Environmentally benign liquid chromatographic method for concurrent estimation of four antihistaminic drugs applying factorial design approach.

In the last few decades, green analytical chemistry (GAC) has become a smart magical solution for the qualification and quantification of many drugs. In the current study, a direct, sensitive, and green RP-HPLC method was used to separate three anti-histaminic combinations rupatadine/montelukast, desloratadine/montelukast, fexofenadine/montelukast, and finally a mixture of rupatadine and its metabolite; desloratadine in less than 20 min. The developed method was optimized by a 23 full factorial design to improve the chromatographic responses. The proposed method was used to analyze these antihistaminic combinations at different pharmaceutical ratios. The linearity range is from 1 to 10 µg/mL for rupatadine, desloratadine, and montelukast, while for fexofenadine from 1 to 24 µg/mL drugs. The proposed method is useful in common quality control analysis of the investigated quaternary combinations because of its non-toxic and eco-friendly effects on the environment and human beings. The proposed procedure was thoroughly validated in accordance with ICH guidelines and was revealed to be accurate, reproducible, and selective. The developed methods were compared with a reported reference comparison method, where no significant difference was observed.

Smart green spectrophotometric assay of the ternary mixture of drotaverine, caffeine and paracetamol in their pharmaceutical dosage form.

Three green and facile spectrophotometric methods were developed for the assay of Petro® components; drotaverine HCl (DRT), caffeine (CAFF), and paracetamol (PAR). The three methods depend on measuring the absorbance of the studied drugs through their ethanolic solution. The first derivative spectrophotometry (FDS) at (Δλ = 10) were good parameters for DRT and CAFF resolution; DRT and CAFF could be well calibrated using FDS at 320 and 285 nm, respectively. PAR could be estimated at 308 nm utilizing the second derivative spectrophotometry (SDS). Method II relies on the double divisor ratio derivative spectroscopy (DDRDS). The first derivative was applied on each drug where they would be assayed at 309, 288, and 255 nm for DRT, CAFF, and PAR, respectively. Method III depends on the mean centering (MCR) technique. DRT, CAFF, and PAR could be determined at 309, 214, and 248 nm, respectively. The concentrations were rectilinear in the ranges of 2-20 µg/mL for DRT, 1.5-15 µg/mL for CAFF, and 2-40 µg/mL for PAR in double devisor and mean centering but PAR from 5 to 40 µg/mL in derivative method. Method validation was performed according to ICH guidelines assured by the agreement with the comparison method. In addition, greenness assessment of the proposed methods was investigated. The application of the proposed method was extended to analyse tablet dosage form and performing invitro dissolution testing.

Spectrofluorometric determination of orphenadrine, dimenhydrinate, and cinnarizine using direct and synchronous techniques with greenness assessment.

Orphenadrine (ORP), dimenhydrinate (DMN), and cinnarizine (CNN) were investigated using green-sensitive spectrofluorometric methods. Method, I used for determination of DMN in 0.1 M hydrochloric acid (HCl) and 1.0% sodium dodecyl sulphate (SDS) at 286 nm after λex 222 nm, while for determination of ORP in 1.0% w/v SDS involves measuring the fluorescence at 285 nm after λex 220 nm. For DMN and ORP, the detection and quantitation limits were 2.99 and 4.71 and 9.08 and 14.29 ng/mL, respectively. The ranges of DMN and ORP were 0.10-1.0 and 0.04-0.5 µg/mL, respectively, in micellar aqueous solution. Method II, the derivative intensities of DMN and CNN were measured at a fixed of different wavelength between the excitation and the emission wavelengths (Δλ) = 60 nm at 282 and 322 nm, at the zero crossing of each other, respectively. The detection and quantitation limits for DMN and CNN were 1.77 and 0.88 ng/mL and 5.36 and 2.65 ng/mL, correspondingly, through the entire range of 0.1-1.0 µg/mL for DMN and CNN. The linearity was perfectly determined through the higher values of the correlation coefficient ranging from 0.9997 to 0.9999 for both direct and synchronous methods. The precision of the proposed methods was also confirmed via the lower values of the standard deviation which ranged from 0.39 to 1.11. The technique was expanded to analyze this mixture in combined tablets and laboratory-prepared mixtures. The method validation was done depending on the international conference on harmonization (ICH) recommendations. An analysis of the statistical data revealed a high agreement between the proposed data and the comparison methodology. Three different assessment methods demonstrated the greenness of the technique.

Micellar eco-friendly HPLC method for simultaneous analysis of ternary combination of aspirin, atorvastatin and ramipril: application to content uniformity testing.

