M To S
- MCN - McNeil Laboratories, now part of Johnson & Johnson
- MDCO - The Medicines Company
- MEM - Memory Pharmaceuticals
- MGX - Victory Pharma
- MK - Merck
- MLN - Millennium Pharmaceuticals
- MT - Micromet, acquired by Amgen in 2012
- NC - Nycomed
- NCX - NicOx, a French Biotech
- NG - Neurogen Corp.
- OGX - OncoGenex
- OPC - Otsuka Pharmaceutical Co.
- PD - Parke-Davis, now Pfizer
- PF - Pfizer
- PHA - Pharmacia, now Pfizer
- R - Janssen Pharmaceutica, now part of Johnson & Johnson
- REGN - Regeneron
- RO - Hoffmann-La Roche
- RU - Roussel Uclaf
- RWJ - R.W. Johnson Pharmaceutical Research, now part of Johnson & Johnson
- SAN - Sandoz Pharmaceuticals, now Novartis
- SB - SmithKline Beecham, now GlaxoSmithKline
- SCH - Schering-Plough
- SPI - Spectrum Pharmaceuticals Inc.
- SU - SUGEN, now Pfizer
Read more about this topic: List Of Pharmaceutical Compound Number Prefixes