A system for spatially resolved measurements of laser-induced fluorescence in laser plasma has been developed. Using aluminum atomic fluorescence as an example, it has been demonstrated that measurements of saturated fluorescence can be conducted during the plasma lifetime, which ranges from 1 to 50 microseconds after the ablation pulse, with a spatial resolution of at least 0.2 mm. This approach enables scanning with high resolution across the cross-section of the laser plume throughout its evolution, with the diameter of the excitation beam waist being significantly smaller than the cross-section. The developed system has been successfully used for fluorescence measurements with high spatial resolution, allowing the assessment of laser plasma size and the investigation of its temporal evolution.

Influence of media containing optical inhomogeneities on the Bessel light beam (BLB) parameters has been studied comprehensively. BLB have been formed by optical setup in two configurations. In configuration I Gaussian (or Laguerre-Gaussian) laser beam is propagating through atmospheric turbulence simulator (ATS). The resulting distorted beam is then used to form the BLB with help of an axicon. In the case of incident Gaussian beam the BLB of the zero order is formed, in the case of Laguerre-Gaussian beam the first order BLB is formed. In configuration II BLB of the zero or the first order is propagating through ATS. Original Gaussian and Laguerre-Gaussian beams correspondingly are undisturbed in this case. The presence of a turbulence of inner scale lower than the diameter of propagating through it laser beam causes significant change in BLB quality parameters in both configurations. The most sensitive is the parameter of constancy, the least sensitive is the parameter of roundness. With the increase of a distance from axicon the sensitivity of all quality parameters increases. Large scale inhomogeneities, that are significantly larger than the diameter of propagating through ATS beam, cause substantial change in beam axis location. Due to the fact, that BLB of the zero order is much easily formed than BLB of the first order, it is optimal to use BLB of the zero order to investigate the turbulence. For unambiguity and more clear interpretation of the obtained results, it is rational to use configuration I with Gaussian beam. The results obtained can be used for the development of analyzers (detectors) of heterogeneity in liquid or gaseous media in natural conditions and in industry, as well as for the quality assessment of extended transparent products.

The paper compares the results of low-alloy steel analysis using classical calibration and partial least squares regression when recording spectra from the “core” and the “tail” of a laser plasma plume. Plasma excitation was performed using an erbium glass laser with a passive shutter. The spectra were recorded using a compact low-resolution (0.5 nm) spectrometer. To improve the quality of the spectra, preliminary processing was used, associated with the alignment of wavelengths and intensities of control sections of the spectrum.

Using in situ Raman spectroscopy, a chemical mechanism for the interaction of lanthanum oxide with a molten fluoride mixture FLiNaK, promising for the use in molten salt nuclear reactors, has been established. High-temperature spectral studies, supplemented with the results of X-ray diffraction and thermodynamic modeling, proved the occurrence of an irreversible heterogeneous reaction La₂O_3s + 2LiF_sol→2LaOF_s + Li₂O_sol. It was shown that in the fluoride system under study, the reaction product (lanthanum oxyfluoride LaOF) forms hexagonal (R3m) and tetragonal (P4/nmm) crystalline modifications. The necessary information on the thermal behavior of vibration modes of lanthanum oxide La₂O₃ in the range of 20–600 ºС, and the mechanism and its interaction with water vapor in the air atmosphere were obtained.

The photoluminescence (PL) spectra, PL excitation spectra (PLES) and kinetics of FL of micropowders of CaGa₂S₄:3%Nd,5%Yb and CaGa₂S₄:3%Nd compounds at room temperature were studied in a wide range of optical excitation levels. In the PL and PLES, the transition bands of Nd³⁺ ions in the wavelength range of 300–1500 nm were identified. It was found that due to doping of CaGa₂S₄:3%Nd crystals with ytterbium ions, an intense violet-green band with a maximum at about 488 nm appears in the PLES. When excited within this band, the PL intensities in the IR bands of neodymium increase by 2 orders of magnitude, and outside this band – by 1 order of magnitude compared to similar intensities of undoped crystal. In the PL kinetics, sections with increasing luminescence intensity over time were found, as well as sections with nonmonoexponential and monoexponential decay laws depending on the wavelength of the exciting light. The main observed regularities in the kinetics of PL decay of CaGa₂S₄:3%Nd,5%Yb are interpreted in the framework of nonradiative energy transfer (Förster Resonance Energy Transfer – FRET) using a mathematical model.

