Document Lor9K8pmxXkvKJQJRvBeJ5aGz

SCHERINC CORPORATION 60 ORANGE STREET B L O O MF I EL D , N. J. 0700 3 TELEPHONE.(201) 743-6000 TELEX' 138183 CABLES'SCHERINC BLOOMFIELD,N. ]. December 1 9 , 1973 Hearing Clerk Food and Drug Administration Room 6-86 5600 Fishers Lane Rockville, Maryland 20852 Dear Sir: This is in response to the publication in the Federal Register, Vol. 3 8 , No. 18 8 , September 28, 1973# requesting comments regarding the Commissioner's proposal to regulate the use of asbestos-containing filters for the manufacture of parenteral drug products. Schering Corporation will make every effort to eliminate asbestoscontaining filtering materials in the manufacture of parenteral drugs by July 1, 1975* However, we must point out a number of factors that could prevent completion of the substitution program by that date. The finding and testing of replacement filters in our basic synthesis and manufacture of raw materials and bulk active substances used in the formulation of drug dosage forms is highly complex and extensive. It will require substantial research to replace some of our current asbestos-containing filtration procedures with others that are equivalent in their effectiveness. The time for completion and success of the program is not now predictable. A membrane filter, which is usually used in the last step in many parenteral manufacturing operations, will remove most of the asbestos particles but not the smallest ones, even though it effec tively removes microorganisms and particulate matter down to 0.22 microns in size. The substitution of membrane or similar filters for the current asbestos-type filters is further complicated by the fact that membrane filters differ in mode of action from asbestos-type filters; membrane filters remove matter by mechanical sieve action, while asbestos-type filters do so by both mechanical and adsorptive action. t Food and Drug Administration Page 2 December 19* 1973 An additional complicating factor is that our manufacture of raw materials and active drug substances requires the use of manyorganic solvents, such as chloroform, alcohol, and acetone, and of acids and alkalies, which generally attack the membrane-type filters but are compatible with the asbestos-type filters. It is for these briefly stated reasons that ample time is requested for development of suitable replacements for asbestoscontaining filters. Sincerely, HIM/lc cc: Mr. C. Joseph Stetler - PMA H. I. Mitchell Director of Quality Assurance