The availability of diltiazem: a study on the sorption by intravenous delivery systems and on the stability of the drug

Stability of extemporaneously compounded diltiazem hydrochloride infusions stored in polyolefin bags

PURPOSE

The stability of extemporaneously compounded diltiazem hydrochloride infusions stored in polyolefin bags was studied.

METHODS

Sterile preparations of diltiazem hydrochloride were compounded to a concentration of 1 mg/mL in 5% dextrose solutions in accordance with United States Pharmacopeia chapter 797. The infusions were stored at -20 °C, 2-6 °C, and 22-25 °C. Three samples from each temperature were withdrawn and assessed for stability immediately after preparation (day 0) and on days 7, 15, 21, and 30 using a high-performance liquid chromatography (HPLC) assay. The physical stability of diltiazem samples was assessed by visual examination. Infusions were evaluated against black and white backgrounds for evidence of visible particulate matter, cloudiness, and color changes. The concentration of diltiazem hydrochloride in all samples was examined using a stability-indicating HPLC method at each time point. Diltiazem was considered stable if the solution retained over 90% of the initial concentration.

RESULTS

No precipitation, cloudiness, or color change was observed at any of the temperatures studied. pH did not significantly increase or decrease among the samples, regardless of temperature, over the study period. The diltiazem hydrochloride infusions retained greater than 90% of the initial concentrations for at least 30 days.

CONCLUSION

Diltiazem hydrochloride diluted to 1 mg/mL in 5% dextrose injection was stable for 30 days when stored at -20 °C, 2-6 °C, and 22-25 °C.

Simultaneous enantioseparation of cis-diltiazem hydrochloride and its metabolite cis-desacetyldiltiazem using high-performance liquid chromatography and capillary electrophoresis

Two alternative methods were developed using high-performance liquid chromatography (HPLC) and capillary electrophoresis (CE) for a simultaneous enantioselective determination of Ca(2+) blocking chiral drug cis-diltiazem hydrochloride (DLT) and its degradation product and metabolite cis-desacetyldiltiazem (Desac-DLT). The methods were compared from the viewpoint of analytical performance. The identification of HPLC peaks were performed using off-line electrospray ionization mass spectrometry. In addition, CE method was evaluated for quantitative determination of minor enantiomeric impurities in pharmacologically active (+)-cis-DLT.