The placing, conducted by Numis Securities Ltd, has raised £50m from institutional investors, including £10m of new money for the company before expenses, at a price of 164p per share.
Dealings in Clinigen shares are expected to commence on AIM at 8am on Tuesday 25 September 2012.
Chief executive Peter George said: "After a period of sustained international growth, a listing of our shares is key and the next logical step in our development. We aim to maintain our strong growth record - based on our unique business model - both organically and through the acquisition of new pharmaceutical products.
"The listing will provide us with additional financial flexibility which, together with our strong balance sheet and the funds raised for the company, will support our ongoing expansion."
Clinigen employs 78 staff across its operations, with offices in Philadelphia and Tokyo, in addition to its Burton headquarters. The company supplies drugs for clinical trials and sells specialist medication only used in hospitals.
The group, since its formation in 2010, has increased revenues from about £22m to £82m and is active in 53 global-wide markets. It comprises two divisions, services and products.
The listing will mean Clinigen will become the first pharmaceutical company to float in London for five years and one of only a handful of Midlands businesses to list during that time.
The IPO will also net windfalls for Clinigen's executive chairman Andrew Leaver and chief executive Peter George. Leaver owns about 64 per cent of the business, while George has a 13 per cent stake.
Numis Securities is acting as the company's nominated adviser and broker, and acted as sole book-runner on the placing.