Eleni Tsanaktsidou - Academia.edu (original) (raw)

Uploads

Papers by Eleni Tsanaktsidou

Research paper thumbnail of Development and Validation of an HPLC-FLD Method for the Determination of NDMA and NDEA Nitrosamines in Lisinopril Using Pre-Column Denitrosation and Derivatization Procedure

Separations

In order to meet the analytical requirements of the European Medicines Agency (EMA), a new HPLC-F... more In order to meet the analytical requirements of the European Medicines Agency (EMA), a new HPLC-FLD method was successfully developed using dansyl chloride for the derivatization and determination of the genotoxic impurities N-Nitrosodimethylamine (NDMA) and N-Nitrosodiethylamine (NDEA) in Lisinopril API and its final product. Samples’ pretreatment includes liquid–liquid microextraction, denitrosation, and derivatization steps. To optimize the process, the parameters contributing to high sensitivity and yielding reliable results were thoroughly studied and optimized using one-factor-at-a-time and experimental design approaches. The analytes were pre-column derivatized with Dansyl-Cl and analyzed by HPLC-fluorescence (λem/λem = 340/530) using a C18 column and a mixture of phosphate buffer (pH = 2.8; 20 mM)/acetonitrile 55:45 v/v as the mobile phase. The six-level concentration calibration was shown to be linear, with R equal to 0.9995 for both analytes. The limit of detection (LOD) w...

Research paper thumbnail of Response Surface and Freezing-Out Methodologies for the Extraction, Separation, and Validation of Seven Vitamins in a Novel Supplement with Determination by High-Performance Liquid Chromatography

Analytical Letters, Sep 19, 2022

Research paper thumbnail of Development and Validation of Hplc-Dad and Lc-(Esi)/Ms Methods for the Determination of Sulfasalazine, Mesalazine and Hydrocortisone 21-Acetate in Tablets and Rectal Suppositories: In Vitro and Ex Vivo Permeability Studies

SSRN Electronic Journal, 2022

Controlled-release tablets and rectal suppositories of sulfasalazine (SLF) and hydrocortisone 21-... more Controlled-release tablets and rectal suppositories of sulfasalazine (SLF) and hydrocortisone 21-acetate (HA) were prepared as recommended dosage forms for the treatment of acute episodes of ulcerative colitis, in patients who do not respond to monotherapy. A High-Performance Liquid Chromatography (HPLC) Diode-array method with a gradient elution mobile phase was developed to evaluate the production quality of both formulations (assay and dissolution profiles in gastric and intestinal fluids). Method's validation was carried out providing good linearity (r ≥ 0.9995), precision (RSD < 1.53%), recovery (96.9% - 103.7%) and limits of detection (LODSLF = 12 ng/mL, LODHA = 15 ng/mL). Experimental design and Plackett-Burman methodology was constructed to study the robustness of the analysis. In all composite substrates, a freezing lipid precipitation approach was used as purification step. The method was optimized by applying Central Composite design mode. The in-vitro/ex-vivo permeability studies of both formulations were evaluated by a Liquid Chromatography-Electron Spray Ionization Mass Spectrometry (LC-ESI/MS) +/- mode. The analysis of sulfamethazine (internal standard, SLM, m/z 279), HA (m/z 449, [M + HCOO]-), SLF (m/z 399) and its active metabolite mesalazine (MSL, m/z 154) was performed using a C18 column and gradient elution. The validation of the method met the requirements of the International Council for Harmonization (ICH) (r ≥ 0.9997, RSD ≤ 4.62%, Recovery > 95%, LODSLF = 1.28 ng/mL, LODHA = 1.07 ng/mL, LODMSL = 3.16 ng/mL). Based on the results, important conclusions were drawn concerning the role of excipients and SLF metabolism.