BACKGROUND: Cardiovascular disease medications such as aspirin (ASP), statins like atorvastatin (ATR), and blood pressure-lowering drugs including ACE inhibitors like ramipril (RAM) have been included in the World Health Organization (WHO) Essential Medicines List (EML) for many years. Therefore, there is a strong demand to develop a simple, rapid, and sensitive analytical method that can detect and quantitate the ternary mixture of these analytes in pharmaceutical preparations in a short run time. Lately, the analytical community focused on eliminating or reducing hazardous chemicals and solvents usage. RESULTS: A green, fast, selective, and cost-effective micellar HPLC method was established and validated for the concurrent determination of ternary combination of ASP, ATR, and RAM in the pure form and pharmaceutical preparations. Resolution of the three drugs was achieved by using a monolithic column and a micellar mobile phase consists of 0.3% triethylamine (TEA) in 90: 10 an aqueous solution of 0.12 M sodium dodecyl sulfate (SDS): n-propanol, (v/v). The pH was adjusted to 2.5 using orthophosphoric acid and a flow rate of 1.5 mL/min. was applied. To ensure method reproducibility, Valsartan (VAL) was utilized as an internal standard (IS). The UV detection of the studied drugs was performed at 210 nm. Good linearity for the three drugs was obtained over the concentration ranges of 1.0-200.0 mg/mL, 0.5-200.0 mg/mL, and 5.0-100.0 mg/mL with correlation coefficients of 0.9998,0.9999 and 0.9999 for ASP, ATR, and RAM respectively. The method sensitivity was revealed by the relatively small values of limits of detection (LOD) (0.19, 0.13 and 0.30 mg/mL) and limits of quantitation (LOQ) (0.63, 0.44 and 0.99 mg/mL) for ASP, ATR, and RAM, respectively. The retention times of ASP, ATR and RAM were 1.50, 2.3 and 4.3 min., respectively. CONCLUSIONS: The suggested technique was employed for the analysis of the three drugs in their prepared tablets maintaining the recommended pharmaceutical ratio without any interference from excipients. The method was further extended to content uniformity testing of RAM. The results were validated according to international council for harmonisation (ICH) guidelines.

Multicomponent spectrophotometric determination of a ternary mixture of widely-prescribed cardiovascular drugs by four different methods.

Four accurate, green, uncomplicated, and fast spectrophotometric procedures were established for the purpose of resolving as well as quantifying a ternary combination prescribed for cardiovascular patients, such as aspirin, atorvastatin, and ramipril. Method (A) is based on the first derivative zero-crossing spectrophotometry for the determination of aspirin and atorvastatin at 247.4 nm and 302.6 nm, respectively. Ramipril was determined using the second derivative at 211 nm. Method (B) depends on the ratio spectra first derivative (RDS) where the absorption spectrum of the ternary combination was divided by the spectrum of one of the analytes. When treated similarly, the concentrations of the other two analytes were measured using their corresponding calibration graphs. For the determination of ASP and RAM, ATR was used as a divisor with a concentration of 26 µg/mL, and the RDS values at 272.0 and 225.8 nm, respectively, were plotted against the ASP and RAM concentrations. Using 40 µg/mL ASP as a divisor, ATR was analyzed, and the RDS values at 295 nm were plotted versus the ATR concentration. Method (C) is based on the double divisor-ratio spectra derivative technique. In this technique, the derivative of the ratio spectrum is computed by dividing the absorption spectra of the studied combination by the standard spectrum of abinary combination of two of the three analytes being studied. The concentrations of the three analytes in the mixture were assayed by determining the absorbance either at the positive or the negative amplitude. For the determination of ASP, ATR, and RAM, the wavelengths used were 244, 295, and 220 nm, respectively. Method (D) was a hybrid double divisor-ratio spectra technique based on convolving the double divisor-ratio spectra with trigonometric Fourier functions. The magnitudes of the Fourier function coefficients at either maximum or minimum points were correlated to the concentration of each drug in the mixture. The specificity of the suggested methods was tested by analyzing synthetic laboratory-prepared combinations and laboratory-made tablets. Furthermore, the accuracy and precision were ensured by statistically comparing the obtained results with those obtained from comparison method using Bartlett's Test for Equality of Variances and ANOVA test.

Investigation of eco-friendly fluorescence quenching probes for assessment of acemetacin using silver nanoparticles and acriflavine reagent.

