NCPDP participants include most segments involved in the pharmacy services sector of healthcare. The membership is in three categories:

Producer/Provider includes all types of retail pharmacies (including chains, independents, online pharmacy), pharmaceutical manufacturers, and long term care providers.
Payer/Processor includes Pharmacy Benefit management companies, health insurers, state and federal agencies, and health maintenance organizations.
Vendor/General Interest includes healthcare consultants, systems vendors, database management organizations, Physician Service Organizations, professional/trade associations, and wholesale drug distributors.

And yes, Doc was a founder!