Določanje nitritnih ionov v vodotopnih polimernih pomožnih snoveh

Malovrh, Monika (author), Roškar, Robert (mentor), Peterlin, Simona (comentor)

V zadnjih letih se veliko pozornosti posveča nitrozaminskim nečistotam in njihovim vplivom na zdravje ljudi. Regulatorni organi so izdali smernice o nečistotah in od imetnikov dovoljenj za promet zahtevajo oceno tveganja v zvezi s tvorbo nitrozaminov. Poleg aktivne učinkovine lahko tudi pomožne snovi, preko prekurzorjev, kot so nitritni ioni prispevajo k nastanku nitrozaminov. Zato je pomembno določati vsebnost nitritnih ionov v vseh pomožnih snoveh zdravila. V okviru magistrske naloge smo razvili metodo tekočinske kromatografije za posredno določanje nitritnih ionov z derivatizacijskim reagentom, 2,3- diaminonaftalenom v vodotopnih polimernih pomožnih snoveh, ki se uporabljajo v farmacevtskih izdelkih. Med razvojem metode smo se soočali s težavami, kot so nizki izkoristki (< 70 %), neprimerna viskoznost raztopin vzorca in vezava makromolekul (> 1000 kDa) na stacionarno fazo ter posledično nestabilnost kromatografskih pogojev. Začetni poskusi priprave vzorca z uporabo citratnih in jodidnih ionov niso bili učinkoviti, zato smo preizkusili uporabo organskega modifikatorja v vodi. Kot najbolj učinkovita se je izkazala uporaba 1 % acetona. Problem viskoznosti vzorcev, ki je povzročala težave pri pripravi vzorcev, in vezavo makromolekul na stacionarno fazo, smo rešili s filtracijo vzorcev skozi membranske filtre z določeno velikostjo por. Razvito pripravo vzorca z derivatizacijo nitritnih ionov in uporabo kromatografske metode s fluorescenčnim detektorjem smo dodatno preverili z neposredno metodo merjenja nitritnih ionov (ionska kromatografija) in potrdili, da je ugotovljena koncentracija nitritnih ionov v polivinilpirolidonu (PVP), raztopljenem v 1 % acetonu, enakovredna koncentraciji nitritnih ionov določeni z ionsko kromatografijo, medtem ko koncentracija nitritnih ionov v PVP, ki je raztopljen v vodi, ni ustrezna. Razlike smo pripisali močnejšim interakcijam nitritnih ionov s PVP v vodi. Z validirano metodo smo določevali nitritne ione v raztopinah vodotopnih polimerov, kot so polivinilpirolidon, polietilenglikol, polietilenoksid in polivinilpirolidon vinilacetat. Primerjali smo koncentracije nitritnih ionov med serijami in med proizvajalci. Ugotovili smo, da se vsebnost nitritnih ionov razlikuje po vrstah pomožnih snovi, proizvajalcih in celo med serijami določene pomožne snovi istega proizvajalca.

• Language: Slovenian
• Keywords: Nitritni ioni, DAN derivatizacija, HPLC-FLD, ionska kromatografija, vodotopni polimeri
• Work type: Master's thesis/paper
• Organization: FFA - Faculty of Pharmacy
• Year: 2024
• PID: 20.500.12556/RUL-166119
• Publication date in RUL: 20.12.2024

Secondary language

• Language: English
• Title: Determination of nitrite ions in water soluble polymer excipients

Abstract

In recent years, much attention has been given to nitrosamine impurities and their impact on human health. Regulatory authorities have issued guidance on impurities and require authorization holders to carry out risk assessments on nitrosamine formation. In addition to the active ingredient, excipients can also contribute to the formation of nitrosamines through precursors such as nitrite ions. It is therefore important to determine their content in all excipients of the medicinal product. In this master's thesis, we developed a liquid chromatography method for the determination of nitrite ions with the derivatization reagent, 2,3-diaminonaphtalene, in water-soluble polymer excipients for pharmaceutical products. During development, we encountered problems such as low yields (< 70%), inappropriate viscosity of sample solutions, and the binding of macromolecules (> 1000 kDa) at the stationary phase, which led to unstable chromatographic conditions. Initial experiments with citrate and iodine ions were ineffective, so we tested the use of an organic modifier in water. The most effective method for sample preparation was the use of 1 % acetone. The problems with sample viscosity that occurred during sample preparation and binding of the macromolecules to the stationary phase were solved by using membrane filters with specific pore size. The developed fluorometric method was verified by a direct method for the determination of nitrite ions (ion chromatography), confirming that the concentration of nitrite ions in polyvinylpyrrolidone (PVP) dissolved in 1% acetone determined by the proposed method was equivalent to the concentration of nitrite ions determined by ion chromatography, while the concentration of nitrite ions in PVP dissolved in water was not suitable. The differences were attributed to stronger interactions between nitrite ions and PVP in water. Using the validated method, we determined nitrite ions in solutions of water-soluble polymers such as polyvinylpyrrolidone, polyethylene glycol, polyethylene oxide and polyvinylpyrrolidone-vinyl acetate. We compared nitrite ion concentrations between batches and manufacturers. We found that the nitrite ion content varies among types of excipients, from manufacturer to manufacturer and even from batch to batch of the same manufacturer.

• Keywords: Nitrite ions, DAN derivatization, HPLC-FLD, ion chromatography, water soluble polymers