Publications by authors named "Darko Ivanovic"

Metabolic Syndrome (MetS) is associated with the risk of developing chronic disease (atherosclerotic cardiovascular disease, type 2 diabetes, cancers and chronic kidney disease) and has an important role in early prevention. Previous research showed that an artificial neural network (ANN) is a suitable tool for algorithmic MetS diagnostics, that includes solely non-invasive, low-cost and easily-obtainabled (NI&LC&EO) diagnostic methods. This paper considers using four well-known machine learning methods (linear regression, artificial neural network, decision tree and random forest) for MetS predictions and provides their comparison, in order to induce and facilitate development of appropriate medical software by using these methods.

View Article and Find Full Text PDF

The diagnosis of metabolic syndrome (MetS) has a leading role in the early prevention of chronic disease, such as cardiovascular disease, type 2 diabetes, cancers and chronic kidney disease. It would be very greatful that MetS diagnosis can be predicted in everyday clinical practice. This paper presents artificial neural network (ANN) prediction of the diagnosis of MetS that includes solely non-invasive, low-cost and easily-obtained diagnostic methods.

View Article and Find Full Text PDF

In this paper, chromatographic analysis of active substance olopatadine hydrochloride, which is used in eye drops as antihistaminic agent, and its impurity E isomer by hydrophilic interaction liquid chromatography (HILIC) and application of design of experiments (DoE) methodology are presented. In addition, benzalkonium chloride is very often used as a preservative in eye drops. Therefore, the evaluation of its chromatographic behavior in HILIC was carried out as well.

View Article and Find Full Text PDF

Hydrophilic interaction liquid chromatography (HILIC) has emerged in recent years as a valuable alternative to reversed-phase liquid chromatography in the analysis of polar compounds. Research in HILIC is divided into two directions: the assessment of the retention mechanism and retention behavior, and the development of HILIC methods. In this work, four polar neutral analytes (iohexol and its related compounds A, B, and C) were analyzed on two silica and two diol columns in HILIC mode with the aim to investigate thoroughly the retention mechanisms and retention behavior of polar neutral compounds on these four columns.

View Article and Find Full Text PDF

This paper presents the chemometrically assisted optimization and validation of the RP-HPLC method intended for the quantitative analysis of itraconazole and its impurities in pharmaceutical dosage forms. To reach the desired chromatographic resolution with a limited number of experiments in a minimum amount of time, Box- -Behnken design was used to simultaneously optimize some important chromatographic parameters, such as the acetonitrile content in the mobile phase, pH of the aqueous phase and the column temperature. Separation between itraconazole and impurity F was identified as critical and selected as a response during the optimization.

View Article and Find Full Text PDF

In this article, a step-by-step optimization procedure for improving analyte response with implementation of experimental design is described. Zwitterionic antiepileptics, namely vigabatrin, pregabalin and gabapentin, were chosen as model compounds to undergo chloroformate-mediated derivatization followed by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) analysis. Application of a planned stepwise optimization procedure allowed responses of analytes, expressed as areas and signal-to-noise ratios, to be improved, enabling achievement of lower limit of detection values.

View Article and Find Full Text PDF

This paper presents exploration of chromatographic behavior in HILIC system by experimental design and improved chromatographic response function denoted as N(CRF)*. As a model mixture six antidepressants were chosen: selegiline, mianserine, sertraline, moclobemide, fluoxetine and maprotiline. Due to complexity of retention mechanisms in HILIC system, detailed examination of experimental space assessing the influence of important factors (acetonitrile content in the mobile phase, buffer concentration and pH of the mobile phase) and their interactions was done by applying 3(3) experimental design.

View Article and Find Full Text PDF

In this paper, the retention prediction models for mixture of β-lactam antibiotics analyzed by hydrophilic interaction chromatography (HILIC) are presented. The aim of the study was to investigate the retention behavior of some organic acids and amphoteric compounds including cephalosporins (cefotaxime, cefalexin, cefaclor, cefuroxime, and cefuroxime axetil) and penicillins (ampicillin and amoxicillin). Retention of substances with acidic functional group in HILIC is considered to be interesting since the majority of publications in literature are related to basic compounds.

View Article and Find Full Text PDF

This paper describes the development and validation of a microemulsion liquid chromatography (MELC) method for simultaneous determination of perindopril tert-butylamine and its impurities in bulk active substances and the pharmaceutical dosage form of tablets. An appropriate resolution with reasonable retention times was obtained for a microemulsion containing 0.24% (w/v) butyl acetate, 0.

View Article and Find Full Text PDF

In this paper, a previously optimized method for HPLC analysis of pramipexole and its impurities was subjected to method validation in accordance with official regulations. The optimized chromatographic conditions were as follows: mobile phase acetonitrile-water phase [15 + 85, v/v, water phase contained 1% triethylamine (TEA), pH adjusted to 7.0 with orthophosphoric acid]; detection at 262 nm for pramipexole, BI-II 751 xx, BI-I 786 BS, BI-II 820 BS, and 2-aminobenzothiazole and at 326 nm for BI-II 546 CL; column temperature, 25 degrees C; and flow rate, 1 ml/min.

View Article and Find Full Text PDF

An RP-HPLC method has been optimized and validated for the simultaneous determination of hydrocortisone acetate and of lidocaine in suppositories. For the method optimization, response surface methodology was applied, and the obtained model was tested using analysis of variance. The optimal separations were conducted on a Beckman-Coulter 150 x 4.

View Article and Find Full Text PDF

Trimetazidine dihydrochloride is an anti-anginal drug, which possesses protective properties against ischemia inducing heart damage. In this paper, a new procedure for liquid chromatographic analysis was successfully developed, optimized, and applied in assessment of trimetazidine dihydrochloride content and its impurities, Y-145, Y-235, and Y-234 at most 1.0%, 0.

View Article and Find Full Text PDF

In order to calculate the structural and compositional characteristics of microemulsions, used as eluents in the investigation of HPLC separation of simvastatin and its six impurities, predictive molecular thermodynamic approach is developed. For calculating fundamental interfacial properties of microemulsions, from pure component properties, the lattice fluid self-consistent field theory (SCF), in conjunction with new classical thermodynamic expressions, was applied. Calculation of predicted radii (PR), area per surfactant (ApS) and film thickness (FT), as well as is interfacial tension and bending moment enabled better understanding of separation of such a complex mixture.

View Article and Find Full Text PDF

The properties of the eluent are the essential factors governing the efficiency in the high-performance liquid chromatography (HPLC) method. A novel approach in retention modelling in the liquid chromatographic separation of fosinopril sodium and its degradation product, fosinoprilat, applying a microemulsion as the mobile phase, was used. The modifications of the mobile phase included the changes to the type of the lipophilic phase, the type and concentration of co-surfactant and surfactant, as well as the pH of the mobile phase.

View Article and Find Full Text PDF

A novel and unique approach was used for retention modelling in the separation of simvastatin and six impurities by liquid chromatographic using a microemulsion as mobile phase. A microemulsion is a modification of a micellar system where a lipophilic organic solvent is dissolved in the micelles; for that reason, microemulsions are usually treated as solvent-modified micellar solutions. When microemulsions are used as eluents in HPLC separations, solutes partition between the charged oil droplets and the aqueous buffer phase.

View Article and Find Full Text PDF