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.

Novel eco-friendly spectrophotometric approaches for resolution of fixed dose formulation of phenylbutazone with minor component of dexamethasone: Greenness assessment by AGREE tool.

Spectrophotometric resolution of severely overlapped binary mixtures with minor component is challenging. Herein, coupling of mathematical manipulation steps with sample enrichment was conducted on the binary mixture spectrum of Phenylbutazone (PBZ) and Dexamethasone sodium phosphate (DEX) to resolve, for the first time each component separately. Simultaneous determination of both components in a mixture ratio of 1:0.002 was achieved in their zero or first order spectra by the recent factorized response method along with ratio subtraction and constant multiplication methods; all coupled with spectrum subtraction. In addition, a novel second derivative concentration value and second derivative constant value methods were developed for PBZ determination. The concentration of the minor component DEX was obtained, without preliminary separation steps by derivative ratio after sample enrichment by either spectrum addition or standard addition. Spectrum addition approach showed superior characteristics compared to standard addition technique. All proposed methods were placed through a comparative study. Linear correlation was found to be 1.5-18.0 µg/mL for PBZ, and 4.0-45.0 µg/mL for DEX. The proposed methods were validated in accordance with ICH guidelines. The greenness assessment of the proposed spectrophotometric methods was evaluated by AGREE software. Results obtained from the statistical data were evaluated by comparing to one another as well as the official USP methods. These methods offer a cost and time effective platform to analyze bulk materials and combined veterinary formulation.

Determination of Clomipramine using eco-friendly solid-contact ionophore-doped potentiometric sensor.

INTRODUCTION: Clomipramine is a tricyclic antidepressant acting as a serotonin reuptake inhibitor. Its maximum plasma concentration (Cmax) is 13-310 ng/mL, the therapeutic range is 220-500 ng/mL and its toxic effect appears in doses above 900 ng/mL. OBJECTIVES: The fabrication of eco-friendly solid-contact ion-selective electrodes to evaluate the concentration of Clomipramine in different matrices based on disposable screen-printed carbon electrode. METHODS: Disposable screen-printed carbon electrode was utilized as a substrate to fabricate the proposed sensors. The sensors were optimized to determine Clomipramine using calix[4]arene as an ionophore into PVC polymeric membrane to enhance selectivity towards the target analyte. The solid-contact sensor potential stability was improved by the incorporation of graphene nanoparticles transducer layer. RESULTS: The sensors were assessed as per the IUPAC recommendations. The linearity range was 1 × 10- 2 to 1 × 10- 5.3 M. The sensors were successfully applied to determine CLM in the pharmaceutical formulation. Furthermore, the ion selective electrodes were applied for Clompiramine assay in spiked plasma for the purpose of Point-of-Care testing to be a diagnostic tool for therapeutic monitoring of the cited central nervous system agent. The findings were statistically compared to the reported method showing no statistically significant difference. CONCLUSION: This work was concerned with developing a green analytical method for the determination of Clomipramine. The proposed SC-ISE was mixed with graphene nanocomposite transducer interlayer. The graphene layer succeeded in preventing the formation of an aqueous layer so resulted in a stable, reproducible standard potential besides the rapid response time.

Smart Eco-Friendly Spectrophotometric Methods Resolving Highly Overlapping Spectra: Application to Veterinary Antibiotic Injections.

