Spectrofluorimetric determination of butylated hydroxytoluene and butylated hydroxyanisole in their combined formulation: application to butylated hydroxyanisole residual analysis in milk and butter.

Butylated hydroxytoluene (BHT) and butylated hydroxyanisole (BHA) are two antioxidants that have been extensively used in many applications. Both are well known for their debatable health risks due to their multiple intake sources. Therefore, conservative limits are set for them in different regulations adapted to the matrices in which they exist. Here we present a simple spectrofluorimetric method for the determination of BHT and BHA based on their native fluorescence and synchronous scanning mode. The type of solvent and the interval between emission and excitation wavelengths were carefully optimized. Under the optimized conditions, good linearities were obtained between the emission intensity and the corresponding concentrations of BHT and BHA over the range of 3-18 µg/mL and 0.1-7 µg/mL, respectively with a good correlation coefficient (r > 0.99). The limits of detection were 0.9 and 0.02 µg/mL, and the quantification limits were 3 and 0.05 µg/mL for BHT and BHA, respectively. The suggested procedure was validated according to ICH guidelines Q2 (R1). Furthermore, the method's greenness was assessed by three different methods, and it proved to be eco-reasonable. The method was successfully applied to the determination of BHT and BHA in pharmaceutical formulations. We also applied the suggested method for monitoring the residual BHA in conventional, powdered milk and butter, with good recovery in spiked samples.

Development of chromatographic methods to determine multivitamins formulation depending on their solubility and polarity: comparative study using three greenness assessment tools.

High performance liquid chromatography is one of the techniques of choice for the separation and quantitative determination of drugs in mixture form. Ipriflavone, ascorbic acid, pyridoxine, vitamin D3, and lysine are formulated together as an adjuvant combination in osteoporosis. In this work, we developed and validated two complementary high performance liquid chromatographic methods to determine the five compounds in their pharmaceutical dosage form. The first method (method A) was capable of determining ipriflavone, ascorbic acid, pyridoxine, and vitamin D3 in their bulk and combined pharmaceutical formulation. The method is based on Liquid Chromatographic separation with UV detection at 254 nm using Agilent Eclipse XDB-C18 column with a mobile phase consisting of 25 mM ammonium acetate buffer (pH 4.2): methanol in gradient mode. Due to the high polarity of lysine, it was difficult to achieve satisfactory retention on reversed phase columns. So, we separated it on a strong cation exchange column (Exsil 100 SCX) without derivatization with a mobile phase consisting of 10 mM sodium dihydrogen phosphate and 200 mM sodium chloride (pH 6) with UV detection at 210 nm (method B). Validation of the proposed methods was performed according to ICH guidelines Q2(R1). The proposed methods proved to be valid for selective analysis of the stated drugs in their bulk and combined pharmaceutical formulation. Greenness assessment of the developed methods was evaluated using three assessment tools: ESA, GAPI and the most recently developed tool AGREE, showing a satisfactory comprehensive guide of the greenness of the developed methods.

Smartphone as a Portable Detector for Thin-Layer Chromatographic Determination of Some Gastrointestinal Tract Drugs.

Thin-layer chromatography (TLC) is an effective and simple technique for screening, evaluating, and quantifying low-quality and counterfeit pharmaceutical products. Smartphones have recently been used as accessible, cheap, and portable detectors that can replace more complicated analytical detectors. In this work, we have developed a simple and sensitive TLC method utilizing a smartphone charged-coupled device (CCD) camera not only to verify and quantify some gastrointestinal tract drugs, namely, loperamide hydrochloride (LOP) and bisacodyl (BIS), but also to detect acetaminophen (ACT) as a counterfeit drug. Both drugs (LOP and BIS) were chromatographed separately on a silica gel 60 F254 plate as a stationary phase under previously reported chromatographic conditions, using ethyl acetate:methanol:ammonium hydroxide (24:3:1, by volume) and ethyl acetate:methanol:glacial acetic acid (85:10:5, by volume) as developing systems to determine LOP and BIS, respectively. Universal stains, namely, iodine vapors and vanillin, were used to visualize the spots on the TLC plates to get a visual image using the smartphone camera and a spotlight as an illumination source with no need for a UV illumination source. The spot intensity was calculated using a commercially available smartphone application for quantitative analysis of the studied drugs utilizing ″acetaminophen″ as an example of a counterfeit substance. Rf values were calculated using the recorded images and found to be 0.77, 0.79, and 0.74 for LOP, BIS, and ACT, respectively, providing drug identity. Linear calibration curves using the smartphone-TLC method were obtained between the luminance and the corresponding concentrations over the ranges of 2.00-10.00 µg/mL and 1.00-10.00 µg/mL with limits of detection of 0.57 and 0.10 µg/mL for LOP and BIS, respectively. The suggested method was validated according to the International Conference of Harmonization (ICH) guidelines. The method was then successfully applied for the qualitative and quantitative determination of LOP or BIS as an example for gastrointestinal tract drugs in pure form and in their pharmaceutical dosage formulations. The proposed method is considered as a perfect alternative to traditional reported densitometric methods due to its simplicity, easy application, and inexpensiveness. No previously reported methods utilizing smartphones have been published for the determination of the studied drugs. The developed approach is considered the first TLC method using smartphones for the determination of some gastrointestinal tract drugs in their pure form and in pharmaceutical formulations.

