Obituary: Stanley Lawrence Hem

Dr Stanley Lawrence Hem, 71, died unexpectedly on 23 January 2011 at his home in West Lafayette, IN, USA. Stan was a Professor of Industrial and Physical Pharmacy at Purdue University, IN, USA, and an internationally recognized expert in aluminum-containing vaccine adjuvants. Stan was born on 5 October 1939 in Brooklyn, NY, USA. He received a BS in Pharmacy with high honors from Rutgers University, NJ, USA in 1961 and a PhD in Physical Pharmacy from the University of Connecticut, CT, USA in 1965. In the late 1960s, he was a senior research pharmacist at Wyeth Laboratories where he studied the antacid properties of aluminum hydroxide gels. This experience was a prelude to a lifelong interest in the pharmaceutical uses of aluminum salts.

He joined the faculty of Purdue University in 1969, where he served for more than 40 years and was active until his death. At Purdue, Stan’s early work addressed the properties of antacids, including aluminum hydroxide gels and pharmaceutical clays, as well as the chemical stability of penicillin and tetracycline antibiotics. Beginning in the mid-1980s, his research focused increasingly on aluminum salts as vaccine adjuvants. Together with Dr Harm HogenEsch, a veterinary pathologist at Purdue, and others, Stan developed a mechanistic understanding of the antigen–adjuvant interactions and their importance in eliciting an immune response. Prior to their work, adjuvants were added to vaccines empirically with little understanding of their critical properties. Stan’s lab characterized the physicochemical factors governing antigen adsorption to aluminum salts, including the effects of pH and counter-ions, and developed methods to modify the adjuvant surface charge to enhance the stability and efficacy of the antigen. They identified ligand exchange as an important mechanism of antigen adsorption. The group investigated the effects of interstitial fluid on antigen–adjuvant interactions, and the mechanisms by which adjuvants affect processing and antigen presentation by dendritic cells. Their 2007 review of aluminum-containing adjuvants [1] published in this journal has been widely cited; their body of work helped create a scientific basis for the selection of vaccine adjuvants and contributed directly to a number of commercial vaccines.

Stan was also a gifted and dedicated teacher. His course in Basic Pharmaceutics inspired a generation of Purdue Pharmacy students, helping them understand the physical chemistry behind the formulations on the shelves. He was a multiple recipient of Purdue’s Henry Heine Award for Excellence in Teaching. He received the Purdue University Outstanding Undergraduate Teaching Award in 2005, when his name was added to Purdue’s Book of Great Teachers. Stan was also a great human, friend of many, husband, father, grandfather, a fan of Purdue sports, supporter of the arts and active in his local Presbyterian Church. He has left behind an admirable professional and personal legacy.