Beyond-use Date of Trimix: A Reproducible Stability Study Using Bracketing Design.

Trimix is a widely prescribed penile injection for patients with erectile dysfunction and is only available as a compounded medication. The instability of alprostadil, one of the major ingredients of Trimix, has been a limiting factor in its utilization. There are published stability data for Trimix formulations that have been used to establish a beyond-use-date. However, a robust bracketed study that is shown to be reproducible is highly desirable and meaningful. The purpose of this study was to test the reproducibility of a bracketed stability study when the preparations were made by two different entities to provide beyond-use date information of Trimix preparations that cover a wide range of strengths. A validated stability indicating method was used to compare the stability of a bracketed Trimix - alprostadil 5 µg/mL to 45 µg/mL, papaverine 15 mg/mL to 30 mg/mL, and phentolamine 0.4 mg/mL to 5 mg/mL, and a single-strength preparation containing alprostadil 30 µg/mL, papaverine 30 mg/mL, and phentolamine 2 mg/mL that were compounded and stored following the same methods and conditions, but at two different practice settings. Beyond-use dates of 60 days and 64 days at cold temperature were obtained for the two preparations from two different settings. The consistent results confirmed the reproducibility of the bracketing designs used to determine the beyond-use dates of Trimix. The clinical value of these results stems from the availability of accurate and widely applicable stability data that can be referenced to establish beyond use dates of a number of Trimix preparations with various strength combinations.

Environmental monitoring: data trending using a frequency model.

Environmental monitoring programs for the oversight of classified environments have used traditional statistical control charts to monitor trends in microbial recovery for classified environments. These methodologies work well for environments that yield measurable microbial recoveries. However, today successful increased control of microbial content yields numerous instances where microbial recovery in a sample is generally zero. As a result, traditional control chart methods cannot be used appropriately. Two methods to monitor the performance of a classified environment where microbial recovery is zero are presented. Both methods use the frequency between non-zero microbial recovery as an event. Therefore, the frequency of events is monitored rather than the microbial recovery count. Both methods are shown to be appropriate for use in the described instances.