In the optical absorption spectra of Si₃N₄/Me/Si₃N₄ structures calculated by the finite difference time domain method, the effect of the structural layer thickness on the absorption peak level and width was found. Reducing the thickness of the upper and lower Si₃N₄ layers from 400 to 100 nm leads to about 20% increase in absorption and broadening of the absorption band with the intensity of >90 % from 0.8 to 1.6 μm. It is shown that in the absorption spectrum of Si₃N₄/Ti/Si₃N₄ structure with the thickness of each layer of 50 nm, the thickness of the absorption band with the intensity of >90 % consists 4.3 μm. Reducing the profiled layer of Ti from 130 to 50 nm leads to an insignificant decrease in the maximum absorption value from 99 to 96%. It has been shown that the absorption band broadening is connected with the effect of Si3N4 thickness to the interferential processes in Si₃N₄/Ti/Si₃N₄ structures. It is established that in the range of 8.3–13 μm there is a dependence of the absorption level on the metal type due to the dependence of free electrons concentration on the metal type.

The experimental dependence of the transparency current of InGaAs/GaAs quantum well-dots on the photon energy, which corresponds to the difference of quasi-Fermi levels for electrons and holes, has been obtained. It is shown that modal gain spectra can be calculated from spontaneous luminescence spectra using the obtained dependence and a relation between spontaneous luminescence and optical absorption. The modal gain spectra of InGaAs/GaAs quantum well-dots at different pump currents have been calculated. The technique can be used to study gain spectra of the devices operating in superluminescence regimes, when the position of the gain maximum is unknown.

Nanostructured thin films on silicon substrate were obtained by high-frequency pulse-periodic (f ~ 13 kHz) action of laser radiation with a wavelength of 1.064 μm and a power density of q = 64 MW/cm² on yttrium vanadate YVO₄ ceramics at a pressure in vacuum chamber of p = 3 Pa. The morphology of thin YVO₄ films was studied using atomic force microscopy. Transmission spectra of YVO₄ films were obtained in the visible, near and mid-IR regions. The electrophysical characteristics of YVO₄ /Si structures were analyzed.

The effect of laser radiation on the formation of film-like deposits on the surface of optical parts located in closed volumes containing sealing compounds such as VGO-1, KLT-30, U-2-28, K-68 has been studied. Methods of X-ray photoelectron spectroscopy and IR spectroscopy were used to determine the composition of the film-like deposits; the composition of the gas medium was determined by the method of mass spectrometry. The kinetics of film-like deposits formation is investigated depending on the temperature of the medium and the parameters of laser radiation. The possible mechanisms of the formation of film-like deposits and methods of their elimination are considered.

High-frequency (HF) plasma ignition in commercial lamps (frequency 3 MHz, current 100 A) for 150—500 μs after its HF (2 MHz) excitation provides a selective decrease in the radiation intensity in the 400—700 nm band compared to the lamp pumping by a capacitor discharge. It was found that the decrease coefficient of radiation intensity increases with a shortening duration of the HF excitation. In addition, in the emission spectrum of the DKRTV-3000 lamp, an increase in the intensity of the krypton atom lines (587, 760, and 810 nm) was revealed. These lines match the absorption bands of Nd³⁺ ions in the spectrum of the Nd³⁺:YAG laser crystal. Therefore, HF ignition is considered as an alternative to diode pumping for increasing the laser efficiency.

The spatial structure of β-amyloid peptide (25-35) was studied using circular dichroism spectroscopy in a medium close to the conditions of the membrane environment. The conformational preference of β-amyloid peptide (25-35) was first studied in dipalmitoylphosphatidylcholine (DPPC) solution with and without cholesterol using circular dichroism spectroscopy. It was found that the peptide adopts the structures of the a- helix, β-sheet, β-turn and irregular regions, and their relative proportions changed depending on the presence of cholesterol. The results of the spectral analysis of β-amyloid peptide (25-35) made it possible to unambiguously assume the secondary structure of the peptide in a lipid solvent. It has been shown that ordering of the secondary structure of the β-amyloid peptide (25-35) is observed in the solution with DPPC, which maximally simulates the environment on the surface of the plasma membrane.

