Green Spectrophotometric Method Research Articles

Development and validation of a green spectrophotometric method for simultaneous determination of combined pharmaceutical dosage form (paracetamol and caffeine) using chemometrics technique in comparison with HPLC

Development and validation of a green spectrophotometric method for simultaneous determination of combined pharmaceutical dosage form (paracetamol and caffeine) using chemometrics technique in comparison with HPLC

Utilization of absorbance subtraction and ratio difference green spectrophotometric methods for the quantification of alfuzosin hydrochloride and tadalafil in their binary mixture

Alfuzosin hydrochloride and tadalafil fixed-dose combination tablets were recently formulated for the treatment of individuals with lower urinary tract symptoms caused by benign prostatic hyperplasia. Herein, the first spectrophotometric methods for quantitative analysis of alfuzosin hydrochloride and tadalafil in their binary mixture were established. The spectral overlapping of alfuzosin hydrochloride and tadalafil made direct simultaneous analysis unfeasible. Therefore, two mathematical methods were used to solve these overlapping spectra: absorbance subtraction and ratio difference. The absorbance subtraction method manipulates the zero absorption spectra of the studied drugs at the isoabsorptive point (272 nm) and uses the absorbance factor of pure ALF to calculate the absorbance of the studied drugs in the mixture at the isoabsorptive point. The ratio spectra method, on the other hand, manipulates the ratio spectra of the studied drugs, which are obtained by dividing each drug’s zero absorption spectra by a divisor spectrum from the second drug. The ratio amplitude difference between 251 nm and 211 nm was directly proportional to alfuzosin hydrochloride, whereas between 292 nm and 222 nm it was directly proportional to tadalafil. The methods used were verified in accordance with the recommendations of the ICH and demonstrated adequate linear regression in working ranges of 1–15 µg/mL for alfuzosin hydrochloride and 3–40 µg/mL for tadalafil. The methods were accurate, precise, and selectively employed to quantify alfuzosin hydrochloride and tadalafil in their combined tablets.

Green Spectrophotometric Method for the Determination of Tigecycline in Different Matrices

Green Spectrophotometric Method for the Determination of Tigecycline in Different Matrices

Greenness appraisal and development of validated spectrophotometric methods for assay of amprolium: Comparative study using Analytical Eco-Scale, GAPI, and AGREEmetric approaches

Intestinal coccidiosis is a serious parasitic disease in poultry. Amprolium hydrochloride(AMP) is widely used for the treatment and prevention of coccidiosis. Three simple and green spectrophotometric methods have been developed for assay of AMP in bulk powder and in dosage form. The first method relies on measuring the first derivative (D1) spectrum at Δλ= 3 nm of AMP. This D1 spectrum possesses a characteristic peak at 234 nm. The second method relies on measuring the difference spectrophotometry (ΔA) and its first derivative (ΔD1) spectra of the drug solutions in 0.1 N HCl against the corresponding solutions in 0.1 N NaOH. The value of amplitudes of ΔA and ΔD1 (∆λ = 3 nm) were measured at 248 and 240 nm, respectively. The third method involves a colorimetric reaction with KMnO4 in alkaline medium and measuring the colored product at 610 nm. The developed methods were validated in accordance with ICH guidelines and evaluated for greenness using three greenness metrics; Analytical Eco-Scale (AES), Analytical GREEness calculator (AGREE), and Green Analytical Procedure Index (GAPI). All proposed methods showed excellent simplicity as they don't require sophisticated instrumentation or tedious analytical procedure steps.

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.

Green Spectrophotometric Method for Determination of Mesalazine Drug by Oxidative Coupling Reaction with Phenoxazine

A novel green, straightforward, and precise spectrophotometric method for determination of mesalazine drug has been developed. This method relies on an oxidative coupling reaction between mesalazine and the environmentally friendly phenoxazine reagent in an acidic medium within the presence of potassium iodate as an oxidizing agent. The resulting colored product exhibits maximum absorbance at 549 nm. The calibration graph was rectilinear over the range of 0.2- 30 µg mL-1 (1.31×10-6 -1.96×10-4 mol L-1 ) with determination Coefficient (R2 ) of 0.9994 and molar absorptivity of 4.8×103 L mol-1 cm-1 . The limits of detection and quantitation were found to be 0.191 and 0.638 µg mL-1 , respectively. The average recovery percentage was 100.9 with a relative standard deviation less than 3.1. The proposed method was effectively applied to determine mesalazine in tablet dosage forms from three different sources, yielding highly satisfactory results that closely align with the standard method outlined in the British Pharmacopeia.

