Graded-index Research Articles

Modeling of Graded-Index Raman Fiber Amplifiers with Pump Depletion

Graded-index (GRIN) fibers are often used for making high-power Raman amplifiers. We employ numerical and semi-analytical techniques to model such amplifiers and include not only the signal’s amplification and pump’s depletion but also various nonlinear interactions between the signal and pump beams and the self-imaging effects within the GRIN fiber. We solve the coupled nonlinear equations of the pump and signal beams numerically. We also employ the variational technique to obtain simpler equations that can be solved much faster than the full model and still agree with it in most cases of practical interest. We discuss the evolution dynamics of the pump and signal beams, along with a novel process of energy exchange between the two beams because of self-imaging inside the GRIN fiber. The dependence of the signal’s amplification on various input parameters is analyzed in detail to optimize the device’s design and enhance the signal’s amplification for a given pump power and fiber length. Based on our analysis, we establish a resonant condition for the maximum energy transfer from the pump to the signal being amplified. We further show that the periodic self-imaging of the pump and signal beams inside a GRIN fiber leads to higher output powers compared to step-index fibers.

Copper Efficacy Field Trials for Control of Pseudomonas syringae pv. tabaci in Nicotiana tabacum Production

Since 2015, Pseudomonas syringae pv. tabaci tox− has become the most significant foliar disease in the dark tobacco growing regions of Kentucky and Tennessee. Streptomycin sulfate, the main control mechanism that growers utilize to combat this bacterial disease, has evidence of resistance at 200 ppm. Field trials were established to evaluate the efficacy of copper-based products for control of angular leaf spot compared with streptomycin sulfate. Field trials were conducted from 2020 to 2022 at the West Farm of Murray State University in Murray, KY, to evaluate the efficacy of streptomycin sulfate, cuprous oxide, copper sulfate pentahydrate, and copper octanoate. In all years, the moderately susceptible dark tobacco variety KT D8LC was planted and inoculated with a streptomycin-sensitive isolate of P. syringae pv. tabaci. Tobacco treated with five applications of copper octanoate had a lower area under the disease progress curve (AUDPC) than tobacco treated with streptomycin sulfate in 2020 and 2022. Data analysis showed that in one of the three years, tobacco treated with cuprous oxide had a higher yield compared with tobacco treated with streptomycin sulfate. Tobacco treated with cuprous oxide had a higher quality grade index compared with streptomycin sulfate in 2020. Although no treatment eliminated this bacterial disease, copper products, particularly cuprous oxide and copper octanoate, are suitable alternatives to streptomycin sulfate for management of angular leaf spot.

Sustainability assessment in food analysis: the application of Green Analytical Chemistry tools to phthalate residue analysis in edible oils

Edible oils are essential in daily diet due to their high contribution of fatty acids, fat-soluble vitamins, and triglycerides. During the processes of growing, processing, storage, transport, or packaging, they can be contaminated by ubiquitous phthalate esters, considered endocrine disruptors. Thus, analytical methodologies to allow tight control of their presence are mandatory. Several sample treatments have been considered in this study: microwave-assisted extraction (MAE), liquid-liquid extraction (LLE), dispersive solid phase extraction (DSPE), magnetic SPE (MSPE), solid phase microextraction (SPME), Surface-enhanced Raman spectroscopy (SERS) or its combinations. However, the selection of an analytical procedure is usually performed from an Analytical Chemistry perspective, without considering factors such as the sustainability of the selected methodology and/or its impact on the environment. In this sense, the Green Analytical Chemistry strategy can play an important role. To demonstrate this fact, six different analytical procedures have been evaluated in terms of sustainability by using several greenness evaluation tools. Procedures from MAE-gel permeation chromatography (GPC)-SPE till SERS, showing adequate analytical characteristics, have been selected. The application of Analytical GREEnness calculator (AGREE), AGREE preparation (AGREE prep), and blue applicability grade index (BAGI) tools showed that MAE-GPC-SPE was the less green analytical procedure while SERS was the greener one. The BAGI evaluation showed that headspace (HS) and SERS were the most applicable procedures.

