Zero-order Spectra Research Articles

Correlations study "structure – property" of model products reaction monosaccharides non-enzymatic coloring in ethanol media

Caramel compositions based on carbohydrates are available food colorants, additionally characterized by a set of practically significant properties, in particular, antioxidant activity. In the present work, the features of the chemical structure of caramels based on the most important monosaccharides – D-glucose, D-mannose and D-galactose, and their correlations with structure-dependent parameters, such as color and reducing capacity, are studied. The syn thesis of target products was performed in water-ethanol media (90% ethanol) in the presence of alkali with thin lay er chromatography (TLC) control and subsequent dialysis. The structural features of the condensed products of the non-enzymatic coloring reaction were studied by Infrared spectroscopy (IS), which were subsequently compared with the values of the reducing capacity expressed by permanganate oxidizability and color estimated by color indices. Qualitative and quantitative analysis of the mid infrared frequency (1800–1000 cm−1) of the initial zero-order spectra and their second derivatives indicates the presence of unsaturated (enolic) fragments (1600 and 1625 cm−1) in the caramel structure. In the spectrum of the D-mannose-based composition, low-frequency shifts of the bands to 1595 and 1620 cm−1 probably indicate a higher degree of enolization. The limiting component of the structure, represent ed by bound polyglycosides, appears in systems based on D-glucose and D-galactose (strengthening of the 1150 cm−1 band). The analysis of the values of structure-dependent parameters shows a decrease in the reducing capacity and color in the series of caramels based on D- mannose > D- glucose > D-galactose. It correlates with the increased con tent of reducing fragments (enols) in the structure of the first system and the excessive presence of bound non-re ducing forms in the structure of the latter, as well as the previously obtained data on the kinetics of caramelization, which forms the basis of the correlation model. Comparison of the reducing capacity and the total color index CI (EBC unit) of the studied products with similar indicators of ascorbic acid and class I food caramels characterizes them with fairly close values of the same order, which suggests further research in the direction of developing and scaling the technology for producing carbohydrate caramels under the described conditions.

Intelligent spectrophotometric resolution platforms for the challenging spectra of ipratropium and fenoterol in their combination inhaler with ecological friendliness assessment.

Asthma and chronic obstructive pulmonary disease (COPD) are the most common diagnoses for adults and children with respiratory tract inflammation. Recently, a novel fixed dose combination consisting of Ipratropium and Fenoterol has been released for the management and control of the symptoms of such disorders. The current research has newly developed andoptimizedthree smart, accurate,simple, cost-effective, and eco-friendly spectrophotometric methods that enabled the simultaneous determination of the drugs under study in their combined inhaler dosage form, without the need for any previous separation steps, using water as a green solvent. The strategy employed was based oncalculating oneor two factors as a numerical spectrum or constant, whichprovided thecomplete removal of any component in the mixture that might overlap and the mathematical filtration of the targeted analyte. The methods developed could be classified into twotypesof spectrophotometric windows. Window I; involved absorption spectrum in their original zero-order forms (°D), which included recently designed methods named induced concentration subtraction (ICS) and induced dual wavelength (IDW). While window III focused on the ratio spectrum as theinduced amplitude modulation (IAM) method. The extremely low absorptivity and lack of distinct absorption maximum in the zero-order absorption spectrum of Ipratropium were two intrinsic challenges that were better overcome by the proposed spectrophotometric methods than by the conventionally used ones. According to ICH guidelines, the proposed methods were validated using unified regression over range 2.0-40.0 µg/mL in the ICS method, while the linearity ranges for the IDW and IAM methods were 5.0-40.0 µg/mL of Ipratropium and 2.0-40.0 µg/mL of Fenoterol. Moreover, the three proposed methods were effectively used to assay the co-formulated marketed inhaler and further expanded to confirm the delivered dose uniformityin compliance with the USP guidelines. Finally, the established methods were evaluated for their greenness and blueness, in comparison to the official and reported analysis methods, using advanced cutting edge software metrics. Furthermore, the suggested techniques adhered well to the white analytical chemistry postulates that were recently published.

