化学药中主要物质含量分析检测方案

CD APPLICATION NOTE 01-04Circular Dichroism SpectrometryFor the Analysis of AmphetaminesJasco，Inc.8649 Commerce Dr.Easton， MD 21601 Amphetamines are controlled substances whichare potent stimulantss that induce feelings ofstrength and energy while decreasing the need tosleep or eat. The majority of illegal amphetamineproducts are racemic； consequently， both isomerswill appear in the biological fluids unchanged.Incomparison the break-down products formed bythe metabolism of most pharmaceutical drugsshowvttheeappearanceof pureeamphetamineenantiomers. Circular dichroism is a form of lightabsorption spectroscopytthatmeasures thedifference： in absorbance of right- andleft-circularly polarized light (rather than the commonlyused absorbance of isotropic light) by a substance.Since different enantiomers absorbbdifferentportions of the light， it provides and excellentmeanss forr enantiomer ddetection. In thisapplication CD will be used to study the isomers ofamphetamine and methamphetamine. Introduction Amphetamines are synthetic drugs that stimulate thecentral nervous system. They are structurally similar toephedrine， a natural stimulant found in plants and tothe hormone adrenaline. They are available legally byprescription and were once widely prescribed as a cureall for everything from asthma to epilepsy. Today，medical use of amphetamines is limited to treatingminimalbbrain dysfunction(MBD) in children andnarcolepsy， a rare disorder in which an individualsuddenly falls into an uncontrollable deep sleep. Amphetamines are a popular "street" drug.Legally produced amphetamines are sold illegally onthe black market with variations in quality and quantity.Enterprising chemists have also developed a "look-alike" amphetamine manufactured to look like realamphetamines and mimic their effects.These arecommonly referred to as "speed" or "uppers". Thesedrugs containvaryingi amountsi of less rpotentstimulants such as caffeine. ephedrine andphenylpropanolamine-all legal substances thatareusually foundinn over-the-counter dietpills anddecongestants. The majority of illegal amphetamine productsare racemic； consequently，both isomers will appear inthe biological fluids unchanged.. In comparison thebreak-down products formed by the metabolism ofmost pharmaceutical drugs show the appearance ofpure amphetamine enantiomers. A large portion ofabused amphetamines are produced surreptitiously byvariousmethods. Thissproducesproductswithdifferent qualities depending on the type of synthesis as well as on the chemicals used. The identification ofby-products of the synthesis and the determination ofthe enantiomeric composition of the active substanceas well as that of the impurities being present in thepreparations， are important aims of the forensic andpharmacological analysis. It is also useful for bothcomparative purposes and for the evaluation of theproduction methods.5.In this note we will show theapplicability of CD to the determination of enantiomericcomposition. Experimental Theeindividual Isomerscamphetamine：andofmethamphetamine(1mg/mL methanol) werepurchased 1from Altech anduused withoutt furtherpreparation..CD spectra were collected at roomtemperature using a Jasco J-810 spectropolarimeter ina low volume 1cm path length cell. The response timeused was 1sec with a data pitch of 0.1nm and a scanspeed of 100nm/min， giving complete analysis in lessthan 2 minutes. Figure 1. CD spectra of D-amphetamine (blue) and D-methamphetamine (red). Results and Discussion Evaluation of the CD spectra of methamphetamine andamphetamine show very few differences. This is dueto the fact that meth-amphetamine is composed of anamphetamine molecule with an additional methyl groupattached to its nitrogen (amine group). lFigures 1-2 show the scans of the isomers of amphetamine andmeth-amphetamine. Figure 2. CD spectra of L-amphetamine (blue) and L-methamphetamine (red)). The most important use for CD is chiral detection anddetermination， and in the case methamphetamine isvery useful for identification of the enantiomers.(Figure 3) Another important feature of the data is theHT[M] which is easily converted via software intoabsorbance units. Thus UV data is collected for everysample at the same time. Since legal amphetaminesare detected as pure enantiomers and street versionsracemic， CD issaa quickmethod fifor determiningprescription from illegal versions.CCD is also aneffective method for determining which enantiomer isused in the drug as an aid to identification. Figure 3. CD spectra of L-methamphetamine (red) andD-methamphetamine (blue). Conclusions CD spectrometry is a fast effective method for thedetermination of the chiral structures in amphetaminesand many other compounds of interest. In addition CDis useful for protein secondary and tertiary structure，ligand binding，carbohydrate interaction and much，much， more. The simultaneous collection of both theCD and UV in one measurement will increase thespeed and efficiency of all chiral determinations. Amphetamines are controlled substances whichare potent stimulants that induce feelings ofstrength and energy while decreasing the need tosleep or eat. The majority of illegal amphetamine