A simple and rapid spectrophotometric method for the determination of trans-chalcone in raw-materialand topical formulation / Método espectrofotométrico simples e rápido paradeterminação de trans-chalcona em matéria-primae em formulação tópica

Trans-chalcone (TC) is a flavonoid precursor characterized by a wide spectrum of action, with anti-inflammatory and antioxidant effects. However, no validated methods are available in official compendia for the analysis of this substance. Thus, the aim of this work was to develop and validate a simple, fast, and reproducible spectrophotometric method for the analysis of TC in raw material, and in topical pharmaceutical formulation containing TC. The established conditions were: methanol as extracting solvent, and detection wavelength of 309 nm by UV spectrophotometer. All tests followed the rules of Resolution RDC 166, 2017. The proposed method was selective. Linearity was demonstrated in the concentration range of 1 to 8 µg/mL (r = 0.999). Repeatability and intermediate precision were confirmed by low relative standard deviation values of 1.53% and 2.70% for TC, and of 1.73% and 2.91% for formulation containing TC. Accuracy, evaluated through recovery test, was adequate, with minimum of 98.24% and maximum of 100.23% of recovery. It was observed that the small deliberate modifications done did not interfere with the results, demonstrating the method is robust. The results showed that the method was considered suitable for the intended purpose, inexpensive, easy to apply, selective, linear, precise, accurate, and robust for the determination TC, and pharmaceutical formulation containing TC. Thus, the method developed satisfies the need for an analytical method for the determination of TC, and topical formulation containing TC, being effective, innovative and able to aid in the development of the pharmaceutical field.

Trans-chalcona (TC) é um precursor de flavonoides caracterizado por um amplo espectro de ação, como efeitos anti-inflamatórios e antioxidantes. No entanto, não há método validado disponível em compêndio oficial para análise deste composto. Então, o objetivo deste trabalho foi desenvolver e validar um método espectrofotométrico, simples, rápido e reprodutível para análise de TC em matéria-prima, e em formulação farmacêutica tópica contendo TC. As condições estabelecidas foram: metanol como o solvente de extração, e detecção no comprimento de onda de 309 nm por espectrofotometria no UV. Todos os testes seguiram as normas da RDC 166, 2017. O método proposto foi seletivo. A linearidade foi demonstrada na faixa de concentração de 1 a 8 µg/mL (r = 0.999). A repetibilidade e a precisão intermediária foram confirmadas pelos valores baixos de desvio padrão relativo de 1,53% e 2,70% para a TC, e de 1,73% e 2,91% para a formulação contendo TC. A exatidão, avaliada por meio de testes de recuperação, foi adequada, com mínimo de 98,24% e máximo de 100,04% de recuperação. Observou-se que pequenas modificações no método não interferiram nos resultados, demonstrando que o método é robusto. Os resultados demonstraram que o método foi adequado para a finalidade pretendida, barato, de fácil aplicação, seletivo, linear, preciso, exato e robusto para determinação de TC, e de formulação contendo TC. Então o método desenvolvido satisfaz as necessidades de um método analítico para determinação de TC, e de formulação tópica contendo TC, e é eficaz, inovador e pode contribuir para o desenvolvimento da área farmacêutica.

Determination of levofloxacin, norfloxacin, and moxifloxacin in pharmaceutical dosage form or individually using derivative UV spectrophotometry.

PURPOSE: In this study, first, second, third, and fourth-order derivative spectrophotometric methods utilizing the peak-zero (P-O) and peak-peak (P-P) techniques of measurement were developed for the determination of levofloxacin, norfloxacin, and moxifloxacin. These methods were applied to their combined pharmaceutical dosage form or individually for levofloxacin, norfloxacin, and moxifloxacin. METHODS: Linearity was established in the concentration range of 2-20 µg/mL. The procedures are simple, quick, and precise. The developed methods are sensitive, accurate, and cost-effective, demonstrating excellent correlation coefficients (R2 = 0.9998) and mean recovery values ranging from 99.20% to 100.08%, indicating a high level of precision. RESULTS: The developed approach was effectively employed to determine the levofloxacin, norfloxacin, and moxifloxacin content in commercially available pharmaceutical dosages. CONCLUSIONS: Statistical analysis and recovery tests confirmed the method's linearity and accuracy. The results suggest that this method can be utilized for routine analysis in both bulk and commercial formulations. The simplicity, accuracy, and cost-effectiveness of the developed methods make them valuable for pharmaceutical analysis.