Exciting Advances in Sustainable Spectrophotometric Micro-Quantitation of an Innovative Painkiller "Tramadol and Celecoxib" Mixture in the Presence of a Toxic Impurity, Promoting Greenness and Whiteness Studies.

Tramadol (TRM) and celecoxib (CLX) form a novel mixture that helps relieve acute pain when other painkillers have no action. It is also reported that these drugs, TRM and CLX, are used to control COVID-19 symptoms. The current work highlights three important pillars of modern pharmaceutical analysis, which are as follows; impurity profiling, greenness/whiteness studies and simplicity accompanied by sensitivity. Since 4-methyl acetophenone inhibits the human carbonyl reductase enzyme (type I) and since this compound may pose a health risk, it is crucial to regulate its concentration in all dosage forms of CLX. Two simple and green spectrophotometric methods were developed, namely third derivative (D3) and Fourier self- deconvulation (FSD), for resolving severely overlapped spectra of TRM and CLX in the presence of 4-methyl acetophenone (4-MAP) as a process-related impurity in their novel tablet combination. The two approaches showed acceptable linearity with an excellent correlation coefficient. In both methods, TRM was measured when CLX and 4-methyl acetophenone were zero-crossing. The same procedure was applied for measuring CLX and its process-related impurity 4-MAP. The methodologies developed were thoroughly validated in compliance with ICH (International Council on Harmonisation) guidelines. Student t- and F-tests revealed no statistically significant variation among the current methods and the reported method. No spectrophotometric methods have been published previously for the simultaneous analysis of TRM and CLX along with 4-MAP. As a result, the newly developed spectrophotometric approaches have great relevance and originality in the field of pharmaceutical analysis.

Spectrophotometric determination of monosodium glutamate in instant noodles’ seasonings and Chinese salt by ligand exchange complexation

A simple green spectrophotometric method was developed and validated for determination of non chromophoric substance; monosodium glutamate (MSG) by its reaction with a metal complexing agent; iron (III) salicylate. The color of the reagent measured at 525 nm fainted with increased absorbance at 299 nm upon addition of MSG, suggesting a ligand exchange reaction. Different parameters that may affect the reaction in the method were investigated such as: iron (III) salicylate concentration, pH, ionic strength and time of the reaction. The developed method was validated according to the guidelines of the International Conference on Harmonization (ICH). The linearity range was 250-2500 µM with correlation coefficient 0.9988. The limits of detection and quantitation were 71.5 µM and 216.76 µM. The developed method was successfully applied for determination of MSG in instant noodles’ seasoning and the Chinese salt and statistically compared to a reported HPLC method and good agreement was observed. The method shows advantages over other published spectrophotometric methods and was suitable for routine analysis of MSG in food preparations.

Charge transfer based green spectrophotometric method to determine remogliflozin etabonate applying response surface methodology supported with computational studies in pharmaceutical formulations