Optimization of Filling Material Ratio in Yellow Phosphorus Slag Mine

Yellow phosphorus slag has been considered as a potential cement substitute for mine filling material due to its cementing activity; however, its slow setting and low early strength have limited broader use. This study investigates the grading, compactness, and strength of yellow phosphorus slag combined with tailing sand. Using yellow phosphorus slag as an aggregate, cement as a binder, and mixing tailing sand in different ratios, this study evaluates its feasibility as a coarse aggregate in mine backfill. The key findings are as follows. (1) The grading index of tailing sand was 0.5, aligning with Fuller grading, but it required mixing with coarse aggregates to enhance strength and reduce cement consumption. Yellow phosphorus slag, with a grading index of 0.97, does not match Fuller’s curve and thus benefits from mixing with tailing sand. (2) For mixtures of waste rock and tailings, the 5:5 ratio aligned closely with Fuller’s theory, showing optimal packing density and strength. Mixtures of yellow phosphorus slag and tailings at ratios of 3:7, 4:6, and 5:5 had R2 values of 0.73, 0.80, and 0.85, respectively, confirming reliable fit. The 5:5 mixture provided the best packing density and strength. (3) A new strength prediction model, accounting for aggregate, cement, and water effects, suggests that a 5:5 ratio with a 71% mass concentration and 1/7 ash–sand ratio meets industrial strength requirements. FLAC3D simulations indicated that cemented backfill reduces stress concentrations caused by excavation and supports stability during mining while also absorbing energy through compaction, creating favorable conditions for safe mining operations.

Eco-friendly RP-HPLC approach for simultaneously estimating the promising combination of pentoxifylline and simvastatin in therapeutic potential for breast cancer: Appraisal of greenness, whiteness, and Box–Behnken design

Abstract Breast cancer affects millions of women worldwide. This study explores the potential of combining pentoxifylline (PTX) and simvastatin (SIM) as a treatment for breast cancer. We aimed to develop six sustainability tools using green and white metrics to evaluate the environmental impact of reversed-phase high-performance liquid chromatography (RP-HPLC) methods for analyzing and separating PTX and SIM in their pure forms. The tools include analytical GREEnness, green analytical procedure index, Complexgreen analytical procedure index, analytical greenness metric for sample preparation, blue applicability grade index, and the RGB 12 algorithm. For the separation, we used a Novapack C8 column (15 × 0.46 cm, 5 µm) at 25°C. The injection volume was 5.0 µL, the wavelength was set to 210 nm, and the total runtime was 5 min. We identified optimal chromatographic conditions efficiently using the Box–Behnken design with minimal trials. We investigated the effects of three factors on retention time and resolution: acetonitrile ratio, pH, and flow rate. We used overlay plots with a 60:40 ratio (v/v) of acetonitrile and bi-distilled water to forecast the most effective mobile phase. The calibration curves for PTX and SIM showed a correlation value of over 0.999 within the range of 5–60 µg·mL−1. The recovery rates ranged from 99.9% to 100.2%, indicating high accuracy. Our RP-HPLC technique proves to be reliable and efficient for the simultaneous estimation of multiple anticancer drugs. We evaluated the environmental sustainability of this approach using green and white metrics, and the recommended method has been thoroughly validated according to International Council for Harmonisation guidelines, making it highly reliable for analyzing new formulations.

Construction of Freezing Injury Grade Index for Nanfeng Tangerine Plants Based on Physiological and Biochemical Parameters.

