49 research outputs found
Validirane RP-RP-HPLC i TLC metode za simultano odreÄivanje tamsulozin hidroklorida i finasterida u istom dozirnom pripravku
Reversed phase high-performance liquid chromatography (RP-HPLC) and thin-layer chromatography (TLC) methods have been developed and validated for simultaneous estimation of tamsulosin hydrochloride and finasteride in bulk drug and in combined dosage forms. RP-HPLC separation was achieved on a Phenomenex C18 column using methanol/0.02 mol L-1 ammonium acetate buffer/triethylamine (79.9 + 20 + 0.1, V/V/V) (pH 9.2) as mobile phase. The TLC separation was achieved on an aluminium-backed layer of silica gel 60F254 using toluene/methanol/triethylamine (9 + 1.5 + 1, V/V/V) as eluent. Quantification was achieved with photodiode array (PDA) detection at 235 nm over the concentration range 0.5â16 and 150 ”g mL1 with mean recovery of 99.8 ± 0.9 and 100.0 ± 0.8 % for tamsulosin hydrochloride and finasteride, respectively, by the RP-HPLC method. Quantification was achieved with UV detection at 270 nm over the concentration range 100â2000 ng per spot and 250â5000 ng per spot with mean recovery of 98.9 ± 0.9 and 99.6 ± 0.7 % for tamsulosin hydrochloride and finasteride, respectively, by the TLC method. Both methods are simple, precise, accurate and sensitive and are applicable to the simultaneous determination of tamsulosin hydrochloride and finasteride in bulk drug and in combined dosage forms.U radu su opisani razvoj i validacija inverzno fazne kromatografije visoke uÄinkovitosti (RP-HPLC) i tankoslojne kromatografije (TLC) za simultano odreÄivanje tamsulozin hidroklorida i finasterida kao Äistih supstancija i u kombiniranim tabletama. Za RP-HPLC odjeljivanje koriĆĄtena je Phenomenex C18 kolona (250 mm, 4,6 mm, 5 ”m) i metanol/0,02 mol Lâ1 pufer s amonijevim acetatom/trietilamin (79,9+20+0,1, V/V/V) (pH 9,2) kao pokretna faza, pri protoku 1 mL min-1. TLC odjeljivanje raÄeno je na silikagelu 60F254 na aluminijskoj podlozi, koristeÄi toluen/metanol/trietilamin (9+1,5+1, V/V/V) kao eluens. Za detekciju u RP-HPLC metodi koriĆĄtena je fotodioda (PDA) pri 235 nm te je provedena kvantitacija u koncentracijskom podruÄju 0,5â16 ”g mLâ1 i 1â50 ”g mLâ1, uz srednji analitiÄki povrat od 99,8 ± 0,9 % za tamsulozin hidroklorid i 100,0 ± 0,8 % za finasterid. Za kvantitaciju u TLC metodi koriĆĄtena je UV detekcija pri 270 nm u koncentracijskom podruÄju 100â2000 ng po toÄki za tamsulozin hidroklorid i 250â5000 ng po toÄki za finasterid, uz srednji analitiÄki povrat od 98,9 ± 0,9, odnosno 99,6 ± 0,7 %. Obje metode su jednostavne, precizne, toÄne i osjetljive i mogu se primijeniti za simultano odreÄivanje tamsulozin hidroklorida i finasterida kao Äistih supstancija i u kombiniranim dozirnim oblicima
Simultaneous pharmacokinetic and pharmacodynamic analysis of 5α-reductase inhibitors and androgens by liquid chromatography tandem mass spectrometry
AbstractBenign prostatic hyperplasia and prostate cancer can be treated with the 5α-reductase inhibitors, finasteride and dutasteride, when pharmacodynamic biomarkers are useful in assessing response. A novel method was developed to measure the substrates and products of 5α-reductases (testosterone, 5α-dihydrotestosterone (DHT), androstenedione) and finasteride and dutasteride simultaneously by liquid chromatography tandem mass spectrometry, using an ABSciex QTRAPÂź 5500, with a Waters Acquityâą UPLC. Analytes were extracted from serum (500”L) via solid-phase extraction (OasisÂź HLB), with 13C3-labelled androgens and d9-finasteride included as internal standards. Analytes were separated on a Kinetex C18 column (150Ă3mm, 2.6”m), using a gradient run of 19min. Temporal resolution of analytes from naturally occurring isomers and mass +2 isotopomers was ensured. Protonated molecular ions were detected in atmospheric pressure chemical ionisation mode and source conditions optimised for DHT, the least abundant analyte. Multiple reaction monitoring was performed as follows: testosterone (m/z 289â97), DHT (m/z 291â255), androstenedione (m/z 287â97), dutasteride (m/z 529â461), finasteride (m/z 373â317). Validation parameters (intra- and inter-assay precision and accuracy, linearity, limits of quantitation) were within acceptable ranges and biological extracts were stable for 28 days. Finally the method was employed in men treated with finasteride or dutasteride; levels of DHT were lowered by both drugs and furthermore the substrate concentrations increased