The influence of lidocaine hydrochloride on environmental pH changes of diluted dispersions of poly(N-isopropylacrylamide) below and over the LCST.
In this study we assessed the influence of lidocaine hydrochloride on the pH of diluted aqueous dispersions of modified poly(N-isopropylacrylamide), at temperature assigned as normalized skin surface temperature, and below and over the lower critical solution temperature value. Three different N-isopropylacrylamide polymer derivatives were synthesized by surfactant free emulsion polymerization, and assessed in the terms of pH in the aqueous dispersions in the presence and absence oflidocaine hydrochloride. The tendency in observed system was similar at three different temperatures, when lidocaine was applied. The pH value increased from the range between 5,39 - 5,90 up to the range 6,22 - 6,55. However, the step of pH between the temperature of 25 degrees C and 32 degrees C was more radical, comparing to 32 degrees C and 45 degrees C. The lidocaine hydrochloride influences the pH patterns observed at various temperature in polymeric systems: measurements of preparations applied on the skin or mucosa should be evaluated in respective temperature range.
Musial
Witold
W
University of Maribor, Department for Textile Materials and Design Laboratory for Chemistry Dyes and Polymers, Slovenia. witold@ktpl.am.wroc.pl
Kokol
Vanja
V
Voncina
Bojana
B
D000178:Acrylamides / Q000138:chemical synthesis / Q000737:chemistry*; D000180:Acrylic Resins; D001831:Body Temperature; D006863:Hydrogen-Ion Concentration; D008012:Lidocaine / Q000737:chemistry*; D011108:Polymers / Q000138:chemical synthesis / Q000737:chemistry*; D012867:Skin / Q000737:chemistry; D012996:Solutions / Q000737:chemistry; D013696:Temperature
D000178:Acrylamides; D000180:Acrylic Resins; D011108:Polymers; D012996:Solutions; C052970:poly-N-isopropylacrylamide; D008012:Lidocaine