Independent concentration extraction as a novel green approach resolving overlapped UV–Vis binary spectra and HPTLC-densitometric methods for concurrent determination of levocloperastine and chlorpheniramine

BackgroundThe proposed research study introduces independent concentration extraction (ICE) as a novel UV–Vis spectrophotometric approach. The approach can be used for extracting the concentration of two analytes with severely overlapped spectra from their binary mixtures. ICE is based on spectral extraction platform involving simple smart successive methods that can directly extract the original zero order spectra of the analytes at their characteristic (λmax). Chlorpheniramine maleate (CPM) and Levocloperastine fendizoate (LCF) are two commonly co-formulated drugs in cough preparations. The combined mixture was used to confirm the validity of the developed ICE tool. Another less green HPTLC was developed for the first time to separate both drugs and help also in confirming the proposed tool.MethodsFor the simultaneous determination of CPM and LCF, two ecologically friendly techniques were employed. The first approach encompasses the use of the ICE spectrophotometric method that could be successively applied for extracting the concentration of two analytes with severely overlapped unresolved spectra in their binary mixtures. Other complementary methods aiming at original spectral extraction; including spectrum subtraction (SS) and unity subtraction (US) were also successfully employed to resolve the zero order spectra of the combined drugs with all their characteristic features and peaks. The second technique used, a high-performance TLC-densitometric one, was performed on silica plates with silica plates F254 and a mobile phase with a ratio of 3:3:3:1 by volume of toluene, ethanol, acetone, and ammonia as a developing system at 230 nm.ResultsThe presented extraction approach was executed without any optimization steps or sample pretreatment for the simultaneous determination of CPM and LCF. The method was found to be valid for their determination within concentration range of 3.0–30.0 μg mL−1 for both drugs. For HPTLC method, the resulting Rf values of CPM and LCF were 0.37 and 0.78, within concentration ranges of 0.3–4.0 μg/spot and 0.8–10.0 μg/spot, respectively. Greenness assessment of both developed methodologies showed that the HPTLC method is less green than the spectrophotometric method, yet with comparable sustainability when it comes to the used technique.ConclusionThe procedures were found to be selective, accurate, and precise for analysis of the studied binary mixture. Furthermore, the environmental impact of the introduced methods was assessed using novel greenness metrics, namely AGREE and Green Analytical Procedure Index (GAPI) to prove their ecological safety. In addition, white analytical chemistry (WAC) evaluation metric was employed to ensure the synergy and coherence of analytical, practical, and ecological attributes.

Risk assessment based on spectrophotometric signals used in eco-friendly analytical scenarios for estimation of carvedilol and hydrochlorothiazide in pharmaceutical formulation

Special attention is given to the pharmacological treatment of combined medication of Carvedilol and hydrochlorothiazide which is the most effective and the most beneficial therapy for hypertensive patients with diabetes and various metabolic comorbidities. This work represents spectrophotometric platform scenarios based on factorized spectrum (FS) using interpoint data difference resolution scenarios (IDDRS) coupled with spectrum subtraction method (SS) for the concurrent quantification of carvedilol (CAR) and hydrochlorothiazide (HCT) when present together in a combination without the need for any initial physical separation steps. This IDD resolution scenario based on manipulating the zero-order spectra (D0) of both drugs in the mixture with various spectral features at different wavelength regions (200–400 nm), region I (220–250 nm), region II (240–300 nm) and region III (270–320 nm) via absorbance resolution (AR) and induced absorbance resolution (IAR) methods coupled with corresponding spectrum subtraction (SS). The calibration curves were established across the linearity ranges of 2.0–12.0 µg/mL at 242.50 nm and 4.0–40.0 µg/mL at 285.5 nm for CAR and 1.0–11.0 µg/mL at 226.10 nm and 2.0–20.0 µg/mL at 270.5 nm for HCT. Moreover, methods’ validation was confirmed via ICH guidelines. A Multicenter comparison between sensitivity, specificity in respect resolution sequence were applied using different wavelength regions with various concentration ranges was applied and finally spectral resolution recommendation is issued and cumulative validation score (CVS) is calculated as an indicator in the risk analysis. In quality control laboratories, the studied approaches are applicable for conducting analysis on the mentioned drugs. In addition, the selection of spectrophotometry aligns with the principles of green analytical chemistry, an approach that resonates with the overarching theme of minimizing environmental impact. Via four metric tools named: analytical greenness (AGREE), green analytical procedure index (GAPI), analytical eco-scale, and national environmental method index (NEMI), methods’ greenness profile was guaranteed.