Low-temperature freezing stress constitutes the most significant meteorological disaster during the overwintering period in the Nanfeng Tangerine (NT) production area, severely impacting the normal growth and development of the plants. Currently, the accuracy of meteorological disaster warnings and forecasts for NT orchards remains suboptimal, primarily due to the absence of quantitative meteorological indicators for low-temperature freezing stress. Therefore, this study employed NT plants as experimental subjects and conducted controlled treatment experiments under varying intensities of low-temperature freezing stress (0 °C, -2 °C, -5 °C, -7 °C, and -9 °C) and durations (1 h, 4 h, and 7 h). Subsequently, physiological and biochemical parameters were measured, including photosynthetic parameters, chlorophyll fluorescence parameters, reactive oxygen species, osmoregulatory substances, and antioxidant enzyme activities in NT plants. The results demonstrated that low-temperature freezing stress adversely affected the photosynthetic system of NT plants, disrupted the dynamic equilibrium of the antioxidant system, and compromised cellular stability. The severity of freezing damage increased with decreasing temperature and prolonged exposure. Chlorophyll (a/b) ratio (Chl (a/b)), maximum quantum yield of photosystem II (Fv/Fm), soluble sugar, and malondialdehyde (MDA) were identified as key indicators for assessing physiological and biochemical changes in NT plants. Utilizing these four parameters, a comprehensive score (CS) model of freezing damage was developed to quantitatively evaluate the growth status of NT plants across varying low-temperature freezing damage gradients and durations. Subsequently, the freezing damage grade index for NT plants during the overwintering period was established. Specifically, Level 1 for CS ≤ -0.50, Level 2 for -0.5 < CS ≤ 0, Level 3 for 0 < CS ≤ 0.5, and Level 4 for 0.5 < CS. The research results provide valuable data for agricultural meteorological departments to carry out disaster monitoring, early warning, and prevention and control.

Angular momentum properties of a circularly polarized vortex beam in the paraxial optical systems

The angular momentum (AM) properties of circularly polarized vortex beams (CPVBs) in two paraxial optical systems [free space and a gradient-index (GRIN) fiber] are demonstrated. The transverse light intensity, the longitudinal light intensity, the phase of the longitudinal electric field, the kinetic momentum, the total spin AM (SAM), the transverse-type SAM (t-SAM), the longitudinal-type SAM (l-SAM), and the orbital angular momentum (OAM) of CPVBs in the two paraxial optical systems are characterized. Spin-orbit coupling of CPVBs is studied during propagation in free space and in a GRIN fiber. When the OAM and the SAM of a CPVB have the same direction of rotation and when they have opposite directions of rotation, the spin-orbit coupling exhibits different characteristics in free space and in the GRIN fiber.

Current echocardiographic indices for right ventricular function are inadequate to predict patient outcomes in chronic tricuspid regurgitation

