Analysis and evaluation of hydroxytyrosol in olive leaf extract

There is a group of phenolic compounds and their glycosidic forms responsible of antioxidant effect in the olive leaf extract. Hydroxytyrosol is one of these compounds considered as building unit for the other phenolic molecules in the extract. A normal phase chromatographic methodwas established for analysis of hydroxytyrosol. It generates clean chromatograms suitable for analytical and preparative purposes and better resolved than those obtained from reversed phase systems. Mobile phase of [1:1] acetonitrile and 1% acetic acid aqueous solution was used. Flow rate was kept constant at 0.5 mL/min. Injection volume was 20 uL and UV detector was set at A=280 nm. The developed HPLC method was found linear within the range of 0.82-4.12 mg%, precise with RSD less than 2% and accurate with a range of 97.6-101.2%. LOQ and LOD of the method were calculated to be 8 and 0.8 jig/ml respectively.Furthermore, antioxidant degree of hydroxytyrosol and its derivatives in the extract was evaluated by Follin-ciocalteu'sreagent and found equivalent to 40 mg gallic acid

On-column approach in the HPLC-UV analysis of non-chromophoric compounds using azelaic acid as a model

The manuscript introduces a detection solution of compounds lacking chromophoric properties [e.g. azelaic acid] by implementing a HPLC-UV analysis with on-column derivatisation of the analyte. Azelaic acid was used to test the feasibility of the method at Lamda [max] = 265 nm. Its chromatographic analysis shows linear [R = 0.999], precise [RSD < 2.0%] and accurate [97.0 - 103.5%] behavior. Furthermore, the method was found selective for azelaic acid in a prepared cream which contains other ingredients such as triethanolamine, vaseline and stearic acid. The limit of detection [LOD] and limit of quantification [LOQ] of azelaic acid were 9 and 30 micro g/ml, respectively

Microscopic trends in methanol/water and acetonitrile/water systems

The most practical measure of therapeutic equivalence between two commercially available and generic formulation of a certain drug is to determine their in vivo bioavailability. However, for the oral dosage from that is not intended to be absorbed [e.g. orlistat], in vivo bioavailability studies are irrelevant to the achievement of the product's intended purposes. However, specific requirements for these drug products may be set in a way that they should meet acceptable in vitro standards. For this purpose, a comparative enzymatic inhibition assay of the target enzyme, pancreatic lipase, was developed to demonstrate orlistat products' pharmaceutical and potency equivalence. In this study we compared the pancreatic lipase inhibition that is achieved by two orlistat formulations: a generic product manufactured by local company [Jordan Sweden Medical Company, JOSWE] and the reference one Xenical [Registered sign] manufactured by Roche. The inhibition was expressed by the concentration of product which inhibits 50% of the activity of the pancreatic lipase enzyme [1C[50]]. The results of these studies showed that both formulations have equivalent potency that was demonstrated by in vitro studies