Spider chart, greenness and whiteness assessment of experimentally designed multivariate models for simultaneous determination of three drugs used as a combinatory antibiotic regimen in critical care units: Comparative study.

In this study, five earth-friendly spectrophotometric methods using multivariate techniques were developed to analyze levofloxacin, linezolid, and meropenem, which are utilized in critical care units as combination therapies. These techniques were used to determine the mentioned medications in laboratory-prepared mixtures, pharmaceutical products and spiked human plasma that had not been separated before handling. These methods were named classical least squares (CLS), principal component regression (PCR), partial least squares (PLS), genetic algorithm partial least squares (GA-PLS), and artificial neural network (ANN). The methods used a five-level, three-factor experimental design to make different concentrations of the antibiotics mentioned (based on how much of them are found in the plasma of critical care patients and their linearity ranges). The approaches used for levofloxacin, linezolid, and meropenem were in the ranges of 3-15, 8-20, and 5-25 µg/mL, respectively. Several analytical tools were used to test the proposed methods' performance. These included the root mean square error of prediction, the root mean square error of cross-validation, percentage recoveries, standard deviations, and correlation coefficients. The outcome was highly satisfactory. The study found that the root mean square errors of prediction for levofloxacin were 0.090, 0.079, 0.065, 0.027, and 0.001 for the CLS, PCR, PLS, GA-PLS, and ANN models, respectively. The corresponding values for linezolid were 0.127, 0.122, 0.108, 0.05, and 0.114, respectively. For meropenem, the values were 0.230, 0.222, 0.179, 0.097, and 0.099 for the same models, respectively. These results indicate that the developed models were highly accurate and precise. This study compared the efficiency of artificial neural networks and classical chemometric models in enhancing spectral data selectivity for quickly identifying three antimicrobials. The results from these five models were subjected to statistical analysis and compared with each other and with the previously published ones. Finally, the whiteness of the methods was assessed by the recently published white analytical chemistry (WAC) RGB 12, and the greenness of the proposed methods was assessed using AGREE, GAPI, NEMI, Raynie and Driver, and eco-scale, which showed that the suggested approaches had the least negative environmental impact. Furthermore, to demonstrate solvent sustainability, a greenness index using a spider chart methodology was employed.

UV-spectrophotometry dataset of technical lignin in solution after aging and looped measurements.

This article provides UV-spectrophotometry data of technical lignin samples in solutions, which were acquired after ambient aging for up to 110 days or looped measurements on fresh solutions. UV-spectrophotometry of lignin is a useful technique, as it can a) quantify the concentration and purity of lignin in a given sample, b) determine the abundance of phenolic hydroxyl groups, and c) yield qualitative information about chemical modification of the lignin macromolecule. In addition, the technique is rapid and easy to use. Still, solutions of lignin are known to be unstable; in particular at high pH or in presence of UV-light. The data in this article may hence serve as guide in the experimental conduct and design, as it shows the reproducibility of UV-spectrophotometry measurements of lignin. Stock solutions of technical lignin were made according to previously published procedure [1]. The solutions in dimethyl sulfoxide (DMSO) were aged in 100 mL volumetric flasks with glass stopper, taking periodic samples for measurements in a Shimadzu UV-1900 UV-vis spectrophotometer. The instrument recorded the spectrum from 500 to 200 nm at 1.0 nm intervals and medium speed, using quartz cuvettes with a pathlength of 1 cm. In addition, looped measurements were conducted on fresh solutions, where the instrument repeated the spectral range of 500 to 200 nm for in total sixteen times. The latter examined solutions of technical lignin in DMSO solvent as well as in 0.2 N NaOH in water.

A Novel Spectrophotometric Method Development for Quantification of Desidustat in Bulk and Pharmaceutical Dosage Form.