Spectrophotometric and computational methods were recognized to determine remogliflozin etabonate (RGE) in pharmaceutical formulations. Remogliflozin’s charge-transfer interaction is significant in pursuing its receptor-effective mechanisms. It helps develop a trustworthy charge-transfer-based spectrophotometric evaluation for remogliflozin with 2, 3-dichloro 5, 6-dicyano 1, 4-benzoquinone (DDQ) and 7,7,8,8-tetracyanoquinodimethane (TCNQ) in its pharmaceutical formulation. The spectrophotometric studies were performed at 445 and 750 nm against the reagent reference for the RGE–DDQ and RGE–TCNQ complexes. The optimization was accomplished by occupying the response surface methodology (RSM) combined with Box-Behnken design (BBD) which included three independent parameters: RGE concentration, DDQ concentration and reaction time. The energy differences associated with the charge transfer band formation were investigated at room temperature. The molar absorptivity and formation constant were attained by employing the Benesi-Hildebrand plot. The method was validated per the International Conference on Harmonization (ICH) guidelines. The current investigation’s linearity was within the range of 10–25 and 5–20 μg/mL, respectively, for the RGE–DDQ and RGE–TCNQ complexes. The formation constant (K) and Gibbs free energy (ΔG°) were found to be 4.58 × 101, 4.55 × 102 L mol−1 and – 2.13 × 103, – 3.6 × 103 k J mol−1, respectively. The results were reproducible with the analysis completed with pharmaceutical dosage samples. The proposed method's greenness profile was determined by applying the Eco-scale protocol. In the forced degradation findings, the degradation amount was within 5–20% as per the ICH guidelines. The extracted RGE was characterized using FTIR spectroscopy and supported with simulated vibrational IR, NMR and UV-visible spectroscopy. The electronic and spectral properties of RGE were examined, and the findings will be useful for further research on RGE.

Green-adapted spectrophotometric determination of fostemsavir based on selective bromophenol blue extraction; reduction of hazardous consumption using computational calculations

A computationally-assisted and green spectrophotometric method has been developed for the determination of fostemsavir, a recently FDA-approved drug used in combination with antiretroviral drugs to treat multidrug-resistant HIV-1 infection. The method was developed using computational studies and solvent selection based on green chemistry principles. The density functional theory method was employed to identify bromophenol blue as the preferred acid dye for efficient extraction of fostemsavir. The solvent selection process involved a careful evaluation of the green ranking of solvents, which led to the use of water as the solvent. The method involved the extraction of fostemsavir with bromophenol blue to form a yellow ion-pair complex, which exhibited maximally sharp peaks at 418 nm, enabling sensitive visible spectrophotometric determination of fostemsavir in bulk and pharmaceutical preparations. The extraction procedures were optimized, and the method was demonstrated to be sensitive over the concentration range of 2–12 μg/mL fostemsavir. Furthermore, the method was evaluated with respect to green chemistry principles using the analytical eco-scale, the green analytical method index, and analytical greenness metric approach, all of which confirmed that the data obtained by the proposed method were environmentally acceptable.

Quantitative analysis of two COVID-19 antiviral agents, favipiravir and remdesivir, in spiked human plasma using spectrophotometric methods; greenness evaluation

Favipiravir and remdesivir have been included in the COVID-19 treatment guidelines panel of several countries. The main objective of the current work is to develop the first validated green spectrophotometric methods for the determination of favipiravir and remdesivir in spiked human plasma. The UV absorption spectra of favipiravir and remdesivir have shown some overlap, making simultaneous determination difficult. Due to the considerable overlap, two ratio spectra manipulating spectrophotometric methods, namely, ratio difference and the first derivative of ratio spectra, enabled the determination of favipiravir and remdesivir in their pure forms and spiked plasma. The ratio spectra of favipiravir and remdesivir were derived by dividing the spectra of each drug by the suitable spectrum of another drug as a divisor to get the ratio spectra. Favipiravir was determined by calculating the difference between 222 and 256 nm of the derived ratio spectra, while calculating the difference between 247 and 271 nm of the derived ratio spectra enabled the determination of remdesivir. Moreover, the ratio spectra of every drug were transformed to the first order derivative using ∆λ = 4 and a scaling factor of 100. The first-order derivative amplitude values at 228 and 251.20 nm enabled the determination of favipiravir and remdesivir, respectively. Regarding the pharmacokinetic profile of favipiravir (Cmax 4.43 µg/mL) and remdesivir (Cmax 3027 ng/mL), the proposed methods have been successfully applied to the spectrophotometric determination of favipiravir and remdesivir in plasma matrix. Additionally, the greenness of the described methods was evaluated using three metrics systems: the national environmental method index, the analytical eco-scale, and the analytical greenness metric. The results demonstrated that the described models were in accordance with the environmental characteristics.