Simultaneous spectrophotometric and chromatographic determination of Ketorolac and Dexamethasone: Overall assessment regarding environmental Impact, Practicality, and functionality principles

Determination of a drug combination that contains a minor component that is also a poorly UV absorbing analyte represents greet challenges in drug analysis. A fixed-dose ophthalmic combination of ketorolac tromethamine (KET) and dexamethasone sodium phosphate (DEX) (in the ratio of 5:1) is used to relieve post-surgical inflammation and seasonal allergic conjunctivitis due to their analgesic and anti-inflammatory activity. Five spectrophotometric methods and a reversed phase chromatographic separation method were developed and validated for simultaneous determination of both drugs in lab-prepared eye drops. Direct spectrophotometric determination of KET (the major, highly UV absorbing analyte) was achieved from the zero-order UV absorption spectra at 323 nm while DEX (which is the minor, poorly UV absorbing analyte) was quantified after applying several spectrophotometric methods. Either fundamental zero-order spectra or ratio spectra were used, and measurements were done at either single or dual wavelengths. The developed methods were: isosbestic point method, absorption factor method, dual wavelength method, ratio difference UV spectrophotometric method, and simultaneous equation method. The developed spectrophotometric methods determine KET in the linearity range of 2.0–12.0 μg/mL and DEX in the range of 5.0 – 35.0 μg/mL. For accurate spectrophotometric determination of DEX in the ratio of the dosage form, multiple standard addition method was applied. HPLC technique was also applied for separation and quantification of both drugs. Chromatographic separation was attained by using Hypersil ODS-C18 (150 x 4.6 mm, 5 μm) column. The mobile phase was composed of 50 % methanol: 50 % phosphate buffer (pH 2.5). The column compartment was maintained at 25 °C. Flow rate was adjusted at 1.2 mL/min and detection was performed by DAD at 254 nm. The linearity of HPLC method was 5.0–100.0 μg/mL, and 5.0–50.0 μg/mL for KET and DEX, respectively. Simultaneous determination of both drugs was applied to lab-prepared eye drops that contain also benzalkonium chloride as inactive ingredient. The developed methods determined the cited drugs with good and acceptable % recovery. The results of the developed methods and a reported HPLC method were compared using one-way ANOVA test, F-test and student’s t-test at confidence level 95 %, and they show no significant statistical difference. Assessment of greenness of the developed methods in comparison with reported HPLC method was performed using different tools, including analytical eco-scale, GAPI and AGREE. HPLC-EAT was also performed to ensure greenness of developed HPLC method. Moreover, assessment of practicality, applicability, and functionality of developed and reported methods was evaluated by BAGI metric tool and WAC calculator, respectively. The developed methods allow simple, rapid, and accurate analysis of quality control samples that contain KET and DEX.

Green analytical chemistry-based spectrophotometric techniques for ternary component analysis of pain relievers

BackgroundThe management of pain presents a significant challenge in healthcare, particularly in cases where conventional therapies prove inadequate. In response to this need, this study aims to devise two innovative UV spectrophotometric techniques rooted in the principles of green analytical chemistry for the analysis of Aceclofenac (ACE), Paracetamol (PAR), and Tramadol (TRM) in both bulk and tablet forms.ResultsUtilizing advanced mathematical methodologies such as the double divisor ratio spectra method and area under the curve, the concentrations of these drugs were accurately determined. Validation of the developed methods adhered to the guidelines outlined by the International Council for Harmonisation in the Q2 (R1), revealing linear calibration curves for ACE (8–12 µg/mL), PAR (22.75–35.75 µg/mL), and TRM (2.62–4.12 µg/mL). Furthermore, statistical analyses employing Student’s t test and F test were conducted to ensure the robustness of the proposed method. The evaluation of environmental impact through green metric tools confirmed the eco-friendliness of the proposed methodologies.ConclusionThe assessment performed utilizing green metric tools has substantiated the environmental sustainability of the proposed approach. Thus, this methodology offers accurate and reliable outcomes for the determination of three drugs, as indicated by the complete overlap observed in the zero-order spectra.