BACKGROUND: Desidustat (DES) belongs to a new category of drugs, i.e., Hypoxia-Inducible Factor (HIF) propyl hydroxylase inhibitor, and is used for the treatment of anemia in chronic kidney disease. However, no method has yet been reported in the literature for the estimation of drugs. OBJECTIVE: The objective of the study is to develop a simple, precise, and accurate method for determining DES in bulk and pharmaceutical dose form. METHODS: The physicochemical characterization of the drug was performed using methanol as a solvent to establish the identity. According to ICH Q2 criteria, validation characteristics, such as specificity, linearity, accuracy, precision, limits of detection and quantification, and robustness, were assessed. RESULTS: Maximum absorbance wavelength was observed at 229 nm. The sample solution remained stable for up to 12 hours. The linear response from 2 to 12 µg/ml of DES was y = 0.1087x + 0.0962 and r2 = 0.9963. The accuracy was between 100 to 101%. Precision was recorded under three criteria: repeatability, intraday and interday, for which results fell within the acceptable ranges (<2%). The limit of detection (LOD) and limit of quantification (LOQ) of the technique were 0.434 µg/ml and 1.316 µg/ml, respectively. CONCLUSION: The proposed method was found to be beneficial for drug monitoring and the ongoing analysis of DES in research and quality control laboratories. This approach is simple, precise, rapid, economical, and sensitive.

Spectrophotometric quantification of paracetamol and tramadol hydrochloride by chemometric calibration methods.

The results of UV spectrophotometric analysis were analysed using partial least squares (PLS) and principal component regression (PCR) techniques to allow simultaneous evaluation of tramadol hydrochloride (TRA) and p-acetaminophen (PAR) in tablets. A calibration set of 16 mixtures, each containing PAR and TRA in various amounts, was created using a 24-full fractional design. The absorbance data set for the calibration set were obtained between 215-280 nm (Δλ = 0.1 nm). Subsequently, the concentration and absorbance sets were used to generate PCR and PLS calibrations. The ratio spectra- first derivative method was devised as a solution to the same problem to compare the outcomes of the chemometric methods used for the same experiment. After the proposed methods were shown to be accurate in the testing of validation samples, they were used in analysing commercial tablet samples. The analytical results showed that PCR and PLS methods can be used as alternative methods to high-performance liquid chromatography (HPLC). Correlation coefficients were determined for the working concentration range of 6-36 g.mL-1 for PAR and 4-22 g.mL-1 for TRA. The limits of detection and quantification were calculated as 0.9104 µg.mL-1 and 3.0347 µg.mL-1, respectively. The test results of the chemometric analyses and ratio spectra- first derivative method of the commercial tablet form are in agreement with the results of the one-way ANOVA with a confidence interval of 95%. This study shows that the ratio spectra- first derivative method, PCR and PLS models based on spectrophotometric measurements are very useful and straightforward techniques for the quantitative resolution of a two-component pharmaceutical preparation, requiring little sample preparation and little time for analysis.

In situ temperature-compensated ultraviolet spectrophotometry to estimate nitrate and chloride concentrations in estuarine seawater with different salinity and composition.

Various methods have been proposed for in situ measurement of nitrate concentrations from the ultraviolet (UV) absorbance spectrum of seawater with stable salinity and constituents. However, salinity and temperature affect the UV absorption spectrum of seawater. In sea areas with large variability in salinity and water temperature, accurate nitrate ion concentration measurements remain challenging. We performed in situ measurements of nitrate, chloride, and bromide in estuarine seawater with different salinity compositions and applied water temperature compensation. First, the impact of water temperature on the UV absorbance of chloride, bromide, and nitrate was experimentally investigated and represented in a mathematical model. Next, chloride, bromide, and nitrate concentrations were estimated by suppressing the impact of residual components from the UV absorbance spectra of seawater using principal component regression (PCR). Hence, the chloride, bromide, and nitrate concentrations were determined by measuring the UV absorbance spectrum of seawater alone, without measuring water temperature and electrical conductivity. The proposed method was more accurate (±1.39 µM below 100 µM and ±0.90 µM below 20 µM) than the conventional method (±2.35 µM below 100 µM and ±1.88 µM below 20 µM) and PCR without water temperature compensation (±3.67 µM). In a field study, an in situ UV spectrophotometer with water temperature compensation was used to measure depth profiles of nitrate concentrations in estuarine seawater. We successfully measured the depth profiles of low chloride and high nitrate concentrations in the surface layer as well as high chloride and low nitrate concentrations in the lower layer. The proposed method enables in situ measurements of nitrate concentrations in waters with either stable or highly variable salinity and composition. Unlike conventional chemical analysis, our method can describe detailed spatiotemporal variations in nitrate concentrations.

Sustainable Stability-Indicating spectra manipulations for the concurrent quantification of a novel Anti-COVID-19 drug and its active Metabolite: Green profile assessment.

