Method For Quantitative Determination Research Articles

Validation of RP-UHPLC Method for Quantitative Determination of Polycyclic Aromatic Hydrocarbons from Soil

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental pollutants composed of two or more fused aromatic rings, which are characterized by low water solubility, low vapor pressure, and high melting and boiling points, depending on their structures. Due to the lipophilic nature of these compounds, they are strongly adsorbed by soil and sediments. The United States Environmental Protection Agency (USEPA) has declared 16 PAHs as priority pollutants in 1983 based on their existence of highest concentrations, greater exposure and toxicity. The purpose of this article is to validate a method for determining ten PAHs in soil by ultra-high pressure liquid chromatography with UV-VIS detection. The evaluated performance parameters are: selectivity, linearity, accuracy, precision, limit of detection (LOD), limit of quantification (LOQ), limit of repeatability (r), recovery (R) and uncertainty of measurement (U). LOD ranged between 0.02 mg/mL and 0.3 mg/mL, LOQ ranged between 0.2 mg/mL and 0.95 mg/mL. The recovery values ranged between 75.4% for benzo(b) fluoranthen and 89.8% for chrysene. These values were established using a soil reference material which was extracted with hexane/acetone using a Soxhlet method. The PAH compounds were separated using a nonpolar stationary phase column and were determined by liquid chromatography with Array Diode Detector at 254 nm.

A Review of the Approved Data on Methods for Quantitative Determination of Sulfadiazine in Pharmaceutical Formulations

A Review of the Approved Data on Methods for Quantitative Determination of Sulfadiazine in Pharmaceutical Formulations

EXPERIMENTAL SEARCH AN UNDERLYING BASIS OF PRINCIPLES FOR MICROBIOLOGICAL QUANTITATIVE ASSESSMENT OF PRESERVATIVE SOLUTIONS

Introduction. Microbiological control of preservative solutions and assessment of the state of anatomical preparations are topical issues, the solution of which requires adaptation of methods for quantitative determination of the level of microbial contamination to the special conditions of equilibrium systems containing biological preparations. The aim of the study is screening, experimental testing and adaptation of microbiological methods for quantitative assessment of the level of microbial contamination for monitoring the microbiological purity of preservative solutions using the Melnikov–Razvedenkov solution as an example. Material and methods. The object of the study was the Melnikov–Razvedenkov preservative solution modified by the Scientific Research Center for Biomedical Technologies of the All-Russian Scientific Research Institute of Medicinal and Aromatic Plants. The study used methods for quantitative assessment of the level of microbial contamination on agar nutrient media. Results. As a result of screening, experimental testing and comparative analysis of methods for quantitative assessment of the level of microbial contamination, the most promising methodological approaches were identified and adapted for microbiological monitoring of modified Melnikov-Razvedenkov solution. Conclusions. The microbiological study of the modified Melnikov-Razvedenkov preservative solution showed the feasibility of using the membrane vacuum filtration method with membrane filters made of a mixture of cellulose acetate and nitrate with a nominal pore diameter of 0.45 μm. For sterilization of the test solution, the use of a vacuum filtration through membrane filters with a nominal pore diameter of 0.22 μm is promising.

Simultaneous Quantitative Determination of Five Process Relevant Impurities in Menatetrenone

ABSTRACTMenatetrenone, a form of vitamin K (MK‐4) is used for various pharmaceutical and agrochemical applications. Monitoring and control of process impurities is crucial in the manufacturing of pharmaceutical‐grade Menatetranone. In this article, we report a gas chromatography (GC)‐based analytical method for the detection and quantification of trace levels of five process‐related impurities in MK‐4 originating from the starting materials and reagents. A GC‐flame ionization detector (GC‐FID)‐based method is presented for simultaneous quantitative estimation of five structurally diverse compounds, some of which are conventionally analyzed by liquid chromatography. After a series of method development trials, an optimized method with a mid‐polar column dura bond‐624 (6% cyanopropyl/phenyl and 94% polydimethylsiloxane) with initial column oven temperature 150°C, detector temperature 280°C was finalized for the separation of these impurities. The developed GC‐FID‐based method was validated for specificity, the limit of detection (LOD), the limit of quantification (LOQ), linearity, range, precision, accuracy, and robustness as relevant to the International Council for Harmonization guidelines. The method was found to be highly sensitive for all the constituents with an LOD ranging from 0.05 to 0.43 pg and a limit of quantification of 0.17–1.41 pg, as estimated by the signal‐to‐noise ratios. This is the first report of an analytical method for the simultaneous quantitative determination of five process impurities of MK‐4.