Green spectrophotometric method for the spectral pattern recognition based on fuzzy inference system compared to continuous wavelet transform for the quantitative determination of anti-psoriasis drugs in commercial skin ointment formulation: Comparison with HPLC

In this study, two chemometrics methods, including fuzzy inference system (FIS) along with principal component analysis (PCA) and continuous wavelet transform (CWT) were proposed for the simultaneous spectrophotometric estimation of betamethasone dipropionate (BMD) and calcipotriol (CP) in pharmaceutical dosage form without any pretreatment. The mean recovery and root mean square error (RMSE) related to the nine rules of the FIS was 100.14%, 100.72% and 0.016 and 0.020 for BMD and CP, respectively. CWT with wavelet families of Daubechies (db2) and Coiflet (Coif2) were selected to give the best zero crossing point at a wavelength of 254 nm and 265 nm, as well as the highest coefficient of determination (R2) for BMD and CP, respectively. The limit of detection (LOD) and limit of quantitation (LOQ) were found to be 5 × 10−5, 1.7 × 10−3 μg/mL and 0.0277, 0.0225 μg/mL through the calibration graphs in the linear concentration ranges of 1–10 μg/L for BMD and CP, respectively. The selected wavelet families were successfully applied for chemometric analysis of BMD and CP in synthetic mixtures with satisfactory mean recovery values of 94.67% and 102.43% for BMD and CP, respectively. The proposed spectrophotometric methods were statistically compared to high-performance liquid chromatography (HPLC) using analysis of variance (ANOVA). The proposed analytical techniques were found to be easy, fast, precise, and robust with less solvent consumption for the concurrent analysis of BMD and CP, which can be used instead of chromatography methods in pharmaceutical quality control laboratories.

Green Spectrophotometric Determination of Two Cephalosporin Drugs Used in COVID-19 Regimen Through Silver Nanoparticle Synthesis.

Cefixime trihydrate (CFX) and cefuroxime axetil (CFU) are antibacterial drugs. They are widely used in the treatment of bacterial infection and recently in COVID-19 treatment. In this article, the two antibacterial drugs, CFX and CFU, were determined by a new simple, sensitive, effective, and green spectrophotometric method via reaction with silver nitrate (AgNO3). The reaction was based on reduction of AgNO3 by the cited drugs to silver nanoparticles (Ag-NPs) in the presence of polyvinylpyrrolidine (PVP) as stabilizing agent. Very intense surface plasmon resonance peaks were obtained at 435 nm for CFX and CFU that allow quantitative determination of the drugs. The calibration curves were linear with concentration ranges of 0.2-1.4 μg/mL and 0.3-2.1 μg/mL for CFX and CFU, respectively. Validation of the proposed method has been done according to ICH (International Conference of Harmonization) guidelines; the method was verified on the Green Analytical Procedure Index and Analytical Greenness metric approach (AGREE) in regard to its greenness and was found to be an excellent green alternative method. A very sensitive and green spectrophotometric method was developed for determination of CFX and CFU in pure and dosage form. The developed method not previously reported for simultaneous determination of CFX and CFU.

Carbon dots as fluorescent nanoprobes for assay of some non-fluorophoric nitrogenous compounds of high pharmaceutical interest

BackgroundCarbon dots, CDs, have excellent photoluminescence properties, good biocompatibility, low toxicity and good light stability. The optical, magnetic and electronic properties of CDs make them a hugely relevant tool to be used in pharmaceutical analysis, bioimaging, drug delivery, and other fields. The fluorescence of carbon nanodots makes it suitable for assay of some nitrogenous compounds of high pharmaceutical interest. In this work, we develop simple, fast and green spectrophotometric methods for quantification of Azithromycin and Rasagiline mesilate using synthesized fluorescent CDs from garlic peels.ResultsThe spectrometric methods depend on stoichiometric reactions of both drugs with fluorescent CDs. Carbon dots exhibit a declared absorption peak λmax at 238 nm and potent fluorimetric emission at λem 528 nm, upon excitation at λex 376 nm. Drugs’ concentrations in ppm are efficiently calculated using Stern–Volmer Equation. Decrease in fluorescence (ΔF = Fo − F) and the F-ratio values are linearly correlated to molar concentration of each quencher (drug). A significant linear diminish in the dots’ measured absorbance and fluorimetric emission values was observed. Validation of all the developed methods was according to the ICH guidelines.ConclusionsIn a new way, this work successfully indicates, spectrometric methods for rapid detection of two non-fluorophoric nitrogenous compounds using potent carbon nanodots. Consequently, these green developed methods offer several benefits as simplicity, ease of quantification, accuracy and precision that encourage the application of the developed methods in routine analysis of Azithromycin and Rasagiline mesilate in quality control laboratories as analytical tool.