The non-steroidal anti-inflammatory medication acemetacin was assessed via two straightforward green spectrofluorimetric techniques. The quenching-dependent derivatizing spectrofluorimetric reactions are the master point of this study. Acriflavine-based method (Method I) depends on forming an ion association complex between acriflavine and the drug in a ratio of 1:1, decreasing the former's fluorescence intensity. Acriflavine or Ag NP's intensity-related quenching action goes linearly with the acemetacin concentration in the 2.0-20.0 µg/mL and 1.0-16.0 µg/mL ranges, respectively. The second quenching mechanism depends on using the silver nanoparticles (Ag NP's) as a fluorescence probe (Method II); Ag NP's were prepared from reducing silver nitrate using sodium borohydride. Both methods could be applied to determine pure and pharmaceutical dosage forms of acemetacin. The methods proved valid according to the international conference on harmonization (ICH) guidelines. In addition to this, this work has been estimated under green criteria assessment tools. There is no significant difference between the proposed and the comparison methods after the statistical interpretation.

Insights into the spectrofluorometric determination of the neuromuscular blocker mivacurium chloride.

Fluorescence spectroscopy is gaining interest in the analysis and quantitative determination of different drugs. This study was carried out to investigate the fluorometric properties of the short-acting muscle relaxant mivacurium in its pure form, injection, and human plasma. It is nondepolarizing skeletal muscle relaxant for intravenous (IV) administration. Mivacurium shows a strong native fluorescence in methanol at 317 nm after excitation at 230 nm (Method I). The critical parameters that may influence the fluorescence of this drug were carefully studied. A linear response between concentration and fluorescence was constructed over the concentration range: 20.0 to 400.0 ng/mL with determination coefficient (r2) equal to 0.9998. Additionally, the correlation coefficient of the linear relationship (r) was found to be 0.9999 with a slope = 2.196 and intercept = -16.61. Limits of quantitation and detection were calculated mathematically to be 17.45 and 5.75 ng/mL respectively. Further estimation of mivacurium in spiked human plasma was performed by construction of specific calibration curve and the obtained correlation coefficient was 0.9948. Moreover, the ability to determine mivacurium in the presence of commonly co-administered drugs were investigated including propofol and thiopental. Method II includes the determination of MVC in the presence of propofol utilizing the first derivative synchronous fluorescence spectroscopy. The results of method II indicated acceptable percentage recoveries from 98.88 to 100.75 %. Statistical evaluation of the results revealed satisfactory accuracy and precision.

Green quantitative spectrofluorometric analysis of rupatadine and montelukast at nanogram scale using direct and synchronous techniques.

Two green-sensitive spectrofluorometric methods were investigated for assay of rupatadine (RUP) [method I] and its binary mixture with montelukast (MKT) [method II]. Method I depends on measuring native fluorescence of RUP in the presence of 0.10 M H2SO4 and 0.10%w/v sodium dodecyl sulfate at 455 nm after excitation at 277 nm. The range of the first method was 0.20-2.00 µg ml-1 with detection and quantitation limits of 59.00 and 179.00 ng ml-1, respectively. Method II depends on the first derivative synchronous spectrofluorometry. The derivative intensities were measured for the two drugs in an aqueous solution containing Mcllvaine's buffer pH 2.60 at fixed Δλ of 140 nm. Each drug was estimated at zero-contribution of the other. The intensity was measured at 261 and 371 nm for RUP and MKT, respectively. The method was linear over 0.10-4.00 and 0.20-1.60 µg ml-1 with limits of detection 31.00 and 66.00 ng ml-1 and limits of quantitation 94.00 and 200.00 ng ml-1 for RUP and MKT, respectively. The method was extended to determine this mixture in laboratory-prepared mixtures and combined tablets. Method validation was performed according to ICH guidelines. Statistical interpretation of data revealed good agreement with the comparison method. Method greenness was confirmed by applying three different assessment tools.

Quantitative assessment of the nature of noncovalent interactions in N-substituted-5-(adamantan-1-yl)-1,3,4-thiadiazole-2-amines: insights from crystallographic and QTAIM analysis.

