Online Program

Mathematical Model of Alexidine Absorption and the Worldwide Fusarium Keratiis Event of 2004-06

Monday, November 2, 2015

John D. Bullock, MD, MPH, MSc, Community Health/Health Systems Management; Mathematics and Statistics, Wright State University Boonshoft School of Medicine, Kettering, OH
BACKGROUND  Our previous studies indicated that: (1) heating the ReNu with MoistureLoc (RML) solution to 56oC for 1 week  in its high density polyethylene (HDPE) plastic (but not a glass) bottle resulted in decreased ability to inhibit Fusarium organisms [Arch Ophthalmol 2011;129:133-6]; (2) alexidine permeates into the walls of heated ReNu HDPE plastic bottles, thereby diminishing its concentration within the solution. [N Eng J Med. 2014;370;1:88-9]

METHODS  Using liquid chromatography with tandem mass spectroscopy (LCMS), alexidine levels were measured in heated/unheated ReNu bottles stored for various time periods. These data were compared with results derived from Fourier transform infrared (FTIR) spectroscopy absorptions of methanol extract evaporate residues of formerly alexidine fluid-exposed bottle walls.

RESULTS  FTIR studies showed that there was approximately 3.1 times more alexidine in the wall of the heated than in the room temperature-stored bottle.  The LCMS study similarly showed that there was approximately 3.0 times more alexidine in the walls of the heated bottles. Alexidine levels correlated closely with timed and dilutional microbiological studies and resembled classic exponential saturation curves.

CONCLUSIONS  Alexidine levels correlated closely with previously performed microbiological and FTIR studies, strongly suggesting alexidine-HDPE plastic interaction as the pharmaceutical failure mechanism of the worldwide RML-related Fusarium keratitis event of 2004-2006.


Learning Areas:

Administer health education strategies, interventions and programs
Basic medical science applied in public health
Clinical medicine applied in public health
Public health biology
Public health or related research

Learning Objectives:
Identify that correlations between totally different research studies (such as liquid chromatography-mass spectroscopy, microbial titers, and Fourier transform infrared spectroscopy) can illuminate unusual causal disease mechanisms.

Keyword(s): Vision Care, Epidemiology

Presenting author's disclosure statement:

Qualified on the content I am responsible for because: I am an ophthalmologist, microbiologist, infectious disease epidemiologist, and professor of mathematics. I have published 8 papers re this event, the last of which was in the New England Journal.
Any relevant financial relationships? No

I agree to comply with the American Public Health Association Conflict of Interest and Commercial Support Guidelines, and to disclose to the participants any off-label or experimental uses of a commercial product or service discussed in my presentation.

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