Spectroscopic In-Vitro Drug-Drug Interaction Studies of Amoxicillin and Paracetamol Solid Dosage Forms

Potential drug-drug interactions (DDIs) are a public health concern in clinical therapy and drug development because of their contribution to actual adverse drug reactions (ADRs) or events. The study aimed to quantify the in-vitro drug-drug interaction of amoxicillin (AMX) and paracetamol (PCM) formulations which are commonly co-administered. Determinations were carried out by spectroscopic methods – zero-order and derivative spectroscopy. The data were analyzed using Microsoft Excel, 2016. The UV-Spectra of AMX and PCM showed two distinctive peaks at 240 nm and 260 nm were observed for AMX, while for PCM at 290nm and 340 nm, with maxima at 240 nm and 340 nm for AMX and PCM respectively. Absorption measurements were taken at the maximum wavelength of 290 nm and 240 nm for PCM and AMX respectively. The content of both drugs and potential DDIs of AMX and PCM were assayed by zero- and 3rd-derivative spectroscopy. The calibration curves for AMX and PCM standards showed good linearity at concentrations, with corresponding correlation coefficients (R) being 0.999 and 0.998. The intercept and slope for AMX were -0.0148 and 0.0732 respectively, while for PCM values were 0.0071 and 0.148. The content of PCM and AMX in the formulations was 98.40 ± 0.44% and 96.04 ± 0.29% respectively. The joint-drug-dissolution studies for AMX and PCM interaction (DDI) were obtained with the 3rd-order derivative spectroscopy at 210 nm (zero-crossing for PCM) and 290 nm (zero-line crossing for AMX) respectively - which showed overlapping spectra for their zero-order derivative spectra. No significant difference was observed in the in-vitro drug release profiles for AMX and PCM, while comparative profiles were observed to have a very strong correlation between individual-release and joint-release profiles.

Simultaneous Determination of Isoniazid and Pyridoxine Hydrochloride in Tablet Dosage Forms using Ratio Subtraction Spectrophotometry

<p>The study focused on the simultaneous quantification of Isoniazid (INH) and Pyridoxine Hydrochloride (PRD) in tablet form, commonly used in antituberculosis treatments. Assessing the accurate concentration of both INH and PRD in tablets is vital to ensure their effectiveness, safety, and quality. Using the ratio subtraction spectrophotometry method, the study analyzed INH and PRD in Pehadoxin forte® tablets (batch no. 36057007, PT. Phapros, Indonesia), with 0.1 N HCl as the solvent. The method involved obtaining ratio absorption spectra by dividing the absorption spectra of INH and PRD, respectively, to derive zero-order spectra for each drug. Method validation parameters included linearity, accuracy, precision, Limit of Detection (LOD), and Limit of Quantification (LOQ). The results showed linearity values of 0.9985 for INH and 0.9988 for PRD. Accuracy was 98.1838% for INH and 100.0205% for PRD, while precision was 1.8769% for INH and 0.2037% for PRD. LOD and LOQ for INH were 0.8116 µg/mL and 2.7053 µg/mL, respectively, and for PRD, 1.3127 µg/mL and 4.3757 µg/mL. The levels of INH and PRD in the tablets were found to be 102.1157% and 101.3874%, aligning with the Indonesian Pharmacopoeia's standards. This methodological approach provides a reliable analytical tool for the simultaneous assessment of INH and PRD in tablets, potentially extendable to other drug combinations and formulations, thereby contributing to pharmaceutical quality control processes. </p>

Quality improvement to holographic microscopy reconstruction based on Kramers-Kronig relations and phase background fitting.

Spectrum aliasing in off-axis digital holography may result in poor image reconstruction quality. This study proposes a method to eliminate the zero-order spectrum and enhance image quality based on Kramers-Kronig relations and phase background fitting. The Kramers-Kronig relations are employed to derive the quotient of the complex wavefront of object and the reference beam, and phase background fitting is performed in a compensatory way to yield the object complex wavefront. The effectiveness of the proposed approach is validated via simulations and experiments. The results show significantly improved off-axis digital holographic microscopy reconstruction quality, making the proposed method a promising option for holographic microscopy imaging.

A method for suppressing spectrum aliasing of off-axis digital holograms based on Kronecker interpolation and backpropagation

The research proposes a new method to solve the spectrum aliasing and improve the resolution of off-axis digital holograms based on Kronecker interpolation and backpropagation algorithms. The method suppresses the direct current (DC) image and increase the low-frequency information with Kronecker interpolation of the hologram. The size of the Fresnel reconstructed image can be controlled with the reconstruction distance, and this feature is used to select the appropriate reconstruction distance for the Fresnel amplitude reconstruction of interpolated holograms to separate the real and imaginary images. To obtain the complete first-order spectral information for the object, the amplitude of the desired image is obtained with spatial domain filtering and then inverted. Finally, the amplitude and phase of the object are reconstructed according to the angular spectrum reconstruction algorithm. The results show that the method can solve the spectrum aliasing problem of the holograms and thus improve the resolution of off-axis holograms. In addition, the background noise of the reconstructed phase is reduced because the influence of the zero-order spectrum can be completely avoided.

