You will be shown an abstract from a biomedical research paper. Given this abstract, your task is to extract all unique entities of the following types: ["Chemical"].

Please return the output as a JSON object of the format: {"Chemical": ["Arsenic", ...]}. The keys should be entity types and values should be lists of extracted entities belonging to the corresponding type. If you cannot find entities belonging to a specific type, the value should be [].

Only output the JSON object and do not include any additional text.

Abstract:

Disposition and metabolism of [¹⁴C]PTZ601 in healthy volunteers. 1. Six healthy male subjects were given a single dose of 500 mg of [14C]PTZ601 (mean radioactivity 79.2 μCi) by intravenous (IV) infusion over 1 h, and observed for 5 days post-dose during which pharmacokinetic (PK) samples were collected. Plasma PTZ601 concentrations and metabolite identification were determined using LC-MS/MS; PK parameters were estimated by non-compartmental analysis. Excretion and mass balance were determined with liquid scintillation analysis and metabolites profiling was characterized by HPLC online radiochemical detection. 2. The disposition of PTZ601 was best described by a fast absorption, followed by a biphasic elimination phase. Peak PTZ601 plasma concentrations were reached within 0.5-1 h. The mean elimination half-life was 1.6 h and clearance was 13 L/h. 3. Recovery of the radioactivity dose was complete (mean 92%). The main route of excretion (parent and metabolites) was the renal route, as urine accounted for 69-77%, while feces only 13-22%, of the total radioactivity. 4. The majority of the drug was excreted in urine as multiple open ring metabolites: M17.3 (oxidative ring-opened product) and M22.2 (di-cysteine conjugate of 17.3); unchanged PTZ601 in urine contributed to 15% of radioactivity. The major metabolites detected in plasma were M17.3, M12.8 (acetylated M17.3), M22.2, and M41.4 (methylated M17.3). 5. PTZ601 was well tolerated.
{"Chemical": ["PTZ601", "di-cysteine", "[\u00b9\u2074C]PTZ601", "[14C]PTZ601"]}