Millions of individuals have lost their lives and changed their routines as a direct consequence of exposure to the coronavirus (Covid-19). Molnupiravir (MOL) is an orally bioavailable tiny molecule antiviral prodrug that is effective for curing the coronavirus that produces serious acute respiratory disorder (SARS-CoV-2). Fully green-assessed stability-indicating simple spectrophotometric methods have been developed and fully validated as per ICH criteria. The potential impact of degradation products of drug components on the safety and efficacy of a medication's shelf life is likely to be negligible. The field of pharmaceutical analysis necessitates various stability testing under different conditions. The conduct of such inquiries affords the prospect of predicting the most probable routes of degradation and ascertaining the inherent stability characteristics of the active drugs. Consequently, a surge in demand arose for the creation of an analytical methodology that could consistently measure the degradation products and/or impurities that may be present in pharmaceuticals. Herein, five smart and simple spectrophotometric data manipulation techniques have been produced for the concurrent estimation of MOL and its active metabolite as its possible acid degradation product namely; N-hydroxycytidine (NHC). Structure confirmation of NHC build-up through IR, MS and NMR analyses. All current techniques verified linearity ranging from 10 to 150 µg/ml and 10-60 µg/ml for MOL and NHC, respectively. The limit of quantitation (LOQ) values were in the range of 4.21-9.59 µg/ml, while the limit of detection (LOD) values were ranging from 1.38 - 3.16 µg/ml. The current methods were evaluated in terms of greenness by four assessing methods and confirmed to be green. The significant novelty of these methods depends on their being the first environmentally soundness stability-indicating spectrophotometric approaches for the concurrent estimation of MOL and its active metabolite, NHC. Also, the preparation of purified NHC delivers significant cost savings, instead of purchasing an expensive ingredient. These smart methods were utilized for analyzing the pharmaceutical dosage form which may be of great benefit to the pharmaceutical market.

Application of TGA/c-DTA for Distinguishing between Two Forms of Naproxen in Pharmaceutical Preparations.

Naproxen is one of the most used non-steroidal anti-inflammatory drugs (NSAIDs). It is used to treat pain of various origins, inflammation and fever. Pharmaceutical preparations containing naproxen are available with prescription and over-the-counter (OTC). Naproxen in pharmaceutical preparations is used in the form of acid and sodium salt. From the point of view of pharmaceutical analysis, it is crucial to distinguish between these two forms of drugs. There are many costly and laborious methods to do this. Therefore, new, faster, cheaper and, at the same time, simple-to-perform identification methods are sought. In the conducted studies, thermal methods such as thermogravimetry (TGA) supported by calculated differential thermal analysis (c-DTA) were proposed to identify the type of naproxen in commercially available pharmaceutical preparations. In addition, the thermal methods used were compared with pharmacopoeial methods for the identification of compounds, such as high-performance liquid chromatography (HPLC), Fourier-transform infrared spectroscopy (FTIR), UV-Vis spectrophotometry, and a simple colorimetric analyses. In addition, using nabumetone, a close structural analog of naproxen, the specificity of the TGA and c-DTA methods was assessed. Studies have shown that the thermal analyses used are effective and selective in distinguishing the form of naproxen in pharmaceutical preparations. This indicates the potential possibility of using TGA supported by c-DTA as an alternative method.

[Study of the possibility of emtricitabine extraction from biomaterial]. / Izuchenie vozmozhnosti ekstraktsii emtritsitabina iz biologicheskogo materiala.

THE AIM OF THE STUDY: Is to investigate the opportunity of emtricitabine extraction from biomaterial and to develop method of emtricitabine chemicotoxicological analysis while acute poisoning. This research represents the methods of emtricitabine isolation from urine, plasma and liver samples (rats of Wistar line weighing 180 g) using liquid-liquid extraction. The identification and quantitation methods of emtricitabine in extractions by thin-layer chromatography, ultraviolet spectrophotometry and high-performance liquid chromatography methods were described. The emtricitabine was found extracted from urine with a therapeutic dose of 6.65±2.21 µg/ml and a toxic dose 35.81±1.05 µg/ml, from plasma with a therapeutic dose of 2.91±0.19 µg/ml and a toxic dose of 16.88±0.90 µg/ml.

