The purpose of this study was to develop a freeze-dried human serum albumin (HSA)-free formulation of interferon-α (IFN-α) that had high safety and stability to reduce the risk of contamination in preparation of a pathogenic virus, an infectious prion and unknown infection factor.

As a result, the usefulness of L-leucine as not only a new stabilizer of IFN-α, but also an excipient for improving appearance and foaming at reconstitution of lyophilized cake was discovered. Moreover, a combination of polysorbate 80, sucrose, L-leucine, glycine and citrate buffer was found to the most stable, improving the appearance and foaming of a freeze-dried HSA-free formulation of IFN-α.

It was reported that a side effect is caused by excessive administration of eye drops containing prostaglandins for glaucoma. Therefore, it was concluded that the volume of each drop squeezed from a container should be designed to meet the minimum requirement. Furthermore, patient compliance would be affected by the ease of squeezing a drop from the container, since the majority of glaucoma patients are elderly people.

We developed a formulation of latanoprost eye drops that could be stored at room temperature. In this study, we investigated the design of eye drop containers of latanoprost eye drops, focusing on the usability of the container by patients. First, we investigated the nozzle on the eye drop container, in order to select an eye drop container that could repeatedly deliver the desired volume (30 μL/drop) in each drop. Then we developed specific apparatuses and reproducible evaluation methods for drop volume, repeatability of each drop, and ease of instillation. Moreover, we established new criteria for eye drop containers which considered their usability by patients using these evaluation methods. It was found that the selected eye drop container had desirable usability.

As a result, we could design an eye drop container for latanoprost eye drops that was appropriate for glaucoma patients. The evaluation methods and criteria established in this study are available as new indices for eye drop containers. In the future, use of these methods and criteria would contribute to the development of “patient-friendly eye drops” that are safe and easy to use.