Elimination of 7-aminoclonazepam in urine after a single dose of clonazepam

The objective of this paper was to determine how long after administration of benzodiazepine clonazepam (CLO), its major metabolite 7-aminoclonazepam (7-ACLO) could be detected in urine collected from 10 healthy volunteers who received a single 3-mg dose of Klonopin (clonazepam). Such data would be of great importance to law enforcement agencies trying to determine the best time interval for urine collection from a victim of drug-facilitated sexual assault in order to reveal drug use. A highly sensitive NCI–GC–MS method for the simultaneous quantitation of CLO and its major metabolite 7-ACLO in urine was developed and validated. The following urine samples were collected from each volunteer: one before CLO administration, and 6 h, and 1, 3, 5, 8, 10, 14, 21 and 28 days after. All urine samples (1 mL) were extracted following addition of the internal standard (D₅-diazepam) and enzymatic hydrolysis (-glucuronidase) using solid-phase extraction columns. Standard curves for CLO (500–4000 pg mL^–1) and 7-ACLO (50–2000 pg mL^–1) were prepared by spiking aliquots of negative urine. The urine from every subject was still positive for 7-ACLO 14 days after administration of the drug. Eight of the ten volunteers had measurable amounts of the metabolite 21 days after administration. One volunteer was still positive 28 days after administration. Six of the volunteers had urine concentrations of 7-ACLO that peaked at 1 day after administration. One volunteer had the highest concentration of 7-ACLO at 3 days, two volunteers at 5 days, and one at 8 days. The range of concentrations detected was from 73.0 pg mL^–1 to 183.2 ng mL^–1. CLO was not detected in any of the samples.     

Tautomer chemistry of thiazolidines. 1-Thia-4-azaspiro[4,5] decanes

The thiazolidine, 1-thia-4-azaspiro[4,5] decane (Ia), which is derived from cyclohexanone and 2-aminoethanethiol (X), forms a thiazolidone (VIII) with mercaptoacetic acid more slowly and in lower yield than with 2-phenylthiazolidine, a case reported previously. A thiazolidine which is related to a non-conjugate chain tautomer such as Ic, might be expected to behave in this way. Alkylation, as another possible example of tautomer chemistry, was studied, and N-, S-, and C-alkylation were all observed under varying circumstances. Thus, thiazolidine la undergoes alkylation with methyl iodide in ethanol to form the N-methylthiazolidine (IIa), and in sodium-liquid ammonia to give the S-methyl derivative (III). In the latter case, alkylation occurs with reductive cleavage. Although no trace of other tautomer derivatives (IV, V) was to be found in the methyl iodide alkylation, I with acrylonitrile did in fact give C-alkylation. An analytically pure mixture of tautomers was obtained, from which 2-oxocyclohexanepropionitrile (VI) was isolated on hydrolysis. In a manner similar to the formation of III, IIa was S-alkylated by treatment with sodium-liquid ammonia followed by benzyl chloride to give a saturated product (XVII). Although such a process might be identified with a chain tautomer (IIb), the evidence is to the contrary, since the intermediate (XIV), which might be involved in such a process, fails to undergo a similar reduction with sodium-liquid ammonia. A greatly improved procedure for the preparation of thiazolidine (XI, 86% yield) is also reported.