Influence of extraction solvent in determination of selected corticosteroids in herbal dermatological products

Danas se sve više koriste prirodni proizvodi kao alternativa tradicionalno korištenim medicinskim preparatima uz pogrešnu pretpostavku da zato što su prirodni su i sigurni. Mnogi takozvani prirodni proizvodi mogu biti krivotvorine u koje su dodane aktivne farmaceutske supstance. Cilj našeg istraživanja je pronaći najprikladnije ekstrakcijsko otapalo koje daje najbolji analitički prinos za dodane sintetske koritkosteroide u topičke pripravke prije određivanja sadržaja kromatografskom metodom. Četiri različita ekstrakcijska otapala su korištena za određivanje devet odabranih kortikosteroida. U tu svrhu, u HALMED-u je ranije razvijana i validirana analitička kromatografska metoda za određivanje devet kortikosteroida. Rezultati pokazuju da je 0,1% V/V octena kiselina u metanolu najprikladnija ekstrakcijska otopina za četiri komponente: alklometazon dipropionat, klobetazol propionat, mometazon furoat i betametazon dipropionat. Metanol je dao najbolji analitički prinos za betametazon dipropionat, mometazon furoat i hidrokortizon acetat. Acetonitril je najbolje ekstrakcijsko sredstvo za metilprednizolon acetat, betametazon valerat i deksametazon, dok je etanol najprikladniji samo za triamcinolon acetonid. Na temelju dobivenih rezultata možemo zaključiti da ako bi se odjednom htjelo ekstrahirati što više kortikosteroida analiziranih u ovom radu, najbolji ekstrakcijski uvjeti bi bili postignuti korištenjem acetonitrila kao ekstrakcijskog sredstva. Iza acetonitrila, drugi izbor za ekstrakciju više od pola spomenutih kortikosteroida bio bi metanol ili 0,1% V/V octena kiselina u metanolu. Rezultati upućuju na to da dodatak octene kiseline mijenja vrstu komponente koja se ekstrahira te s time i efikasnost ekstrakcijskog postupka.Natural herbal products are being used more and more today instead of traditional pharmaceutical products. Unfortunately many so-called natural products can be counterfeit by the addition of the active pharmaceutical ingredient. The aim of the study was to find the most appropriate extraction solution for the best recovery of added synthetic corticosteroids in topical preparations before assay determination by chromatographic method. Four different extraction solutions were used and nine corticosteroids were determined. For that purpose a validated analytical chromatographic method was used, previously developed and validated for assay determination of above mentioned compounds. Results show that 0.1 % V/V acetic acid in methanol is the most appropriate extraction solution for 4 compounds namely, alclometazon dipropionate, clobetason propionate, mometason fuorate and bethametazon dipropionate. Methanol gave the best recovery for bethametazon dipropionate, mometason fuorate and hydrocortison acetate. Acetonitrile was the best choice for methylprednisolon acetate, bethametazon valerate and dexamethason., while ethanol was the best extraction solution for only triamcinolon acetinide. It can be seen from all of the obtained results that the best extraction conditions, if one would like to extract most of the above mentioned corticosteroids, would be accomplished by using acetonitrile as the extraction solution. Following acetonitrile, second choice for good extraction of more than half of mentioned corticosteroids would be both methanol or 0,1 % V/V acetic acid in methanol. The results suggest that addition of acetic acid changes the type of compounds that are extracted and the efficiency of the extraction procedure