides at the same concentration. Cryogenic transmission electron microscopy indicates the formation of micelle-like aggregates above the CAC, which can thus be considered a critical micelle concentration, and the formation of aggregates with a hydrodynamic radius of ∼6–7 nm is also evidenced by dynamic light scattering. We also used synchrotron radiation X-ray diffraction to determine the single-crystal structure of captopril and lisinopril. Our results improve the accuracy of previous data reported in the literature, obtained using conventional X-ray sources. We also studied the structure of aqueous solutions containing captopril or lisinopril at high concentrations. The aggregation may be driven by intermolecular interactions between the proline moiety of captopril molecules or between the phenylalanine moiety of lisinopril molecules.

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Section: Resultsmentioning

confidence: 77%

Section: Resultsmentioning

confidence: 95%

Section: ■ Experimental Sectionmentioning

confidence: 97%

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Self-Assembly of Angiotensin-Converting Enzyme Inhibitors Captopril and Lisinopril and Their Crystal Structures

et al. 2021

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“…As the calculated t ‐test (paired) and F‐values at the 95% confidence level were less than the tabulated ones, it was concluded that no significant difference between the two methods was observed. In the interval hypothesis test, the true bias based on recovery experiments was evaluated from the following equation:

θ^{2} ([], x_{1}^{2} - \frac{S_{p}^{2} t^{2}}{{normaln}_{1}}) - 2 normalθ x_{1} x_{2} + ([], x_{2}^{2} - \frac{S_{p}^{2} t^{2}}{{normaln}_{2}}) = 0

The lower limit ( θ L ) and upper limit ( θ U ) of the confidence interval are obtained:

θ_{U} = \frac{- normalb + \sqrt{b^{2} - 4 ac}}{2 normala}

θ_{L} = \frac{- normalb - \sqrt{b^{2} - 4 ac}}{2 normala}

where,

normala = ((), x_{1}^{2} - S_{p}^{2} t^{2} / n_{1})

normalb = 2 x_{1} x_{2}

normalc = ((), x_{2}^{2} - S_{p}^{2} t^{2})

…”

Section: Resultsmentioning

confidence: 99%

Micellar‐based spectrofluorimetric method for the selective determination of ledipasvir in the presence of sofosbuvir: application to dosage forms and human plasma

et al. 2019

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A fast, low-cost, sensitive, and selective spectrofluorimetric method for the determination of ledipasvir was developed and validated. The method is based on an enhancement in the native fluorescence intensity of ledipasvir by 500% of its original value by the formation of hydrogen bonds between the cited drug and Tween-20 in the micellar system (pH = 5.0). All fluorescence measurements were carried out at 425 nm and 340 nm for emission and excitation wavelengths, respectively. A linear relationship between the concentration of ledipasvir and the observed fluorescence intensity was achieved in the range of 0.1-2.0 μg ml −1 with 0.028, 0.084 μg ml −1 , for detection and quantitation limits, respectively. The acquired selectivity and sensitivity using the proposed method facilitate the analysis of ledipasvir in spiked human plasma with sufficient percentage recovery (95.36-99.30%). The proposed method was developed and validated according to International Council for Harmonisation (ICH) guidelines. Moreover, the cited drug was successfully determined in its pharmaceutical dosage form using the proposed method. In addition, the validity of the proposed results was statistically confirmed using Student's t-test, variance ratio F-test, and interval hypothesis test. K E Y W O R D Shuman plasma, ledipasvir, pharmaceutical tablets, sofosbuvir, spectrofluorimetric, Tween-20

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“…With respect to the challenges encountered by these classical techniques of absorbance/luminescence, we propose the use of circular dichroism (CD) spectroscopy for the quantification of anthracycline drugs on nonchiral nanoparticles, since these drugs present chromophores alongside the chiral carbon backbones in their structures. From the literature, CD analysis has been reportedly used for the quantification of chiral drugs, , and commonly explored to supplement proteins’ conformation analysis. , Nevertheless, the use of this technique to identify the analytical concentration of chiral drugs on the conjugated nanomaterial system was not yet reported to our knowledge. For this work, we conduct experiments using carbon nitride dots (CNDs), a nanomaterial previously used as a biomarker and a nanocarrier of different oncology drugs without diminishing their activity. , …”

mentioning

confidence: 99%

Drug Loading of Anthracycline Antibiotics on Carbon Dots Using Circular Dichroism Spectrometry

2021

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Drug delivery systems using nanoparticles are currently in the panorama of nanomedicine studies. In oncology, chemotherapeutic regimens using anthracycline antibiotics rely on the dosage of treatments to minimize the severity of side effects on the patient. Therefore, even in targeted delivery systems it is of great importance to quantify the level of drug administrated for dosage and quality control of the treatment. Herein, as a feasible pathway to shed light on improving nano drug quantification procedures, we proposed a simple analytical protocol to quantify the anthracyclines loaded on our nonchiral carbon nitride dots (CNDs) with circular dichroism spectrometry (CD). The calibration curves from the linear relation between ellipticity and concentration of the anthracycline drugs followed by measurements on the CNDs conjugates were used in achieving the quantification technique which showed different drug loading for each anthracycline used such as daunorubicin, doxorubicin, and epirubicin.

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Circular Dichroism Spectroscopy: A Facile Approach for Quantitative Analysis of Captopril and Study of Its Degradation

Cited by 25 publications

References 41 publications

Self-Assembly of Angiotensin-Converting Enzyme Inhibitors Captopril and Lisinopril and Their Crystal Structures

Self-Assembly of Angiotensin-Converting Enzyme Inhibitors Captopril and Lisinopril and Their Crystal Structures

Micellar‐based spectrofluorimetric method for the selective determination of ledipasvir in the presence of sofosbuvir: application to dosage forms and human plasma

Drug Loading of Anthracycline Antibiotics on Carbon Dots Using Circular Dichroism Spectrometry

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