2,4,6-Tri(2'-pyridyl)-1,3,5-triazine for determination of iron(II), Iron(III), and total iron contents on human palms.

When iron-based tools, such as knives or guns, are held, traces of iron can transfer to the skin. However, no previous studies have been published regarding the effect of the elapsed contact time on the transfer of iron species with different valences to the palm. Compared with 3-(2-pyridyl)-5,6-diphenyl-1,2,4-triazine (PDT), 2,4,6-tri(2'-pyridyl)-1,3,5-triazine (TPTZ) was found to exhibit a higher sensitivity to iron(II) spectrophotometrically. This work employed 2,4,6-tri(2'-pyridyl)-1,3,5-triazine (TPTZ) and UV spectrophotometry to determine the amounts of iron(II), iron(III), and total iron transferred to human palms from iron tools. It was found that the palmar moisture level was an important factor in determining the amounts of total iron, including iron(II), transferred to the palm. For identical contact times, the amounts of total iron transferred to the palm was proportional to the palmar moisture, and the difference between the maximum and minimum amounts was 12 µg per hand. However, the amounts of iron(II) transferred to the palm gradually decreased over time for low palmar moisture levels, but steadily increased over time for high palmar moisture levels. Additionally, for average levels of palm moisture, the amounts of iron(II) and iron(III) transferred to the palm gradually decreased and increased, respectively, with longer contact times. Notably, this research could serve as a theoretical basis and guide for the detection of trace iron species with different valences on human palms for criminal investigations.

Novel ICP-OES-Based Method for the Reliable Determination of the Total Content of 15 Elements in Yerba Mate Drinks along with the Determination of Caffeine and the In Vitro Bioaccessibility of the Compounds.

A fully validated inductively coupled plasma optical emission spectrometry (ICP-OES)-based method combined with a simplified sample preparation procedure for the determination of up to 15 elements (Al, Ba, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, Sr, and Zn) in caffeinated yerba mate (YM) drinks was proposed. Various "green" treatments (acidification or dilution with a HNO3 solution and direct analysis of untreated YM with or without sonication (US)) that could replace the traditional total sample decomposition before spectrometric measurements were tested and compared. The key selection parameter was the analytical performance of the ICP-OES method obtained with each sample preparation procedure in terms of the precision and the trueness of results and limits of detection (LODs) of elements. It was found that the acidification of YMs with concentrated HNO3 to 5%, supported by US (10 min, room temperature (RT)), provided the best results, i.e., LODs at 0.11-8.5 ng g-1, precision below 5%, and trueness better than 5% (97.0%-105% as recoveries). Eleven YM drinks, commercially available on the Polish market, were analyzed with the proposed method. In addition to the mineral content, the concentration of caffeine in all analyzed YMs was determined and compared. Finally, the studies were completed by determining the bioaccessible fraction of selected elements and caffeine in YMs using in vitro gastrointestinal digestion (GID) in order to evaluate the nutritional value/risk assessment of these drinks. Accordingly, the bioaccessibility of nutritious elements (Ca, Fe, Mg, Mn, Zn) and caffeine was within 40%-59%. Except for Mn, it was established that by drinking daily 1 L of YMs, the recommended dietary intakes (RDIs) of the aforementioned essential elements were covered to a low degree (<4.5%). Hence, they are not an important source of these elements in the human diet. On the other hand, potentially toxic elements (Al, Ba, Sr) were found in a relatively inert form. Opposite to minerals, YMs can supply human organisms with quite high amounts of natural caffeine in bioaccessible form (31-70 mg per serving).

Quantitative Analysis of Camellia oleifera Seed Saponins and Aqueous Two-Phase Extraction and Separation.

At present, the technology used for the extraction and purification of Camellia oleifera saponins generally has the problems of high cost and low purity, and the quantitative detection of Camellia oleifera saponins also has the problems of low sensitivity and easy interference from impurities. To solve these problems, this paper aimed to use liquid chromatography for the quantitative detection of Camellia oleifera saponins, and to adjust and optimize the related conditions. In our study, the average recovery of Camellia oleifera saponins obtained was 100.42%. The RSD of precision test was 0.41%. The RSD of the repeatability test was 0.22%. The detection limit of the liquid chromatography was 0.06 mg/L, and the quantification limit was 0.2 mg/L. In order to improve the yield and purity, the Camellia oleifera saponins were extracted from Camellia oleifera Abel. seed meal by methanol extraction. Then, the extracted Camellia oleifera saponins were extracted with an ammonium sulfate/propanol aqueous two-phase system. We optimized the purification process of formaldehyde extraction and aqueous two-phase extraction. Under the optimal purification process, the purity of Camellia oleifera saponins extracted by methanol was 36.15%, and the yield was 25.24%. The purity of Camellia oleifera saponins obtained by aqueous two-phase extraction was 83.72%. Thus, this study can provide a reference standard for rapid and efficient detection and analysis of Camellia oleifera saponins for industrial extraction and purification.

