Abstract

The author provides a means for estimating the relative amount of sodium chloride needed to ensure that parenteral, nasal, ophthalmic or oral inhalation dosage forms are iso-osmotic or isotonic with body fluids. He presents an Excel spreadsheet that allows rapid calculation of the sodium-chloride equivalents (or E values) and an indicator of the relative extent of ionization of the drug in solution (or i factor). After the user loads the spreadsheet into Excel and inputs the drug name, molecular weight, pH (if required), pKa and number of ions formed by the drug in solution, the spreadsheet automatically calculates the E value and i factor for the drug. The spreadsheet is divided into calculations for weak acids and weak bases, and the user must determine the classification of the drug, along with the number of ions formed by the drug in solution. The author then provides step-by-step instructions for preparing the spreadsheet and a table providing a list of common drugs, the spreadsheet-calculated E values and the reference reported E values.

Related Keywords

• Isotonic solutions, formulation of
• Nasal administration, compounding for
• Ophthalmic administration, compounding for
• Oral inhalation, compounding for
• Parenteral administration, compounding for
• Sodium-chloride equivalents, for drugs, estimation of

Related Categories

• SUPPORT
• TECHNOLOGY
• QUALITY CONTROL