Application of aeration-assisted homogeneous liquid-liquid microextraction procedure using Box-Behnken design for determination of curcumin by HPLC

Spectrophotometric determination of phenol impurity in phenoxyethanol and phenol index of drinking water and municipal wastewater effluent after salting-out assisted liquid phase microextraction (SA-LPME)

In this study, a novel and convenient analytical method based on salting-out-assisted liquid phase microextraction (SA-LPME) has been developed. A spectrophotometric technique was employed to quantify the concentration of phenol in drinking water and treated wastewater, as well as the phenol impurity in 2-phenoxyethanol (PE). To accomplish this, a solution containing dissolved PE was supplemented with 4-aminoantipyrine (4-AAP) and hexacyanoferrate. Subsequently, NaCl was added to induce the formation of a two-phase system, consisting of fine droplets of PE as an extractant phase in the aqueous phase. The resulting red derivative was then extracted into the extractant phase and separated through centrifugation. Finally, the absorbance of the extracted derivative was measured at 520 nm. The Response Surface Methodology (RSM) based on the Box-Behnken Design (BBD) was employed to optimize the influential factors, namely 4-Aminoantipyrine (4-AAP), buffer (pH = 10), hexacyanoferrate, and NaCl. By utilizing the optimal conditions (buffer: 50 μL, 4-AAP (1% w/v): 80 μL, hexacyanoferrate (10% w/v): 65 μL, and NaCl: 0.7 g per 10 mL of the sample), the limit of detection was determined to be 0.7 ng mL-1 and 0.22 μg g-1 for water and PE samples, respectively. The relative standard deviation (RSD) and correlation of determination (r2) obtained fell within the range of 2.4-6.8% and 0.9983-0.9994, respectively. Moreover, an enrichment factor of 65 was achieved for a sample volume of 10 mL. The phenol concentration in two PE samples (PE-1, PE-2), provided by a pharmaceutical company (Pars Sadra Fanavar, Iran), were determined to be 0.83 ± 0.05 μg g-1 and 2.70 ± 0.14 μg g-1, respectively. Additionally, the phenol index in drinking water and treated municipal wastewater was found to be 3.60 ± 1.06 ng mL-1 and 4.60 ± 1.17 ng mL-1, respectively. These mentioned samples were spiked in order to evaluate the potential influence of the matrix. The relative recoveries from PE-1, PE-2 samples, drinking water, and treated municipal wastewater samples were measured as 104.5%, 97.5%, 101.6%, and 107.8%, respectively, indicating no matrix effect.

A rapid cotton swab for on-site screening of coloring curcumin on durian skin: food safety aspects

Exported durians from Thailand are sometimes immersed in curcumin to give the fruits a good appearance. Curcumin is regarded as non-toxic additive, however some importing countries prohibited use of any additive to fresh fruits and vegetables. This work aims to develop a rapid, low cost and convenient cotton swab device for curcumin detection. The detection principle involves a colorimetric acid-base characteristic of curcumin. Curcumin in an acidic/neutral solution presents a bright yellow color, while it displays an intense orange-red color in basic solution. A cotton swab acted for both sample collection and as a sensing platform. A pre-moistened swab was used to wipe a durian surface. Afterward, a NaOH solution was dropped onto the swab. A distinct orange-red color appearing on the swab indicates the presence of curcumin. The cotton swab was applied for qualitative analysis of curcumin contaminated on durian husks via visual detection. The developed device provided good reliability, 93.75% (36 samples). Furthermore, the device was demonstrated for quantitative determination using camera detection. Two linear calibrations were obtained in ranges of 10-75 and 75-250 mg L^-1, with a detection limit of 3.2 mg L^-1. The method was also successfully applied to quantification of curcumin in durians (three samples) and dietary supplements (two samples). The test can be done in a few minutes. The developed device was established as an useful tool for food safety and control of contamination by curcumin in an on-site application.