The software processing of fluorescent images of histological sections of the cervix with different levels of pathology (with squamous cell carcinoma and healthy epithelium) stained with CdSe/ZnS quantum dots (QD) using Stark spectroscopy is presented. The shift of the maximum of the luminescence band of CdSe/ZnS quantum dots is determined by the influence of the electric field of the cell. Pathological changes in malignant tissues of squamous cell carcinoma of the cervix are accompanied by a short-wave spectral shift of the luminescence band of CdSe/ZnS QD by a value equal to 16 nm. Software processing of fluorescent images allows us to attribute this shift to the manifestation of the linear Stark effect, and comparison with the results obtained for aqueous solutions of CdSe/ZnS QDs show that in this case the medium in tissues with squamous cell carcinoma of the cervix is acidic. Healthy epithelial tissues when stained with CdSe/ZnS CT give an optical response corresponding to neutral pH. The practical significance of the obtained results lies both in the differentiation of tissues with malignant changes and the visualization of the border between healthy epithelial tissue and squamous cell carcinoma of the cervix.

The results of the analysis of the dispersed and optical characteristics of atmospheric particles according to measurements at the background station of ZOTTO tall Tower in the period of 2021–2022 are presented. Seasonal spectra of particle size distributions and correlations with the total scattering coefficient for different aerosol modes are studied. The possibility of approximating the distribution spectra by analytical functions is investigated: the best approximation corresponds to a lognormal distribution of a unimodal form predominantly. The features of the seasonal course are analyzed: the aerosol concentration has a maximum in summer of 2021 and in spring of 2022. For the specified periods, the analysis of the backward trajectories of the movement of air masses using the HYSPLIT model was performed. In the northern regions, industrial mining plants are the sources of increased aerosol particle content. The atmospheric air coming from the eastern and south-western directions is enriched with products of biomass combustion as a result of forest fires and grass fall, respectively. It is shown that the scattering properties of aerosol particles from different sources have their own characteristic values.

An expression is obtained for the probability generating functional of the photon arrival processes in fluorescence fluctuation spectroscopy systems under the assumption of an arbitrary fluorescence intensity over the observation interval. The use of generating functionals generalizes the theory of photon counting distribution analysis methods based on the application of photon counts generating functions and opens up the possibility of analyzing the systems with non-stationary intensity over the observation interval. Expressions are found for the process intensity and the probability to obtain a certain number of photocounts per observation interval. Based on the obtained expressions, a method for estimating the concentration of fluorescent molecules with an arbitrary fluorescence intensity is developed. The method is applicable for both single-photon and two-photon excitation and does not depend on the form of the brightness profile function.

It has been shown experimentally that the phase response of the new polymer with side anthracene groups is created by their photooxidation and photodimerization. Both photoreactions lead to approximately equal photorefraction in the volume of the material (Δn » –0.02 for λ = 633 nm) and formation of a photorelief on the layer surface. Estimation of the refractive index modulation depth in the structure of twodimensional holographic gratings indicates the possibility of achieving maximum diffraction efficiency, which for three-dimensional gratings is limited by their non-sinusoidality. It has been shown that the polymer and its compositions with various photosensitizers in thin (~ 1 μm) layers effectively form surface photoreliefs with a spatial frequency of up to 1000 mm^–1 and an amplitude of up to 25% of the layer thickness when using post-exposure reversible plasticization. It has been experimentally established that the resistance of surface photoreliefs to the action of temperatures above 90°C can be increased manyfold by photocrosslinking the material of the formed relief structure.

Thermo-optic coefficients of monoclinic KYb_xY_1–x(WO₄)₂ (х = 0, 0.05, 0.1, 0.2, 0.5 и 1.0) crystals for E//Np, E//Nm и E//Ng light polarizations at wavelength of 1.06 μm were studied using laser beam deviation technique for a medium with a linear temperature gradient. KYb_xY_1–x(WO₄)₂ crystals were grown by the modified Czochralski method using a dynamic growth regime and selection of the required temperature gradient at the crystallisation front. The coefficients dn/dT obtained for all light polarizations are negative, and their absolute values decrease with increasing coefficient x. It is shown that the coefficients dni/dT (i = p, m, g) for KYb_xY_1–x (WO₄)² crystals depend linearly on their stoichiometry coefficient x.