Validation of HPLC method for quantitative determination of zerumbone in the rhizome of Zingiber ottensii Valeton

Validation of HPLC method for quantitative determination of zerumbone in the rhizome of Zingiber ottensii Valeton

Spectrophotometric Methods for Quantitative Determination of Imeglimin HCl in Pure and Dosage Forms

Spectrophotometric Methods for Quantitative Determination of Imeglimin HCl in Pure and Dosage Forms

DEVELOPMENT AND VALIDATION OF SPECTROPHOTOMETRIC METHOD FOR THE QUANTITATIVE DETERMINATION OF LANSOPRAZOLE AND RABEPRAZOLE

The article is devoted to the development and validation of methods for spectrophotometric quantitative determination of lansoprazole and rabeprazole in the substance and various prepara-tions. 96% ethyl alcohol was chosen as a common solvent. The working wavelengths for lanso-prazole were set at 285 nm, and for rabeprazole at 275 nm. The relative error of determination is ± 0.32% for “Lansil” capsules, ± 0.58% for “Rabeloc” lyophilized powder. The validation of methods for spectrophotometric quantitative determination of lansoprazole and rabeprazole in standard samples for some parameters was carried out.

Modification of the method of quantitative determination of flavonoids in the grass of Polýgonum aviculáre L.

Aim – modification of the method of quantitative determination of total flavonoids in the raw material of Polýgonum Aviculáre L., presented in State Pharmacopoeia, XIV Ed. Material and methods. The raw material of knotgrass (grass) was harvested near the villages of Ponomarevka, Dombarovka, Alekseevka, Orenburg region in June and July, 2022. The harvested material was dried in accordance with the requirements of the SP. The quantitative content was studied using the Vilitek VBS ultrasonic bath at a temperature of 40°C and power of 60 W, the LAB-TB-6/W water bath at a temperature of 90°C, rotary evaporator "IR-1 LT" at a temperature of 70°C. The electronic spectra were measured on the UNICO 2800 UV spectrophotometer, in 10 mm thick cuvettes in the wavelength range from 190 to 700 nm. The comparison solution was prepared using 96% ethyl alcohol concentration. Results. The presented method of quantitative determination can be used in "end-to-end" standardization, for raw material of other types of Polýgonum Aviculáre L., as well as medicinal herbal preparations based on Polýgonum AviculáreL. We selected the extraction conditions using 50% ethyl alcohol in the ratio (raw material-extractant) of 1:50 and boiling in the water bath for 60 minutes, which allowed us to achieve the yield of total flavonoids more than 0.5% as stated in SP XIV (FS.2.5.0069.18). Conclusion. The new conditions for the analysis of the quantitative determination of the amount of flavonoids in the grass of the Polýgonum Aviculáre L. are proposed that are different from the ones stated in the pharmacopoeia. Main differences: single extraction vs. three-stage extraction described in the pharmacopoeia; reduction of extraction time in the water bath to 60 minutes, which is 30 minutes less than in the method of SP XIV; concentration of the extractant and the ratio of "raw materials to extractant". Thus, the method of quantitative determination of the grass of the Polýgonum Aviculáre L. has been modified in the terms of basic conditions of extraction of raw materials. Based on the data obtained, the average content of flavonoids in the raw material of Polýgonum Aviculáre L. was 1.8 ± 0.08%.

