1. INTRODUCTION

The purpose of this chapter is to provide information and guidance regarding how to evaluate whether an osmolality instrument is suitable for use with certain pharmaceutical formulations. This chapter discusses how to assess what the ideal behavior of a solution should be, how to determine what nonideal behaviors dominate in a solution, and how to evaluate whether a freezing point measurement is suitable for an undiluted sample. Additionally, this chapter provides suggestions and recommendations on situations when the procedure needs to be validated or revalidated due to the test condition changes. This chapter briefly discusses the correlation and difference between tonicity and osmolality to add clarification for users.