The present work explores the nonlinear interaction of q-Gaussian laser beam with unmagnetized plasma. Relativistic and ponderomotive nonlinearities are taken together in the present investigation. The Wentzel–Kramers–Brillouin (WKB) approximation and paraxial theory are used for deriving the secondorder ODE-expressing variation of beam waist against the normalized propagation distance. Further, the behavior of the beam waist against normalized propagation distance is explored through the RK4 method. The impact of established parameters of laser and plasma such as plasma temperature, laser intensity, plasma density, and q parameter on the beam waist is also analyzed.

X-ray absorption fine structure (XAFS) at the Co K-edge in three mixed ligand pyridine Co(II) complexes, viz., [Co(py)₄(SCN)₂] (1), [Co(py)₄(Cl)₂]ꞏH₂O (2), and [Co(py)₄(Br)₂] (3), have been investigated using synchrotron radiation. Extended X-ray absorption fine structure (EXAFS) has been analyzed using two methods to present their comparative study. In the first method, the coordination number N is fixed, and the amplitude reduction factor S ² ₀  is varied. In the second method, N is varied and S ² ₀ is fixed. EXAFS analysis indicated that the absorbing Co atom is surrounded by four N atoms (of pyridine ligands) in the equatorial positions forming the square planar base. Two N atoms (of thiocyanate), two chlorides, and two bromide ions in the axial sites complete the distorted octahedral coordination in complexes 1, 2, and 3, respectively. Whereas in 1, the axial bond lengths are shorter than the equatorial bond lengths, indicating compressed octahedral geometry, in 2 and 3 the axial bond lengths are longer than the equatorial bond lengths, exhibiting elongated octahedral geometry. The results agree with those obtained previously using X-ray crystallography. Using ab initio calculations, X-ray absorption near edge structure (XANES) spectra have been simulated and compared with the experimental XANES spectra. Further, p- and d-DOS calculated simultaneously to absorb the metal center of Co have been correlated with the features and shapes of the simulated XANES spectra, as well as the experimental spectra

LiSr_1–xPb_xBO₃ (x = 0, 0.0025, and 0.005) materials were synthesized at 750ºC for 6 h in air. Powder X-ray diffraction and FTIR were used to determine the phase and bond structure of the synthesized LiSrBO₃. Spectrofluorometry was used to investigate the photoluminescence properties of the prepared phosphors at room temperature. LiSrBO₃:Pb²⁺ was found to have emission and excitation bands at 362 and 275 nm, respectively. Finally, the prepared material LiSrBO₃:Pb²⁺ was found to have a Stokes shift of 8739 cm^–1, using the excitation band at 275 nm and the emission band at 362 nm. As a result of this work, a new UVA radiation-emitting substance has been introduced to the literature.

A comprehensive computational study of the energy levels and lifetimes of the 64 states arising from the 3s² 3p⁶ 3d⁷ and 3s² 3p⁵ 3d⁸ configurations of Sr XIV, Ru XX, Rh XXI, and Pd XXII of fusion interest is carried out via the relativistic multiconfiguration Dirac–Hartree–Fock method followed by calculations that consider the correlations within the n = 8 complex, the Breit interaction, self-energy, and vacuum polarization corrections. Moreover, to display detailed information about the decay properties of these ions, the radiative transition wavelengths and emission transition probabilities of the electric dipole, electric quadrupole, magnetic dipole, and magnetic quadrupole transitions among the levels of the above configurations are given. The energy-level calculations are performed by taking the fully relativistic flexible atomic code as an independent check on the present values. Comparisons are made between the two datasets used here and previous experimental and computational work, and good agreement is found. The results reported here are useful for the identification of emission lines and in the field of fusion modeling, where experimental data are limited.