Abstract Background/Introduction The presence of chronic tricuspid regurgitation (TR) can lead to pseudo-normalization of right ventricular (RV) functional indices on transthoracic echocardiography (TTE). Thus, the current cutoffs for RV free wall strain (FWS), functional area change (FAC), and tricuspid annular plane systolic excursion (TAPSE) (1) are not optimal for the volume overload associated with TR (2). Purpose We aimed to evaluate the sensitivity and specificity of the current cutoffs for RV FWS (&amp;gt;-23%), FAC (&amp;lt;35%), and TAPSE (&amp;lt;17 mm) in predicting adverse patient outcomes in a multi-centric population with chronic TR. We also evaluated whether interventricular septal shape was correlated with patient outcomes and aimed to develop cutoffs for this novel index. Methods We studied 753 patients (mean age 70.3 ± 15.0 years, 42.5% male) with &amp;gt;mild, medically managed TR who presented to our centers between 2018 and 2023. We measured TR grade (3), RV size, RV FWS, FAC, TAPSE, and eccentricity index (EI) for each patient (Figure 1). We subsequently tracked time to cardiac-related hospitalization or death, whichever came first. Using receiver operating characteristics (ROC), we estimated the area-under-the-curve (AUC) for RV FWS, FAC, and TAPSE as well as systolic and diastolic EI in predicting adverse patient outcomes. We used the modified Youden index (4) to analyze the current cutoffs for RV FWS, FAC, and TAPSE and specify novel cutoffs for all indices (including systolic and diastolic EI). Results Over a mean follow-up of 52 ± 16 months, there were 282 hospitalizations and 146 deaths across the 753 patients. AUC values for RV FWS, FAC, and TAPSE in predicting adverse clinical outcomes were 0.54, 0.62, and 0.54, respectively (p &amp;lt; 0.05 each, Figure 2A). Systolic and diastolic EI had the highest AUC (0.86 each, p &amp;lt; 0.0001) and were equivalent to one another in predicting adverse outcomes (Z-score = 0.0471, p = 0.9624) (Figure 2B). Sensitivity and specificity for the current cutoffs for RV FWS, FAC, and TAPSE are shown in Figure 2C. Using maximized Youden indices, the proposed cutoffs for normal RV FWS, FAC, TAPSE, systolic EI, and diastolic EI in chronic TR were ≤-24%, ≥38%, ≥22 mm, &amp;lt;1.3, and &amp;lt;1.3, respectively, which are all notably higher than the currently cutoffs (Figure 2C). Conclusions Given the pseudo-normalization of RV FWS, FAC, and TAPSE in chronic TR, waiting to intervene until these values become "abnormal" (per the current cutoffs) may in fact be too late. Our data suggest that the new cutoffs are needed to identify compensated RV function in the setting of TR. Moreover, interventricular septal shape (assessed via EI) predicts adverse patient outcomes with greater accuracy than conventional indices and should perhaps be incorporated in clinical decision-making.Figure 1.Eccentricity MeasurementFigure 2.ROC Curves for RV Indices

The Effectiveness of Counseling Using Dental Puppets in Improving Knowledge of Dental and Oral Health Maintenance

Children may have a high debris index because they do not know enough about maintaining oral hygiene. The high debris index in grade II students of SDN Bendul Merisi Surabaya is a problem in this study. The purpose of this study was to evaluate how well the response of grade II students of SDN Bendul Merisi Surabaya to counseling using tooth dolls to improve their understanding of maintaining good oral health. Quantitative research was used in this methodology. 52 students registered in grade II of SDN Bendul Merisi Surabaya were the focus of this study. The tool used to collect data was a questionnaire. The survey sheet was the tool used to collect data. The data analysis technique used was the Wilcoxon test. The results of students' knowledge before counseling using tooth dolls were in the poor criteria, after counseling using tooth dolls it was in the good category, in addition, P &lt; 0.05 which was indicated by the Wilcoxon test effectiveness test showed that tooth dolls had an impact on improving students' understanding in maintaining oral health. The study concluded that the counseling of tooth puppet media is a very good way to improve the understanding of grade II students about maintaining oral health at SDN Bendul Merisi Surabaya. INDEX TERMS Knowledge, Tooth Doll Media, Dental and Oral Health Maintenance.

The Effect of Brushing Teeth on the Debris Index in Elementary School Children

The average debris index in grade II students of SDN 225 Gresik is included in the bad category. The poor level of debris index for grade II students of SDN 225 Gresik is caused by several factors, including the way they brush their teeth. Debris is food debris that sticks to teeth and gingivas. Brushing your teeth is one of the easiest and cheapest preventive efforts to prevent tooth decay. Good brushing skills can also affect dental and oral hygiene and health, including in reducing food debris, plaque, and other dental problems. The purpose of this study is to determine the effect of brushing teeth on the debris index of grade II students of SDN 225 Gresik. This type of research is an analytical research with a cross sectional design, with a sample of 30 grade II students at SDN 225 Gresik. The data collection instruments used are observation sheets and examination sheets. The data analysis technique uses the Chi-Square test. The results of the research on how to brush the teeth of grade II students at SDN 225 Gresik are in the bad category, which is 53%. The debris index of grade II students at SDN 225 Gresik is in the medium category, which is 47%. The results of this study obtained a p value of 0.000 or a p value of significance below α (0.05). There is an effect of brushing teeth on the debris index of grade II students of SDN 225 Gresik. There is an effect between the way you brush your teeth on the debris index of grade II students of SDN 225 Gresik.

