[Complete]
Updates:
11 May 2012: added perspective for LD50
11 May 2012: Added oral LD50 and LD100 data for mice and approximate LD50 for humans. Added note on comparison to amounts used in DC.
*all information provided here is from Toxnet unless otherwise noted*
Structure:
Chemical Formula: KCN
Appearance: White crystalline powder
image from Wikipedia
LOAEL (lowest observable adverse effect level): 1.2mg/kg
LD50(Inhalation): ~150-300mg/kg (Time to death ranging from 30min to immediate) from HPA
LD50 Inhalation Perspective: The average adult in the USA is 86kg (~190lbs). So it would take approximately 25,800mg (or 0.9oz) of KCN to kill an average USA Adult male. To further simplify, that is slightly less than 1.5 tablespoons (estimated, based on the the molecular weight of NaCl, which is slightly lighter, using this converter)
LD50(oral human): 0.7-2.9 mg/kg (Of CN-) (from health canada)
LD50 Perspective estimate (oral human): It would take about 0.25 teaspoon to kill an adult human male, using 1.5mg/kg as an average of pure Cyanide ion. (so it would actually take about double that because Potassium more than doubles mass of cyanide ion)
LD50(oral mice): 5-10mg/kg
LD50Perspective (oral): Using the same as before, the calculations come to 0.15 teaspoon to kill.
Please see notes at the end for additional information and context.
LD100 (oral mice): ~40mg/kg
LD100Perspective (oral): Using same methods and figures from before it would take 0.7 teaspoons to kill lab mice 100% of the time.
T1/2: 20min - 1hr (conversion from Cyanide to thiocyanate)
ADME
Absorption: Inhalation of airborn crystals (or of HCN after hydrolysis reaction occurs), ingestion, injection (IV), skin absorption
Distribution: KCN is distributed by the cardiovascular system (through the blood) It has a higher affinity for Red Blood Cells than plasma.
Excretion: 72% excretion by feces and urine, 25% through exhalation, 3% retained in one month. Urine is the primary method after cyanide is converted into thiocyanate, which usually occurs in the first 24h of exposure. Sweat and saliva via HPA
Metabolism (Technical stuff incoming):
Note: This works for ALL forms of Cyanide! I know other forms of Cyanide have been used by Gosho, but due to the metabolism and mechanism (next section) being identical, I won't do the others unless I find *significant* differences between the forms of cyanide.
Note 2: All forms of cyanide are converted into HCN when ingested. The acid of the stomach creates a hydrolysis reaction that converts it.
The cyanide ion (just the CN-) is conjugated with Sulphur, which creates the anion thiocyanate (SCN-). This reaction is catalyzed by the enzyme Rhodanese. Rhodanese is produced in MOST ANIMAL TISSUES, so this reaction need not occur in the liver or in the kidneys. It does need the cofactor sulphane-sulfer (via HPA) for this conversion to occur. After its conversion to thiocyanate, it is in such a form that it can be excreted through the urine.
Translation for lay people: KCN becomes K+ and CN-. The cyanide reacts with sulphur in the biological system. This is aided by Rhodanese enzyme, which makes this reaction occur faster. After the reaction is done, it is thiocyanate (SCN-). Thiocyanate can be excreted through the urine, thus being expelled.
Mechanism of toxicity (aka: how it kills you):
Information on the mechanism from Detective Conan Desperate Revival Case is as follows:
According to justwantanaccount, the translation I read was wrong. Gosho did describe it as a electron transfer.
From justwantanaccount "The original Japanese for the 'electron signaling' is 電子伝達系, which directly translates to 'electron transfer system'"
Verdict: Correct.
In reality: Cyanide has an affinity for iron in ferric state (Fe3+). This allows it to react with the iron in cytochrome c oxidase in the mitochondria of cells. This interaction blocks cytochrome c's ability to participate in the electron transfers that are involved in cellular respiration. This blocks the cell's utilization of oxygen. Basically what happens is that the Cyanide takes the place of the cytochrome c oxidase's open site for electrons, which would be transferred to oxygen allowing the oxygen to be converted to water for use within the biological system which is for the creation of ATP.
Translation for lay people: There is more to this reaction, but I'm sticking to Cyanide here. Basically, Cyanide interacts with iron, iron interacts with enzyme involved in cellular respiration, this prevents electron transfer between enzyme and oxygen, preventing oxygen from being utilized in cellular respiration. This stops cellular respiration and thus oxygen is not used. This naturally leads to death.
Note on toxicity as depicted in Detective Conan: Gosho has overestimated the affects of KCN on a human system. From what I have found, that is the estimated in a general system. However, lethal affects are NOT immediate, unless concentrations are significantly higher. 0.25 teaspoons is what can kill on average. According to the data, it took 35-40mg/kg of CN- to kill mice ~100% of the time (all but one died). Now, the time it took until death was 19 minutes at that dosage. This is further cooroborated with a case I found, that stated a woman, after ingesting 2.5g NaCN, died after 30 minutes. Symptoms occur far before it (tingling sensations, and the like) followed by unconsciousness. Death is NOT immediate. On average for a lethal dose in humans takes approximately One hour to kill. Immediate death (as seen in DC) would take significantly more what could be fit into an ice cube with a small cavity created. The amount Gosho uses is probably around 2-5 times off the minimum lethal amount in humans in Desperate Revival (due to an ice plug being needed, the amount couldn't have been more than about ~10-20 milligrams)
FINAL NOTE: I excluded a few things for simplicity, such as the the treatment for Potassium Cyanide. I also did not include symptoms of nonlethal exposure or chronic exposure. If you want that information included, please leave a comment in my profile or in the status update announcing the completion of KCN analysis!