The extensive use of pesticides can pose potential risks to food safety and human health. Therefore, establishing simple and effective detection methods for pesticide residues is necessary. In this study, ultraviolet (UV) spectroscopy is used for the simultaneous detection of imidacloprid, acetamiprid, and clothianidin in apple juice. A total of 84 samples with different concentrations of imidacloprid, acetamiprid, and clothianidin in apple juice are prepared, and the corresponding UV spectra are collected using a UV‒visible spectrophotometer. The quantitative detection model is built using the back propagation neural network (BPNN), and the BPNN model is optimized using the sparrow search algorithm (SSA). To verify the performance of the model, the prediction results of the SSA-BPNN model are compared with those of the extreme learning machine (ELM), BPNN, and particle swarm optimization back propagation neural network (PSOBPNN) models. The results show that UV spectroscopy coupled with the SSA-BPNN model is effective for the simultaneous detection of imidacloprid, acetamiprid, and clothianidin in apple juice; this method is important for ensuring food safety and human health.

This study used UV–visible spectroscopy to investigate the effectiveness of telmisartan tablets after their shelf life, employing the solubility of the drug in methanol and subsequent dilution with water to obtain an absorption maximum at 297 nm. At concentrations ranging from 0.8–4 µg/mL, the study complied with the Beer–Lambert law, and regression analysis revealed a strong correlation coefficient of 0.999. The suggested technique was found to be easy to follow, accurate, precise, and specific when applied to the analysis of tablet formulations. The developed method was validated. To study the post-shelf-life efficacy of telmisartan tablets utilizing two different brands of marketed tablets, the developed technique was followed. The results show that both expired and unexpired telmisartan tablets continue to be useful after their shelf life. The preliminary dissolution tests were performed on an electro-lab dissolution tester at 37°C. The results of the analysis showed no appreciable change in the drug concentration, suggesting that the telmisartan tablet formulation might be stable over time. The percentage release of non-expired tablets observed in the test was 99%, whereas the percentage of expired tablets was 90%.

Lobeglitazone sulfate and glimepiride are type 2 antidiabetic drugs in which lobeglitazone sulfate functions as an insulin sensitizer and glimepiride lowers blood sugar by causing the pancreas to produce insulin. This research article proposes a novel, simple, accurate, reproducible, and economical tandem method that can be used in the future for small-scale project analyses. Method A (absorption correction), in which the absorption maximum for lobeglitazone sulfate was 350 nm, also showed absorbance at 226 nm, which was found to be the absorption maximum for glimepiride, which shows zero absorbance at 350 nm. The techniques developed exhibited good linearity, ranging from 4 to 10.4 µg/mL for lobeglitazone sulfate and from 8 20.8 µg/mL for glimepiride, with excellent correlation coefficients (R² = 0.999) for the two drugs. Method B (absorption ratio) explains the absorption ratio by selecting the maximum wavelength of one drug and one isosbestic point where both drugs show the same absorbance. The method developed showed good linearity, ranging from 0.8 to 7.2 µg/mL for lobeglitazone sulfate at 250 nm and 226 nm and from 1.6 to 14.4 µg/mL for glimepiride at 250 nm and 226 nm, with excellent correlation coefficients (R² = 0.9987 for lobeglitazone sulfate at two wavelengths and R² = 0.9987 for glimepiride). Both methods exhibited good linearity with excellent correlation coefficients. The intraday and interday accuracy and precision, with a low percentage relative standard deviation, demonstrated better recovery and reproducibility. A sensitivity test was performed by calculating the limit of detection and the limit of quantification.

A highly sensitive, rapid, and straightforward LC‒MS/MS technique has been developed and meticulously validated for the detection of prucalopride in human plasma using prucalopride-13CD3 as an internal standard. The thorough validation process, conducted as per the US FDA guidelines, ensures the reliability and accuracy of our method. The analytes were extracted from human plasma via a liquid–liquid extraction technique using methyl tertiary butyl ether. The sample extract was separated on a Kromasil C18 column using a mixture of methanol and 5 mM ammonium formate in 0.1% formic acid (w/v) (80:20, v/v) as the mobile phase at a flow rate of 1.0 mL/min within a run time of 2.20 min. The eluents were quantified in positive ion mode by multiple reaction monitoring to observe the transitions from m/z 368.0 to 196.0 for prucalopride and from m/z 372.0 to 196.0 for the internal standard. The linearity of the method was established within the range 50–12,000 pg/mL, and the recoveries obtained were 89.92 and 90.42% for the analyte and internal standard respectively. The proposed method can be applied to quantify prucalopride during therapeutic drug monitoring and bioavailability/bioequivalence studies in humans.

