ABSTRACT
Both hard and soft types of capsule shells were first patented and used in France in the first half of the nineteenth century. This chapter describes their manufacturing processes and explains the properties of each. Hard capsule shell manufacturing remained almost exclusively in the United States from the 1880s until after the Second World War. Eli Lilly Co. and Parke, Davis & Co. were leaders in this field. The chapter describes the process used for gelatin. Gelatin solutions are a good substrate for bacterial growth at ambient temperatures. The empty capsules go through a further series of processes in order to meet customer requirements: sorting, printing, and packaging. Eli Lilly & Co. was the first large-scale manufacturer of a non-gelatin hard capsule in the early 1950s. They utilized a property of cellulose solutions, the viscosity of which increases as the temperature rises. Plasticizers are chosen in relation to the properties of fill formulation and the required shell properties.