The effectiveness of multivariate and univariate spectrophotometric techniques for the concurrent estimation of ornidazole and ciprofloxacin HCl in tablet formulation and spiked serum: estimating greenness and whiteness profile

In this manuscript, the effectiveness of multivariate and univariate tools in conjunction with spectrophotometric techniques was evaluated for the concurrent analysis of ciprofloxacin (CI) and ornidazole (OR) in prepared mixtures, tablets, and human serum. The artificial neural network was chosen as the multivariate Technique. Bayesian regularization (trainbr) and Levenberg–Marquardt algorithms (trainlm), were constructed and trained using feed-forward back-propagation learning. The optimal logarithm was determined based on mean recovery, mean square error of prediction (MSEP), relative root mean square error of prediction (RRMSEP), and bias-corrected MSEP (BCMSEP) scores. Trainbr outperformed trainlm, yielding a mean recovery of 100.05% for CI and 99.84% for OR, making it the preferred algorithm. Fourier self-deconvolution and mean-centering transforms were chosen as the univariate Techniques. Fourier self-deconvolution was applied to the zero-order spectra of ciprofloxacin and ornidazole by electing an appropriate full width at half maximum, enhancing peak resolution at 380.1 nm and 314.2 nm for CI and OR, respectively. Mean centering transform was applied to CI and OR ratio spectra to eliminate constant signals, enabling accurate quantification of CI and OR at 272.0 nm and 306.2 nm, respectively. The introduced approaches were optimized and validated for precise CI and OR analysis, with statistical comparison against the HPLC method revealing no notable differences. The sustainability of these approaches was confirmed through the green certificate (modified eco-scale), AGP, and whiteness-evaluation tool, corroborating their ecological viability.

Derivative spectroscopy and wavelet transform as green spectrophotometric methods for abacavir and lamivudine measurement

Herein, two different sustainable and green signal processing spectrophotometric approaches, namely, derivative spectroscopy and wavelet transform, have been utilized for effective measurement of the antiretroviral therapy abacavir and lamivudine in their pharmaceutical formulations. These methods were used to enhance the spectral data and differentiate between the absorption bands of abacavir and lamivudine in order to accurately measure their concentrations. For determining abacavir and lamivudine, the first derivative spectrophotometric method has been applied to the zero-order and ratio spectra of both drugs. The same approach has been tested using the continuous wavelet transform method where a second order 2.4 of rbio and bior wavelet families were found to be optimum for measuring both drugs. Validation of the proposed methods affirmed their reliability in terms of linearity over the concentration range 1.5–30 µg/mL and 1.5–36 µg/mL for abacavir and lamivudine, respectively, precision (RSD < 2 %), and accuracy with mean recoveries ranging between 98 % and 102 %. Additionally, these spectrophotometric methodologies were applied to real pharmaceutical preparations and yielded results congruent with a prior chromatographic method. Most prominently, the proposed methods stood out for their greenness and sustainability with 97 points as evaluated by the analytical eco-scale method and a score value of 0.79 as analyzed by AGREE method, thereby making them suitable for resource-limited settings and highlighting the potential for broader application of green analytical methods in pharmaceutical analysis.

Three new, UV spectrum filtration protocols for the synchronous quantification of ciprofloxacin HCl and ornidazole in the existence of ciprofloxacin-induced degradation compound