Development of the Spectrophotometric Method for the Determination of Metoprolol in Tablets by using Bromothymol Blue

A simple, eco-friendly, rapid, and economic spectrophotometric method for the determination of metoprolol tartrate in tablets has been developed. The procedure for metoprolol determination is based on a reaction with bromothymol blue (BTB) in acetonitrile medium. The maximum formation of the colored product was observed in acetonitrile at the absorption maximum at a wavelength of 402 nm. The stoichiometry of molecular complexes was determined by Job's method and it was found to be 1 to 1. The optimal concentration of BTB was 1.6·10-4 M. The linear relationship between absorbance at λmax and concentration of analyte ranging 16.00-24.00 μg mL-1 was found. Regression analysis of Beer’s law plot at 402 nm yielded the regression equation, y = 0.0199x + 0.0721. High values of correlations coefficient R2 = 0.9990 and small values of intercept validated the linearity of calibration curve and obedience to Beer’s law. The calculated LOD and LOQ values were 1.90 and 5.78 μg mL-1, respectively. The proposed green spectrophotometric method is simple, rapid, and suitable for routine pharmaceutical analysis.

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

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

Analysis of two mixtures containing racetams in their pharmaceuticals using simple spectrophotometric methodologies

Green spectrophotometric methods were developed and validated for determination of some CNS active drugs as antiepileptics and brain stimulants. Piracetam (PIR), Levetiracetam (LEV) and Brivaracetam (BRV) were assayed as a ternary mixture using double divisor-ratio spectra derivative (DDRSD) (method I). One more binary co-formulated mixture of Piracetam (PIR) and Vincamine (VIN) was assayed using difference spectrophotometric procedures (method II). I was applied to determine PIR at 302nm in the first derivative of the ratio spectra in the selected spectral region. The content of LEV was determined by measuring the spectra at 215nm in the first derivative of the ratio spectra in the selected spectral region. The concentration of BRV was estimated by measuring the first derivative of the ratio spectra in the chosen spectral region and detecting the signals at 229.7nm. The application of method (II) procedures resulted in measuring the absorbance of PIR at 220nm which is the zero crossing point on the difference spectra of VIN in 0.1M NaOH vs. 0.1M HCl. Similarly, the absorbance of VIN was measured at 245.0nm, which is the zero crossing point on the difference spectra of PIR. The suggested methods were fully validated adopting ICH guidelines. The linearity ranged from 10-100μg/mL for the three racetams and from 2-20 for VIN. The recovery percentages were ranged from 98.72% to 101.8% for method I and from 98.13% to 101.06% for method II. Moreover, the proposed methods were proved environmentally benign using the most recent assessment tool named AGREE. Both procedures were successfully applied for the determination of each drug in bulk powder, checked using laboratory prepared mixtures, and directly applied on commercially available pharmaceutical products without interference. The obtained results revealed a good agreement with those obtained by the reported methods.

In situ green analytical methods for the rapid and sensitive determination of a newly launched orphan anticancer drug; Tigecycline in infusion bags: comparative study

