A class of β-keto analogs of phenethylamine known as synthetic cathinones has been identified as the most emergent new class of psychoactive chemicals in the last ten years. Synthetic cathinones (SC) are becoming more varied, which represents a serious danger to social security and public health worldwide. In this work, an analytical technique based on UHPLC-MS/MS was developed for the simultaneously measurement of 36 synthetic cathinones and two metabolites in hair keratin samples. The separation was conducted by Atlantis Premier BEH C18 AX (2.5 μm, 2.1 × 100 mm) column using elution with 5 mM ammonium acetate in water with 0.1 % formic acid (v/v) (mobile phase A) and 2 mM ammonium formate in MeOH/Acetonitrile 50/50, +0.1 % formic acid (v/v) (mobile phase B). The analysis time was 11 min. Mass spectrometer was equipped with electrospray ionization (ESI). Multiple reaction monitoring (MRM) mode was used for the detection and quantification of the studied compounds. The methodology was successfully validated according to the Organization Scientific Area Committee guidelines, with linearity (r2 ≥ 0.99) from LOQ to 500 pg/mg concentrations for all the compounds investigated. This method was subsequently applied to nine hair samples positive for ten different synthetic cathinones. The most common SCs identified were 3,4-methylenedioxypyrovalerone (3,4-MDPV), in a concentration range 6.0–1000.0 pg/mg, along with alpha-pyrrolidinopentiophenone (α-PHP (54.0 and 554.0 pg/mg, respectively)), followed by the two positional isomers 3-MMC (556.0 and 5000.0 pg/mg) and 4-MMC (11.5 and 448.0 pg/mg). In conclusion, a validated LC-MS/MS method with high specificity was developed offering an easy and affordable sample preparation, and a run time that makes it suitable for use in a high throughput forensic laboratory for the multi-analyte quantification of 36 novel synthetic cathinones and 2 metabolites in hair.
This work introduces a novel strategy to selectively and sensitively determine Hemoglobin (Hb) using a microwave-synthesized molecularly imprinted polymer (MIP) and chemiluminescence (CL) as the detection method. Studies conducted on both MIP and non-imprinted polymer (NIP) evidenced that the MIP material exhibits a high adsorption capacity (48 µg/mg) and an imprinted factor of about 3, in addition to a selective adsorption property towards Hb in the presence of other proteins, whose structures are very similar to that of Hb. The high selectivity and sensitivity of the proposed biosensor were also assured by the CL detection, whose mechanism is based on Hb's ability to enhance luminol oxidation in an alkaline medium in the presence of hydrogen peroxide, emitting a blue light whose intensity is related to the Hb concentration. The emitted light intensities from the CL reaction, directly proportional to Hb concentration, were captured and analyzed using a smartphone and RGB Color application, avoiding the use of sophisticated equipment and facilitating the measurement process. In order to streamline and speed up the detection process, all the experimental steps including Hb adsorption on MIPHb, supernatant removal, CL reaction, and smartphone readout occur in a single 8-well strip. Therefore, the proposed approach offers one-pot detection for the sensitive (LOD = 0.03 µg.mL−1, equivalent to 1.5 nmol.L−1) and selective determination of Hb in blood samples, for biomedical or forensic applications, through a rapid, low-cost, simple, and affordable approach.
