ADVANCED AMPLITUDE CENTERING AS AN INVIGORATING MANIPULATION FOR UNIFIED WAVELENGTH SPECTRAL RESOLUTION OF TERNARY MIXTURES

Objective: This work presented the novel spectrophotometric approach namely, advanced amplitude centering (AAC). The method was applied for the resolution of ternary mixtures with partially or completely overlapped spectra.Methods: Advanced amplitude centering was based on the determination of ternary mixtures using single divisor where the concentrations of the components are determined through progressive manipulation performed on the same ratio spectrum. The centered amplitude at unified wavelength was resolved and applied for the determination of three components with partially and severely overlapped spectra. The work discussed the applications and advantages of the novel univariate advanced amplitude centering compared to the chemometric model, partial least square (PLS).Results: The specificity of the proposed methods was checked using laboratory-prepared mixtures of amlodipine (AML), valsartan (VAL) and hydrochlorothiazide (HCT) and was successfully applied for the analysis of two pharmaceutical formulations. The validity of results was assessed by applying the standard addition technique.Conclusion: The results obtained were found to agree statistically with those obtained by a reported method, showing no significant difference with respect to accuracy and precision

A comparative study of validated spectrophotometric and TLC- spectrodensitometric methods for the determination of sodium cromoglicate and fluorometholone in ophthalmic solution

AbstractThe determination of sodium cromoglicate (SCG) and fluorometholone (FLU) in ophthalmic solution was developed by simple, sensitive and precise methods. Three spectrophotometric methods were applied: absorptivity factor (a-Factor method), absorption factor (AFM) and mean centering of ratio spectra (MCR). The linearity ranges of SCG were found to be (2.5–35μg/mL) for (a-Factor method) and (MCR); while for (AFM), it was found to be (7.5–50μg/mL). The linearity ranges of FLU were found to be (4–16μg/mL) for (a-Factor method) and (AFM); while for (MCR), it was found to be (2–16μg/mL). The mean percentage recoveries/RSD for SCG were found to be 100.31/0.90, 100.23/0.57 and 100.43/1.21; while for FLU, they were found to be 100.11/0.56, 99.97/0.35 and 99.94/0.88 using (a-Factor method), (AFM) and (MCR), respectively. A TLC-spectrodensitometric method was developed by separation of SCG and FLU on silica gel 60 F254 using chloroform:methanol:toluene:triethylamine in the ratio of (5:2:4:1v/v/v/v) as developing system, followed by spectrodensitometric measurement of the bands at 241nm. The linearity ranges and the mean percentage recoveries/RSD were found to be (0.4–4.4μg/band), 100.24/1.44 and (0.2–1.6μg/band), 99.95/1.50 for SCG and FLU, respectively. A comparative study was conducted between the proposed methods to discuss the advantage of each method. The suggested methods were validated in compliance with the ICH guidelines and were successfully applied for the determination of SCG and FLU in their laboratory prepared mixtures and commercial ophthalmic solution in the presence of benzalkonium chloride as a preservative. These methods could be an alternative to different HPLC techniques in quality control laboratories lacking the required facilities for those expensive techniques

Stability Indicating Spectrophotometric Methods Determination of Nicardipine in the Presence of its Alkaline Induced Degradation Products

Objective: Derivative, ratio spectra derivative and ratio difference spectrophotometric methods were developed and validated for simultaneous determination of Nicardipine (NIC) in the presence of its alkaline induced degradation products. Methods: In these methods the overlapped spectra of NIC and its alkaline induced degradation products were well resolved by measuring the amplitudes of first derivative (D1) spectra and the second derivative (D2) at 382.3 and 239 nm, respectively. NIC was determined by ratio spectra derivative by measuring the amplitude at 244 nm. The ratio difference spectrophotometric method was developed in which the difference between amplitudes at 237.5 nm and 260 nm of the ratio spectra were recorded. The linearity range for the applied methods was 2-18 μg/ml.Results: All the developed methods were validated according to ICH Guidelines, NIC was determined with acceptable accuracy and precision.Conclusion: These methods were suitable as stability indicating methods for the determination of NIC in the presence of its alkaline induced degradation products either in bulk powder or in a pharmaceutical formulation. Statistical analysis of the results with those obtained by applying a reported method has been carried out revealing high accuracy and good precision.Keywords: Nicardipine, Spectrophotometry, Pharmaceutical preparations, Stability indicating, derivative, ratio derivative and ratio differenc