Efficient and Scalable Radiative Cooling for Photovoltaics Using Solution‐Processable and Solar‐Transparent Mesoporous Nanoparticles

AbstractContinuous heat generation in perovskite solar cells (PSCs), caused by solar radiation, poses a significant challenge to their lifespan. Existing active cooling methods require extra energy input and might not be effective at high temperatures. Most reported passive radiative cooling materials either lack solar transparency or require complex fabrication processes. Here, mesoporous silica nanoparticles are designed, synthesized, and assembled into multilayered stacks with a graded refractive index (GRI) by spray coating them on top of PSCs made from methylammonium lead iodide (MAPbI3) over a large scale (15.6 × 15.6 cm2). This coating offers both high transparency in the visible wavelength and high emissivity in the mid‐infrared region, leading to an average temperature reduction of 6.65 ± 1.48 °C in GRI‐coated MAPbI3 PSCs under outdoor conditions compared to non‐coated references. After 50 d, the GRI‐coated PSCs maintain 80.9 ± 8.7% of their initial photoconversion efficiency, in contrast to 6.1 ± 5.9% for the noncoated ones. The calculated cooling power of the GRI‐coated PSCs is 28.9% higher than that of the reference cells.

Random Raman Lasing in Diode-Pumped Multi-Mode Graded-Index Fiber with Femtosecond Laser-Inscribed Random Refractive Index Structures of Various Shapes

Diode-pumped multi-mode graded-index (GRIN) fiber Raman lasers provide prominent brightness enhancement both in linear and half-open cavities with random distributed feedback via natural Rayleigh backscattering. Femtosecond laser-inscribed random refractive index structures allow for the sufficient reduction in the Raman threshold by means of Rayleigh backscattering signal enhancement by +50 + 66 dB relative to the intrinsic fiber level. At the same time, they offer an opportunity to generate Stokes beams with a shape close to fundamental transverse mode (LP01), as well as to select higher-order modes such as LP11 with a near-1D longitudinal random structure shifted off the fiber axis. Further development of the inscription technology includes the fabrication of 3D ring-shaped random structures using a spatial light modulator (SLM) in a 100/140 μm GRIN multi-mode fiber. This allows for the generation of a multi-mode diode-pumped GRIN fiber random Raman laser at 976 nm with a ring-shaped output beam at a relatively low pumping threshold (~160 W), demonstrated for the first time to our knowledge.

First fluorescence method for monitoring the doping stimulant drug solriamfetol in plasma and urine: A pharmacokinetic study in volunteers’ urine with greenness, whiteness, and blueness assessments

A green, sustainable, simple, and highly sensitive spectrofluorimetric method was developed to determine solriamfetol hydrochloride for the first time in biological fluids and dosage form. To the best of our knowledge, no Fluorimetric methods have been reported for solriamfetol determination in plasma and urine. The method is based on measuring the intrinsic fluorescence of solriamfetol hydrochloride at 522 nm after excitation at 260 nm in ammonium acetate buffer solution at pH 4. All factors influencing the response have been carefully investigated. The method was linear over a concentration range of 10 to 1800 ng/mL (r = 0.9998). The limit of detection (LOD) and limit of quantification (LOQ) values were found to be 3.2 and 9.8 ng/mL, respectively, indicating the excellent sensitivity of the proposed method. The pharmaceutical dosage form, spiked human plasma, and urine samples were successfully analyzed using the described method with average recoveries of 99.79 ± 0.739, 99.27 ± 1.885, and 99.57 ± 1.701, respectively. Plasma samples were first subjected to protein precipitation using 10 % perchloric acid, while urine samples were analyzed directly without any pretreatment. Furthermore, the suggested method was applied effectively on real human volunteers’ urine to measure renal clearance, the cumulative amount of solriamfetol excreted unchanged in the urine, and the percent of the dose recovered. The eco-friendly nature and sustainability of this work were evaluated using trending greenness, whiteness, and blueness assessment metrics. The greenness assessment tools, namely the Analytical GREEnness metric tool (AGREE), Analytical Eco-scale, and complementary green analytical procedure index (complex GAPI) were selected to prove the eco-friendly nature of the method. Additionally, whiteness and blueness assessments were conducted using the Red-Green-Blue model (RGB model), and high Blue Applicability Grade Index (BAGI), respectively. The proposed method is a promising analytical tool for routine analysis in quality control labs, therapeutic drug monitoring, and pharmacokinetics studies.

