Lack of Effect of Frost-Free Refrigeration on the Volume of Antibiotic Liquids

Abstract

Objective:

To determine whether sealing liquid penicillin bottles in resealable plastic bags during storage in a household frost-free refrigerator prevents clinically significant evaporative losses.

Design:

Sixty bottles of penicillin VK 250 mg/5 mL, 100 mL (10 bottles from each of 6 different manufacturers: Apothecon, Biocraft, Lederle, SmithKline Beecham, Warner-Chilcott, and Wyeth-Ayerst) were mixed according to the manufacturers' recommendations. Five bottles from each manufacturer were stored inside a resealable plastic bag and the other 5 bottles were stored outside a bag (both at 2–8 °C in a frost-free refrigerator). Twice daily, 5-mL doses were removed from the bottles. The mean total volume removed from bottles stored inside resealable plastic bags was compared with that from bottles stored outside bags.

Results:

There was no difference in the average total amount removed from bottles between the two storage conditions.

Conclusions:

Sealing bottles containing liquid penicillin in plastic bags during storage in a household frost-free refrigerator seems to offer no advantage in protection from volume depletion via evaporation over 10 days. Factors other than evaporation are probably responsible when antibiotics that require refrigeration have insufficient volume to provide the expected number of doses.