Analytical Purity Determinations of Universal Food-Spice Curcuma longa through a QbD Validated HPLC Approach with Critical Parametric Predictors and Operable-Design's Monte Carlo Simulations: Analysis of Extracts, Forced-Degradants, and Capsules and Tablets-Based Pharmaceutical Dosage Forms

Applications of analytical quality by design (QbD) approach for developing HPLC (High Performance Liquid Chromatography) methods for food components assays, and separations of complex natural product mixtures, are still limited. The current study developed and validated, for the first time, a stability-indicating HPLC method for simultaneous determinations of curcuminoids in Curcuma longa extracts, tablets, capsules, and curcuminoids' forced degradants under different experimental conditions. Towards separation strategy, critical method parameters (CMPs) were defined as the mobile phase solvents' percent-ratio, the pH of the mobile phase, and the stationary-phase column temperature, while the peaks resolution, retention time, and the number of theoretical plates were recognized as the critical method attributes (CMAs). Factorial experimental designs were used for method development, validation, and robustness evaluation of the procedure. The Monte Carlo simulation evaluated the developing method's operability, and that ensured the concurrent detections of curcuminoids in natural extracts, commercial-grade pharmaceutical dosage-forms, and the forced degradants of the curcuminoids in a single mixture. The optimum separations were accomplished using the mobile phase, consisting of an acetonitrile-phosphate buffer (54:46 v/v, 0.1 mM) with 1.0 mL/min flow rate, 33 °C column temperature, and 385 nm wavelength for UV (Ultra Violet) spectral detections. The method is specific, linear (R2 ≥ 0.999), precise (% RSD < 1.67%), and accurate (% recovery 98.76-99.89%), with LOD (Limit of Detection) and LOQ (Limit of Quantitation) at 0.024 and 0.075 µg/mL for the curcumin, 0.0105 µg/mL and 0.319 µg/mL for demethoxycurcumin, and 0.335 µg/mL and 1.015 µg/mL for the bisdemethoxycurcumin, respectively. The method is compatible, robust, precise, reproducible, and accurately quantifies the composition of the analyte mixture. It exemplifies the use of the QbD approach in acquiring design details for developing an improved analytical detection and quantification method.

Validated high-performance thin-layer chromatographic analysis of curcumin in the methanolic fraction of Curcuma longa L. rhizomes

Background

In the present study, an HPTLC (high-performance thin-layer chromatography) method was developed for the quantitative determination and validation of the curcumin in the methanolic fraction of Curcuma longa L. For achieving good separation of curcumin, the mobile phase of chloroform:methanol (97:3) was used. The densitometric analysis of curcumin was performed at 420 nm in reflection/absorption mode.

Results

Linearity of the method was obtained in the range of 100‒600 ng per spot. During analysis, the methanolic fraction of the C. longa showed the presence of a quantifiable amount of curcumin. The content of curcumin was found to be 1.5% (per dry weight).

Conclusions

The method is specific, simple, precise, and accurate. The obtained data can have used for the routine analysis of the reported biomarkers in crude drugs and extracts. The quantification and the method validation of curcumin have not yet been reported in C. longa which can be utilized for the proper standardization of the plant.

Validation of an innovative analytical method for simultaneous quantification of curcumin and fluconazole using high-performance liquid chromatography from nanostructured lipid carriers

Vulvovaginal candidiasis is a public health problem with a high incidence among female patients. Currently, there is an increase in the identification of Candida spp. resistant to current therapy, making it necessary to search for new therapeutic alternatives. The synergistic potential of curcumin with fluconazole is described in the literature. However, due to its high lipophilicity, it is necessary to use drug-delivery systems to adequately explore its potential, among which is the nanostructured lipid carrier. However, to date, there is no validated method of high-performance liquid chromatography for simultaneous determination of fluconazole and curcumin in the literature. Thus, the present work developed a high-performance liquid chromatography method for simultaneous determination of fluconazole and curcumin co-encapsulated in nanostructured lipid carrier which was validated according to the International Conference on Harmonization (Technical Requirements for Registration of Pharmaceuticals for Human Use) - Q2 (R1) and the Food and Drug Administration - Guidance for Bioanalytical Method. The method was applied to determine the encapsulation efficiency and drug-loading of curcumin and fluconazole in nanostructured lipid carriers. The developed method proved to be selective, precise, accurate, and robust for the simultaneous determination of both drugs, enabling the quantification of encapsulation efficiency and drug-loading of curcumin and fluconazole in nanostructured lipid carriers.