RECENT DEVELOPMENT IN ULTRAVIOLET SPECTROPHOTOMETRY THROUGH THE LAST DECADE (2006–2016): A REVIEW

Several techniques have been proposed for treatment of spectrophotometric data, with the objective of extracting the largest amount of analytical information from spectra composed of unresolved bands. The instrumental development and analytical applications of UV regions absorption spectrophotometry produced in the last 10 y (since 2006) are reviewed. The methods were classified according to the spectra data used, including zero order absorption, derivative and ratio amplitudes. The proposed methods were applied to solve different complex pharmaceutical mixtures and the obtained results were accepted when compared to other reported methods.Â

RECENT DEVELOPMENT IN ULTRAVIOLET SPECTROPHOTOMETRY THROUGH THE LAST DECADE (2006–2016): A REVIEW

Vol 8, Issue 10Several techniques have been proposed for treatment of spectrophotometric data, with the objective of extracting the largest amount of analytical information from spectra composed of unresolved bands. The instrumental development and analytical applications of UV regions absorption spectrophotometry produced in the last 10 y (since 2006) are reviewed. The methods were classified according to the spectra data used, including zero order absorption, derivative and ratio amplitudes. The proposed methods wer

Investigating Advanced Approaches Based on Iso-Absorptivity Coefficient in Unresolved Spectral Signals of Binary Mixtures

Several spectrophotometric approaches utilize different functions of the iso-absorptivity coefficient in zero-order absorption signals and its manipulated spectra. This work introduced an investigation concerning the efficiency power of recent methods based on iso-absorptivity coefficient in different spectral signals. These methods were as follows: absorptivity centering method (a-Centering), absorbance subtraction method (AS), amplitude modulation method (AM,) and amplitude summation method (A-Sum). These methods were applied to determine the binary mixture of ofloxacin (OFX) and dexamethasone (DXM). Linearity of the proposed methods was investigated in the range of 1.0–10.0 μg/ml for both drugs. The proposed methods were validated as per ICH guidelines and were successfully applied for the simultaneous determination of OFX and DXM in their pharmaceutical preparation without interference from additives. Statistical analysis of the results obtained by the proposed spectrophotometric methods compared with a reported method revealed no significant difference between the proposed and reported methods, confirming accuracy and precision at 95% confidence limit

Environmentally sustainable computationally spectrophotometric resolution strategy for analysis single-tablet regimens of antihypertension with overlapped spectra

Single tablet regimens (STRs) for hypertension suppression improve patient satisfaction, quality of life, medication and adherence compared to multi-tablet regimens (MTRs). Development of simple cost effective and at the same time green an ecofriendly method for analysis and resolution of multicomponent and complex mixtures is an increasingly important issue in the field of pharmaceutical industry in general and analytical chemistry in specific. Thus, the presented research deals with two main goals, the first one is concerned with developing and applying a fully validated resolution plan using numerical data of signals on manipulated spectra for successive extraction of parent spectra of drugs in single-tablet Regimens (STRs) used in antihypertensive treatment. The STRs contains three drugs with deconvoluted spectra, Atenolol (ATL), Amiloride (AMD) and Chlortalidone (CLN). The resolution plan encompasses two simple and affordable spectrophotometric methods employing resolving spectra either normalized spectrum (NS) or factorized spectrum (FS) which acts as a master key for unlocking the overlapped spectra of ternary mixture with no need for any preliminary physical separation, sample pretreatment or pH adjustment. These two main methods namely, dual amplitude difference (DAD) and derivative ratio transformation (DDT). The presented approaches required a simple spectrophotometer with its built-in program using primitive mathematical operations to restore the parent spectrum for individually drug cited in the mixture understudy. The proposed methods validity was checked and evaluated through the ICH guidelines and displayed linearity within concentration range 4.0-40.0μg/mL for ATL, 3.0-20.0μg/mL for both AMD and CLN. While the specificity evaluation was performed via assaying the three drugs accurately and precisely in their synthetic mixtures and in their STRs. Generally, these methods could be recruited for the fast and effective analysis and determination of the purity index for AMD, CLN and ATL in bulk materials and available market formulation, Teklo ® tablets.The second main goal of the research was the evaluation of the methods greenness and whiteness where the applied UV-methods and the reported HPLC one had significantly different greenness scores when compared using three metrics: the Green Certificate Classification (GCC), the Complex Green Analytical Procedure Index (Complex-GAPI), and the Analytical Greenness metric approach (AGREE).Also, the whiteness scores, which reflected the degree of the achieved sustainability for the HPLC reported technique and the produced UV ones were done by using the ideologies of the white analytical chemistry (WAC) tool. All the differences between the four aforementioned metrics are discussed in this study

Development and validation of LC–MSMS assay for the determination of the prodrug dabigatran etexilate and its active metabolites in human plasma