Three new spectrum filtration protocols have been developed and adapted to overcome some difficulties in dealing with highly overlapping triple drug mixtures by proposing new smart mathematical techniques that facilitate the resolution of the ternary mixture and the recovery of a filtrated zero-order spectrum (D0 spectrum) of each component without any overlapping from the accompanying components. The three established spectrophotometric protocols were conducted on the combination of ciprofloxacin hydrochloride and ornidazole as a green alternative to the usual chromatographic technique: the first protocol is ratio difference-isosbestic points coupled with ratio difference-areas under the curve (RD-ISO/RD-AUC); the second protocol is ratio difference-isosbestic points coupled with dual-wavelength equation (RD-ISO/DWE); and the third protocol is signal retrieval by zero-crossing point (SRZ). All three developed protocols have the power to recover a filtrated zero-order spectrum of each ornidazole and ciprofloxacin hydrochloride without any involvement from the ciprofloxacin-induced degradation substance through processing their spectral data either in the zero-order spectrum, ratio spectrum, or derivative spectrum. The correctness of the spectral filtration process for each protocol was checked by involving the spectral print recognition index to ensure the drug's purity and freeness from impurities or degradation products. The validation process was performed as per the directions of ICH, which confirmed the effectiveness of the elaborated protocols and their usability as daily analysis methods with a linearity range of (3.5–15 μg/ml) for ciprofloxacin in (RD-ISO/RD-AUC) and (RD-AUC/DWE) protocols and (1.5–15 μg/ml) in (SRZ) protocol; and a linearity range of (3–20 μg/ml) for ornidazole in (RD-ISO/RD-AUC) and (SRZ) protocols and (3–15 μg/ml) in (RD-ISO/DWE) protocol. A statistical comparison and greenness evaluation utilizing NEMI, AGREE, GAPI, and CALIFICAMET-HEXAGON tools were made with the reference approach, confirming no statistical variations and a better greenness profile for the newly established protocols.

State-of-the-art mathematically induced filtration approaches for smart spectrophotometric assessment of silodosin and solifenacin mixture in their new challenging formulation: Multi-tool greenness and whiteness evaluation

Benign prostatic hyperplasia is one of the most predominant health disorders in men with increasing incidence by age and usually accompanied with other bothersome symptoms. A new fixed dose combination, containing Silodosin and Solifenacin, has been recently launched for relieving such disorder associated with overactive bladder syndrome. In the current work, three smart, innovative and white spectrophotometric methods have been newly developed and optimized for simultaneous determination of the studied drugs in their binary mixture using water as an eco-friendly solvent. The adopted strategy relied on calculation of one or two factors as numerical constant or spectrum allowing mathematical filtration of desired analyte and full removal of any overlapped components in the mixture. The developed methods are categorized over two spectrophotometric platform windows. Window I deals with absorption spectra in its native forms (zero-order) including a newly developed method termed induced concentration subtraction (ICS) as well as induced dual wavelength (IDW) methods. Whereas window III is concerned with ratio spectra as in induced amplitude modulation (IAM) method. Compared to classical spectrophotometric methods, the proposed ones are superior in overcoming the inherited challenges in zero-order absorption spectrum of Solifenacin, particularly its very low absorptivity and lack of unique absorption maximum. Validity of the methods were thoroughly assured as per ICH guidelines with unified regression over 3.0–50.0 µg/mL in ICS method while IDW and IAM ones possessed linearity ranges of 3.0–50.0 µg/mL of Silodosin and 5.0–60.0 µg/mL of Solifenacin. The work was also extended to verify content uniformity of dosage units in accordance with USP recommendations. Greenness profile of the proposed methods was clearly assessed, in comparison to the reported analysis ones, via state-of-the-art software metrics, namely, green solvent selection tool (GSST), complementary green analytical procedure index (ComplexGAPI) and analytical greenness (AGREE). Finally, the proposed methods were in good adherence to the recently published postulates of white analytical chemistry.

Innovative UV Protocols Based on Straightforward Mathematical Filtration for Concurrent Estimation of Two Antidiabetic Drugs in Their Brand-New Combination: A Comparative Study.