Homogeneous liquid-liquid extraction as an alternative sample preparation technique for biomedical analysis

Liquid-liquid extraction is a widely used technique of sample preparation in biomedical analysis. In spite of the high pre-concentration capacities of liquid-liquid extraction, it suffers from a number of limitations including time and effort consumption, large organic solvent utilization, and poor performance in highly polar analytes. Homogeneous liquid-liquid extraction is an alternative sample preparation technique that overcomes some drawbacks of conventional liquid-liquid extraction, and allows employing greener organic solvents in sample treatment. In homogeneous liquid-liquid extraction, a homogeneous phase is formed between the aqueous sample and the water-miscible extractant, followed by chemically or physically induced phase separation. To form the homogeneous phase, aqueous samples are mixed with water-miscible organic solvents, water-immiscible solvents/cosolvents, surfactants, or smart polymers. Then, phase separation is induced chemically (adding salt, sugar, or buffer) or physically (changing temperature or pH). This mode is rapid, sustainable, and cost-effective in comparison with other sample preparation techniques. Moreover, homogeneous liquid-liquid extraction is more suitable for the extraction of delicate macromolecules such as enzymes, hormones, and proteins and it is more compatible with liquid chromatography with tandem mass spectrometry, which is a vital technique in metabolomics and proteomics. In this review, the principle, types, applications, automation, and technical aspects of homogeneous liquid-liquid extraction are discussed.

Nitrogen-doped fluorescence carbon dots as multi-mechanism detection for iodide and curcumin in biological and food samples

Iodine ion is one of the most indispensable anions in living organisms, particularly being an important substance for the synthesis of thyroid hormones. Curcumin is a yellow-orange polyphenol compound derived from the rhizome of Curcuma longa L., which has been commonly used as a spice and natural coloring agent, food additives, cosmetics as well as Chinese medicine. However, excess curcumin may cause DNA inactivation, lead to a decrease in intracellular ATP levels, and trigger the tissue necrosis. Therefore, quantitative detection of iodine and curcumin is of great significance in the fields of food and life sciences. Herein, we develop nitrogen-doped fluorescent carbon dots (NCDs) as a multi-mechanism detection for iodide and curcumin in actual complex biological and food samples, which was prepared by a one-step solid-phase synthesis using tartaric acid and urea as precursors without adding any other reagents. An assembled NCDs-Hg2+ fluorescence-enhanced sensor for the quantitative detection of I- was established based on a fluorescence "turn-off-on" mechanism in a linear range of 0.3-15 μM with a detection limit of 69.4 nM and successfully quantified trace amounts of I- in water samples and urine sample. Meanwhile, the as-synthesized NCDs also can be used as a fluorescent quenched sensor for curcumin detection based on the synergistic internal filtration effect (IFE) and static quenching, achieving a good linear range of 0.1-20 μM with a satisfactory detection limit of 29.8 nM. These results indicate that carbon dots are potential sensing materials for iodine and curcumin detection for the good of our health.

Analytical Quality by Design Approach of Reverse-Phase High-Performance Liquid Chromatography of Atorvastatin: Method Development, Optimization, Validation, and the Stability-Indicated Method

The use of analytical quality by design (AQbD) approach in the optimization of the high-performance liquid chromatography (RP-HPLC) method is a novel tool. Three factors and three levels of Box–Behnken statistical design (BBD) were used for method optimization and analysis of atorvastatin. The mobile phase (acetonitrile: water), flow rate (Rt), and UV wavelength were used as independent variables. Their effects were observed in the area of the chromatogram (AU), retention time (Rt, min), and tailing factor (%). The optimized HPLC condition was found as acetonitrile:water (50 : 50), flow rate (0.68 ml/min), and UV wave length (235 nm). It gives the retention time of 2.43 min with the linearity range of 5–30 μg/ml with a high regression value (r² = 0.999). The method was found to be precise and accurate with low % RSD (<5%). The refrigeration stability indicated that atorvastatin was stable. The force degradation study showed that the atorvastatin was fully unstable in UV light and stable in 0.1 M basic condition. It concluded that this QbD optimized method is suitable for quantification of the atorvastatin from the formulation as well as pharmacokinetic parameters.