Organic matter distributions and concentrations at various stages of an urban wastewater treatment plant were analyzed via ultraviolet‒visible (UV‒Vis) absorption and three-dimensional fluorescence spectroscopy. Six components identified via the excitation‒emission matrix and PARAFAC analysis revealed that components related to tryptophan (components 1, 3, and 6) correlated strongly with the chemical oxygen demand (COD) concentration, with Pearson correlation coefficients of 0.656, 0.447, and 0.674 respectively. Analysis of the fluorescence and UV‒Vis absorption parameters revealed a reduction in the organic matter content, increased humification, and a shift from exogenous organic substances to endogenous organic substances throughout the sewage treatment process. Notably, the humification index had the highest correlation with the COD level (–0.834). Based on the use of Monte Carlo–uninformative variable elimination‒partial least squares for characteristic wavelength extraction from normalized fluorescence and absorption spectra, a COD characteristic fusion spectral analysis model was developed. The results revealed good agreement between the COD concentrations obtained via feature fusion spectral analysis and the true COD values obtained via the potassium dichromate method. The coefficient of determination between the predicted COD values and the true COD values in the testing set reached 0.9725, the root mean square error was only 10.51 mg/L, and the residual predictive deviation was 4.74. These findings suggest the efficacy of using UV‒Vis absorption and three-dimensional fluorescence spectroscopy for direct COD tracking and detection in wastewater treatment processes without any pretreatment.

Green synthesis techniques have gained much attention, as they serve as an environmentally friendly substitute for the synthesis of nanoparticles. Here, we present a cheap, energy-efficient, and eco-friendly approach to producing magnesium oxide nanoparticles (MgONPs) utilizing maize leaves as a bio-reducing agent. This method reduces the effects of traditional chemical-based synthesis, by utilizing the reducing characteristics of maize leaves to promote the synthesis in a sustainable way. Using various analytical tools such as UV–visible, XRD, FE-SEM, and FTIR, we thoroughly characterized the synthesized nanoparticles. Biogenic MgONPs are of spherical morphology, and the size ranges from 40 to 100 nm, reflecting their multifunctionality. This work highlights the synthesis of maize-mediated MgONPs as a viable strategy for the environmentally friendly and sustainable synthesis of nanoparticles.

Valsartan and labetalol are the drugs that belong to the class of antihypertensive drugs, angiotensin II receptors. A simple, less time-consuming, cost-effective, and green first-order derivative approach is developed for the effective and simultaneous detection of valsartan and labetalol. The first-order approach is well known for the estimation of mixed drugs. The present method is validated as per the recommendations of the ICH guidelines (ICH Q2R1). Validation parameters include linearity that contains r² values 0.9945 and 0.9967, respectively, for valsartan and labetalol. For the intraday and interday precision study, the assay value was found at 99.86 and 101.45%, and percentage recovery was achieved at 100.45 and 99.78% respectively for valsartan and labetalol. Based on the accuracy study the percentage recovery of valsartan was between 98.14 and 101.48%, and for labetalol, it was between 101.39 and 101.38%. The percentage recovery of robustness study found for valsartan and labetalol was between 98 and 102%. The limit of detection found for labetalol was 1.16 µg/mL and for valsartan it was 0.9 µg/mL. The quantification limit was achieved up to 3.52 and 2.72 µg/mL for valsartan and labetalol, respectively. Furthermore, the analytical greenness of the method was confirmed twice by utilizing the AGREE and GAPI greenness checker tools. Moreover, the method was applied to the estimation of the combined drug with the same medicinal applications in forensic science.

