Laboratory diagnosis of the Tropicamide non-drug consumption

Introduction. Lately, medical services have reported a lot of cases caused by taking Tropicamide alone or with other drugs together. Moreover, it has been declared that the increase in the number of resistance cases to Tropicamide consumption has. Due to those facts, Tropicamide was included in the List of Drugs for Medical Use that should be served by the prescriptions in 2015. However, nowadays in Russia there are many combinations of medicines, for instance, Tropicamide and α-adrenergic agonist (phenylephrine) (Midrimax, Fenikamid, Appamide plus) that are not under that regulation. As a result, those medicines are served in pharmacies without any prescriptions. Thus, method developing for Tropicamide determination in the hair samples to establish his consumption period has become a perspective one.Aim. The research aimed to develop a method for the isolation and determination of Tropicamide in the hair samples.Materials and method. Reference standard of Tropicamide was used in this research. The following enzymes – papain, chymopsin, chymotrypsin, and hyaluronidase – were applied in the experiment. To design the long-term consumption of Tropicamide, laboratory animals (Guinea pigs, average masses about 200 – 250 g) with fair and brown nature colour hair were used in this research. The hair of laboratory animals was dyed by professional hair-dye "Estel Professional De Luxe". The following equipment was applied: balance "Sartorius СР224S", pH-meter " FiveEasy ", ball mill Retsch MM-200. The hair samples extracts were analyzed by gas chromatography with mass selective detection (Gas chromatograph model 7890А with mass selective detector model 5977 and MassHunter GC/MS software by Agilent Technologies).Results and discussion. All developed methods of enzymatic hydrolysis (by papain, chymopsin, chymotrypsin, and hyaluronidase) revealed comparable results for the Tropicamide determination in the hair samples. The research showed that the amount of the analyte isolated from the pigmented hair was a bit higher in comparison with the other hair samples (fair hair), despite the melanin gives chemical steadiness property to hair stuff. Moreover, the amount of Tropicamide extracted from the dyed hair samples increased by 30 %. The degradation products of the analyte of interest were not found in the extracts obtained for the dyed hair samples. Thus, the colorant does not destroy the xenobiotic during the hair dying procedure and does not impact the enzymatic hydrolysis process. The values of the validation parameters (precision and accuracy) met the required criteria for bioanalytical methods. Therefore, the enzymatic hydrolysis method can be recommended for application in laboratory practice.Conclusion. In the course of the study, a method for laboratory diagnostics of non-drug use of tropicamide was developed, the reproducibility of which meets the acceptance criteria for bioanalytical methods, which makes it possible to recommend it for work in laboratory practice.

A Review: Method Development Validation and Degradation Studies of some Anticancer Drugs

This article reviews the various analytical methods reported so far in the literature for the determination of stability and impurity profile the lenalidomide and palbociclib anti cancer drugs in single or combination with other drugs in bulk, pharmaceutical dosage forms, biological fluids, stability indicating and impurity profiling methods. The analytical methods used for the estimation of lenalidomide and palbociclib anticancer drugs reviewed in this paper includes ultraviolet spectrophotometry,high performance liquid chromatography (HPLC) ,ultra performance liquid chromatography (UPLC) ,liquid chromatography-mass spectrometry (LC-MS) and electrophoresis. This review focus on the effect of all chromatographic parameters so as to provide as fast, reliable and cost effective methodology of testing. Method development is the process of proving that analytical method is acceptable for use to measure the concentration of active pharmaceutical ingredient in a specific compound dosage form which must be validated to provide reliable data for regulatory submissions. This reviewed is mainly on analytical method development and validation, stability indicating methods, simultaneous estimation methods and bioanalytical methods. The review covers the time period from 2007 to 2019 during which analytical methods including all types of spectrophotometric and chromatographic techniques were reported. The Review covers lenalidomide and palbociclib API and formulation analytical and bioanalytical methods.

Exponential Amplification by Redox Cross-Catalysis and Unmasking of Doubly Protected Molecular Probes

The strength of autocatalytic reactions lies in their ability to provide a powerful means of molecular amplification, which can be very useful for improving the analytical performances of a multitude of analytical and bioanalytical methods. However, one of the major difficulties in designing an efficient autocatalytic amplification system is the requirement for reactants that are both highly reactive and chemically stable in order to avoid limitations imposed by undesirable background amplifications. In the present work, we devised a reaction network based on a redox cross-catalysis principle, in which two catalytic loops activate each other. The first loop, catalyzed by H2O2, involves the oxi-dative deprotection of a naphthylboronate ester probe into a redox-active naphthohydroquinone, which in turn catalyzes the production of H2O2 by redox cycling in the presence of a reducing enzyme/substrate couple. We present here a set of new molecular probes with improved reactivity and stability, resulting in particularly steep sigmoidal kinetic traces and enhanced discrimination between specific and nonspecific responses. This translates into the sensitive de-tection of H2O2 down to a few nM in less than 10 minutes or a redox cycling compound such as the 2-amino-3-chloro-1,4-naphthoquinone H2O2 down to 50 pM in less than 30 minutes. The critical reason leading to these remarkably good performances is the extended stability stemming from the double masking of the naphthohydroquinone core by two boronate groups, a counterintuitive strategy if we consider the need for two equivalents of H2O2 for full deprotection. An in-depth study of the mechanism and dynamics of this complex reaction network is conducted in order to better understand, predict and optimize its functioning. From this investigation, the time response as well as detection limit are found highly dependent on pH, nature of buffer, and concentration of the reducing enzyme.

A survey of pharmacokinetic bioanalytical methods in biosimilar biological license applications (BLAs) for the assessment of target and antidrug antibodies effects

The presence of circulating targets and antidrug antibodies can influence the ability of a bioanalytical method to measure therapeutic protein (TP) concentration relevant to exposure-response evaluations. This project surveyed biosimilar submissions for their bioanalytical methods. Survey results revealed that 97% of pharmacokinetic methods designed to measure theoretically free or partial-free TPs with respect to target indeed measured free or partial-free TPs when considering experimental testing results for target effects. Antidrug antibody effect is less often evaluated. The observed trend of measuring biologically active forms of TP is consistent with the scientific understanding that pharmacokinetics of biologically active forms is more likely to be relevant to the clinical responses and evaluation of clinically meaningful differences to contribute to biosimilarity assessments.

The impact of ligand binding based assays critical reagent characterization and storage

Biological critical reagents are the foundation of many bioanalytical methods and often chemically modified or conjugated with various chemical tags. As such, the quality and performance of these methods are inherently tied to the quality and stability of critical reagents. This article will outline recommendations for conjugated critical reagent development and characterization. Examples of the impact of regent quality will be discussed for the two common bioanalytical assays in support of drug development for biotherapeutics. Finally, a brief discussion of conjugated reagent stability and recommendations for storage and testing will be presented.