Background Indomethacin 1 mg is used in premature infants to close the patent ductus arteriosus. The commercial product Indocid PDA is no longer available in Switzerland. Nevertheless, on our paediatric ward there is a great need for an intravenous indomethacin solution that can be used at a dose of 0.1–0.2 mg/kg body weight.

Purpose To produce a parenteral ready-to-use solution containing 0.2 mg/ml indomethacin and to determine the long-term stability using a stability indicating high-pressure liquid chromatography (HPLC) method.

Materials and Methods Liometacen, containing 50 mg sterile indomethacin (as meglumine salt), was reconstituted with 2 ml water for injection and then diluted with 250 ml NaCl 0.9% to a final indomethacin concentration of 0.2 mg/ml. Finally, a 5 ml indomethacin solution was filled into 10 ml sterilised brown glass vials. The entire process took place under aseptic conditions. Sterility testing was performed before final batch release.

The vials were stored for up to 18 months frozen at −20°C, at 2–8°C or at room temperature, and the solutions were assessed by HPLC for indomethacin and its degradation products.

Results Indomethacin solutions were submitted to conditions of oxidative or heat degradation, and the HPLC method was found to indicate stability.

The stability testing revealed that the solutions retained at least 95% of their initial indomethacin concentration when they were stored at room temperature for 12 days or at 2–8°C for 23 days.

In contrast, when the solutions were stored in a deep-freezer, they were stable for at least 18 months. During this time, no degradation of indomethacin occurred and the indomethacin concentration remained stable.

Conclusions Indomethacin solutions may be prepared in advance and stocked for at least 18 months at −20°C. After thawing they can be kept at room temperature for 7 days or alternatively at 2–8°C for 14 days. This procedure is used successfully in our hospital for the treatment of the patent ductus arteriosus.

No conflict of interest.