Numerical Analysis of Optical Fiber Refractive Index in the Miniaturized Graded‐Index Fiber Probe

ABSTRACTWe analyze the impact of the refractive index of optical fibers on the focusing properties of a miniaturized graded‐index (GRIN) fiber probe. The ABCD ray transfer matrix and characteristic parameters are employed to characterize the working distance, focusing spot size, and the depth of field effectively. The three‐dimensional (3‐D) function diagrams and two‐dimensional (2‐D) graphs are used to illustrate the impact of the no‐core fiber (NCF) refractive index and the center refractive index of GRIN fiber on the focusing properties. Numerical analysis results show that when the length of the NCF is 0.36 mm and the GRIN fiber is 0.1 mm, the variation of the refractive index of the NCF between 1.44 and 1.52 leads to the variation of the working distance in the range of 0.02 mm, while the focusing spot size varies in the range of 5 μm. A comparison of 12 probe samples reveals that a 0.02 difference in the center refractive index of GRIN fiber could result in a 0.16 mm variation in working distance and a variation in focusing spot size of over 3 μm. The experimental results indicate that alterations in the length of the fibers have a considerable effect on the focusing properties of the probe. In contrast, the range of variation in focusing properties with fiber refractive index is relatively limited.

Mode conversion in graded-index few-mode fiber via hollow cylindrical long-period fiber gratings.

We demonstrate the realization of mode conversion using hollow cylindrical long-period fiber gratings (LPFGs) inscribed in graded-index few-mode fibers (FMFs) by a femtosecond laser. By precisely shaping the refractive index modulation into a hollow cylindrical structure, we enable efficient coupling from the fundamental mode to high-order modes (LP11, LP02, LP21, LP12, LP31, LP03, and LP22 modes). The method achieves high-efficiency and low-loss mode conversion across various mode groups, marking a first for graded-index FMFs with different grating periods. The influence of the hollow cylindrical LPFG radius on mode conversion efficiency and spectral characteristics is thoroughly investigated. Additionally, incorporating a linear polarizer allowed for distinguishing between LP modes within a mode group, enhancing the tunability of the mode converter. These mode conversion devices have significant potential for applications in mode gain equalization and mode scrambling for mode division multiplexing (MDM) systems.

Novel eco-friendly HPTLC method using dual-wavelength detection for simultaneous quantification of duloxetine and tadalafil with greenness evaluation and application in human plasma

A novel, environmentally friendly, and sensitive HPTLC method has been developed and validated for simultaneous quantification of duloxetine (DLX) and tadalafil (TDL) in their pure state, laboratory-prepared mixtures, and spiked human plasma. This method is particularly important for patients dealing with depression and sexual issues, as it allows for the measurement of these co-administered antidepressant and sexual stimulant drugs in biological fluids. The separation process employed a stationary phase of pre-coated silica gel 60 F254 and a mobile phase consisting of ethyl acetate, acetonitrile, and 33% ammonia (8:1:1, v/v). The optimized mobile phase resulted in well-defined bands for DLX and TDL, with Rf values of 0.3 and 0.8, respectively with dual-wavelength detection at 232 nm for DLX and 222 nm for TDL. Polynomial regression analysis revealed exceptional linearity for both drugs, with correlation coefficients of 0.9999 over concentration ranges of 10–900 ng/band for DLX and 10-1200 ng/band for TDL. The quantitation limits were 8.2 ng/band for DLX and 8.6 ng/band for TDL, while the detection limits (LOD) were 2.7 ng/band for DLX and 2.8 ng/band for TDL. The validation of this method followed the guidelines set by the International Council for Harmonization (ICH). Additionally, the suggested method’s greenness was assessed by means of four up-to-date ecological tools, namely the Eco-Scale, the National Environmental Method Index (NEMI), the Green Analytical Procedure Index (GAPI), and the Analytical Greenness metric approach (AGREE). The proposed method was also assessed using the Blue Applicability Grade Index (BAGI), a recently developed metric for assessing the practicality (blueness) of procedures.