A portable solid-state potentiometric sensor based on a polymeric ion-exchanger for the assay of a controversial food colorant (sunset yellow).

Food additives are chemicals added to enhance the appearance, taste, or lifetime of food products. Authorities continuously update the lists of the allowed additives and their daily intake limits. Thus, authorities and food suppliers strictly monitor additives in food products to guarantee their safety and compliance with national laws and safety criteria. The daily intake of the food colorant sunset yellow is banned in some countries and strictly controlled in others. Herein, a chemically modified solid-state potentiometric sensor was fabricated and used for the direct, fast, sensitive and selective assay of sunset yellow in soft drink and pharmaceutical formulation samples. The study optimized the sensor composition and the optimized carbon paste included a novel polymeric ion-exchanger, dioctyl phthalate, chitosan, and calix-[8]-arene and produced a rapid and near-Nernstian response of -32.9 ± 0.821 mV per decade for sunset yellow in the concentration range 7.94 × 10-5 M to 1.0 × 10-2 M and in the pH range 5-10. The sensor revealed good selectivity toward sunset yellow in the presence of commonly encountered ionic species. The method was validated according to the International Council for Harmonization guidelines and the results were statistically comparable to those of a reported method. The solid-state sensor represents a tool for fast and direct assay of sunset yellow in food products without sample pretreatment.

Validated High Performance Liquid Chromatographic Method for Stability Study of Eptifibatide.

Eptifibatide (EPT) is a cyclic heptapeptide derived from a protein found in the venom of the south-eastern pygmy rattle snake used as an antiplatelet drug. In this study, a newly developed HPLC method demonstrating no interference from the different degradation products of EPT has been optimized and validated. The method was based on HPLC separation of eptifibatide from its degradation products using reversed phase C18 column at ambient temperature with mobile phase consisting of acetonitrile: 50 mM sodium dihydrogen orthophosphate dihydrate, pH was adjusted to 2.2 with orthophosphoric acid (25:75 v/v). Quantitation was achieved with UV detection at 220 nm based on peak area. The proposed method was validated according to the ICH guidelines and applied to evaluate the stability of EPT under different stress conditions including temperature, oxidation and hydrolysis over wide pH range (2-10). Moreover, kinetic study of EPT oxidation and its hydrolysis at pH 10 was demonstrated. The proposed method was successfully applied to quantify EPT in bulk powder and in pharmaceutical formulation with a runtime shorter than all the reported methods.

Spectrofluorimetric determination of eptifibatide in human plasma and dosage form.

A spectrofluorimetric method for the determination of eptifibatide is presented based on its native fluorescence. The type of solvent and the wavelength of maximum excitation and emission were carefully selected to optimize the experimental conditions. Under the specified experimental conditions, the linearities obtained between the emission intensity and the corresponding concentrations of eptifibatide were in the range 0.1-2.5 µg/ml for the calibration curve constructed for direct determination of eptifibatide in dosage form and 0.05-2.2 µg/ml for the calibration curve constructed in spiked human plasma with a good correlation coefficient (r > 0.99). The lower limit of quantification for the calibration curve constructed in human plasma was 0.05 µg/ml. Recovery results for eptifibatide in spiked plasma samples and in dosage form, represented as mean ± % RSD, were 95.17 ± 1.94 and 100.29 ± 1.33 respectively. The suggested procedures were validated according to the International Conference on Harmonization (ICH) guidelines for the direct determination of eptifibatide in its pure form and dosage form and United States Food and Drug Administration (US FDA) Guidance for Industry, Bioanalytical Method Validation for the assay of eptifibatide in human plasma.

Study of Thermal Analysis Behavior of Fenbendazole and Rafoxanide.

Purpose: Thermal analysis techniques have been applied to study the thermal behavior of fenbendazole (Fen) and rafoxanide (Raf). Semi-empirical molecular orbital calculations were used to confirm these results. Methods: Thermogravimetric analysis, derivative thermogravimetry, differential thermal analysis and differential scanning calorimetry were used to determine the thermal behavior and purity of the drugs under investigation. Results: Thermal behavior of Fen and Raf were augmented using semi-empirical molecular orbital calculations. The purity values were found to be 99.17% and 99.60% for Fen and Raf, respectively. Conclusion: Thermal analysis techniques gave satisfactory results to obtain quality control parameters such as melting point and degree of purity at low cost, furthermore, its simplicity and sensitivity justifies its application in quality control laboratories.