Green highly sensitive and selective spectroscopic detection of guaifenesin in multiple dosage forms and spiked human plasma.

Guaifenesin (GUA) is determined in dosage forms and plasma using two methods. The spectrofluorimetric technique relies on the measurement of native fluorescence intensity at 302 nm upon excitation wavelength "223 nm". The method was validated according to ICH and FDA guidelines.

Simultaneous Determination of Montelukast Sodium and Loratadine by Eco-Friendly Densitometry and Spectrophotometric Methods.

Recently, the aim of analytical community is to reduce the usage of hazardous chemicals; so eco-friendly, rapid, selective and cost-effective methods were developed for simultaneous determination of montelukast sodium (MKT) and loratadine (LRT). The first method was based on chromatographic separation performed on precoated silica gel 60 GF254 plates with ethyl acetate-ethanol 9: 1 (v/v) as the mobile phase. The developed plates were scanned and quantified at 260 nm.

Simultaneous quantitative determination of insulin aspart and insulin degludec in human plasma using simple shoot LC method.

Combining short-acting and long-acting insulin analogs was a real challenge that was overcome by NovoNordisk through the co-formulation of insulin aspart and insulin degludec in single-dosage form. The proposed study provides a simple, short, and reliable HPLC method with diode array detection that is developed and validated for the simultaneous determination of insulin aspart and insulin degludec in human plasma. The proposed method achieved good separation between the two analytes utilizing a C8 column at 35°C in a very short run time (6 min), with a simple, low-cost, and reliable extraction method through precipitation of plasma protein.

Quality control of dietary supplements: An economic green spectrofluorimetric assay of Raspberry ketone and its application to weight variation testing.

Although Dietary supplements are readily accessible and extensively used worldwide, they are inadequately regulated and consumers are victims of manufacturers' fraud. Thus, quality regulations are required to ensure safety of products available to the public. We propose the first native spectrofluorimetric quality control assay of raspberry ketone, a popular dietary supplement ingredient for weight loss.

A comprehensive stability assessment of insulin degludec using New customized validated RP-HPLC and SEC-HPLC methods in an orthogonal testing protocol.

Stress testing of biopharmaceuticals plays an important role in preparation of their stability profiles through investigation of possible degradation pathways and identification of degradation products, so in this study Insulin Degludec which is a new generation ultra-long-acting basal insulin is subjected to stress conditions as different temperatures, different pH, oxidation, mechanical agitation, and repeated freeze and thaw cycles to generate possible degradation products and aggregation that are investigated by two new validated RP-HPLC and SEC-HPLC methods in addition to dynamic light scattering (DLS) and native polyacrylamide gel electrophoresis (Nu-PAGE). SEC-HPLC was used to investigate formation of aggregates whose results were correlated with those obtained from DLS and Nu-PAGE, while RP-HPLC was used to investigate any possible chemical modifications. The Proposed RP-method had limit of detection (LOD) and limit of quantitation (LOQ) of 0.

Spectrophotometric Determination of Polyvinyl Pyrrolidone in Pure and Pharmaceutical Dosage Form.

Background: Recently, functional polymers have attracted significant attention in the areas of pharmaceuticals and biomedical applications, so it is important to develop simple techniques to analyze functional polymers in their pharmaceutical dosage forms.

Objective: Three simple, accurate, and sensitive UV spectrophotometric methods have been developed and validated for determination of polyvinyl pyrrolidone (PVP) in the presence of benzalkonium chloride (BZ) and sodium lactate in ternary mixtures.

Method: Method A is a derivative ratio spectra zero-crossing (DRSZ) method which measures PVP peak amplitude at 303.

New and validated RP-HPLC Method for Quantification of Safinamide Mesylate in Presence of Its Basic Degradate, Levodopa and Ondansetron: Application to Human Plasma.

A simple, precise, rapid and accurate reversed-phase high-performance liquid chromatography (RP-HPLC) method was developed and validated for analysis of safinamide mesylate (SAF) in presence of its basic degradate, and co-administered drugs levodopa and ondansetron. The mobile phase consisted of acetonitrile and 20 mM potassium dihyrogen orthophosphate buffer having pH = 5 (40: 60 v/v). Quantification was achieved with ultraviolet detector at 226 nm.

Ecofriendly Long Life Nanocomposite Sensors for Determination of Carbachol in Presence of Choline: Application in Ophthalmic Solutions and Biological Fluids.

