RT Journal Article
SR Electronic
T1 Automated Limulus Amebocyte Lysate (LAL) Test for Endotoxin Analysis using a Mew Toxinometer ET-201
JF PDA Journal of Pharmaceutical Science and Technology
JO PDA J Pharm Sci Technol
FD Parenteral Drug Association (PDA)
SP 194
OP 200
VO 39
IS 5
A1 Haruki Oishi
A1 Aya Takaoka
A1 Yasumichi Hatayama
A1 Tetsuya Matsuo
A1 Yoshitsugu Sakata
YR 1985
UL http://journal.pda.org/content/39/5/194.abstract
AB A precise, efficient, automated method to perform Limulus Amebocyte Lysate (LAL) tests has been developed by using a new Toxinometer ET-201, which measures the turbidity change in gel-clotting in the LAL/endotoxin reaction. This instrument monitors the ratio R(t) of the sequential to the initial transmittance of up to 64 samples simultaneously and independently at 12 sec increments, and quantifies endotoxin by determining the gelation time of the sample defined as the time required to obtain a 5% decrease of R(t). The well correlated standard curve was obtained for endotoxin concentration from 0.0005 EU/ml to 500 EU/ml. CVs of the calculated endotoxin concentration were 5.64 to 14.1%. The detection of endotoxin obtained by this new method agreed well with positive or negative score obtained by the conventional gel-clot method. This method also made it possible to determine precise amounts of endotoxin among these samples previously only scored as negative or positive. Furthermore, using this instrument, inhibition or enhancement of various drugs on the LAL/endotoxin reaction could be quantitatively determined by observing alteration in the gelation time. We also found out that the titrating curves inhibited or enhanced by drugs shifted in parallel with the titrating curve obtained without these drugs. We can estimate the contamination of endotoxin in drugs by graphical extrapolation to the presumed titrating curve with endotoxin-free drugs. The Toxinometer ET-201 method will be very useful for the objective, quantitative determination of endotoxin in routine clinical and pharmaceutical analysis.