Three adamantane-1,3,4-thiadiazole hybrid derivatives namely; N-ethyl-5-(adamantan-1-yl)-1,3,4-thiadiazole-2-amine I, N-(4-fluorophenyl)-5-(adamantan-1-yl)-1,3,4-thiadiazole-2-amine II and (4-bromophenyl)-5-(adamantan-1-yl)-N-1,3,4-thiadiazole-2-amine III, have been synthesized and crystal structures have been determined at low temperature. The structures revealed that the orientation of the amino group is different in non-halogenated structures. Intra- and intermolecular interactions were characterized on the basis of the quantum theory of atoms-in-molecules (QTAIM) approach. Intermolecular interaction energies for different molecular pairs have been obtained using the PIXEL method. Hirshfeld surface analysis and 2D-fingerprint plots revealed that the relative contributions of different non-covalent interactions are comparable in compounds with halogen (Br and F) substitutions. Crystal structures of II and III show isostructural behaviour with 1D supramolecular constructs. In all three structures, the N-H⋯N hydrogen bond was found to be stronger among other noncovalent interactions. The H-H bonding showed a closed shell in nature and played significant roles in the stabilization of these crystal structures.

Assessment of lipophilicity of newly synthesized celecoxib analogues using reversed-phase HPLC.

BACKGROUND: Lipophilicity is a physicochemical property of an essential importance in medicinal chemistry; therefore, fast and reliable measurement of lipophilicity will affect greatly the drug discovery process. RESULTS: A series of N-benzenesulfonamide-1H-pyrazoles, oximes and hydrazones as celecoxib analogues was investigated with regard to their retention behavior using reversed-phase high performance liquid chromatography (RP-HPLC). The mobile phases employed for this study consist of a mixture of water and methanol in different proportions. In addition, the stationary phase utilized for this separation was C18 silanized silica gel and using 200 nm as a detection wavelength. The retention behavior of the investigated compounds was determined based on practical determination of log k at different concentrations of methanol (as an organic modifier) in the mobile phase ranging from 60 to 80%. It was observed that the retention of these compounds (expressed as log k) decreased in a linear manner with increasing the concentration of methanol. High correlation coefficients (more than 0.90 in most cases) were obtained for the relationship between the volume fraction of the organic solvent and the retention values represented as log k w. A comparative evaluation was carried out between chromatographically-obtained lipophilicity parameters (represented as lipophilicity chromatographic index log k w or isocratic chromatographic hydrophobicity index, φ 0) and the computationally calculated log P values (miLogP, ALOGP, ACD/Labs and ALOGPs). CONCLUSION: It was found that a good correlation exists between the experimental and computed log P values. In the future, these results can give a deep insight about the anti-inflammatory and analgesic activity of the newly synthesized compounds.

Simultaneous determination of metolazone and losartan in their combined tablets using synchronous fluorescence spectroscopy.

Synchronous spectrofluorimetry is utilized to carry out a rapid, sensitive and reliable method for determination of the binary mixture of metolazone (MTL) and losartan potassium (LSP). Under optimized experimental conditions, the synchronized fluorescence spectra of the two drugs were measured at Δλ = 80 nm in acidic methanolic solution and intensities were recorded at 260 nm for MTL and 335 nm for LSP. Linear correlation between fluorescence intensity and concentration were obtained through the ranges 0.02-0.2 µg/mL and 0.2-2.0 µg/mL for MTL and LSP, respectively. Limits of detection were 3.02 and 0.12 ng/mL, whereas limits of quantification were 9.16 and 0.35 ng/mL for MTL and LSP, respectively. The designated procedure was easily and successfully adopted to determine the two compounds in their single, as well as in co-formulated, tablets and the results showed high precision and accuracy without any significant interference from common tablet excipients. A comparison of the obtained results with a published reference method was carried out and both showed good agreement with respect to accuracy and precision.

Spectrofluorimetric investigation with green analytical procedures for estimation of bambuterol and terbutaline: Application to pharmaceutical dosage forms and content uniformity testing.

Bambuterol (BAM) and terbultaline (TER) are well known and effective bronchodilators. In this article highly sensitive, green and cost-effective spectrofluorimetric methods are designed to determine low concentrations of such drugs. The proposed methods are based on an investigation of the native fluorescence properties of aqueous solutions of BAM at 298 nm after excitation at 263 nm and of TER at 313 nm after excitation at 275 nm. Under optimum conditions, the plots of the relative fluorescence intensity versus concentration were rectilinear over the range 0.1-1.2 µg/mL for BAM and 0.05-0.5 µg/mL for TER with a limit of quantitation of 0.067 µg/mL for BAM and 0.018 µg/mL for TER. The methods are simple and hence suitable for application to the quantification of BAM and TER in syrups and tablets without interference from common excipients. Furthermore, based on United States Pharmacopeia (USP) guidelines, the application was extended to determine the content uniformity of the cited drugs in low dose tablets. The developed methods were fully validated according to the guidelines of the International Conference on Harmonization (ICH).