Research paper thumbnail of Homogeneous liquid phase microextraction using hydrophilic media for the determination of fluoroquinolones in human urine using HPLC-FLD

Microchemical Journal, 2021

Research paper thumbnail of Titanium and Chromium Determination in Feedstuffs Using ICP-AES Technique

Separations, 2019

The present study represents the determination of Ti and Cr in dry animal feeds using wet acid di... more The present study represents the determination of Ti and Cr in dry animal feeds using wet acid digestion and inductively coupled plasma–atomic emission spectrometry (ICP-AES), in order to use these metals as digestibility markers. A radiofrequency power of 1350 W and a nebulizer argon flow of 0.8 L/min was selected. The limits of detection were between 11.4 and 16.1 μg/g for titanium and between 10.7 and 38.2 μg/g for chromium. The recovery values for the aqueous solutions were 89.5–103.9% (titanium) and 85.3–104.2% (chromium), with relative standard deviations (RSD%) under 2.1% and standard errors under 2.32%, demonstrating that the method offered good accuracy and repeatability. Six different samples of commercially available feedstuffs (two cat foods, two dog foods, and two poultry foods) were analyzed and the levels of investigated metals were found to be in the ranges of 0.10 g/kg and

Research paper thumbnail of Partial Least Square Model (PLS) as a Tool to Predict the Diffusion of Steroids Across Artificial Membranes

Molecules, 2020

One of the most challenging goals in modern pharmaceutical research is to develop models that can... more One of the most challenging goals in modern pharmaceutical research is to develop models that can predict drugs’ behavior, particularly permeability in human tissues. Since the permeability is closely related to the molecular properties, numerous characteristics are necessary in order to develop a reliable predictive tool. The present study attempts to decode the permeability by correlating the apparent permeability coefficient (Papp) of 33 steroids with their properties (physicochemical and structural). The Papp of the molecules was determined by in vitro experiments and the results were plotted as Y variable on a Partial Least Squares (PLS) model, while 37 pharmacokinetic and structural properties were used as X descriptors. The developed model was subjected to internal validation and it tends to be robust with good predictive potential (R2Y = 0.902, RMSEE = 0.00265379, Q2Y = 0.722, RMSEP = 0.0077). Based on the results specific properties (logS, logP, logD, PSA and VDss) were pro...

Research paper thumbnail of Development and Validation of an HPLC-FLD Method for the Determination of NDMA and NDEA Nitrosamines in Lisinopril Using Pre-Column Denitrosation and Derivatization Procedure

Separations

In order to meet the analytical requirements of the European Medicines Agency (EMA), a new HPLC-F... more In order to meet the analytical requirements of the European Medicines Agency (EMA), a new HPLC-FLD method was successfully developed using dansyl chloride for the derivatization and determination of the genotoxic impurities N-Nitrosodimethylamine (NDMA) and N-Nitrosodiethylamine (NDEA) in Lisinopril API and its final product. Samples’ pretreatment includes liquid–liquid microextraction, denitrosation, and derivatization steps. To optimize the process, the parameters contributing to high sensitivity and yielding reliable results were thoroughly studied and optimized using one-factor-at-a-time and experimental design approaches. The analytes were pre-column derivatized with Dansyl-Cl and analyzed by HPLC-fluorescence (λem/λem = 340/530) using a C18 column and a mixture of phosphate buffer (pH = 2.8; 20 mM)/acetonitrile 55:45 v/v as the mobile phase. The six-level concentration calibration was shown to be linear, with R equal to 0.9995 for both analytes. The limit of detection (LOD) w...

Research paper thumbnail of Response Surface and Freezing-Out Methodologies for the Extraction, Separation, and Validation of Seven Vitamins in a Novel Supplement with Determination by High-Performance Liquid Chromatography

Analytical Letters, Sep 19, 2022

Research paper thumbnail of Development and Validation of Hplc-Dad and Lc-(Esi)/Ms Methods for the Determination of Sulfasalazine, Mesalazine and Hydrocortisone 21-Acetate in Tablets and Rectal Suppositories: In Vitro and Ex Vivo Permeability Studies