Several emerging nano scale forms of carbon are showing great promise in electrochemical sensing such as graphene and multi-walled carbon nanotubes (MWCNTs). Herein we present an ecofriendly method to fabricate long life and sensitive ion selective sensors based on graphene and MWCNTs nanocomposites with no need for volatile organic solvents. Both sensors were fabricated, for the analysis of carbachol in ophthalmic solutions, plasma and urine where ion- association complex was formed between cationic carbachol and anionic Sodium tetra phenyl borate (NaTBP) in a ratio 1:1.

Graphene nanoplatelets in potentiometry: A nanocomposite carbon paste and PVC based membrane sensors for analysis of Vilazodone HCl in plasma and milk samples.

Graphene is the ''new star'' material for electrochemical sensing. It has unique mechanical, thermal and electrical properties, in addition to its ultra light weight. In the present work we combine for the first time the special features offered by graphene and the advantages of ion selective potentiometric sensors in a single study.

HPLC Method for Simultaneous Determination of Bisphenol-A-Diglycidyl Ether and Some of Its Reaction Products in Canned Foods Using Photodiode Array Detector.

Gradient reversed-phase high-performance liquid chromatography with photodiode array detection was used for separation, detection and quantification of bisphenol-A-diglycidyl ether (BADGE) and some of its reaction products, namely, BADGE·HCl·H2O, BADGE·H2O and BADGE·2HCl in pure form and in canned foods, where canned beans and tuna were used as representatives of aqueous and oil-in-water food matrices, respectively. The proposed method had a linear range of 0.01-0.

Validated chemometrics-assisted spectrophotometric methods for simultaneous determination of bisphenol-A-diglycidyl ether and some of its reaction products in canned foods in the Egyptian market.

Two multivariate calibration methods, namely principal component regression (PCR) and partial least squares (PLS-2) have been developed, validated and compared for the simultaneous determination of bisphenol-A-diglycidyl ether (BADGE) and some of its reaction products, including BADGE·HCl·HO, BADGE·HO and BADGE·2HCl. Chemometrics allowed rapid, accurate and precise simultaneous quantification of the analytes of interest which was not possible by other spectrophotometric methods due to their severe spectral overlap. PCR and PLS-2 techniques successfully quantified BADGE, BADGE·HCl·HO, BADGE·HO and BADGE·2HCl in the ranges of 1.

Degradation product characterization of therapeutic oligonucleotides using liquid chromatography mass spectrometry.

Synthetic antisense phosphorothioate oligonucleotides (PS) have undergone rapid development as novel therapeutic agents. The increasing significance of this class of drugs requires significant investment in the development of quality control methods. The determination of the many degradation pathways of such complex molecules presents a significant challenge.

Comparative Study of Univariate Spectrophotometry and Multivariate Calibration for the Determination of Levamisole Hydrochloride and Closantel Sodium in a Binary Mixture.

Six simple, accurate, reproducible, and selective derivative spectrophotometric and chemometric methods have been developed and validated for the determination of levamisole HCl (Lev) either alone or in combination with closantel sodium (Clo) in the pharmaceutical dosage form. Lev was determined by first-derivative, first-derivative ratio, and mean-centering methods by measuring the peak amplitude at 220.8, 243.

Micelle enhanced and native spectrofluorimetric methods for determination of sertindole using sodium dodecyl sulfate as sensitizing agent.

Two stability indicating spectrofluorimetric methods were developed and validated for the determination of sertindole (SER) in the presence of its acid and oxidative degradates at λ(ex) 257 nm and λ(em) 335 nm. Method A was based on measuring the native fluorescence of SER using isopropanol as solvent. Method B was based on the enhancement of native fluorescence of SER quenched in aqueous media by using micellar microenvironment created by sodium dodecyl sulfate (SDS) anionic micelles using Britton Robinson Buffer (BRB) pH3.

New methods for amlodipine and valsartan native spectrofluorimetric determination, with factors optimization study.

Four native fluorescence methods were suggested for simultaneous determination of amlodipine (AML) and valsartan (VAL). These methods were based on excitation of both drugs at λ(ex) 300 nm, in one step, to give maximum emission at λ(em) 378 and 496 nm for AML and VAL, respectively. The first method, single λ(ex) method, was used without any additions.

Sensitive spectrofluorimetric methods for determination of ethopabate and amprolium hydrochloride in chicken plasma and their residues in food samples.