Dabigatran etexilate (DABE) is a low-molecular-weight prodrug that is converted after oral administration to dabigatran (DAB)—a directly acting oral anticoagulant. In this study, an LC–MSMS assay was developed and validated for the determination of DABE, free DAB and its equipotent O-glucuronide conjugates in plasma. Owing to the susceptibility of DABE and DAB to chemical hydrolysis, cleavage of the O-glucuronide moiety was carried out using -glucuronidase enzyme. Free and total plasma concentrations of DAB were determined in incurred plasma samples before and after enzymatic cleavage (50 C and 3 h), respectively. RP-HPLC separation was carried out using acetonitrile: water (30:70, v/v), adjusted to pH 3.0 using formic acid. Tandem mass spectrometric detection at positive electrospray ionization in the MRM mode was then employed for the determination of DABE and DAB. The analysis was carried out within 5.0 min over a linear concentration range of 1.00–600.00 ng/mL for the prodrug and its active metabolite. Validation was carried out according to FDA guidelines for bioanalytical method. The recov- eries were higher than 89.48%, the accuracy was within 98.33–110.12% and the RSD was below 10% for the studied compounds in both incurred plasma and quality control samples. Results of incurred sample re-analysis and incurred sample stability revealed less than 10% variability. This indicated good assay precision and sufficient stability of target analytes in their real matrix at the employed experimental conditions. The applicability of the assay for therapeutic drug monitoring and the determination of the pharmacokinetic parameters were demonstrated

Investigation of the profile and kinetics of degradation of rivaroxaban using HPLC, TLC-densitometry and LC/MS/MS: Application to pre-formulation studies

Rivaroxaban (RIVA), an amide group-containing oral anticoagulant was subjected to stress conditions commonly required for the registration of pharmaceuticals: base and acid-catalyzed hydrolysis (0.1 M, 60 °C, 3–6 h), oxidation (10% H2O2, 24 h), photodegradation (300–800 nm, 24 h) and thermal decomposition (50 °C, 6 h). Two major degradation products were separated and identified using TLC and LC/MS/MS, respectively. An orthogonal stability-indicating testing protocol (RP-HPLC and NP-TLC-densitometry) was developed and validated according to ICH guidelines. Both assays enabled the determination of RIVA in the presence of its degradation products as well as the kinetics of degradation. Determination was carried out over a concentration range of (5.00–50.00 μg/mL) and (0.40–12.00 μg/band) with an accuracy of (100.81% ± 1.03) and (100.29% ± 1.08) for HPLC and TLC-densitometry, respectively. Results indicated that RIVA was stable towards oxidation, photodegradation and thermal decomposition but extremely sensitive to hydrolysis. Two major degradation products were detected in the case of base-catalyzed hydrolysis while only one degradation product was detected upon acid-catalyzed hydrolysis. This could be attributed to the presence of amide groups in RIVA structure of different stability profiles. The kinetics of hydrolysis was investigated in more detail and the reaction was found to follow the pseudo first order kinetics, as confirmed by the results of both HPLC and TLC-densitometric assays. The applicability of the assay for the determination of RIVA content and dissolution pattern of the innovator product as well as three generic formulations was demonstrated

Development and validation of LC-MS/MS assay for the determination of Butoconazole in human plasma: Evaluation of systemic absorption following topical application in healthy volunteers

Butoconazole is an imidazole antifungal that is more effective than miconazole and clotrimazole for treatment of vaginal candidiasis. A highly sensitive tandem mass spectrometric assay was developed and validated to evaluate systemic absorption of Butoconazole following intravaginal administration. Chromatographic separation was achieved using Waters Xterra C18 column (3 µm, 3.0 Ã 50.0 mm). Liquid-liquid extraction using tert-butyl methyl ether was used for preparation of plasma samples. The mobile phase was solvent A: 0.1% formic acid in water and solvent B: acetonitrile: methanol (30:70, v/v), using gradient elution mode at 0.5 mL/min. Detection at positive electrospray ionization in the MRM mode was then employed. Analysis was carried out within 5.5 min over a linear concentration range of 0.10â30.00 ng/mL. Validation was carried out according to US FDA guidelines for bioanalytical method validation. Matrix effect, recovery efficiency and process efficiency have been investigated for the analyte and internal standard in neat solvent, post-extraction matrix and plasma. The mean percentage recoveries were higher than 80%, the accuracy was 93.51â106.85% and the RSD was below 10% throughout the studied concentration range. Results indicated sufficient stability of the target analyte in plasma at the employed experimental conditions. Results of incurred sample re-analysis and incurred sample stability revealed less than 5% variability. The applicability of the assay for monitoring of the systemic absorption of Butoconazole following intra vaginal application to healthy volunteers was demonstrated. Results confirmed that Butoconazole was detected shortly after intra vaginal administration with Cmax and tmax of 30 ng/mL and 6 h, respectively. Keywords: Butoconazole, LC-MS/MS, Matrix effect, Process efficiency, Recovery efficienc