ABSTRACT
Flexible tubings are extensively used in pharmaceuticals, food industry, and in hospitals. This study was undertaken to compare various flexible tubings to determine their sorption characteristics, using methyl and propyl parabens. After 24 h, some tubings showed 100% sorption of propylparaben and over 40% for methylparaben. Significant losses were observed within a few hours using several tubings. For methylparaben, the losses were in the following decreasing order of sorption: Tygon, Clearflo, silicone, Nylotube, and Newtex. For propylparaben, the losses were in the following order: Tygon, Clearflo, silicone, Newtex, and Nylotube. Teflon, Zelite, and Vitube showed little to no losses of methyl and propylparaben over 120 h of study. The silicone tubing, refilled after 120 h with fresh methylparaben or propylparaben solutions, again showed significant losses within a few hours. The tubings show slow desorption when filled with the buffer vehicle. For Silastic tubing, increase in temperature from 25 to 40 degrees C, increase in pH from 3.5 to 6.5, tubing lot to lot variation, or curing with peroxide or platinum had little or no effect on paraben sorption. As expected, the sorption of parabens increased with increasing surface area of Silastic tubing. Results provided can be used to select the best tubings and to minimize paraben losses during production and filling of liquid pharmaceuticals andfood products containing these antimicrobial preservatives.
Subject(s)
Biomedical and Dental Materials/pharmacokinetics , Enteral Nutrition/instrumentation , Intubation, Gastrointestinal/instrumentation , Parabens/pharmacokinetics , Preservatives, Pharmaceutical/pharmacokinetics , Adsorption , Biomedical and Dental Materials/chemistry , Coated Materials, Biocompatible/chemistry , Coated Materials, Biocompatible/pharmacokinetics , Dimethylpolysiloxanes/chemistry , Dimethylpolysiloxanes/pharmacokinetics , Parabens/chemistry , Pliability , Preservatives, Pharmaceutical/chemistry , Silicones/chemistry , Silicones/pharmacokinetics , Surface PropertiesABSTRACT
Earlier studies using methylparaben and propylparaben showed extensive losses due to sorption by silicone, polyvinyl chloride, and other flexible tubing. As much as 100% loss of propylparaben and significant loss of methylparaben was reported within 24 hours using Tygon, Clearflo, or Silastic tubing. The fluoropolymer Teflon FEP did not show sorption losses. The current study was conducted using three different fluoropolymer resin tubing pieces (FEP, PFA, and NXT or PTFE) as well as a Tygon tubing lined with FEP to show that these do not show paraben sorption losses over an extended period of time. The results of this study show that sorption losses can be avoided or reduced by proper selection of flexible tubing.