New Approaches to Determining the D/H Ratio in Aqueous Media Based on Diffuse Laser Light Scattering for Promising Application in Deuterium-Depleted Water Analysis in Antitumor Therapy

The development of affordable and reliable methods for quantitative determination of stable atomic nuclei in aqueous solutions and adjuvant agents used in tumor chemotherapy is an important task in modern pharmaceutical chemistry. This work quantified the deuterium/prothium isotope ratio in aqueous solutions through an original two-dimensional diffuse laser scattering (2D-DLS) software and hardware system based on chemometric processing of discrete interference patterns (dynamic speckle patterns). For this purpose, 10 mathematical descriptors (di), similar to QSAR descriptors, were used. Correlation analysis of bivariate “log di—D/H” plots shows an individual set of multi-descriptors for a given sample with a given D/H ratio (ppm). A diagnostic sign (DS) of differentiation was established: the samples were considered homeomorphic if 6 out of 10 descriptors differed by less than 15% (n ≥ 180). The analytical range (r = 0.987) between the upper (D/H ≤ 2 ppm) and lower (D/H = 180 ppm) limits for the quantification of stable hydrogen nuclei in water and aqueous solutions were established. Using the Spirotox method, a «safe zone» for protozoan survival was determined between 50 and 130 ppm D/H. Here, we discuss the dispersive (DLS, LALLS) and optical properties (refractive index, optical rotation angle) of the solutions with different D/H ratios that define the diffuse laser radiation due to surface density inhomogeneities. The obtained findings may pave the way for the future use of a portable, in situ diffuse laser light scattering instrument to determine deuterium in water and aqueous adjuvants.

LC-MS/MS-Based Concurrent Quantification of Cannabidiol and Melatonin in Mouse Plasma to Elucidate Complex PK Interactions

Objective: This study aimed to develop a quantitative analytical method for the simultaneous determination of cannabidiol (CBD) and melatonin (MT) in mouse plasma using the protein precipitation method coupled with LC-MS/MS. Additionally, this study sought to investigate the impact of CBD on the pharmacokinetics of MT in mice using this method. Methods: Mouse plasma samples were precipitated with acetonitrile and analyzed using a Kromasil 100-5-C8 (2.1 × 50 mm) column. Following a single administration, thirty male ICR mice were randomly assigned to five groups: MT 2 mg/kg intravenously (i.v.), MT 10 mg/kg orally (p.o.), MT + CBD (10 + 10) mg/kg p.o., MT + CBD (10 + 40) mg/kg p.o., and MT 10 mg/kg p.o. followed by CBD 2 mg/kg i.v. Pharmacokinetic parameters were calculated using a non-compartmental model and analyzed to investigate the interactions of CBD with MT. Results: The calibration curves for CBD and MT were linear over the range of 2 to 1000 ng/mL. Co-administration of a high dose of CBD (40 mg/kg) orally reduced the Cmax of MT (10 mg/kg) to 57% of the control, while the area under the curve from 0.5 to 8 h (AUC(0.5–8h)) was 2.85-fold that of the MT-only group. When CBD (2 mg/kg) was administered intravenously alongside MT orally, the AUC(0.5–8h) was 1.54 times that of MT given orally alone. The AUC of CBD was positively correlated with the AUC of the distribution and elimination phases of MT, while the Cmax of CBD negatively correlated with the Cmax of MT. Conclusions: The developed LC-MS/MS method is robust and suitable for pharmacokinetic studies involving CBD and MT. The in vivo effects of CBD on MT pharmacokinetics are complex. High oral doses of CBD inhibit both the intestinal absorption and metabolic clearance of MT, resulting in a more smooth PK profile.

A clinical case of factitious hypoglycemia in a patient with type 1 diabetes mellitus

Artificial hypoglycemia (Munchausen syndrome) is a condition caused by low blood glucose due to the deliberate taking of insulin or oral hypoglycemic drugs. Artificial hypoglycemia remains one of the problems that endocrinologists face in their practice; a diagnostic search for its etiological factor can lead to expensive and unnecessary studies. Diagnosis of artificial hypoglycemia in patients with diabetes mellitus on insulin therapy seems to be a labor-intensive task, since unlike most factitious disorders, which may be indicated by atypical manifestations of the disease or conflicting medical information about the patient, in patients with diabetes mellitus hypoglycemic syndrome is an expected unwanted event due to insulin therapy. Therefore, deliberate insulin administration is often not diagnosed until self-induced hypoglycemia becomes recurrent and/or severe. If artificial hypoglycemia is suspected, a number of authors currently recommend testing С peptide and a combination of two methods for quantitative determination of insulin in the blood using different analyzer systems. Active collaboration between clinical and laboratory specialists is the key to successfully solving such a diagnostic problem.This article presents a clinical case of Munchausen syndrome in a 28-year-old patient with type 1 diabetes mellitus with recurrent hypoglycemia during 21 years, repeated severe hypoglycemia, including loss of consciousness, and proven intentional administration of an insulin analog drug during hospital stay; the complex diagnostic path passed before making the correct diagnosis is described.

