Liquid chromatography with tandem mass spectrometry for the simultaneous identification and quantification of cardiovascular drugs applied to the detection of substandard and falsified drugs

The counterfeiting of pharmaceuticals has been detected since about 1990 and has alarmingly continued to pick up steam. We have been recently involved in an evaluation program of some of the most commonly prescribed cardiovascular drugs in Africa, for analysing an important number of tablets or capsules obtained from different places in seven African countries. A reversed‐phase high‐performance liquid chromatography with tandem mass spectrometry method was developed and validated to simultaneously control the identity and the quantity of acenocoumarol, amlodipine, atenolol, captopril, furosemide, hydrochlorothiazide and simvastatin in tablets. Their separation was performed on a Kinetex® C₁₈ (100 mm × 2.1 mm inside diameter, 2.6 μm) column using a gradient elution of 20 mM ammonium formate buffer and acetonitrile (90:10 10:90 v/v) at a flow rate of 0.5 mL/min. The analytes were detected using electrospray ionisation tandem mass spectrometry in both positive and negative modes with multiple reaction monitoring. Tandem mass spectrometry fragmentation patterns of captopril, furosemide and acenocoumarol, up to now not detailed in the literature, were also studied to assist in the selection of the most relevant transitions towards the objectives. The developed method was validated as per International Conference on Harmonisation guidelines with respect to specificity, linearity, trueness, precision, limits of detection and quantification. It has been successfully applied to the control of oral forms of seven cardiovascular drugs collected in African countries.     

Phenolic profile,antioxidant capacity and anti-inflammatory activity of Anethum graveolens L. essential oil

This study reports the chemical composition, antioxidant and anti-inflammatory properties of Anethum graveolens essential oil and its main compounds. The essential oil was obtained from the aerial parts of the plant by hydrodistillation and analysed by using GC/MS. α-Phellandrene (19.12%), limonene (26.34%), dill ether (15.23%), sabinene (11.34%), α-pinene (2%), n-tetracosane (1.54%), neophytadiene (1.43%), n-docosane (1.04), n-tricosane (1%), n-nonadecane (1%), n-eicosane (0.78%), n-heneicosane (0.67%), β-myrcene (0.23%) and α-tujene (0.21%) were found to be the major constituents of the oil. A. graveolens oil exhibit a higher activity in each antioxidant system with a special attention for β-carotene bleaching test (IC₅₀: 15.3 μg/mL) and reducing power (EC₅₀: 11.24 μg/mL). The TLC-bioautography screening and fractionation resulted in the separation of the main antioxidant compounds, which were identified as limonene (45%) and sabinene (32%). The essential oil and its main compounds exhibited a potent NO-scavenging effect and inhibited the expression of inducible NO synthase.     

The interaction of antitumor active vanadocene dichloride with sulfur-containing amino acids

Vanadocene dichloride (1) reacts with sulfur-containing amino acids, cysteine and methionine, giving new complexes with five- or six-membered chelate ring, but the structure of isolated compounds is affected by the pH value of the reaction mixture. Methionine reacts with aqueous 1 in the pH range of 3-8 affording chelate structure [Cp₂V(N,O-met)]Cl (4). Similar reaction with cysteine gives two different products depending on pH. In the acidic solution, the complex [Cp₂V(O,S-cys)]Cl (2) is present, whereas in neutral media the compound [Cp₂V(N,S-cys)] (3) could be identified. On inspection of spectroscopic measurements, particularly EPR and vibrational spectroscopy, it is evident that sulfur atom of amino acid is bonded directly to the vanadium atom of [Cp₂V]²⁺ moiety. For the purpose of comparison the complexes [Cp₂V(O,S-mpa)] (5) and [Cp₂V(N,S-csam)]⁺ (6a) with related chelating ligands, 3-mercaptopropionic acid (mpa) and cysteamine (csam), respectively, were prepared and spectroscopically characterized. The structure of the complex [Cp₂V(N,S-csam)]BPh₄ (6b) was also determined by X-ray diffraction analysis.     

Application of micellar and microemulsion electrokinetic chromatography for characterization of gallium(III) complexes of pharmaceutical significance

CE with conventional UV detection has recently been shown as a highly effective means to assaying cytotoxic gallium(III)-based compounds with regard to desirable drug-like properties such as the stability and binding to serum proteins. In this extension of that work, different CE techniques are used to further characterize a given set of gallium coordination compounds with established antiproliferating efficacy. Using free-zone CE mode, the electrophoretic profiles of complexes are recorded in order to assess their actual charge state under physiological buffer conditions. Micellar and microemulsion electrokinetic chromatographic techniques are tested as tools for the rapid estimation of the n-octanol-water partition coefficient (log P) that provides a rationale estimate of a drug's ability to cross biological membranes. A range of electrolyte buffer systems with varying (both in the nature and concentration) organic modifiers are examined to evaluate their effect on the relationship between experimental or calculated log P and the retention factors of compounds (log k'). Both methods were found to be better applicable for neutral than for cationic Ga complexes, the microemulsion mode demonstrating superior lipophilicity estimations as well as statistically meaningful log P versus log k' correlations when all the complexes were included in one regression set.     

