Comparative in vitro antimicrobial potency, stability, colouration, and dissolution time of generics vs. innovator of meropenem in Europe.Int J Antimicrob Agents 2019IJ
Meropenem generics are often imposed to prescribers but scanty specific information is available on key properties such as antimicrobial potency, stability and colouration in solution, and dissolution times. Our aim was to generate comparative information for products available in Europe. The originator (ASTRA) and 4 generics (HOSPIRA, SANDOZ, FRESENIUS, AUROVIT [colouration and stability only] were compared for (i) MICs against clinical Pseudomonas aeruginosa isolates (range: 0.125-191 mg/L); (ii) colouration (visual and photometry) and stability (LC-MS-MS) of concentrated solutions intended for prolonged or continuous infusion and maintained at 25 to 37°C for up to 8h [acceptable limit: 90% of original concentration]; (iii) dissolution time of concentrated solutions (50 mg/mL; bolus administration; turbidimetry and nursing personnel assessment). No significant difference was observed for MICs (except for 2 of 80 isolates). For concentrated solutions storage, (i) SANDOZ produced about twice more yellow-coloured degradation products than the other preparations; (ii) meropenem loss was time-, concentration- and temperature-dependent; (iii) FRESENIUS was the least stable (limit for 1g/48mL: ∼8h at 25°C and ∼4.5 h at 37°C); (iv) at 2 g/48mL, the limit storage time was 5-6 h at 25°C and ∼3h at 37°C for all preparations. Complete dissolution (turbidimetry) required 240 sec for generics (120 sec for ASTRA), and nurses reported longer but highly variable times for generics. Substantial differences between originator and generics have been identified that could impact on their clinical use and/or made multicentric studies difficult to interpret, requiring suitability studies in the environments of their intended use.