Application of response surface modeling optimization in UV spectrophotometric determination of 4-aminobenzoic acid by molecularly imprinted polypyrrole.

Selective determination of 4-aminobenzoic acid (ABA) in pharmaceutical and human serum samples was performed by molecularly imprinted polypyrrole and ultraviolet (UV) spectrophotometry, based on precipitation polymerization. The molecularly imprinted polymer (MIP) was prepared using pyrrole functional monomer and ABA template molecules. The significant factors controlling the performance of the synthesized ABAMIP sorbent were screened and optimized using Plackett- Burman design (PBD) and central composite design (CCD), respectively. The model was used to obtain the optimal values of the significant response factors. The predicted MIP to NIP response ratio demonstrated an approximate deviation of 5 % from the experimental value. Under the obtained optimal conditions, the calibration curve showed a linear range of 0.05-2 mM with a correlation coefficient (r2) of 0.9920 and a limit of detection (LOD) of 0.0310 mM. The method recovery for the analyte was obtained 88.10-100.5 in the investigated real samples. The proposed ABA-MIP sorbent showed an acceptable selectivity in the presence of some pharmaceuticals.

Application of Thermal Analysis to Evaluate Pharmaceutical Preparations Containing Theophylline.

Confirmation of the composition of pharmaceutical products is an essential pharmaceutical issue. The purity and identity of active pharmaceutical ingredients (API) in the finished drug impact the effect of correct and safe pharmacotherapy. The currently frequently used advanced analytical methods are laborious and time-consuming. On the other hand, less advanced techniques such as UV-Vis spectrophotometry are less specific. In the presented study, thermogravimetry analysis (TGA)-supported by calculated differential thermal analysis (c-DTA)-was proposed to evaluate the composition of pharmaceutical preparations containing theophylline and aminophylline. Due to its advantages, the TGA method can be an alternative used for screening assessment of the composition of pharmaceutical preparations. The obtained results show that TGA supported by c-DTA is a suitable screening method for assessing the composition of pharmaceutical preparations containing theophylline and aminophylline. Both thermal techniques complement each other to obtain reliable results. In contrast to the pharmacopoeial UV-Vis method, TGA allows for unambiguous identification and distinction of one- and two-component pharmaceutical preparations. Moreover, thanks to TGA and c-DTA, it was possible to identify the excipient used in the formulation of a commercial drug and to detect considerable amounts of lactose in the experimentally prepared counterfeit formulation. The research herein indicates the multifaceted application and usefulness of TGA and c-DTA in pharmacology.

A green spectrophotometric method for the simultaneous determination of nasal binary mixture used in respiratory diseases: Applying isosbestic point and chemometric approaches as a resolving tool, greenness evaluation.

Nasal drug combination is a very useful therapy for elevating the symptoms of various respiratory diseases as seasonal allergic rhinitis and infectious respiratory illness as pandemic COVID-19. One of best combination is Fluticasone propionate (FLU) and Azelastine (AZE). In this study, different UV spectrophotometric and chemometric methods have been applied for quantitative analysis of FLU and AZE without previous separation in their pure form, laboratory prepared mixture and pharmaceutical dosage form. Absorbance subtraction (AS) and Amplitude modulation (AM) spectrophotometric methods have been applied for the simultaneous determination of the cited drugs. Besides, three well-known chemometric techniques; namely, classical least squares (CLS), partial least square (PLS), and principal component regression (PCR) have been applied for the simultaneous analysis of both drugs by using spectrophotometric data. To be friendly to the environment, the greenness of the proposed methods was taken into consideration and evaluation of the analytical methods' greenness was done using two green analytical chemistry metrics known as, Analytical Greenness Calculator and an eco-scale scoring method. They indicated that the methods were environmentally friendly in relation to numerous approaches like instrument, reagents, and safety of waste. Analyzing laboratory prepared mixtures including different quantities of FLU and AZE, as well as their marketed dose form, was used to assess the selectivity of the applied methods. The validity of the developed methods was investigated by applying the standard addition technique. The resulting data were statistically compared to those obtained by the official or reported HPLC methods for FLU and AZE, which revealed no significant difference in accuracy and precision at p = 0.05.

