A pharmacy technician is preparing a 0.2% hydrocortisone ointment, but the pharmacy only has 2.5% hydrocortisone ointment available. Which of the following should the technician use to dilute the ointment?

To achieve a 0.2% hydrocortisone ointment from a 2.5% concentration, the technician needs to dilute the stronger ointment. When diluting ointments, it is essential to use an appropriate base that does not alter the properties of the active ingredient and provides a suitable consistency and stability to the final product.

Using petroleum jelly as a diluent is ideal because it not only serves as a stable and non-reactive medium but also retains the ointment's consistency and can aid in the absorption of the hydrocortisone. Petroleum jelly is commonly used in topical formulations to create emulsions and maintain the integrity of the ointment while achieving the desired concentration.

Other options, such as water or hydrocortisone ointments with lower concentrations, could lead to instability or inconsistent potency in the final product. Water, for instance, can change the ointment's properties and might not blend well with oily bases. Using another hydrocortisone ointment for dilution could still maintain some of the original concentration, which would not achieve the desired 0.2% concentration. Thus, petroleum jelly provides the best solution for effectively diluting a 2.5% hydrocortisone ointment to 0.2%