ВИТАМИН D3: ПОДРОБНАЯ ХАРАКТЕРИСТИКА СУБСТАНЦИИ И АНАЛИЗ

The article examines in detail the issues of standardization of the obtained vitamin D substance using its own original technological scheme, and the possibility of further use of the substance to create a standard sample (SS). The work traces the current problem associated with the lack of production of domestic vitamin D substance. The object of study is the vitamin D substance isolated from natural raw materials. To assess the quality of the obtained substance, quantitative and qualitative determination methods, high-performance liquid chromatography (HPLC) at a wavelength of 265 nm, IR spectroscopy in the emission range of the spectrum from 4000 cm-1 to 400 cm-1, organoleptic method, polarimetry, refractometry and other methods of analysis were used. The obtained vitamin D substance, according to its quality characteristics, can be confidently used not only as a material for the manufacture of SS, but also as a starting substance in the pharmaceutical, food and agricultural sectors of the national economy.

Advanced HPLC Method with Diode Array Detection Using a Phenyl-Bonded Column for Simultaneous Quantitation of Three Sunscreen Filters in a Moisturizing Sunscreen Cream for Acne-Prone Skin

This study introduces a novel, robust, and efficient method for the simultaneous quantitative determination of three sunscreen filters, namely, 4-methylbenzylidene camphor, octyl methoxycinnamate, and avobenzone, in a moisturizing sunscreen cream specifically designed for acne-prone skin. The method employs high-performance liquid chromatography with photodiode-array detection, providing a reliable separation of the analytes. Chromatographic separation was achieved using a Fortis Phenyl analytical column (150.0 × 2.1 mm, 5 μm), with isocratic elution at a flow rate of 0.4 mL/min. The mobile phase was composed of a 57/43 (v/v) mixture of acetonitrile/45 mM aqueous ammonium formate solution, ensuring sufficient resolution and peak symmetry for the target compounds. The method was validated comprehensively for critical performance parameters, including linearity, precision, accuracy, and robustness. Linearity was established across a suitable range for all three analytes, with high correlation coefficients. Precision was confirmed with intra-run and total precision coefficients of variation of ≤4.6%, while accuracy assessments yielded a percent recovery between 98.6 and 100.4, for all quality control levels. Additionally, the method was able to effectively separate the sunscreen filters from other cosmetic ingredients, such as [β-(1.3), (1.6)-D-glucan], low molecular weight (LMW) hyaluronic acid and plant extracts ensuring specificity in complex formulations. This straightforward and time efficient sample preparation process, involving methanol extraction followed by serial dilution, makes the method suitable for routine quality control in cosmetic laboratories. The method was successfully applied to the analysis of two different lots of a commercial sunscreen cream, achieving excellent recovery for all filters, ranging between 94.6% and 99.8%, thus demonstrating its reliability and applicability for the quality control of cosmetics.

Sensitive determination of volatile nitrosamines with ambient pressure ammonium-adduct ionization mass spectrometry.

In recent years, the control of volatile N-nitrosamines (NAs) has been of interest in the pharmaceutical and food industries, as many of these compounds are probable human carcinogens. Thus, rapid and trace-level quantitative determination methods are in urgent demand. In this work, ambient pressure ammonium-adduct ionization mass spectrometry was proposed for the sensitive detection of volatile nitrosamines in various pharmaceutical headspaces. The ammonium ions produced through electrospray ionization acted as reactant ions for NAs to generate ammonium-NA adduct ions and underwent in-source collision-induced dissociation to produce protonated NAs, which were detected by mass spectrometry. The ionization selectivity and sensitivity for various volatile NAs were improved significantly using the developed method, which was demonstrated by the limit of quantification (LOQ) below 52ng L-1 for all NAs, and the quantitative performance was consequently improved. Different NAs exhibited almost equimolar response using NH4+ as the reactant ion, with at least a twofold enhancement in intensity for the individual compounds relative to when using H+ as the reactant ion. The proposed method is a rapid, sensitive, and environmentally economical approach that uses few reagents.