Green and Sensitive Analysis of the Antihistaminic Drug Pheniramine Maleate and Its Main Toxic Impurity Using UPLC and TLC Methods, Blueness Assessment, and Greenness Assessments

For the first time, two direct and eco-friendly chromatographic approaches were adapted for the simultaneous estimation of pheniramine maleate (PAM) and its major toxic impurity, 2-benzyl pyridine (BNZ). Method A used reversed-phase ultra-performance liquid chromatography; separation was achieved within 4 min using a C18 column with a developing system of methanol/water (60:40 v/v) with a 0.1 mL/min flow rate. Photodiode array detection was adjusted at 215 nm. The method was linear in the ranges of 5.0–70.0 and 0.05–10.0 µg/mL for PAM and BNZ, correspondingly. Method B used thin-layer chromatography; separation was applied on silica gel TLC F254 using ethanol/ethyl acetate/liquid ammonia (8:2:0.1, in volumes) at room temperature, at 265 nm. Linearity was assured at concentration ranges 0.5–8.0 and 0.1–3.0 µg/band for the two components, respectively. Generally, the new UPLC and TLC methods outperform the old ones in terms of quickness, greenness, and sensitivity. Concisely, the greenness features were partially achieved using the Green Analytical Procedure Index (GAPI) and the Analytical Greenness (AGREE) pictograms. In contrast, the usefulness of the novel approaches was assured via the Blue Applicability Grade Index (BAGI) tool.

Harnessing spectrophotometry resolution power for determining ternary mixture for respiratory disorders treatment in their pharmaceutical formulation.

A ternary mixture incorporating Hydroxyzine hydrochloride (HYX), Ephedrine hydrochloride (EPH) and Theophylline (THP) frequently prescribed for the treatment of respiratory diseases. Herein, two spectrophotometric methods are designated and applied to resolve these three components in their mixture. Method A is ratio-subtraction combined with derivative spectrophotometry, where THP can be determined directly at its λmax 271 nm (neither HYX or EPH interfere), then for determination of HYX and EPH, the ternary mixture was divided by 22 μg/mL of THP and after subtraction of the plateau region, HYX can be determined directly at its λmax 234.2 nm (absence of EPH intervention). Finally, the third derivative (3D) spectrophotometric approach was utilized to estimate EPH by detecting the peak amplitude at 222 nm with Δλ = 4 and a scaling factor 100. Principal Component Regression (PCR) and Partial Least Squares (PLS), two multivariate calibration approaches, were applied effectively in Method B. This method effectively quantified the mixture under investigation by using the absorption spectra obtained from suitable solutions of the three components in the 210-230 nm region. The calibration models were evaluated using cross-validation with PCR and PLS, producing statistical characteristics that demonstrate the effectiveness of the calibration models. Synthetic and pharmaceutical preparations were also used to conduct external validation. In pharmaceutical formulation, these methods were successfully applied to analyze HYX, EPH, and THP without overlap from formulation's excipients. Moreover, the study's findings were statistically contrasted with those of earlier reported HPLC method. Appraisal approaches were used to determine whether the new spectrophotometric methods had an adverse environmental impact involving the Green Analytical Procedure Index (GAPI) and the AGREE (Analytical Greenness). These evaluations delivered information about the methods' eco-friendliness and sustainability, proving that they are in line with ecologically attributed practices. Furthermore, the Blue Applicability Grade Index (BAGI) was utilized to identify and verify the feasibility and practicality of the suggested approaches.

