PDA Italy Chapter announced the winners of the first PDA Student Awards during the 2023 Annual Meeting Conference in Milan, Italy. The award was open to all students of chemistry, pharmacy, pharmaceutical biotechnology and related disciplines.
One of the winners of the prize for the best thesis is Immacolata Russo, who completed her master’s degree in chemical and industrial pharmacy at the Università degli Studi di Chieti with a thesis entitled Detection of Endotoxins in Injectable Drugs Consisting of Lipid Nanoparticles and Low Endotoxin Recovery Effect.
This contribution was considered relevant to the multidisciplinary field of parenteral drug products since nanocarriers and positively charged lipid nanoparticles can interact with endotoxins, causing false negative or false positive results. Therefore, the need to define ad-hoc protocols and run experiments to investigate this phenomenon is crucial to guarantee the safety of complex drug products.
Abstract
As part of the microbiological quality control of sterile injectables, sterility and endotoxin contaminationtests are carried out, as endotoxins are among the most dangerous pyrogens for the patient’s life. The most widely used methods for the detection of endotoxins are those that exploit the amebocyte lysate of a particular crab called Limulus Polyphemus, specifically the turbidimetric kinetic methodology that measures the time required for the sample/lysate soluon to reach a certain turbidity developed as a result of the reaction between endotoxin and LAL. In the case of drugs consisting of lipid nanoparticles that incorporate the endotoxin, it is necessary, before carrying out the analysis, to perform a pre-treatment that allows it to be released and reacted with LAL.
Recently, an effect of reducing the recovery of endotoxin added to an undiluted product (LER or Low Endotoxin Recovery effect) has been discovered. This effect is given by particular formulations containing chelating agents and ionic surfactants that can cause false negatives in release analyses; for this reason, holding time studies are carried out. The latter consist of adding a known amount of endotoxin to the undiluted product and analyzing it at various checkpoints with the aim of verifying whether the formulation masks the endotoxin present, making it impossible to detect. If the recovery at the various checkpoints falls within the range established by guidelines and therefore no LER effect occurs, the product can be routinely tested with the certainty that a negative result will not be given by a masking of the endotoxin by the formulation but by an actual absence; this allows to guarantee the safety of the drug and consequently the patient’s health. The LER effect characterizing the formulation object of the thesis’ holding time study was overcome by diluting the sample in a magnesium sulphate solution.