BACKGROUND: Over the last few years, mathematical manipulation has proved to be a very powerful means of successfully resolving severely overlapped spectra for various multicomponent mixtures. OBJECTIVE: Smart and environmentally friendly spectrophotometric determination approaches were used for two binary mixtures of fixed dose veterinary injections containing flunixin meglumine (FLU) combined with either florfenicol (FLR), or oxytetracycline HCl (OXY). METHODS: Regarding the first mixture, both FLU and FLR were determined by three successive resolution techniques, which were; constant multiplication coupled with spectrum subtraction (CM-SS), derivative ratio (DD1), and ratio difference (RD), and two progressive resolution techniques which were absorbance subtraction (AS) and amplitude modulation (AM). Also, graphical representation of concentration of the two drugs through concentration value (CNV) method was also applied. Concerning the second mixture, both FLU and OXY showed severely overlapped spectra and a comparative study was conducted for the determination of each drug by constant center (CC), ratio subtraction via amplitude difference coupled with spectrum subtraction (RS/AD-SS), constant value via amplitude difference (CV-AD), and advanced concentration value (ACV) methods. RESULTS: Calibration graphs of the first mixture were linear over the range 5-40 µg/mL for FLU, and 3-40 µg/mL for FLR. The proposed methods overcame the problem of the overlapped spectra and the presence of a minor component in the mixture. Regarding the second mixture, calibration graphs were linear over the range 2.5-24 µg/mL for FLU and 4-28 µg/mL for OXY. CONCLUSION: The proposed methods were successfully validated as per International Council for Harmonization (ICH) guidelines. The obtained results were statistically compared with the official or reported methods, showing no significant difference concerning accuracy and precision. The methods were evaluated for greenness by three different assessment tools: NEMI, analytical ecoscale, and GAPI. HIGHLIGHTS: The methods were successfully applied for the simultaneous determination of the two combinations in synthetic mixtures and their marketed antibiotic veterinary injections: Megluflor® and Floxon®.

Mathematical filtration of quaternary mixture to the zero order spectra of its individual components.

Simple accurate and precise validated UV spectrophotometric methods have been described here for the simultaneous determination of Tretinoin (TN) Eusolex (EX) Hydroquinone (HQ) & Hydrocortisone acetate (HC) in their dosage form. Simultaneous determination of these four drugs was a major challenge till now. Each spectrum was filtered alone to its zero-order absorption spectrum (D0) form getting spectra typical to each pure component separately. Four methods were applied depending upon constants obtained from extended regions of partially overlapped spectra in the zero or first derivative forms. The methods applied are constant multiplication coupled with spectrum subtraction method (CM-SS) derivative transformation coupled with spectrum subtraction method (DT-SS) constant value method (CV) and concentration value (conc.value) method. The partially overlapped spectra of TN and EX in the mixture were obtained by CM-SS in their zero-order form allowing direct measurement at their λmax while the resolved binary mixture of HQ and HC obtained by SS; was determined by derivatization and transformed to their zero order by DT-SS. Also Ex and HQ concentrations were determined by the graphical representation of data only without regression equation by concentration value method and the results were compared to the conventional constant value method using a regression equation. The methods applied to the quaternary mixture under study were successfully applied for the simultaneous determination of the four drugs in synthetic mixtures and in their combined dosage form Tritospot® cream. Comparing the acquired results statistically together and to official methods demonstrated no significant difference.

Three Different Approaches Based on Derivative Ratio Spectra for Spectrophotometric Resolution of a Quaternary Mixture in Semisolid Dosage Form.

BACKGROUND: Recent incorporated spectrophotometer software supporting mathematical methods was considered as an optimum key for the resolution of multicomponent mixtures. OBJECTIVE: Several spectrophotometric techniques are introduced for the determination of mixtures of tretinoin (TN), hydroquinone (HQ), and fluocinolone acetonide (FA), in the presence of the preservative methyl paraben (MP), without any separation procedure, taking into consideration the presence of two minor components and the severe overlap of their spectra. METHOD: Constant multiplication coupled spectrum subtraction resolved the quaternary mixture into the zero-order absorption spectrum of TN alone and a severely overlapped, ternary mixture of HQ, FA, and MP. Three approaches based on the derivative ratio spectra were applied to resolve this ternary, severely overlapped mixture: derivative ratio-zero-crossing point method, factorized derivative ratio method, and double divisor derivative ratio method. RESULTS: The work was conducted over a concentration range of 1-10, 4-38, and 4-35 µg/mL, for TN, HQ, and FA, respectively. The results obtained were compared statistically to each other and to the official methods, showing no significant difference. CONCLUSIONS: The proposed methods were successfully applied for the simultaneous determination of the three drugs in the presence of MP in synthetic mixtures and in their combined dosage form (Trimelasma® cream) with very good accuracy and precision. HIGHLIGHTS: This was a comparative study between conventional and new methods for resolving ternary, severely overlapped mixtures. Mathematical manipulation steps and enrichment techniques aided accurate quantification of the minor components in mixtures.

