Riverside, a global private investor focused on the smaller end of the middle market, completed the acquisition of Medical Marketing Solutions Group, a provider of strategic services, scientific and medical communications, and operational and event management services to global biopharmaceutical companies. Financial terms were not disclosed. "MMSG is highly complementary for Red Nucleus. We are focused on expanding our portfolio of medical communications and publication planning services, hiring more talented scientific staff, adding expertise in new high-growth therapeutic areas and in growing our blue-chip client base. This addition boosts all those areas," Peter Tsang, Riverside Co-CIO.