Characterization of phagolysosomal simulant fluid for study of beryllium aerosol particle dissolution A.B. Stefaniak a,b, * ,1 , R.A. Guilmette a ,G.A.Day c,d , M.D. Hoover d , P.N. Breysse b , R.C. Scripsick a a Health Safety and Radiation Protection Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA b Division of Environmental Health Engineering, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA c Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA d National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV 26505, USA Received 19 May 2004; accepted 5 August 2004 Abstract Asimulantofphagolysosomalfluidisneededforberylliumparticledissolutionresearchbecauseintraphagolysosomaldissolution isbelievedtobeanecessarystepinthecellularimmuneresponseassociatedwithdevelopmentofchronicberylliumdisease.Thus,we refinedandcharacterizedapotassiumhydrogenphthalate(KHP)bufferedsolutionwithpH4.55,termedphagolysosomalsimulant fluid (PSF), for use in a static dissolution technique. To characterize the simulant, beryllium dissolution in PSF was compared to dissolution in the J774A.1 murine cell line. The effects of ionic composition, buffer strength, and the presence of the antifungal agent alkylbenzyldimethylammonium chloride (ABDC) on beryllium dissolution in PSF were evaluated. BerylliumdissolutioninPSFwasnotdifferentfromdissolutionintheJ774A.1murinecellline(p =0.78)orfromdissolutionin another simulant having the same pH but different ionic composition (p = 0.73). A buffer concentration of 0.01-M KHP did not appear adequate to maintain pH under all conditions. There was no difference between dissolution in PSF with 0.01-M KHP and 0.02-M KHP (p = 0.12). At 0.04-M KHP, beryllium dissolution was increased relative to 0.02-M KHP (p =0.02).Useofa 0.02-MKHPbufferconcentrationinthestandardformulationforPSFprovidedstabilityinpHwithoutalterationofthedissolution rate. The presence of ABDC did not influence beryllium dissolution in PSF (p =0.35). PSFappearstobeausefulandappropriatemodelof in vitro berylliumdissolutionwhenusingastaticdissolutiontechnique.In addition,thecriticalapproachusedtoevaluateandadjustthecompositionofPSFmayserveasaframeworkforcharacterizingPSF to study dissolution of other metal and oxide particles. Published by Elsevier Ltd. Keywords: Alveolar macrophage phagolysosome; Dissolution; Simulant; Chronic beryllium disease 0887-2333/$ - see front matter Published by Elsevier Ltd. doi:10.1016/j.tiv.2004.08.001 Abbreviations: ABDC, alkylbenzyldimethylammonium chloride; BAS, Baron and Ahmed solution; BeO, beryllium oxide; ICP-MS, inductively coupled plasma-mass spectroscopy; KHP, potassium hydrogen phthalate; M D , dissolved beryllium mass; M 0 , initial particulate beryllium mass; MEM-a,minimumessentialmedium-alpha;PBS,phosphatebufferedsaline;PSF,phagolysosomalsimulantfluid;SUF,serumultrafiltrate;USEPA, United States Environmental Protection Agency * Corresponding author. Tel.: +304 285 6302; fax: +304 285 5820. E-mail addresses: astefaniak@cdc.gov (A.B. Stefaniak), boq9@cdc.gov (A.B. Stefaniak). 1 Currentaddress:NationalInstituteforOccupationalSafetyandHealth,CentersforDiseaseControlandPrevention,Morgantown,WV,USA. www.elsevier.com/locate/toxinvit Toxicology in Vitro 19 (2005) 123–134