The story behind the nations largest correctional pharmacy provider begins in 1970 when pharmacists Gilbert and Joan Zilner purchase Diamond Drugs, a corner drug store located in the quaint community of Indiana, Pennsylvania.

The Zilners little drug store at 639 Philadelphia Street filled prescriptions for local residents and even a few nearby long-term care communities. They also sold an assortment of medical supplies. Not much would change in the ensuing decade.

Nineteen eighty-three, however, was a pivotal year. The Zilners moved the flagship drug store across Philadelphia Street to a roomier, more visible storefront. And that year also saw Diamond submit its first-ever bid to provide pharmacy services to a correctional facility.