Nowadays, breast cancer is the most affecting and globally diagnosed malignancy among women, yet Letrozole (LTZ) was considered the first-line treatment as hormonal anticancer drug. Unfortunately, LTZ develops osteoporosis as a main side effect which was overcome by using the co-administered; Zoledronic Acid (ZDA). Thus, there was a crucial need for this simultaneous quantification innovation, especially there were no any previously reported methods regarding both drugs together. In this study, an integrated framework was conducted between the experimental analytical quality-by-design (AQbD) approach and green analytical chemistry (GAC), emerging sensitive and robust RP-HPLC method. Box-Behnken Design was the developed model for optimizing an isocratic chromatographic separation on C18 Equisil® ODS (4.6 × 250 mm, 5.0 μm) column at ambient temperature, using the mobile phase of 0.1 % aqueous trifluroacetic acid (pH 2.8): acetonitrile (54.5:45.5, v/v), at 1.0 mL/min flow rate with PDA detection at 254.0 nm and 210.0 nm for LTZ and ZDA, respectively. Model statistical and residual plots analysis was significant and normally distributed. Method was fully validated as per ICH guidelines, where good linearity was 0.20–10.00 µg/mL for both drugs in presence of Tadalafil (TDF) as an internal standard, obtaining adequate correlation coefficients (r) values. Calculated LOD results were 0.058 and 0.040 µg/mL while calculated LOQ results were 0.175 and 0.122 µg/mL for LTZ and ZDA, respectively. The proposed method was effectively applied on bulk, pharmaceutical dosage forms, and spiked human plasma. Statistical comparison of the anticipated results with the reported ones was performed. Greenness assessment was evaluated using Green Analytical Procedure Index (GAPI) and Analytical Greenness (AGREE) tools; where superiority results were achieved relative to other reported methods. Finally, an EVG method evaluation tool was assessed, and the attained results were represented through its radar chart.
The aim of this study is to validate a high-performance liquid chromatography (HPLC) – UV assay method for a stability assay of an oral suspension of PYR developed for newborns. Analyses were performed by HPLC with a Kinetex Coreshell C18 column, thermostated at 40°C, coupled to a diode array (λ=230 nm, 280 nm, scan from 190 to 400 nm) with an acetonitrile/methanol/KH2PO4 buffer gradient (pH 3, 10 mM). A forced degradation study was performed to validate the stability-indicating character. PYR was subjected to acidic (pH 2) and basic (pH 12) hydrolysis stress, thermal hydrolysis stress at native pH (60°C and 4°C), H2O2 oxidation stress (3 % and 15 %) and photolysis stress (UV and natural light) at day 0, 3 and 16. Linearity, specificity, precision, and accuracy of this assay method have been tested. Forced degradation tests demonstrated the stability indicator character of the method and showed that PYR was very sensitive to oxidation, sensitive to light (UV) and insensitive to hydrolysis (thermal and pH). The method of quantification was linear, specific, precise, and accurate according to ICH recommendations. A stability study on the formulation under development will be carried out with this HPLC – UV method.
To investigate the stability of Azilsartan kamedoxomil (AKM) under stress conditions and to identify the degradation products, it was subjected to force degradation/stress under basic, acidic, oxidative, thermal, humidity, and photolytic conditions as per international council for harmonisation (ICH) guidelines. AKM degradation was found under basic, acidic, oxidative, thermal, photolytic, and humidity stress. Separation of the four degradation products of AKM was carried out utilizing a C-18 column, employing preparative High-performance liquid chromatography (HPLC) and gradient mode elution. The structures were elucidated with spectroscopic HRMS, 1D, and 2D NMR and the products were identified as 2-hydroxy-1-[[2′-(5-oxo-4,5-dihydro-1,2,4-oxadiazol −3-yl)[1,1′-biphenyl]-4-yl]-methyl]-1 H-benzimidazole-7-carboxylic acid (AKMDP-1), 2-ethoxy-1-[[2′-(5-oxo-4,5-dihydro-1,2,4-oxadiazol-3-yl)biphenyl-4-yl]methyl]-1 H-benzimidazole-7-carboxylic acid (AKMDP-2), (5-methyl-2-oxo-1,3-dioxol-4-yl)methyl 2-hydroxy-1-[[2′-(5-oxo-4,5-dihydro-1,2,4-oxadiazol-3-yl)[1,1′-biphenyl]-4-yl]methyl]-1 H-benzimidazole-7-carboxylate (AKMDP-3) and 2-hydroxy-3-oxobutyl 2-ethoxy-1-((2′-(5-oxo-4,5-dihydro-1,2,4-oxadiazol-3-yl)-[1,1′-biphenyl]-4-yl)methyl)-1 H-benzo[d]imidazole-7-carboxylate (AKMDP-4). Out of them, two degradants AKMDP-1 and AKMDP-3 were reported earlier, AKMDP-2 was one of the process intermediate (Azilsartan) used in the preparation of Azilsartan kamedoxomil.


