Stability evaluation of morphine, hydromorphone, metamizole and esketamine containing analgesic mixtures applied for patient-controlled analgesia in hospice and palliative care.

In this study, different injection solutions containing opioid and nonopioid compounds used for patient-controlled analgesia in hospice and palliative care were evaluated in terms of analyte stability. Investigated injection solutions contained different combinations of morphine, hydromorphone, metamizole and esketamine. For the practical implementation, samples from infusion pumps were daily drawn over a period of 7 days at 22 and 37°C. Quantitative measurements were performed on a high-performance liquid chromatography system with ultraviolet detection applying a validated analytical method. All compounds apart from morphine showed no evident changes in concentration. However, a significant loss of morphine was observed for injection mixtures containing both morphine and metamizole at 37°C. After 7 days, only 72% of the initially measured morphine concentration was measured in the binary and 77% in the ternary mixture. Furthermore, an additional compound was detected that could represent the morphine-metamizole-adduct, "metamorphine". Based on these results, a significantly reduced morphine concentration must be expected after only 3 days if an injection solution mixture containing both morphine and metamizole is administered to a patient at 37°C. Since the analgesic effects of morphine-metamizole adducts have not yet been thoroughly investigated, further clinical studies are necessary before accurate conclusions can be drawn in this regard.

Overcoming limitations in the availability of swabs systems used for SARS-CoV-2 laboratory diagnostics.

The diagnosis of COVID-19 relies on the direct detection of SARS-CoV-2 RNA in respiratory specimens by RT-PCR. The pandemic spread of the disease caused an imbalance between demand and supply of materials and reagents needed for diagnostic purposes including swab sets. In a comparative effectiveness study, we conducted serial follow-up swabs in hospitalized laboratory-confirmed COVID-19 patients. We assessed the diagnostic performance of an in-house system developed according to recommendations by the US CDC. In a total of 96 serial swabs, we found significant differences in the accuracy of the different swab systems to generate a positive result in SARS-CoV-2 RT-PCR, ranging from around 50 to 80%. Of note, an in-house swab system was superior to most commercially available sets as reflected by significantly lower Ct values of viral genes. Thus, a simple combination of broadly available materials may enable diagnostic laboratories to bypass global limitations in the supply of swab sets.