Application of TA and Kinetic Study to Compatibility and Stability Problems in Some Commercial Drugs. Remarks on statistical data

A thermal analysis and kinetic study on decomposition processes of some commercial drugs have been carried out to find their thermal stability. DSC/TG curves of some commercial drugs were compared with those of their active components, the excipients, the active component/excipient and the excipient/excipient mixtures. A kinetic study was carried out using both isothermal and dynamic TG curves. Both active components and commercial drugs tested show a first order decomposition mechanism. The kinetic data showed that excipients cause a decrease of the kinetic stability of the active components. Statistical analysis allowed us to select reliable kinetic parameters related to decomposition processes. This procedure showed that the values obtained by extrapolation,outside the temperature range where the processes occurred must be used with caution. Indeed half-time and shelf-time values, commonly used at room temperature, seemed to be unrealistic. This revised version was published online in July 2006 with corrections to the Cover Date.     

Competitive Binding of Drugs to the Multiple Binding Sites on Human Serum Albumin: A calorimetric study

A multiple-site competitive model has been developed to evaluate quantitatively the equilibrium competition of drugs that bind to multiple classes of binding sites on human serum albumin (HSA). The equations, which are based on the multiple-class binding site model, assume that competition exists at individual sites, that the binding parameters for drug or drug competitor pertain to individual sites, and also that the binding parameters for drug or competitor at any given site are independent of drug or competitor bound at other sites. For the drug-competitor pairs, ethacrynic acid (EA) -caproic acid (C6), -lauric acid (C12), and -palmitic acid (C16), the reaction heat of EA binding to HSA was measured in the absence and the presence of fatty acids at the molar ratio of 3:1 with HSA at pH 7.4 and 37°C by isothermal titration microcalorimetry. The calorimetric titration data induced by the presence of fatty acids were directly compaired to the computer simulation curves by the corresponding multiple-site competititve models, which were precedently calculated from binding parameters of EA and fatty acids. In the case of EA-C12 or -C16 competitive binding, EA binding at the first and the second classes of binding sites on HSA were instantaneously inhibited by C12 or C16, resulting that the binding constant of the first class of binding sites of EA were decreased and that the second class of binding sites on HSA entirely disappeared. In the competition between EA and C6, the first class of binding sites of EA was diminished by C6, resulting in the decrease of the binding constants and the number of binding sites in the first class of EA, whereas, the second class of binding sites was unaffected. The multiple-site competitive model assuming site-site competition could be directly comparable to the calorimetric data and be suitable to account for the competitive processes for drugs bound to the multiple-class of binding sites on HSA.This revised version was published online in November 2005 with corrections to the Cover Date.     

Pharmacological Potential and Chemical Composition of Crocus sativus Leaf Extracts

Crocus sativus L. (saffron) has been traditionally used as a food coloring or flavoring agent, but recent research has shown its potent pharmacological activity to tackle several health-related conditions. Crocus sp. leaves, and petals are the by-products of saffron production and are not usually used in the medicine or food industries. The present study was designed to determine the chemical composition of the water and ethanolic extracts of C. sativus leaves and test their cytotoxic activity against melanoma (IGR39) and triple-negative breast cancer (MDA-MB-231) cell lines by MTT assay. We also determined their anti-allergic, anti-inflammatory, and anti-viral activities. HPLC fingerprint analysis showed the presence of 16 compounds, including hydroxycinnamic acids, xanthones, flavonoids, and isoflavonoids, which could contribute to the extracts’ biological activities. For the first time, compounds such as tectoridin, iristectorigenin B, nigricin, and irigenin were identified in Crocus leaf extracts. The results showed that mangiferin (up to 2 mg/g dry weight) and isoorientin (8.5 mg/g dry weight) were the major active ingredients in the leaf extracts. The ethanolic extract reduced the viability of IGR39 and MDA-MB-231 cancer cells with EC₅₀ = 410 ± 100 and 330 ± 40 µg/mL, respectively. It was more active than the aqueous extract. Kaempferol and quercetin were identified as the most active compounds. Our results showed that Crocus leaves contain secondary metabolites with potent cytotoxic and antioxidant activities.     

Lipid Profiles of the Heads of Four Shrimp Species by UPLC–Q–Exactive Orbitrap/MS and Their Cardiovascular Activities

Lipids are key factors in nutrition, structural function, metabolic features, and other biological functions. In this study, the lipids from the heads of four species of shrimp (Fenneropenaeus chinensis (FC), Penaeus japonicus (PJ), Penaeus vannamei (PV), and Procambarus clarkia (PCC)) were compared and characterized based on UPLC–Q–Exactive Orbitrap/MS. We compared the differences in lipid composition of four kinds of shrimp head using multivariate analysis. In addition, a zebrafish model was used to evaluate pro-angiogenic, anti-inflammatory, anti-thrombotic, and cardioprotective activities of the shrimp head lipids. The lipids from the four kinds of shrimp head had different degrees of pro-angiogenic activities, and the activities of PCC and PJ shrimp lipids were more significant than those of the other two species. Four lipid groups displayed strong anti-inflammatory activities. For antithrombotic activity, only PCC (25 μg/mL) and PV (100 μg/mL) groups showed obvious activity. In terms of cardioprotective activity, the four kinds of lipid groups significantly increased the zebrafish heart rhythms. The heart distances were shortened, except for those of the FC (100 μg/mL) and PJ (25 μg/mL) groups. Our comprehensive lipidomics analysis and bioactivity study of lipids from different sources could provide a basis for the better utilization of shrimp.