In 2019, the U.S. Food and Drug Administration approved a brand-new combination of linagliptin and empagliflozin in a formulation called Glyxambi® tablets for managing type 2 diabetes mellitus. Nowadays, spectrophotometric techniques occupy the first place among their peers in terms of ease of application, friendliness to the environment, and low costs. This research discusses the development of two very simple spectrophotometric protocols based on zero-order spectra for the determination of linagliptin and empagliflozin. The developed protocols were the induced dual-wavelength and absorption correction protocols. Linagliptin could be determined directly at 305 nm, at which the empagliflozin spectrum was zero-crossing. Empagliflozin was determined using the two developed protocols. The induced dual-wavelength technique was developed by calculating the equality factor of linagliptin to cancel its interference. The absorption correction technique was developed by measuring the correction absorption factor. The concentration ranges of linagliptin and empagliflozin were 1-10 µg/mL and 3-30 µg/mL, respectively. Excellent recovery results were found in bulk, dosage form, and synthetic mixtures. Low LOD and LOQ values were obtained, indicating the high sensitivity of the protocols. The statistical Student's t-test was performed to compare the results of the applied and reported protocols, indicating no difference between them. The proposed protocols have the advantages of being straightforward, affordable, and requiring no sophisticated manipulations, just simple mathematical calculations. The proposed protocols are acceptable for routine usage in QC laboratories and in future research applications. Two novel univariate methods were developed for quantitative analysis of linagliptin and empagliflozin in their pharmaceutical and laboratory mixtures, and produced satisfactory results.

High-resolution reconstruction of spectrum-overlapped off-axis holography by deflecting reference beam of Gaussian symmetry

In digital holography, extracting the +1-order spectrum accurately and making full utilization of the spatial bandwidth of the CCD sensor are essential for high-resolution and artifacts-free quantitative phase imaging. In this paper, using the light intensity symmetry of the Gaussian laser beam, we delicately eliminate the zero-order spectrum by means of subtraction of two off-axis hologram spectra acquired by symmetrically deflecting the reference beam. Therefore, the +1-order spectrum can be extracted accurately even if it is completely overlapped with the zero-order spectrum. Compared with phase-shifting methods, such as pi-phase and random phase, which require accurate control or calculation of the phase-shifting amount, this proposed method does not need to precisely control the deflection angle of reference beam. Being achievable the maximum utilization of half-space bandwidth of the CCD sensor, the proposed method has realized high-resolution imaging demonstrated by the experimental results of three specimens. This method has general applications in digital holography, such as eliminating the zero-order spectrum and extracting the +1-order spectrum.

Spectrum subtraction as a complementary method for six resolution techniques resolving overlapping spectra; application to multicomponent veterinary formulation with greenness and whiteness assessment

Mathematical filtration is an efficient tool to resolve the overlapping spectra of binary mixtures in zero or first order form. Herein, a comparative study was conducted between six economic, accurate and precise spectrophotometric methods for determination of Triclabendazole (TCB) and Levamisole HCl (LVM). Each component was resolved with minimum mathematical steps in its zero-order absorption spectrum by ratio subtraction, constant multiplication, and the recent factorized response method; coupled with spectrum subtraction. In addition, the mixture was resolved in its first derivative form by derivative subtraction, D1 constant multiplication, and the recent D1 factorized response method; coupled with spectrum subtraction. Results obtained were also compared to those obtained from constant value, concentration value, and derivative ratio methods. The linearity range was found to be either 1.0–10.0 µg/mL or 2.0–20.0 µg/mL for TCB, and 2.0–14.0 µg/mL for LVM with LOD of 0.08 µg/mL and 0.19 µg/mL, respectively. Validation of the proposed methods was performed according to VICH guidelines. Results obtained from the statistical data showed no significant difference regarding accuracy and precision compared to the reported methods. The developed spectrophotometric methods followed the principles of green analytical chemistry, in which the green assessment was done through four tools, called, National Environmental Methods Index (NEMI), Analytical Eco-Scale (AES), Green Analytical Procedure Index (GAPI) and Analytical greenness metric (AGREE). Also, a white assessment was performed using RGB model. The proposed methods could offer an economic alternative for the routine analysis of bulk materials and combined veterinary dosage form.Graphical

Development and Validation of Derivative UV Spectrophotometric method for Simultaneous Determination of Amoxicillin and Clavulanic acid in Tablets (Augmentin 1000mg)

The simultaneous analysis of pharmaceutical mixtures by classical spectrophotometric methods without prior separation is a challenge owing to the strong overlapping of their zero order spectra (low selectivity). Hence, several techniques have been developed for solving this problem, such as derivative spectrophotometry. The aim of this study was to develop a simple, fast, accurate, precise, economical, and eco-friendly derivative spectrophotometric method for the quantitative determination of a binary mixture of amoxicillin (Amox) and clavulanic acid (Clav) without prior separation steps. The developed method is based on the use of first derivative spectra resulting from derivatisation of zero order, with using these parameters (d𝛌=4 and scaling factor=15). The measurements were achieved by using zero-crossing technique (𝛌= 278.5nm for Amox and 𝛌= 228.3nm for Clav), which eliminated the overlapping caused by two drugs and excipients of tablets. The method showed significant linearity in the range (5 45μg/ml with =0.9998) and (1 - 10μg/ml with =0.9986) for Amox and Clav, respectively. The developed technique was validated according to the ICH guidelines. The method was successfully utilized for the simultaneous determination of Amox and Clav in the formulation. The obtained results were statistically compared with the reported method (HPLC) by applying t-test and F-value at 95% confidence level. No significant difference was observed regarding accuracy and precision. Hence,the proposed procedure can be utilized for regular quality control studies as alternative to chromatographic techniques.