Comparative Study for the Assay of Plant Derived Chemicals in Pharmaceutical Formulation Using Methods Dependent on Factorized Spectra.

BACKGROUND: Modern built-in spectrophotometer software supporting mathematical processes provided a solution for increasing selectivity for multicomponent mixtures. OBJECTIVE: Simultaneous spectrophotometric determination of the three naturally occurring antioxidants-rutin(RUT), hesperidin(HES), and ascorbic acid(ASC)-in bulk forms and combined pharmaceutical formulation. METHOD: This was achieved by factorized zero order method (FZM), factorized derivative method (FD1M), and factorized derivative ratio method (FDRM), coupled with spectrum subtraction(SS). RESULTS: Mathematical filtration techniques allowed each component to be obtained separately in either its zero, first, or derivative ratio form, allowing the resolution of spectra typical to the pure components present in Vitamin C Forte® tablets. The proposed methods were applied over a concentration range of 2-50, 2-30, and 10-100 µg/mL for RUT, HES, and ASC, respectively. CONCLUSIONS: Recent methods for the analysis of binary mixtures, FZM and FD1M, were successfully applied for the analysis of ternary mixtures and compared to the novel FDRM. All were revealed to be specific and sensitive with successful application on pharmaceutical formulations. Validation parameters were evaluated in accordance with the International Conference on Harmonization guidelines. Statistical results were satisfactory, revealing no significant difference regarding accuracy and precision. HIGHLIGHTS: Factorized methods enabled the resolution of spectra identical to those of pure drugs present in mixtures. Overlapped spectra of ternary mixtures could be resolved by spectrum subtraction coupled FDRM (SS-FDRM) or by successive application of FZM and FD1M.

A Comparative Study Between Conventional ICP-OES and the Innovative PLS Model-Assisted ICP-OES for the Assay of Trace Elements.

BACKGROUND: Inductively coupled plasma is widely used for elemental analysis with the advantage of being eco-friendly since the discharge is free of contaminants. OBJECTIVE: A rapid, novel method was developed for the quantitation of trace elements using inductively coupled plasma with optical emission spectrometry.This method has the advantage of simultaneous calibration compared to the conventional method. METHOD: The assay was carried out for iron, copper, zinc, and molybdenum using the linear regression model partial least-squares. RESULTS: The method was optimized and validated as per the International Conference on Harmonization guidelines, showing highly accurate and precise results. The linearity range was 0.25-4 ppm for all trace elements under investigation. The method was applied for the assay of the cited elements in non-chelated and amino acid chelated multi-mineral preparations in the Egyptian market with acceptable mean percent recovery. CONCLUSIONS: In comparison with the official method by flame emission, statistical analysis showed no significant difference with Student's t-test and F-values. HIGHLIGHTS: Inductively coupled plasma is superior as all of the elements can be measured simultaneously. The method was found to have a high degree of specificity and can be easily applied in routine elemental analysis in laboratories.

Coupling of liquid-liquid extraction and mathematical filtration techniques for the separation and quantification of five components in semisolid dosage form with severely overlapped spectra.

Quadriderm cream was a combination of four components; Clioquinol (CLIO), Betamethasone (BETA), Tolnaftate (TOL), Gentamicin (GEN) in addition to the preservative Chlorocresol (CC). Four components CLIO, TOL, BETA, and CC were extracted in methanol and determined by mathematic filtration spectrophotometric techniques. The partially overlapped spectrum of CLIO was determined by constant value, constant multiplication, and concentration value methods then eliminated via spectrum subtraction (SS) to get the resolved ternary mixture of TOL, BETA, and CC with severely overlapping spectra. TOL was determined by derivative ratio at zero crossing point of BETA using CC as a divisor. While, BETA could be determined using TOL as a divisor at zero crossing of CC. BETA and CC were obtained using novel (DD1FS) followed by SS. By applying these novel procedures, the DD1 spectrum of each component alone was recovered where Pmax-min was directly proportional to its concentration. Liquid-liquid extraction technique was used for the semisolid dosage form where GEN was extracted with a mixture of chloroform: water (50:50, v/v); and the induced fluorescence obtained by derivatization with o-phthalaldehyde was measured at 419 nm after excitation at 359 nm. Accuracy and precision testing of the developed methods showed good results. Specificity of the methods was ensured and was successfully applied for the analysis of pharmaceutical formulation of the five components in combination. ICH guidelines were used for validation of the proposed methods. Statistical data were calculated, and the results were satisfactory revealing no significant difference regarding accuracy and precision.