BackgroundTigecycline (TIG), an antimicrobial agent indicated for complex bacterial infections, is now approved by FDA as an orphan chemotherapeutic agent for the treatment of acute myeloid leukemia due to its inhibitory effects on pathways of activating, signaling and abnormal mitochondrial function in cancer cells. TIG is mainly administered as intravenous infusion through centralized unit of oncology centers. This necessitates the continuous analytical quality control of the prepared solution in order to identify and quantify TIG for safe intravenous administration to patients. Moreover, the clinical staff exposure risk to toxic drugs during daily handling must be considered. Such concerns require a fast, cost-effective and green analytical procedure for sensitive determination of TIG directly in infusion bags. In this work, we propose a simple, rapid and green capillary zone electrophoretic (CZE) method for the sensitive assay of TIG directly in infusion bags, in addition to three simple and green spectrophotometric methods.ResultsTIG solutions corresponding to clinical ranges were detected in 5%glucose. Validation of all the proposed methods was according to ICH guidelines. Greenness assessment was performed depending on Green Analytical Procedure Index (GAPI) and the Eco-scale approach which showed that the proposed methods are better eco-friendly methods than reported ones. It also revealed the superiority of our proposed methods in terms of simplicity and sensitivity for TIG determination in infusion bags. Quantification limits obtained were significantly lower than the administered range of TIG in infusion bags and lower than its maximum serum concentration (Cmax). This promotes the application of the proposed methods for the pharmacokinetics and bioavailability studies of TIG in various biological fluids.ConclusionsThis work reports, for the first time, CZE method for the direct and rapid determination of TIG and its separation from other components in intravenous infusion solution. The developed CZE method has several advantages over current chromatographic methods such as higher efficiency of separation within short analysis time, consumption of fewer quantities of chemicals and offering better resolution than HPLC. Moreover, three green spectrophotometric methods are also proposed for TIG determination that offer many advantages such as accuracy, precision, simplicity, specificity and facility of quantification and separation of the selected drug in infusion bags and pharmaceutical preparations without any techniques for extraction.

Spectrophotometric methods for the determination of lisinopril in medicines

Two simple, rapid and green spectrophotometric methods are described for the determination of lisinopril medicines. The determination is based on the reaction of the primary amino group of the lisinopril with ninhydrin in aqueous medium (Method I) and reaction on the carboxylic group of the lisinopril with copper (II) sulfate (Method II). For both methods, optimal spectrophotometric conditions were established. The linear relationship was found between absorbance at λmax and concentration of drug in the range 40–60 µg/mL (Method I) and 0.592–2.072 mg/mL (Method II). Regression analysis of Beer’s law plot at 400 nm yielded the regression equation, y = 7.4929x – 0.0545 (Method I) and at 730 nm y = 0.0443x – 0.0832 (Method II). High values of correlations coefficient (R2 = 0.9917 (Method I) and R2 = 0.999 (Method II)) and small values of intercept validated the linearity of calibration curve and obedience to Beer’s law. The LOD and LOQ values were calculated to be 6.91 µg/mL and 23.01 µg/mL respectively (Method I) and 0.11 mg/mL and 0.36 mg/mL respectively (Method II). Intra-day and inter-day accuracy and precision were in acceptable limits. The proposed methods were applied for the quantification of lisinopril in tablets pertaining to three commercial formulations. Analytical eco-scale for greenness assessment of the proposed spectrophotometric methods showed that both methods correspond to excellent green analysis.

Determination of Sulphasalazine and Its Related Compounds by Simple, Smart, Validated, Green Spectrophotometric Methods.

Sulphasalazine (SZ) is a prodrug. Its active metabolite (mesalazine, MZ), which is also available in pharmaceutical formulations, and the major active metabolite of MZ (N-acetyl-5-aminosalicylic acid, AS) are commonly used for the treatment of inflammatory bowel diseases. Two accurate, precise, sensitive, and specific spectrophotometric methods were developed and validated for determination of the studied components. The first method is a modified ratio difference spectrophotometric method. In this method, SZ was determined by measuring the peak area from 410-500 nm, while MZ and AS were determined by measuring the difference of the selected amplitude values. The second method is a mean centering of ratio spectra spectrophotometric method. The developed methods were linear over the concentration ranges of 2-35, 2-30 and 1-25 µg/mL for SZ, MZ and AS, respectively. The developed methods were validated according to International Conference on Harmonization guidelines. They were successfully applied for determination of studied analytes. A greenness assessment was undertaken using three different tools. Spectrophotometric methods were developed for determination of SZ and its related compounds for the first time. They were designated to be green and eco-friendly and their greenness profiles were evaluated using green solvents to keep the environment clean.