Unraveling the Source of Self-Induced Diastereomeric Anisochronism in Chiral Dipeptides.

Mastering of analytical methods for accurate quantitative determinations of enantiomeric excess is a crucial aspect in asymmetric catalysis, chiral synthesis, and pharmaceutical applications. In this context, the phenomenon of Self-Induced Diastereomeric Anisochronism (SIDA) can be exploited in NMR spectroscopy for accurate determinations of enantiomeric composition, without using a chiral auxiliary that could interfere with the spectroscopic investigation. This phenomenon can be particularly useful for improving the quantitative analysis of mixtures with low enantiomeric excesses, where direct integration of signals can be tricky. Here, we describe a novel analysis protocol to correctly determine the enantiomeric composition of scalemic mixtures and investigate the thermodynamic and stereochemical features at the basis of SIDA. Dipeptide derivatives were chosen as substrates for this study, given their central role in drug design. By integrating the experiments with a conformational stochastic search that includes entropic contributions, we provide valuable information on the dimerization thermodynamics, the nature of non-covalent interactions leading to self-association, and the differences in the chemical environment responsible for the anisochronism, highlighting the importance of different stereochemical arrangement and tight association for the distinction between homochiral and heterochiral adducts. An important role played by the counterion was pointed out by computational studies.

Universally Applicable Methods for Comprehensive Risk Assessment of Elemental Impurities in Vitamin A and D Preparations

Background: Vitamin A and D deficiency in children is a common public health problem. In China, almost all children are administered vitamin A and D preparations daily and they should be consumed continuously until the age of 18. Children are sensitive to elemental impurities, including heavy metals. However, there are no regulatory requirements or reports on the risk assessment of elemental impurities in marketed vitamin A and D preparations. Objective: The aim of this study was to propose an accurate and efficient method suitable for samples from different manufacturers to detect elemental impurities and conduct risk assessments according to the ICH Q3D guidelines. Methods: We developed a universally applicable digestion method for capsules and an ICP–MS method for quantitative analysis of 28 elemental impurities in vitamin A and D formulations. These methods were validated according to the USP 233 guidelines. Elemental impurities in 15 batches of vitamin A and D products from 10 manufacturers and their capsule shells were determined, and risk assessment was conducted according to the International Council for Harmonization Q3D guidelines. Results: All elemental impurities of toxicological concern met the Q3D requirements. However, the concentrations of various elements, including those of lead (not detected to 4.1 μg/g), arsenic (not detected to 7 μg/g), aluminum (not detected to 888 μg/g), and palladium (not detected to 36 μg/g), varied markedly. Moreover, the lead content in one batch from one manufacturer exceeded the control threshold. Conclusion: In this study, we successfully developed an effective digestion method for processing capsules containing samples from different sources and a sensitive ICP–MS method for quantitative determination of 28 elemental impurities in vitamin A and D preparations. ICP–MS should be implemented for the evaluation and control of elemental impurities in vitamin A and D preparations. This will ensure safe long-term vitamin A and D supplementation in children

Pharmacokinetics of a new drug based on polysaccharide from acorus calamus in an experiment on laboratory animals

