Eco-Friendly Chromatographic Methods for Determination of Acemetacin and Indomethacin; Greenness Profile Assessment

BACKGROUND

Green chemistry approach was developed for the purpose of saving the environment by using green solvents. Applying the green analytical chemistry principles for traditional methods is considered a challenge. Acemetacin is a commonly used analgesic prodrug that bioactivated to indomethacin.

OBJECTIVES

Developing two simple Eco-friendly chromatographic methods for simultaneous determination of acemetacin and indomethacin.

METHODS

The first is HPLC-DAD method, separation was performed on Waters XBridge® Shield RP18 (250 × 4.6 mm, 5 µm) analytical column with ethanol-ammonium acetate buffer (50 mM, pH 3.5 ± 0.1) (60:40, v/v) as a mobile phase at a flow rate of 1 mL/min at 25 ± 0.5 °C and UV detection at 254 nm. The other method is TLC method coupled with densitometric quantification using pre-coated silica TLC-plates and butanol-ethyl acetate (70:30, v/v) elution system. The plates were scanned at 254 nm.

RESULTS

Both methods were validated according to the ICH guidelines, linearity was confirmed, for both, over a concentration range of 1-100 µg/mL for the HPLC method and 0.2-7 µg/band for TLC-densitometric one. Methods' greenness was evaluated by the National Environmental Methods Index, Eco-Scale, Green Analytical Procedure Index metrics and Analytical GREEnness Metric Approach.

CONCLUSION

The proposed methods were found to be suitable for determination of studied drugs in their marketed formulations and suggested for routine analysis in quality control laboratories.

HIGHLIGHTS

HPLC and TLC methods were validated for the assay of acemetacin and indomethacin. Methods' greenness was evaluated by NEMI, Eco-Scale, GAPI and AGREE metrics and were compared to published methods. The developed HPLC method shortened the elution time of the analyzed drugs saving more time and money and the TLC method lowered the drugs' detection limit.

Microextraction techniques coupled to liquid chromatography with mass spectrometry for the determination of organic micropollutants in environmental water samples

Until recently, sample preparation was carried out using traditional techniques, such as liquid–liquid extraction (LLE), that use large volumes of organic solvents. Solid-phase extraction (SPE) uses much less solvent than LLE, although the volume can still be significant. These preparation methods are expensive, time-consuming and environmentally unfriendly. Recently, a great effort has been made to develop new analytical methodologies able to perform direct analyses using miniaturised equipment, thereby achieving high enrichment factors, minimising solvent consumption and reducing waste. These microextraction techniques improve the performance during sample preparation, particularly in complex water environmental samples, such as wastewaters, surface and ground waters, tap waters, sea and river waters. Liquid chromatography coupled to tandem mass spectrometry (LC/MS/MS) and time-of-flight mass spectrometric (TOF/MS) techniques can be used when analysing a broad range of organic micropollutants. Before separating and detecting these compounds in environmental samples, the target analytes must be extracted and pre-concentrated to make them detectable. In this work, we review the most recent applications of microextraction preparation techniques in different water environmental matrices to determine organic micropollutants: solid-phase microextraction SPME, in-tube solid-phase microextraction (IT-SPME), stir bar sorptive extraction (SBSE) and liquid-phase microextraction (LPME). Several groups of compounds are considered organic micropollutants because these are being released continuously into the environment. Many of these compounds are considered emerging contaminants. These analytes are generally compounds that are not covered by the existing regulations and are now detected more frequently in different environmental compartments. Pharmaceuticals, surfactants, personal care products and other chemicals are considered micropollutants. These compounds must be monitored because, although they are detected in low concentrations, they might be harmful toward ecosystems.