SSRN Electronic Journal, 2022

Controlled-release tablets and rectal suppositories of sulfasalazine (SLF) and hydrocortisone 21-... more Controlled-release tablets and rectal suppositories of sulfasalazine (SLF) and hydrocortisone 21-acetate (HA) were prepared as recommended dosage forms for the treatment of acute episodes of ulcerative colitis, in patients who do not respond to monotherapy. A High-Performance Liquid Chromatography (HPLC) Diode-array method with a gradient elution mobile phase was developed to evaluate the production quality of both formulations (assay and dissolution profiles in gastric and intestinal fluids). Method's validation was carried out providing good linearity (r ≥ 0.9995), precision (RSD < 1.53%), recovery (96.9% - 103.7%) and limits of detection (LODSLF = 12 ng/mL, LODHA = 15 ng/mL). Experimental design and Plackett-Burman methodology was constructed to study the robustness of the analysis. In all composite substrates, a freezing lipid precipitation approach was used as purification step. The method was optimized by applying Central Composite design mode. The in-vitro/ex-vivo permeability studies of both formulations were evaluated by a Liquid Chromatography-Electron Spray Ionization Mass Spectrometry (LC-ESI/MS) +/- mode. The analysis of sulfamethazine (internal standard, SLM, m/z 279), HA (m/z 449, [M + HCOO]-), SLF (m/z 399) and its active metabolite mesalazine (MSL, m/z 154) was performed using a C18 column and gradient elution. The validation of the method met the requirements of the International Council for Harmonization (ICH) (r ≥ 0.9997, RSD ≤ 4.62%, Recovery > 95%, LODSLF = 1.28 ng/mL, LODHA = 1.07 ng/mL, LODMSL = 3.16 ng/mL). Based on the results, important conclusions were drawn concerning the role of excipients and SLF metabolism.

Research paper thumbnail of Homogeneous liquid phase microextraction using hydrophilic media for the determination of fluoroquinolones in human urine using HPLC-FLD

Microchemical Journal, 2021

Research paper thumbnail of Titanium and Chromium Determination in Feedstuffs Using ICP-AES Technique

Separations, 2019

The present study represents the determination of Ti and Cr in dry animal feeds using wet acid di... more The present study represents the determination of Ti and Cr in dry animal feeds using wet acid digestion and inductively coupled plasma–atomic emission spectrometry (ICP-AES), in order to use these metals as digestibility markers. A radiofrequency power of 1350 W and a nebulizer argon flow of 0.8 L/min was selected. The limits of detection were between 11.4 and 16.1 μg/g for titanium and between 10.7 and 38.2 μg/g for chromium. The recovery values for the aqueous solutions were 89.5–103.9% (titanium) and 85.3–104.2% (chromium), with relative standard deviations (RSD%) under 2.1% and standard errors under 2.32%, demonstrating that the method offered good accuracy and repeatability. Six different samples of commercially available feedstuffs (two cat foods, two dog foods, and two poultry foods) were analyzed and the levels of investigated metals were found to be in the ranges of 0.10 g/kg and

Research paper thumbnail of Partial Least Square Model (PLS) as a Tool to Predict the Diffusion of Steroids Across Artificial Membranes

Molecules, 2020

One of the most challenging goals in modern pharmaceutical research is to develop models that can... more One of the most challenging goals in modern pharmaceutical research is to develop models that can predict drugs’ behavior, particularly permeability in human tissues. Since the permeability is closely related to the molecular properties, numerous characteristics are necessary in order to develop a reliable predictive tool. The present study attempts to decode the permeability by correlating the apparent permeability coefficient (Papp) of 33 steroids with their properties (physicochemical and structural). The Papp of the molecules was determined by in vitro experiments and the results were plotted as Y variable on a Partial Least Squares (PLS) model, while 37 pharmacokinetic and structural properties were used as X descriptors. The developed model was subjected to internal validation and it tends to be robust with good predictive potential (R2Y = 0.902, RMSEE = 0.00265379, Q2Y = 0.722, RMSEP = 0.0077). Based on the results specific properties (logS, logP, logD, PSA and VDss) were pro...