Amobarbital Ethanol

To the residue in the flask containing 6/10 of extract, add 100 /il of ethanol. Stopper the flask and rotate it to ensure complete dissolution of the residue. Inject an aliquot part (usually 2 or 3 jal) of this solution into the gas chromatograph. Figure 32 shows the results obtained by this procedure using a postmortem sample of blood which was found to contain amobarbital and secobarbital. The chromatogram of a mixture of nine common barbiturates is illustrated in Fig. 33. 

Fig. 32. Gas chromatogram of an extract of blood from a case of suspected overdose of drugs. Total blood barbiturates (by ultraviolet spectrophotometry) = 0.7 mg per 100 ml. Amount of amobarbital + secobarbital present in the injected aliquot part of the residual solution = 0.9 jag, in 5 /rl of ethanol. For column preparation see text. Column temperature prt rammed from 150 at 5 per minute. Attenuation X 100. Perkin-Elmer Model 800 gas chromatograph.

Noninterfering acetaminophen, acetylmorphine, amiodarone, amobarbital, amphetamine, bendroflumethiazide, benzocaine, benzoylecgonine, benzthiazide, butalbital, carbamaze-pine, chlorothiazide, clonazepam, cocaine, codeine, cotinine, cyclosporine, cyclothiazide, desalkylflurazepam, diamorphine, dicumerol, ephedrine, ethaciynic acid, ethanol, eth-chlorvynol, ethosuximide, furosemide, glutethimide, hydrochlorothiazide, hydrocodone, hydroflumethiazide, hydromorphone, lorazepam, mephentermine, meprobamate, meth-amphetamine, metharbital, methoxsalen, methoxyphenteramine, methsuximide, meth-ylcyclothiazide, metoprolol, MHPG, monoacetylmorphine, morphine, normethsuximide, oxazepam, oxycodone, oxymorphone, pentobarbital, phencyclidine, phenteramine, phenylephrine, phenytoin, polythiazide, primidone, prochlorperazine, salicylic acid, sulfanilamide, THC-COOH, theophylline, thiazolam, thiopental, thioridazine, tocainide, trichlo-romethiazide, trifluoperazine, valproic acid, warfarin... 

Figure 5.5.2. Solvent effect on the solubilities of barbituric acid derivatives in ethanol-water mixtures. Top to bottom metharbital, butabarbital, amobarbital. The smooth Unes were drawn with eq. 5.5.23. (Reproduced with permission from the Journal of Pharmaceutical Sbie/ices, reference 1.)...

Without any particular condition, the second acidity cannot be totally titrated by a sodium hydroxide solution in water. When the titration is carried out in pyridine with a sodium hydroxide solution in ethanol in the presence of thymolphthalein as indicator, the difficulty no longer remains. It is the same state of affairs with phenobarbital and amobarbital. In the presence of pyridine, the following overall reaction occurs ... 

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