Two sensitive and selective spectrofluorimetric methods are proposed to determine ethopabate (ETH) and amprolium hydrochloride (AMP). First derivative synchronous spectrofluorimetry determines the natively fluorescent ethopabate at 288 nm in presence of amprolium hydrochloride which is a non fluorescent quaternary compound with average recovery 100.54±0.

Spectrophotometric, spectrofluorimetric, and potentiometric assays of cetyltrimethylammonium bromide in industrial wastewater samples.

This work deals with spectrophotometric, spectrofluorimetric, and potentiometric analyses of cetyltrimethylammonium bromide (CTAB) cationic detergent. The spectrophotometric procedure depends on measuring the absorbance of its binary complex with eosin yellow in Britton-Robinson buffer (pH 4) at Lambda max 547 nm in the range of 2.0-14.

Synchronous spectrofluorimetric determination of naphthalene in water samples using mixed micellar medium.

A mixed micellar medium of sodium dodecyl sulfate and Pluronic F-127 was used to enhance the fluorescence of naphthalene and to obtain lower LODs. The method was based upon measuring the first-derivative synchronous fluorescence spectrum of naphthalene by using a mixed micellar medium at a constant wavelength difference delta lambda = 60 nm, where a greater fluorescence enhancement was observed if compared to using a single surfactant separately. A linear fluorimetric calibration curve was obtained for naphthalene in a concentration range of 10-200 ng/mL.

Comparative study of 2-hydroxy propyl beta cyclodextrin and calixarene as ionophores in potentiometric ion-selective electrodes for neostigmine bromide.

Three novel neostigmine bromide (NEO) selective electrodes were investigated with 2-nitrophenyl octyl ether as a plasticiser in a polymeric matrix of polyvinyl chloride (PVC). Sensor 1 was fabricated using tetrakis(4-chlorophenyl)borate (TpClPB) as an anionic exchanger without incorporation of an ionophore. Sensor 2 used 2-hydroxy propyl β-cyclodextrin as an ionophore while sensor 3 was constructed using 4-sulfocalix-8-arene as an ionophore.

Stability-indicating spectrophotometric and spectrodensitometric methods for the determination of diacerein in the presence of its degradation product.

Three sensitive, selective, and precise stability-indicating methods for the determination of the novel osteoarthritis drug, diacerein (DIA) in the presence of its alkaline degradation product (active metabolite, rhein) and in pharmaceutical formulation were developed and validated. The first method is a first derivative (D(1) ) spectrophotometric one, which allows the determination of DIA in the presence of its degradate at 322 nm (corresponding to zero crossing of the degradate) over a concentration range of 4-40 µg/mL with mean percentage recovery 100.21 ± 0.

Spectrophotometric and spectrodensitometric methods for the determination of rivastigmine hydrogen tartrate in presence of its degradation product.

Three sensitive, selective and precise stability-indicating methods for the determination of the anti-Alzheimer's drug, rivastigmine hydrogen tartrate (RIV) in the presence of its alkaline degradation product (major metabolite, NAP 226-90) and in pharmaceutical formulation were developed and validated. The first method is a second derivative (D(2)) spectrophotometric one, which allows the determination of RIV in the presence of its degradate at 262 nm (corresponding to zero crossing of the degradate) over a concentration range of 50-500 microg/ml with mean percentage recovery 100.18 +/- 0.

Membrane electrodes for the determination of pyridostigmine bromide.

Two pyridostigmine bromide (PB) selective electrodes were investigated with 2-nitrophenyl octyl ether as a plasticizer in a polymeric matrix of carboxylated polyvinyl chloride (PVC-COOH), based on the interaction between the drug solution and the dissociated COOH groups in the PVC-COOH. One of the sensors was fabricated by using PVC-COOH only as anionic site without incorporation of an ionophore (sensor 1). The second sensor was constructed by using 2-hydroxy propyl beta-cyclodextrin as an ionophore (sensor 2).

Membrane electrodes for the determination of glutathione.

Four glutathione (GSH)-selective electrodes were developed with different techniques and in different polymeric matrices. Precipitation-based technique with bathophenanthroline-ferrous as cationic exchanger in polyvinyl chloride (PVC) matrix was used for sensor 1 fabrication. beta-Cyclodextrin (beta-CD)-based technique with either tetrakis(4-chlorophenyl)borate (TpClPB) or bathophenanthroline-ferrous as fixed anionic and cationic sites in PVC matrix was used for fabrication of sensors 2 and 3, respectively.