Evaluation of ultrafiltration for the free-fraction determination of single photon emission computed tomography (SPECT) radiotracers: beta-CIT, IBF, and iomazenil

J Pharm Sci. 1994 Jul;83(7):1014-9. doi: 10.1002/jps.2600830718.

Abstract

An ultrafiltration system was evaluated for the free-fraction measurement of SPECT radiotracers (beta-CIT, IBF, and iomazenil) used in functional brain imaging. The effect of temperature, storage, centrifugal force, tracer concentration, and percentage filtered demonstrated a relative error of < 9%. As a result of the minimal temperature effect, 25 degrees C was employed for all measurements. A comparison of the ultrafiltration system with equilibrium dialysis revealed < 5% difference for beta-CIT and iomazenil, but 16% for IBF. Additionally, the time and ease of operation considerably favored the ultrafiltration system. The precision quantitated by repetition was < 6% for between-run and within-run variability. In conclusion, ultrafiltration provided rapid results, demonstrated minor analytical errors, revealed generally good correlation with equilibrium dialysis, and allowed excellent precision.

Publication types

  • Comparative Study
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adsorption
  • Benzofurans / analysis*
  • Benzofurans / blood
  • Benzofurans / pharmacokinetics
  • Blood Proteins / metabolism
  • Cocaine / analogs & derivatives*
  • Cocaine / analysis
  • Cocaine / blood
  • Cocaine / pharmacokinetics
  • Dialysis
  • Evaluation Studies as Topic
  • Flumazenil / analogs & derivatives*
  • Flumazenil / analysis
  • Flumazenil / blood
  • Flumazenil / pharmacokinetics
  • Humans
  • Iodine Radioisotopes
  • Membranes, Artificial
  • Protein Binding
  • Pyrrolidines / analysis*
  • Pyrrolidines / blood
  • Pyrrolidines / pharmacokinetics
  • Reproducibility of Results
  • Temperature
  • Tomography, Emission-Computed, Single-Photon / methods
  • Ultrafiltration / methods

Substances

  • Benzofurans
  • Blood Proteins
  • Iodine Radioisotopes
  • Membranes, Artificial
  • Pyrrolidines
  • 5-iodo-N-((1-ethyl-2-pyrrolidinyl)methyl)-2,3-dihydrobenzofurancarboxamide
  • Flumazenil
  • 2beta-carbomethoxy-3beta-(4-iodophenyl)tropane
  • iomazenil
  • Cocaine