A comparative study of novel spectrophotometric resolution techniques applied for pharmaceutical mixtures with partially or severely overlapped spectra.

Simultaneous determination of mixtures of lidocaine hydrochloride (LH), flucortolone pivalate (FCP), in presence of chlorquinaldol (CQ) without prior separation steps was applied using either successive or progressive resolution techniques. According to the concentration of CQ the extent of overlapping changed so it can be eliminated from the mixture to get the binary mixture of LH and FCP using ratio subtraction method for partially overlapped spectra or constant value via amplitude difference followed by ratio subtraction or constant center followed by spectrum subtraction spectrum subtraction for severely overlapped spectra. Successive ratio subtraction was coupled with extended ratio subtraction, constant multiplication, derivative subtraction coupled constant multiplication, and spectrum subtraction can be applied for the analysis of partially overlapped spectra. On the other hand severely overlapped spectra can be analyzed by constant center and the novel methods namely differential dual wavelength (D(1) DWL) for CQ, ratio difference and differential derivative ratio (D(1) DR) for FCP, while LH was determined by applying constant value via amplitude difference followed by successive ratio subtraction, and successive derivative subtraction. The spectra of the cited drugs can be resolved and their concentrations are determined progressively from the same ratio spectrum using amplitude modulation method. The specificity of the developed methods was investigated by analyzing laboratory prepared mixtures and were successfully applied for the analysis of pharmaceutical formulations containing the cited drugs with no interference from additives. The proposed methods were validated according to the ICH guidelines. The obtained results were statistically compared with those of the official or reported methods; using student t-test, F-test, and one way ANOVA, showing no significant difference with respect to accuracy and precision.

Successive spectrophotometric resolution as a novel technique for the analysis of ternary mixtures of pharmaceuticals.

A novel spectrophotometric technique was developed for the simultaneous determination of ternary mixtures, without prior separation steps. This technique was called successive spectrophotometric resolution technique. The technique was based on either the successive ratio subtraction or successive derivative subtraction. The mathematical explanation of the procedure was illustrated. In order to evaluate the applicability of the methods a model data as well as an experimental data were tested. The results from experimental data related to the simultaneous spectrophotometric determination of lidocaine hydrochloride (LH), calcium dobesilate (CD) and dexamethasone acetate (DA); in the presence of hydroquinone (HQ), the degradation product of calcium dobesilate were discussed. The proposed drugs were determined at their maxima 202 nm, 305 nm, 239 nm and 225 nm for LH, CD, DA and HQ respectively; by successive ratio subtraction coupled with constant multiplication method to obtain the zero order absorption spectra, while by applying successive derivative subtraction they were determined at their first derivative spectra at 210 nm for LH, 320 nm or P(292-320) for CD, 256 nm or P(225-252) for DA and P(220-233) for HQ respectively. The calibration curves were linear over the concentration range of 2-20 µg/mL for both LH and DA, 6-50 µg/mL for CD, and 3-40 µg/mL for HQ. The proposed methods were checked using laboratory-prepared mixtures and were successfully applied for the analysis of pharmaceutical formulation containing the cited drugs with no interference from other dosage form additives. The proposed methods were validated according to the ICH guidelines. The obtained results were statistically compared with those of the official BP methods for LH, DA, and CD, and with the official USP method for HQ; using student t-test, F-test, and one way ANOVA, showing no significant difference with respect to accuracy and precision.