Polymers in Medicine

Polim. Med.
Scopus CiteScore: 3.5 (CiteScore Tracker 3.6)
Index Copernicus (ICV 2023) – 121.14
MEiN – 70
ISSN 0370-0747 (print)
ISSN 2451-2699 (online) 
Periodicity – biannual

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Polymers in Medicine

2009, vol. 39, nr 3, July-September, p. 47–55

Publication type: original article

Language: English

Creative Commons BY-NC-ND 3.0 Open Access

The pH changes of diluted dispersions of poly(N-isopropylacrylamide) below and over the LCST in the presence of chlorhexidine

Zmiany odczynu rozcieńczonych rozproszeń polimerów N-izopropyloakryloamidu poniżej i powyżej LCST w obecności chlorheksydyny

Witold Musial1,2,, Vanja Kokol1,, Bojana Voncina1,

1 University of Maribor, Department for Textile Materials and Design Laboratory for Chemistry Dyes and Polymers, Slovenia

2 Wroclaw Medical University, Chair and Department of Pharmaceutical Technology, Poland

Abstract

The pH of diluted aqueous dispersions of modified poly(N-isopropylacrylamide) with chlorhexidine was evaluated, at normalized skin surface temperature, as well below and over the lower critical solution temperature value. Three different poly-N-isopropylacrylamides were synthesized by surfactant free emulsion polymerization. They were evaluated in the terms of pH in the aqueous dispersions in the presence of chlorhexidine. The tendency was similar in all investigated systems at increasing temperature between 25ºC and 45ºC. The pH value decreased from the range between 9,87 - 9,94 down to the range 9,38 - 9,46. The course of pH decrease between the temperature of 32ºC and 45ºC was more radical, comparing to 25ºC and 32ºC, however in general the decrease was monotonic. The systems with chlorhexidine tend to change the pH with temperature increase more radically, in the comparison to the chlorhexidine alone. The formulations applied on the skin surface or in the oral cavity should be evaluated in proper temperature spectrum.

Streszczenie

Odczyn rozcieńczonych rozproszeń modyfikowanego poli(N-izopropyloakryloamidu) z chlorheksydyną oceniano w temperaturze powierzchni skóry, oraz poniżej i powyżej wartości LCST (lower critical solution temperature). Zsyntetyzowano trzy różne pochodne tego polimeru za pomocą SFEP (surfactant free emulsion polymerization). pH wymienionych polimerów z chlorheksydyną badano w rozcieńczonych rozproszeniach. Kierunek zmian pH był zbliżony we wszystkich mieszaninach polimerów, w zakresie temperatury pomiędzy 25ºC i 45ºC. Wartości pH obniżały się od zakresu 9,87–9,94 do zakresu 9,38–9,46. Zmiana pH pomiędzy 32ºC i 45ºC była znacznie większa niż pomiędzy 25ºC i 32ºC, aczkolwiek spadek temperatury był regularny. Zgodnie z otrzymanymi wynikami zmiana pH mieszanin polimeru z chlorheksydyną jest większa, niż zmiana pH samej chlorheksydyny w obserwowanym zakresie temperatury. Preparaty przeznaczone do stosowania miejscowego oraz doustne, powinny podlegać ocenie pH w odpowiednim zakresie temperatury.

Key words

chlorhexidine, microgels, N-isopropylacrylamide, thermosensitivity

Słowa kluczowe

chlorheksydyna, mikrożele, N-izopropyloakryloamid, termowrażliwość

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