Quality Control: Lessons Learned from a Trimix Stability Study in a 503A Compounding Pharmacy.

Changes in California regulations regarding beyond-use dates of sterile preparations have prompted many compounders to consider stability studies for their formulas. Traditionally, 503A compounders have relied on published data and professional experience to determine stability. However, due to these new regulations, stability studies are now required for California resident and nonresident licensees to extend the beyond-use date of sterile preparations. Conducting studies for the first time can be costly and difficult for compounding pharmacists. This article shares several lessons learned from the author's experience performing stability studies on Trimix injection, a sterile preparation for erectile dysfunction. Avoiding easily made errors can save the compounder unnecessary time and expense.

Recreational technical diving part 1: an introduction to technical diving methods and activities.

Technical divers use gases other than air and advanced equipment configurations to conduct dives that are deeper and/or longer than typical recreational air dives. The use of oxygen-nitrogen (nitrox) mixes with oxygen fractions higher than air results in longer no-decompression limits for shallow diving, and faster decompression from deeper dives. For depths beyond the air-diving range, technical divers mix helium, a light non-narcotic gas, with nitrogen and oxygen to produce 'trimix'. These blends are tailored to the depth of intended use with a fraction of oxygen calculated to produce an inspired oxygen partial pressure unlikely to cause cerebral oxygen toxicity and a nitrogen fraction calculated to produce a tolerable degree of nitrogen narcosis. A typical deep technical dive will involve the use of trimix at the target depth with changes to gases containing more oxygen and less inert gas during the decompression. Open-circuit scuba may be used to carry and utilise such gases, but this is very wasteful of expensive helium. There is increasing use of closed-circuit 'rebreather' devices. These recycle expired gas and potentially limit gas consumption to a small amount of inert gas to maintain the volume of the breathing circuit during descent and the amount of oxygen metabolised by the diver. This paper reviews the basic approach to planning and execution of dives using these methods to better inform physicians of the physical demands and risks.