Spectrophotometric Methods for Determination of Dopamine Hydrochloride in Bulk and in Injectable Forms.

Two highly simple, economical, accurate and sensitive spectrophotometric methods for determination of dopamine hydrochloride (DAH) in either pure form and pharmaceutical formulations are described. The first method is based on determination of (DAH) spectrophotometrically at maximum absorbance 280 nm (method A). The second one is based on reduction of alkaline KMnO4 by (DAH) leading to the formation of green manganate species which are measured at 610 nm (method B). Under optimized conditions, the calibration graphs were linear in the range of 3.793 - 45.513, 0.190 - 4.362 µg.mL-1 of (DAH) for methods A and B respectively. The developed methods were successfully applied for the determination of dopamine hydrochloride in pharmaceutical samples.

Label-Free Uric Acid Estimation of Spot Urine Using Portable Device Based on UV Spectrophotometry.

The maintenance of uric acid levels is crucial for the human body. In this study, the feasibility of using portable ultraviolet (UV) spectrophotometry to measure the uric acid of spot urine without the need to add reagents has been demonstrated for the first time. UV spectral analysis has been used to inspect the uric acid concentration in urine. It is found that the absorption spectrum of urine has a high correlation with the concentration of uric acid at a wavelength of around 290-300 nm. Uric acid levels measured with a spectral analyzer compared to uric acid concentrations measured with a traditional biochemical analysis showed good agreement. The portable prototype is label-free and capable of displaying the inspection result of each measurement within 10 s. In the long run, this device can assist people in checking uric acid levels of spot urine with higher frequency and can adjust diet or medication in real time for more efficient health management.

Application of Fourier transform-based algorithms to resolve spectral overlapping for UV spectrophotometric co-assay of spiramycin and metronidazole in tablets.

Fourier transform-based algorithms were investigated to resolve UV spectral overlapping of spiramycin and metronidazole in binary mixtures. UV spectra and ratio spectra were both subjected to fast Fourier transform-based first-order differentiation and discrete Fourier transform {i.e. using trigonometric functions such as sin xi - sin (xi + 450), cos xi + cos (xi + 450), sin 2xi - sin 2(xi + 450), cos 2xi + cos 2(xi + 450), sin xi - sin (xi + 600), cos xi + cos (xi + 600)} that followed by 3 passes of 17-point triangular smooth. Such signal transforms generated linear calibration graphs for either drug in the concentration range of 6.25 - 25 mg/L with R2 > 0.990. In comparison with the RP-HPLC reference method, the developed UV spectrophotometric methods had no significant difference in terms of accuracy and precision (p > 0.05) when quantifying spiramycin and metronidazole in their coated tablets. They are suggested as analytical quality control methods for their being environmentally friendly, technically simple, quick and economic.

Influence of Storage Conditions on the Stability of Gum Arabic and Tragacanth.

Storage conditions should be chosen so that they do not affect the action and stability of the active pharmaceutical substance (API), and excipients used in pharmacy. UV irradiation, increased temperature, and relative humidity can decompose storage substances by photolysis, thermolysis, and hydrolysis process, respectively. The effect of physical factors may be the decomposition of pharmaceutical substances or their inappropriate action, including pharmacological effects. Polymers of natural origin are increasingly used in the pharmaceutical industry. With this in mind, we evaluated the effect of storage conditions on the stability of gum arabic (GA) and tragacanth (GT). The influence of higher temperature, UV irradiation, and relative humidity on GA and GT was tested. Thermogravimetry (TG, c-DTA), colorimetric analysis, UV-Vis spectrophotometry, and optical microscopy were used as research methods. The TGA and c-DTA examination indicated that decomposition of GA starts at a higher temperature compared to GT. This indicate that gum arabic is more resistant to higher temperatures compared to tragacanth. However, the conducted analysis showed that gum arabic is more sensitive to the tested storage conditions. Among the tested physical conditions, both polymers were most sensitive to conditions of increased relative humidity in the environment.