Factors contributing to variability in metformin concentration in polycystic ovary syndrome.

Aim: To investigate the factors affecting metformin concentrations after chronic administration in patients with polycystic ovary syndrome (PCOS), focusing on the pharmacokinetic variability and its implications for personalized therapy.

Methods: This study enrolled 53 PCOS patients undergoing long-term metformin treatment at the Clinic for Gynecology and Obstetrics in Niš, Serbia, from February to December 2019. Pharmacokinetic parameters were measured from blood samples, and metformin concentrations were determined with validated analytical techniques.

Sample pretreatment and HPLC determination of antiplatelet drug ticagrelor in blood plasma from patients with acute coronary syndromes.

A simple HPLC method was developed for the determination of antiplatelet drug ticagrelor (TCG) in blood. Sample preparation and extraction conditions were investigated and optimized. The preparation of blood plasma was investigated by protein precipitation using perchloric acid, methanol, acetonitrile (ACN), and trifluoroacetic acid.

In vitro effect of beer, red and white wine on the morphology and surface roughness of human enamel.

Background: Beer, red and white wine are acidic drinks whose frequent consumption can increase the risk of dental erosion.

Objectives: To establish the effect of beer, red and white wine on the morphology and surface roughness (SR) of human enamel using different exposure times in a cyclic deand remineralization model in vitro.

Material And Methods: The experiment included 33 surgically extracted impacted human third molars from patients aged 18-25 years.

Caffeine in Hair Care and Anticellulite Cosmetics: Sample Preparation, Solid-Phase Extraction, and HPLC Determination.

Caffeine is extensively used in cellulite and hair growth cosmetic products. Regulations in the field of cosmetics require manufacturers to list caffeine in the ingredient list on product labels, but its exact content in these products is not declared. On the other hand, daily exposure to caffeine from all sources may approach health reference values.

Ultrastructural changes in the cemento-enamel junction caused by acidic beverages: An in vitro study.

The present in vitro study was aimed at evaluating the morphological changes in the cemento-enamel junction (CEJ) after exposure to acidic beverages using the scanning electron microscopy (SEM). The initial pH and titratable acidity (TA) was analyzed from follow groups: (I) Coca cola, (II) orange juice, (III) Cedevita, (IV) Red Bull, (V) Somersby cider, and (VI) white wine. The CEJ samples (n = 64), obtained from unerupted third molars, were allocated to one control (artificial saliva, n = 16) and six experimental groups (n = 8).

Maternal age has more pronounced effect on breast milk retinol and β-carotene content than maternal dietary pattern.

Objective: The effects on breast milk composition of advanced maternal age and maternal dietary habits during pregnancy and lactation have not, to our knowledge, been investigated in southeastern Europe and the Balkans. The aim of this study was to compare the content of retinol and β-carotene in colostrum and mature milk samples obtained from different maternal age (MA) groups and to assess the potential relationship with maternal and demographic characteristics, dietary patterns, and lifestyle habits during pregnancy and lactation.

Methods: Forty-three nursing mothers were divided in two groups according to MA: ≥35 y of age (n = 22) and <35 y of age (n = 21).

Physicochemical and biochemical parameters in milk of Serbian breastfeeding women.

Background/aim: This study was undertaken to determine the changes and relationships between some important milk constituents as well as physical, rheological, and biochemical parameters of milk obtained from Serbian breastfeeding mothers.

Materials And Methods: Physicochemical and biochemical parameters and the concentrations of vitamins, uric acid, and minerals were determined during the three periods of lactation covering colostrum, transitional, and mature milk collected from 67 mothers who had a term-pregnancy.

Results: Large interindividual variations regarding many parameters were found between mothers at the same period of lactation, but the average values were mostly in the expected and recommended ranges.

Erosive Effect of Different Soft Drinks on Enamel Surface in vitro: Application of Stylus Profilometry.

Objective: To assess the erosive potential of various soft drinks by measuring initial pH and titratable acidity (TA) and to evaluate enamel surface roughness using different exposure times.

Materials And Methods: The initial pH of the soft drinks (group 1: Coca-Cola; group 2: orange juice; group 3: Cedevita; group 4: Guarana, and group 5: strawberry yoghurt) was measured using a pH meter, and TA was measured by titration with NaOH. Enamel samples (n = 96), cut from unerupted human third molars, were randomly assigned to 6 groups: experimental (groups 1-5) and control (filtered saliva).

HPLC method development for determination of doxycycline in human seminal fluid.

The present paper reports the development and validation of an analytical method for doxycycline quantification in human seminal fluid by HPLC with UV detection. The separation of doxycycline was achieved at 40°C on a reversed-phase C18 column using isocratic elution. The mobile phase consisted of acetonitrile (A) and water buffered at pH 2.

Determination of ibuprofen in combined dosage forms and cream by direct UV spectrophotometry after solid-phase extraction.

Solid-phase extraction method followed by direct UV spectrophotometry at 264 nm was developed and applied for the selective ibuprofen determination in two-component formulation of ibuprofen and pseudoephedrine-HCl, combined powder which contains ibuprofen in the form of salt with L-arginine and 10% ibuprofen cream. Procedures for ibuprofen determination in complex pharmaceutical preparations by direct UV spectrophotometry lack selectivity because of interferences of other active substances and fat components. A limited number of spectrophotometric methods applicable to these samples are based on derivative (first and second-order) UV spectroscopy.

RP-HPLC assay of doxycycline in human saliva and gingival crevicular fluid in patients with chronic periodontal disease.

A reversed-phased HPLC method with fluorescence detection was optimized and validated for determination of DOXY in human saliva and gingival crevicular fluid (GCF) with tetracycline as internal standard. Single step extraction with acetonitrile for both types of samples was performed. The separation was achieved at Zorbax Extend-C18 analytical column at 30°C.

Determination of streptomycin in a pharmaceutical sample based on its degradation by hydrogen peroxide in the presence of copper(II).

The kinetics of streptomycin degradation by hydrogen peroxide at pH 7.4 was investigated. The reaction was catalyzed by traces of Cu(II) ions, and it was followed spectrophotometrically at 322 nm by applying the initial-rate method.