The stability of Iysergic acid diethylamide (LSD) in biological fluids was studied by Radcliffe et al. using radioimmunoassay. Serum, heparinized whole blood, and urine containing LSD at a concentration of 3.9µg/L were stored for 3 days at room temperature in a room lit by fluorescent tubes. After this time, 80% of the original IBID activity remained in urine or serum, whereas only 30% of the activity originally in blood was detected. Peel and Boynton determined qualitatively that LSD stored in blood or urine that was kept frozen or at room temperature was still detectable after 6 weeks. In a urine sample stored for 6 months at room temperature, a decrease in drug concentration was observed, with or without fluoride in the urine. Francom et al. monitored the stability of LSD in urine using a GC-MS; method.
LSD concentrations in urine were within 10% of control values after 4 weeks when stored in polyethylene bottles, protected or unprotected from light, both at room and refrigerated temperatures. Additionally, LSD was similarly stable in urine refrigerated for 3 months. Similar results were obtained by Li et al.; (LSI) was stable in urine specimens for up to 4 weeks when stored at room temperature in containers that can block ultraviolet light, such as amber-glass or high-density polyethylene bottles. In normal light, LSD was stable in urine specimens at room temperature for approximately 1 week. LSD was also more stable in acid urine than in alkaline urines. A metabolite of LSD, 2-oxo-3-hydroxy LSI (O-H-LSD) has been identified in urine specimens of LSD users at higher concentrations than parent drug.
Klette et al. examined the stability of the metabolite in urine specimens under a variety of storage conditions. Within a pH range of 4.6 to 8.4, there was no significant loss of OH-LSD at -20 °C and 8 °C over an 8 day period. O-H-LSD was stable at – 20 °C for up to 60 days. However, at room temperature or higher, O-H-LSD was unstable. This instability was a function of urine pH, as the metabolite was less stable at alkaline pH than at acid pH. LSD is not produced by the breakdown of O-H-LSD. Skopp et al. conducted a comprehensive stability study of LSD and 2 metabolites (nor-LSD and O-H-LSD) in urine.
All analytes were stable at -20 °C. At 4 °C and 22 °C, the concentrations of the 3 analytes steadily decreased. LSD was stable for 3 days at 4 °C and 22 °C provided the urine specimens were protected from light. When exposed to light, LSD, norLSD, and O-H-LSD were 3%, 21%, and 69% of their initial concentrations, respectively, after 1 day at 22 °C. In general, the 2 metabolites were more stable than the parent drug.