A novel green cloud point extraction-based switchable hydrophilicity solvent method for antimony separation and quantification from various bottled beverages by HGAAS

Herein, switchable hydrophilicity solvent (SHS) was used as a synergistic reagent in the cloud point extraction (CPE) protocol to increase the procedure’s efficiency and sensitivity. At room temperature, the CPE-SHS method was created for the fast and accurate extraction of antimony from a variety of drinks. Hydride generation atomic absorption spectroscopy (HGAAS) was used to antimony detection in various samples following the CPE-SHS protocol. The N,N-dimethylamine (DMA), TritonX-100, and p-tert-butyl-tetrakis[(diethylamide)methoxy]tetrathiacalix[4]arene (BTDMTA) were used as a SHS, surfactant, and chelation reagent, respectively. This procedure’s criteria for validation have been identified, including linearity (0.01–700 µg/L), accuracy, precision, limit of detection (LOD = 0.007 µg/L), limit of quantification (LOQ = 0.023 µg/L), enhancement factor (EF = 160), and matrix influence. This approach was validated using certified reference material. The environmentally friendly practices of this method were assessed using recent tools like Complex Modified GAPI (ComplexMoGAPI) software, Analytical GREEnness Calculator (AGREE) software, Blue Applicability Grade Index (BAGI) software, and Sample Preparation Metric of Sustainability (SPMS) program.

Sustainable chemometric analysis of tension headache drugs in the presence of nephrotoxic impurities

A three-drug combination of caffeine, aspirin and paracetamol is widely prescribed as a first-line treatment for tension headaches and migraine attacks. Being of easy access as an over-the-counter medication, renal papillary necrosis may be caused if large doses are taken chronically. Moreover, several toxic impurities such as p-aminophenol and p-hydroxy acetophenone may be formed during the synthesis or storage of paracetamol. These impurities are classified as nephrotoxic and teratogenic materials which obliges pharmaceutical companies to develop cost-effective methodologies for their detection along with paracetamol itself. During the current study, multivariate chemometric-assisted spectrophotometric models namely; Partial Least Squares, Genetic Algorithm-Partial Least Squares and Multivariate Curve Resolution-Alternating Least Squares were developed for assaying and resolving the complex spectral overlap of the ternary combination in the presence of the nephrotoxic impurities; p-aminophenol and p-hydroxy acetophenone. A comparison was held between the three models where the optimized Genetic Algorithm-Partial Least Squares and Multivariate Curve Resolution-Alternating Least Squares models reduced the root mean square by 18.1%, 21.7%, 20.0%, 43.9% and 11.5% and 31.5%, 32.6%, 39.3%, 54.6% and 37.9% for caffeine, aspirin, paracetamol, p-aminophenol and p-hydroxy acetophenone, respectively. Panadol® migraine tablets were successfully analyzed using the constructed models without interference from the excipients. A statistical comparative analysis and greenness evaluation were carried out using two assessment tools including the “Green Analytical Procedure Index” and the “Analytical Greenness metric”. Also, the “Whiteness Analytical Chemistry tool” using the RGB12 model and the Blueness Applicability Grade Index were applied. Greener quadrants and a high score of 0.74 for the greenness tools were achieved with accepted statistical parameters regarding t and f values. Also, the high scores of the Blueness Applicability Grade Index and RGB12 metrics of 90 and 98.3, respectively confirmed the method's wide practicality and utility. Although other chemometric methods were reported for assaying the ternary combination, our developed method was the only one that incorporated toxic impurities during the analysis along with implementing greenness, whiteness and blueness assessments to ensure the method's sustainability.