Introduction. α(1,2)-L-rhamno-α(1,4)-D-galactopyranosyluronane is a water-soluble heteropolysaccharide isolated from the rhizomes of calamus marsh (Acorus calamus L.) and has antitumor, antimetastatic, immunomodulatory and hepatoprotective effects, protective effect on hematopoiesis suppressed during cytostatic treatment.Aim. Validation of the bioanalytical method for the determination of α(1,2)-L-rhamno-α(1,4)-D-galactopyranosyluronane Acorus calamus L. and the study of the pharmacokinetic parameters of a new drug based on it after a single administration of 120 mg/kg to rats and 24, 30, 42 mg/kg to rabbits.Materials and methods. In the study, 8 male rats (average weight – 300 g) were used as the main animals. 6 male rabbits (average body weight – 2.5 kg) were used as an additional animal species. The dose assessment experiment was carried out on 24 rabbits (body weight – 2.3–2.5 kg). The quantitative determination of α(1,2)-L-rhamno-α(1,4)-D-galactopyranosyluronane Acorus calamus L. in the blood plasma of animals was carried out by HPLC-MS/MS, the analytical form was galacturonic acid. The method of sample preparation of biological samples included the stage of enzymatic hydrolysis of α(1,2)-L-rhamno-α(1,4)-D-galactopyranosyluronane Acorus calamus L. with a solution of pectinase for the formation of galacturonic acid.Results and discussions. The pharmacokinetics of the new drug α(1,2)-L-rhamno-α(1,4)-D-galactopyranosyluronane Acorus calamus L. was studied after a single dose of 120 mg/kg to rats and 24, 30, 42 mg/kg to rabbits. The average residence time of the drug in the rabbit's body was 1.0 ± 0.21 hours, the half-life was 0.7 ± 0.15 hours. The average residence time of the drug in the rat body was 1.16 hours, the half-life T1/2 was 0.80 hours. After a single intravenous administration to rabbits of 24, 30 and 42 mg/kg, the maximum concentration in the systemic bloodstream is reached 5 minutes after administration and averages 133.95 ± 27.04, 145.86 ± 40.90 and 226.13 ± 41.27 µg/ml, respectively, the half-life ranged from 0.22 to 0.26 h, the half-life from 3.52 to 3.96 hours.Conclusion. The pharmacokinetic parameters of α(1,2)-L-rhamno-α(1,4)-D-galactopyranosyluronane Acorus calamus L. were evaluated in animals based on the use of the method of quantitative determination of galacturonic acid by HPLC-MS/MS.

Determination of sodium and potassium in Dan Hong injection by atomic absorption spectrometry

To establish and validate the determination method of the content of sodium ion and potassium ion in Dan Hong injection by atomic absorption spectrometry (AAS). [Methods] Microwave digestion system was applied to deteriorate samples, and the content of sodium ion and potassium ion was determined by AAS. [Results] The calibration curve of sodium was liner (r=0.9998) in the range from 0.1to0.6mg/L. The average recovery was 101.1% with RSD 1.8%. The limit of detection was 5.3μg/L. The calibration curve of potassium was liner (r=0.9998) in the range from 0.1 to 0.8mg/L. The average recovery was 99.8%with RSD 2.3%. The limit of detection was 7.7μg/L. The determination results of 10 batches Dan Hong injection sample showed that the content of sodium ion was 562.3 to 734.7 mg/L and potassium ion was 206.9 to 314.4mg/L. [Conclusion] The method is simple and accurate and can be used for determination of the contents of sodiumion and potassium ion in Dan Hong injection. The accurate quantitative determination method can be promoted to quality control of Dan Hong injection

Molecularly Imprinted Polypyrrole-Modified Screen-Printed Electrode for Dopamine Determination.

This paper introduces a quantitative method for dopamine determination. The method is based on a molecularly imprinted polypyrrole (e-MIP)-modified screen-printed electrode, with differential pulse voltammetry (DPV) as the chosen measurement technique. The dopamine molecules are efficiently entrapped in the polymeric film, creating recognition cavities. A comparison with bare and non-imprinted polypyrrole-modified electrodes clearly demonstrates the superior sensitivity, selectivity, and reproducibility of the e-MIP-based one; indeed, a sensitivity of 0.078 µA µM-1, a detection limit (LOD) of 0.8 µM, a linear range between 0.8 and 45 µM and a dynamic range of up to 350 µM are achieved. The method was successfully tested on fortified synthetic and human urine samples to underline its applicability as a screening method for biomedical tests.

Development of new methods for Determination of Sulpha Drugs with N-Chlorosacchrin Reagent

Sulpha drugs (sulphanilamide and their derivatives) are widely used as antibacterial drugs. An accurate and rapid method for quantitative determination of sulpha drugs and sulphanilamide would be of great importance. In literature several methods have been discussed for determination of sulphanilamide. The previous methods upon the evaluation of their nitrogen and sulphur contents while the latter were based upon the reaction of functional groups present in them.