Stability Study of Fluconazole Applying Validated Bioassay and Stability-Indicating LC Methods

Abstract

Chemical degradation of drugs may result in altered therapeutic efficacy and even toxic effects. Therefore, understanding the factors that change the stability of pharmaceuticals and identifying ways to guarantee their stability are important. In this work stability-indicating Liquid Chromatographic (LC) and bioassay methods were validated and employed in the fluconazole stability studies. The correlation of sample results from both methods was evaluated. Fluconazole raw material stability was investigated in aqueous, acid (0.1 M HCl), alkaline (0.1 M NaOH) and oxidative (3% v/v H 2 O 2 ) reflux for 6 hours, by LC method. Fluconazole capsules were exposed to UVC (254 nm, 66 and 180 days), climatic chamber (40°C, 75% RH, 90 days) and oven (60°C, 60 days), these samples were analyzed by LC and bioassay methods It was found that the drug is degraded (10% decrease) with arising of a possible degradation product in an oxidative medium and UVC exposure, in all the others conditions fluconazole remained chemically stable (higher than 98%) when analyzed by LC. However when the capsules stressed samples were evaluated through bioassay very low antifungal activity was found (about 30%). Fluconazole showed to be an unstable drug and it indicates that special care must be taken during the handling, storage and quality control using appropriated methods to analyze this therapeutic agent. This work suggests monitoring the fluconazole stability by bioassay and the stability-indicating LC methods. The aims of this study were verifying the drug stability under stress conditions and quantify it by validated bioassay and Liquid Chromatographic (LC) stability-indicating methods. Material and Methods ChemicalsFluconazole chemical reference (assigned purity of 100%) was obtained from Sigma Aldrich, fluconazole raw material was kindly donated by EMS (Campinas, Brazil). It was standardized against fluconazole chemical reference. Capsules were purchased from local markers with label of 150 mg of drug.Methanol LC grade was purchased from Tedia (Fairfield, USA). Ultrapurified water was prepared in-house by using Direct-Q® water system (Millipore Corporation, Billerica, USA). Prior to use, mobile phase solvents were degassed in an ultrasonic bath for 30 min. Sodium hydroxide, hydrochloric acid, and hydrogen peroxide (reagent grade) were purchased from Merck (Darmstadt, Germany). Purified water (<18<mu>S) was used to prepare the mobile phase, the sample and the standard solutions. Solvents were filtered through a 0.45 µm membrane filter. ApparatusLiquid Chromatography apparatus (Waters Corporation, Milford, MA, USA), equipped with a Waters 1525 binary pump, a Rheodyne Breeze 7725i manual injector, a Waters 2487 UV-VIS wavelength detector was used. In addition a Liquid Chromatography apparatus Shimadzu® CLASS-VP, with PDA detector (Shimadzu Corporate, Japan) was employed. HPLC analysis was conducted by using a RP C18 column (Symmetry Waters, Milford, MA, USA), with 5 µm particle size, 4.6 mm x 250 mm.Oven (FABBE® Ltda), climatic cham...

Stability Study of Darunavir Ethanolate Tablets Applying a New Stability-Indicating HPLC Method

“…Stability can be defined as the capacity of a drug substance or product to remain within established specifications and to maintain its identity, strength, quality, and purity throughout expiration dating period [7]. Stability test of an active pharmaceutical ingredient or drug product can provide evidence on the drug quality and if it can be influenced by a variety of environmental factors such as temperature and humidity [7]. Chemical and physical degradation of drugs may result in altered therapeutic efficacy and even toxic effects.…”

“…Chemical and physical degradation of drugs may result in altered therapeutic efficacy and even toxic effects. Therefore, understanding the factors that change the stability of pharmaceuticals and identifying ways to guarantee their stability are important [7]. In recent years, the investigation about the influence of light on the stability of drugs has gained more and more importance.…”