Utilization of Chemometric Aided UV- Spectrophotometric Methods for Concurrent Assessment of Emtricitabine, Tenofovir Disoproxil Fumarate, Elvitegravir and Cobicistat in Tablet Formulation.

Emtricitabine (ETC), Tenofovir disoproxil fumarate (TNF), Elvitegravir (EVG), and Cobicistat (CBS) are antiviral drugs used to treat human immunodeficiency virus (HIV) infections. To develop chemometric-aided UV spectrophotometric methods for concurrent estimation of the aforementioned drugs used to treat HIV. This method can be used to reduce the modification of the calibration model by assessing the absorbance at various points in the zero-order spectra within the selected wavelength range. Additionally, it eliminates interfering signals and provides sufficient resolution in multi-component systems. Two Chemo-metric assisted UV-spectrophotometric methods, namely, partial least square (PLS) and principal component regression (PCR) models, were established for the concurrent assessment of EVG, CBS, TNF, and ETC in tablet formulations. The proposed methods were applied to decrease complexity of overlapped spectra and to achieve maximum sensitivity and the lowest error. These approaches were performed in accordance with ICH criteria and compared to the reported HPLC method. The proposed methods were used to assess EVG, CBS, TNF, and ETC in the range of 5-30 µg/mL, 5-30 µg/mL, 5-50 µg/mL and 5-50 µg/mL, respectively, with an excellent correlation coefficient (r ≥ 0.998). The accuracy and precision results were found to be within the acceptable limit. No statistical difference was observed between the proposed and reported studies. The chemometric aided UV-spectrophotometric approaches could be taken into consideration as an alternative of chromatographic procedures in the pharmaceutical industry for routine analysis and testing of readily accessible commercial formulations. Novel chemometric-UV assisted spectrophotometric techniques were developed for assessment of multicomponent antiviral combinations in single tablet formulations. The proposed methods were performed without using harmful solvents, tedious handling, or expensive instruments. The proposed methods were compared statistically with reported HPLC method. Assessment of the EVG, CBS, TNF, and ETC was performed without interference from excipients in their multicomponent formulations.

Effective spectrophotometric methods for resolving the superimposed spectra of Diclofenac Potassium and Methocarbamol

The UV spectra of Diclofenac Potassium DIC and Methocarbamol MET are superimposed making their analysis using direct or derivative spectrophotometric methods quite complicated. This study presents four effective spectrophotometric methods that enable simultaneous determination of both drugs without interference. The first method is based on application of simultaneous equation method on their zero order spectra where DIC has shown absorbance maxima at 276 nm and MET displays two absorbances maxima at 273 nm and 222 nm in distilled water. The second method relies on dual wavelength method, the two wavelengths (232 and 285 nm) were chosen for determination of DIC where the absorbance differences at these wavelengths are proportional to DIC concentration while the absorbance differences of MET are equal to zero. For the determination of MET, the two wavelengths (212 and 228 nm) were selected. The third method of first-derivative ratio has been applied where the derivative ratio absorbances of DIC and MET were measured at 286.1 and 282.4 nm, respectively. The fourth method utilizing ratio difference spectrophotometric (RD) method was eventually performed on the binary mixture. The amplitude difference between the two wavelengths (291and 305 nm) was calculated for DIC estimation while the amplitude difference between the two wavelengths (227and 273 nm) for MET determination. All methods show linearity range from 2.0–25 μg. mL−1 and 6.0–40 μg. mL−1 for DIC and MET respectively. The developed methods have been statistically compared with a reported method based on first derivative method and the results of statistical comparison confirm the accuracy and precision of the proposed methods therefore they can be effectively applied for determination of MET and DIC in pharmaceutical dosage form.