Several assessment tools were recently introduced for the evaluation of the greenness of analytical methods. Each tool has advantages, disadvantages, and a unique assessment protocol. The final results obtained from each assessment tool may lead to a dissimilar conclusion about the selection of the greenest method, which makes the decision confusing as to which an assessment tool relies on. Accordingly, in this comparative case study, four greenness assessment tools—National Environmental Methods Index (NEMI), Eco-Scale Assessment (ESA), Green Analytical Procedure Index (GAPI), and Analytical GREEnness metric (AGREE)—were tested to evaluate 16 chromatographic methods described in the literature for the assessment of the commonly used antispasmodic drug Hyoscine N-butyl bromide (HNBB). The importance of applying more than one assessment tool when evaluating the greenness of analytical methods is explained in this study. Despite NEMI tool simplicity, it was the least effective in providing information about the analytical method as 14 out of 16 methods had the same NEMI pictogram. ESA and AGREE provided reliable numerical assessments that differed in their total scores whereas the total scores were out of 100 and 1 for each, respectively. AGREE has the merits over ESA with respect to automation and highlighting the weakest points in analytical techniques that need further improvements in terms of greenness. GAPI and AGREE provide fully descriptive three-colored pictograms. The main disadvantage of GAPI is complexity compared to NEMI and ESA. AGREE has the merits of simplicity and automation over GAPI. Based on the results, recommendations are made for ESA, GAPI, and AGREE tools, which provide reliable and precise results about the greenness of the method. Planning for the greenness of analytical methods should be assured before practical trials in a laboratory for reduction of chemical hazards released into the environment. Moreover, inclusion of the evaluation of greenness of analytical methods in method validation protocols is strongly recommended.

Staphylococcus aureus (S. aureus) is a Gram-positive bacteria considered one of the leading causes of community and hospital-acquired illnesses or public health concerns. Antibiotic resistance in this microorganism is one of the greatest issues in global health care. The use of metal nanoparticles and their oxides is one of the potential approaches to combating bacteria resistance to antibiotics. The antibacterial properties of ZnO NPs against enterotoxigenic S. aureus were studied. ZnO NPs were tested in vitro by agar diffusion test. They resulted in 26 and 22 mm zones of inhibition for a size of 20 nm and a concentration of 20 mM against 10⁵ and 10⁷ CFU/mL S. aureus, respectively. The MIC of ZnO NPs of various sizes, 20 and 50 nm, with 10⁵ CFU/mL was 2.5 and 5 mM, respectively. MIC with 10⁷ CFU/mL was five mM for 20 and 50 nm ZnO NPs. Further, the highest growth reduction percentage, 98.99% in the counts of S. aureus was achieved by ZnO NPs of size 20 nm and concentration of 10 mM. Moreover, the obtained ELISA results indicated a significantly decreased concentration of enterotoxin A with all concentrations and sizes of ZnO NPs. PCR analysis showed a significant effect on sea gene in response to ZnO NPs treatments leading to loss of the gene, unlike the unaffected nuc gene. Moreover, morphological changes and cell shape distortion were detected by scanning electron microscope for bacterial cells treated with ZnO NPs.

The main objective of this study was to prepare and characterize oleogel as potential carrier for quercetin skin delivery. The formulations were prepared by adding olive oil (5–30%) to Pluronic F127 hydrogel and were evaluated for particle size, zeta potential, viscosity in vitro quercetin release and stability, and were compared with that of Pluronic F127 hydrogel. The selected formulation was characterized for its interaction possibility, ex vivo skin permeation and skin histological changes and safety. The particle sizes ranged from 345.3 ± 5.3 nm to 401.5 ± 2.8 nm, and possessed negative charges. The viscosities of the formulations were found in the range of 6367–4823 cps with inverse proportionality to olive oil percentage while the higher percentages showed higher quercetin release. Percentages of 25% and 30% olive oil showed instability pattern under the conditions of accelerated stability studies. Differential scanning calorimetry verified the existence of quercetin in micellar aggregation and the network in the case of hydrogel and oleogel respectively. Ex vivo skin permeation showed an improved skin permeation of quercetin when 20% olive oil containing oleogel was used. Skin histology after 10 days of application showed stratum corneum disruption and good safety profile. Based on these findings, the proposed oleogel containing 20% olive oil denotes a potential carrier for topical delivery of quercetin.

One of the main aims of green analytical chemistry (GAC) is the reduction of solvents and chemicals consumed. Recycling the mobile phase in chromatographic techniques provides an efficient way to implement GAC principles. However, this is not an easy job, particularly in the case of the gradient mode. Analysis of multi-pharmaceuticals for the same manufacturer using one mobile phase system dramatically reduces consumed solvents, time, and cost for pharmaceuticals analysis in quality control laboratories. This work is an attempt to reduce time, cost and effort needed for quality control analysis of several dosage forms produced by the same manufacturer. Our novel and green RP-HPLC method is able to separate and quantify a tertiary mixture of piracetam, ketoprofen and omeprazole produced by the same manufacturers. The analyst can easily quantify the three drugs in the three dosage forms in one run using the gradient elution mode of methanol and water (from 50% methanol to 85% methanol in ten minutes) with a flow rate 1.5 mL min⁻¹ on a non-polar C₁₈ column. Suitable dilutions were done for the working solution of the mixed pharmaceutical formulations prior to chromatographic analysis. This procedure will dramatically reduce the consumed solvents and save time and money during pharmaceutical analysis. The calibration ranges are (5–25), (5–25) and (3–20) μg mL⁻¹ for the three studied drugs. The International Council for Harmonization (ICH) procedures were followed in the validation process and the results were evaluated in comparison with official HPLC methods, where no noteworthy differences were found. The green profile of the method and pictograms of AGREE and Green Analytical Procedure Index (GAPI) approaches proved the eco-friendly character for the studied drugs. The simultaneous quantitative analysis for Stimulan® and Hyposec® capsules, and Ketolgin® tablets from the Amoun Pharmaceutical Company, Egypt, can be accomplished via the novel method. Also, Memoral® ampoules, Topfam® tablets, and Gastroloc® capsules from Sigma Pharmaceutical Industries, Egypt, could be analyzed simultaneously. Omez® capsules and Ketogesic® tablets from the Pharaonia Pharmaceuticals, Egypt, could be determined simultaneously too. Applying this RP-HPLC method, a significant reduction of the total cost is assured as the required amount of solvent is noticeably decreased when performing multi-analyses in comparison to single component analysis.

Waste resulting from edible plants is considered one of the best sources of valuable phytochemicals. A promising approach for using these appreciated wastes is extracting precious medically important constituents, for example, free quercetin. Two new cost-effective and green extraction methods are introduced in the present study: ultrasound-assisted glycerol extraction (UAGE) and microwave-assisted extraction (MAE). These extraction protocols are optimized using factorial design to define the highest yield of extraction, and HPLC-UV at 370 nm was used as a method of yield analysis. Quercetin remained stable during the whole process in both extraction protocols. A standard addition technique was performed to quantify quercetin in different extracts and eliminate the matrix effect. In UAGE and MAE, extraction yields were 16.55 ± 0.81 and 27.20 ± 1.55 mg/1g from red onion scales on a dry base, respectively. The amount of quercetin extracted using MAE was superior to UAGE in terms of time and yield. A greenness assessment of the offered studies compared to previously published relevant extraction methods was performed using the analytical eco-scale assessment method (ESA) and national environmental methods index (NEMI). MAE showed to be a greener method with a higher ESA score and a greener NEMI pictogram.