Metronidazole, a nitroimidazole antimicrobial, is used in combination with povidone iodine in the form of a topical ointment for treating and preventing skin infections in several skin conditions such as otitis externa, sycosis barbae, tinea infestations, cutaneous candidosis, burns, boils, or ulcers. The study presented is aimed at developing a stability-indicating method for the determination of metronidazole in the presence of povidone-iodine in dermatological formulations by a first-order derivative UV spectrophotometric method that provides an enhanced resolution of overlapping spectra. The λ_max was found at 319 nm for metronidazole and at 235 nm for povidone-iodine. First-order detection wavelength has been taken at 298 and 221 nm for metronidazole and povidone-iodine, respectively. Beer’s law was obeyed in a concentration range of 5–45 µg/mL with R² values of metronidazole and povidone of 0.999 and 0.9967, respectively, using distilled water as an economical solvent. The developed method was validated on various parameters such as accuracy, precision, robustness, limit of quantification and limit of detection. It can be perceived from the results that a minimum intraday and interday variation limiting below 2% of relative standard deviation was established. The percentage recovery using the stated method was worthy of characteristics with its label claim and found within the range 100.22–101%, within the acceptable limits of International Conference on Harmonization guidelines for the forced degradation and establishes a validated method for metronidazole and povidone-iodine and its main degradants in the active pharmaceutical ingredients (API) and the marketed formulations. The exclusivity of the presented first-order derivative UV spectroscopic method lies in it being simple, economical, safe, precise, accurate, and reproducible for future studies of the prediction of stability of the drugs in the marketed formulation. The technique is established to be unambiguous for the determination of a drug and its degradants.

Analyzing the drug substance serves as a crucial step in verifying the quality of the active pharmaceutical ingredient. This research is aimed at developing an isocratic high-performance liquid chromatography method for the quantitative analysis of ketoconazole in its stable form. The novelty of this work lies in its remarkable specificity and sensitivity, ensuring highly accurate results. Chromatographic separation was performed using an Xterra RP C18 column (250´3.0 mm) with a particle size of 5 μm, and detection was carried out with UV at 244 nm. The sequence run time was 8 min, with the average analyte peak eluting at 3.469 min while maintaining a flow rate of 1.0 mL/min. The preparation of both the sample and the mobile phase is rapid and highly economical, significantly reducing the chances of manual error. The analysis duration has been notably reduced to approximately 8 min, with the analyte eluting in under 5 min. This represents a significant improvement in efficiency compared with earlier reports. The method performance was validated following the current International Conference on Harmonization (ICH) guidelines, covering aspects such as specificity, system suitability, limits of detection (LOD) and quantification (LOQ), linearity, accuracy, and precision. Regression analysis revealed a correlation coefficient value of 0.9982. The LOD and LOQ were found to be 10 and 30 μg/mL respectively. The accuracy of the method was evaluated through a recovery study at levels of 80, 100, and 120%, and the values were found to be within the acceptable range (% relative standard deviation [RSD] less than 2%). The RSD for method precision experiments was found to be 1.0%, which complies with the ICH guidelines. This method was successfully developed for the estimation of ketoconazole using a straightforward and effective isocratic technique.

Sunitinib malate (SNM), a vital antineoplastic drug, needed a greener and more rapid spectrophotometric method for its pharmaceutical quantification. This study involves developing and validating two effective and environmentally friendly ultra-violet visible (UV–Vis) spectrophotometric methods for measuring SNM in bulk form and capsule formulations produced in-house. These methods were developed using the zeroorder UV–Vis spectrophotometry (method 1) and area under the curve (UV–Vis–AUC) (method 2) approaches. The method sensitivities and selectivity were optimized using ethanol as a green solvent, which was not found to be reported before for estimation of SNM. Both devised methods underwent validation to ensure precision, accuracy, and sensitivity to comply with the International Council for Harmonization Q2 R1 guideline. SNM was formulated as in-house capsules using microcrystalline cellulose. The validated methods were used to estimate SNM as a bulk assay from in-house capsules. The results demonstrated excellent Beer–Lambert linearity within 3–18 µg/mL with acceptable accuracy and adequate precision. The limit of detection (method I: 0.43 μg; method II: 0.15 μg) and limit of quantification (method I: 1.32 μg; method II: 0.45 μg) values confirmed the method’s sensitivity. Additionally, the method exhibited exceptional specificity and was free from interferences from used excipients. These newly developed UV-spectrophotometric method complies with principles for green analytical chemistry as assessed with the Analytical Greenness Assessment Tool and was found to be rapid, simple, cost-effective, and reliable for the routine analysis of SNM to assist with its pharmaceutical research in the future.