Posterske teme Poster topics - Biochemia Medica
Posterske teme Poster topics - Biochemia Medica
Posterske teme Poster topics - Biochemia Medica
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P15-1 (UP10-1) Toksikologija i TDM<br />
P15 – Toksikologija i TDM, P15-1 (UP10-1)<br />
Određivanje lamotrigina u plazmi metodom<br />
tekućinske kromatografi je visokog<br />
razlučivanja uz primjenu ultraljubičastog<br />
detektora<br />
Petek-Tarnik I1 , Coce I1 , Petek M1 , Cvitanović-Šojat LJ2 , Kusić Z3 1Endokrinološki laboratorij, Zavod za nuklearnu medicinu i onkologiju,<br />
KB Sestre milosrdnice, Zagreb, Hrvatska<br />
2Klinika za pedijatriju, KB Sestre milosrdnice, Zagreb, Hrvatska<br />
3Zavod za nuklearnu medicinu i onkologiju, KB Sestre milosrdnice,<br />
Zagreb, Hrvatska<br />
Lamotrigin (LTG) je antiepileptik novije generacije djelovanje<br />
kojega se očituje u blokiranju potencijala ulaznih<br />
vrata natrijskih kanala. Lamotrigin suzbija patološko otpuštanje<br />
glutamata i glutamatom izazvano izbijanje akcijskog<br />
potencijala. Terapeutsko praćenje LTG je važno kako<br />
bi se izbjeglo njegovo toksično djelovanje, kao i utjecaj na<br />
ostale antiepileptike. Cilj rada bio je uvesti metodu HPLC<br />
za određivanje LTG te istražiti kakav je odnos između primijenjene<br />
doze LTG i koncentracije u plazmi. Uzorku plazme<br />
(100 µL) dodaje se unutarnji standard (kloramfenikol)<br />
te se LTG ekstrahira dodatkom smjese kloroform:izopropanol<br />
u omjeru 95:5. Nakon odvajanja organski sloj se odpari<br />
do suhog, a LTG otopi u metanolu. Dobiveni ekstrakt<br />
(5 µL) injicira se na sustav HPLC. Odvajanje se provodi na<br />
koloni C18 uz mobilnu fazu sastava: fosfatni pufer, pH 6,0,<br />
acetonitril i metanol u omjeru 70:20:10, pri protoku od 1,0<br />
mL/min. LTG se određuje UV detekcijom pri 214 nm. Vrijeme<br />
zadržavanja LTG na koloni je 4,7 minuta, a unutarnjeg<br />
standarda 7,8 minuta. Preciznost metode ispitana je određivanjem<br />
kontrolnog uzorka plazme kojem su dodavane<br />
poznate koncentracije LTG. Koefi cijenti varijacije kretali su<br />
se između 3,1% i 4,5% za uzastopne analize unutar dana, te<br />
između 2,3% i 6,7% među opetovanim analizama tijekom<br />
nekoliko dana. Iskorištenje ekstrahiranog LTG kao i unutarnjeg<br />
standarda bilo je između 88,1% i 91,7%. Metoda je<br />
primijenjena određivanjem koncentracije LTG u 39 djece<br />
oboljele od epilepsije, od čega ih e 17 bilo na monoterapiji<br />
lamotriginom (4,66 mg/kg), a ostali na kombiniranoj terapiji<br />
LTG (3,92-5,66 mg/kg) i ostalim antiepilepticima (VPA,<br />
CLB, CZP). Prekoračena dozvoljena koncentracija LTG u<br />
plazmi (5 mg/L) pronađena je u 5 bolesnika na monoterapiji<br />
i 11 bolesnika na kombiniranim terapijama. Najviše<br />
vrijednosti LTG nađene su u bolesnika na kombiniranoj<br />
terapiji LTG i VPA. Također je zaključeno kako nema međusobnog<br />
odnosa između primijenjene doze LTG i koncentracije<br />
u plazmi. Metoda HPLC uz UV detektor može se<br />
preporučiti kao metoda izbora za određivanje LTG u plazmi<br />
zbog osjetljivosti, preciznosti i jednostavnosti.<br />
E-mail: petektarnik@net.hr<br />
<strong>Biochemia</strong> <strong>Medica</strong> 2006;16(Suppl 1):S1–S268<br />
S162<br />
P15 – Toxicology and TDM, P15-1 (UP10-1)<br />
Toxicology and TDM<br />
Determination of lamotrigine in plasma by<br />
high performance liquid chromatography<br />
with UV detection<br />
Petek-Tarnik I 1 , Coce I 1 , Petek M 1 , Cvitanović-Šojat LJ 2 , Kusić Z 3<br />
1 Laboratory of Endocrinology, Department of Nuclear Medicine and<br />
Oncology, Sestre milosrdnice University Hospital, Zagreb, Croatia<br />
2 University Department of Pediatrics, Sestre milosrdnice University<br />
Hospital, Zagreb, Croatia<br />
3 Department of Nuclear Medicine and Oncology, Sestre milosrdnice<br />
University Hospital, Zagreb, Croatia<br />
Lamotrigine (LTG) is a novel antiepileptic, which has a<br />
phenytoin-like membrane stabilizing mechanism via<br />
blockade of voltage-dependent sodium channels and<br />
inhibition of glutamate release. Therapeutic monitoring<br />
of lamotrigine is useful for patient management and<br />
avoidance of toxicity. The aim of the study was to develop<br />
HPLC method for determination of plasma LTG and<br />
to investigate the relationship between oral dose and<br />
plasma concentration of LTG. To 100 µL of plasma sample<br />
the internal standard (chloramphenicol) was added. The<br />
extraction was performed by a mixture of chloroform<br />
and isopropanol (95:5% v/v) in the presence of phosphate<br />
buff er. After evaporation the residue was reconstituted<br />
with methanol and injected to HPLC system. The separation<br />
was performed on a C18 stainless steel column.<br />
Mobile phase consisted of phosphate buff er pH 6.0, acetonitrile<br />
and methanol (70:20:10 v/v/v), with a fl ow rate of<br />
1 mL/min. The detection was obtained by UV detector at<br />
214 nm.The retention times for LTG and IS were 4,7 and<br />
7,8 minutes, respectively. Within- and between-day precision<br />
was examined by analysis of control plasma sample<br />
with coeffi cients of variation of 3.1%-4.5% and 2.3%-<br />
6.7%, respectively. The absolute recovery of LTG and of<br />
IS ranged from 88.1% to 91.7%. The method was used to<br />
analyze plasma LTG concentrations from 39 children with<br />
epilepsy; 17 samples were obtained from patients receiving<br />
LTG monotherapy (4.66 mg/kg), and the others received<br />
combined therapy with LTG (3.92-5.66 mg/kg) and<br />
other antiepileptics (VPA, CLB, CZP). In 16 plasma samples<br />
LTG level exceeded the reference range of 5 mg/L (5 on<br />
monotherapy and 11 on combined therapy). The highest<br />
plasma LTG levels were found in 4 patients receiving VPA.<br />
There was no relationship between oral dose and plasma<br />
concentration. The HPLC method with UV detection is the<br />
method of choice for the measurement of lamotrigine in<br />
plasma because of its sensitivity, selectivity and simplicity.<br />
E-mail: petektarnik@net.hr