Divide the total peptide amount (mg) by your desired concentration (mg/mL) to determine the water volume needed. For example, a 5mg vial reconstituted to 0.5mg/mL requires 10mL of bacteriostatic water (5mg ÷ 0.5mg/mL = 10mL).
USP Chapter 795 provides pharmaceutical compounding guidelines for accurate reconstitution calculations.