HILIC UPLC/ QTof MS method development for the quantification of AGEs inhibitors : trouble shooting protocol

Abstract: Objective: The paper reports an attempt to develop and validate a HILIC UPLC/ QTof MS method for quantifying N-\u3b5-carboxymethyl-L-lysine (CML) in vitro, testing N-\u3b5-carboxy- [D2]methyl-L-lysine (d2-CML), and N-\u3b5-carboxy[4,4,5,5-D4]methyl-L-lysine (d4-CML) as internal standards. Method: During the method development, several challenging questions occurred that hindered the successful completion of the method. The study emphasizes the impact of issues, generally overlooked in the development of similar analytical protocols. For instance, the use of glassware and plasticware was critical for the accurate quantification of CML. Moreover, the origin of atypical variation in the response of the deuterated internal standards, though widely used in other experimental procedures, was investigated. Result: A narrative description of the systematic approach used to address the various drawbacks during the analytical method development and validation is presented. Conclusion: Reporting those findings can be considered beneficial while bringing an insightful notion about critical factors and potential interferences. Therefore, some conclusion and ideas can be drawn from these trouble-shooting questions, which might help other researchers to develop more reliable bioanalytical methods, or to raise their awareness of stumbling blocks along the way

Development and validation of an HPLC-DAD method for rapid quantification of vasicine in Adhatoda vasica leaves and commercial products

Leaves from Adhatoda vasica Nees, Acanthaceae (synonym Justicia adhatoda L.) have been widely used in traditional medicine for their beneficial effect in the treatment of respiratory diseases. Vasicine, the main quinazoline alkaloid in A. vasica, has been linked to its medicinal properties. The purpose of this work was to develop and validate a reliable analytical method for the quantification of vasicine in A. vasica leaves and commercially available products. For this purpose, a high-performance liquid chromatography method coupled to diode array detection (HPLC-DAD) was used. After optimization of the extraction process and the HPLC conditions, linearity, precision, accuracy, and specificity were checked. During the validation, six commonly available food supplements and dosage forms were tested using the validated method. The calibration model was found to be linear in the concentration range of 5.125–205 μg/mL. The average vasicine content at different concentration levels was 0.99 g/100 g with an RSD% of 0.05%. The average recovery was found to be 102.3% with an RSD of 4.3%. Additionally, it was confirmed that the validated method was still precise and accurate for quantifying vasicine in other matrices like the tested preparations. In summary, the validated method was suitable for the determination of vasicine in leaves of Adhatoda vasica, as well as for investigating the quality and the prescribed intake of several commercial products

Facial dermatitis caused by undeclared methylisothiazolinone in a gel mask: is the preservation of raw materials in cosmetics a cause of concern?

status: publishe