Stability of a less-painful intravenous emulsion of clarithromycin

Abstract The chemical stability of a less-painful ready-to-use o/w emulsion for intravenous (i.v.) delivery of clarithromycin was investigated. The formulation contained 0.5% w/v drug, 2% w/v soybean oil, 5% w/v egg phosphatide, 0.6% w/v oleic acid, 0.3% hexanoic acid and 2.5% w/v glycerin in water. The change in the initial pH of emulsion (range: 6.5–8.0) did not significantly influence drug stability over a period of 30 days at 5 and 30°C. The increase in the initial pH of emulsion as well as its storage temperature gradually decreased the final pH over time. The emulsion prepared at pH 7.5 demonstrated a constant drop in pH over 9 months at 30°C at the rate of about 0.002 units drop in pH per day; however, it did not demonstrate significant loss of drug. Actual as well as projections using accelerated stability studies indicated the shelf-life (i.e., time to retain 90% of the label claim, t 90% ) of the emulsion formulation, at 25°C, to be ≥ 21 months. Overall, the results suggest that the development of a less-painful ready-to-use o/w emulsion of clarithromycin is feasible.