Simultaneous determination of diosmin and hesperidin in pharmaceuticals by RPLC using ionic liquids as mobile phase modifiers

Diosmin and hesperidin are natural flavonoid glycosides found in various plant materials, mainly in citrus fruits in different concentrations. Diosmin for pharmaceutical use is obtained mainly semi-synthetically from hesperidin. Hesperidin often accompanies diosmin as a natural impurity in different pharmaceutical formulations; therefore, a simple, fast and precise method for the simultaneous assay of diosmin and hesperidin in pharmaceutical formulations has been developed to control their contents. Chromatographic resolution was performed using a column with C-18 packing and the following mobile phase: methanol/water [45: 55, v/v] with 0.025% added didecyldimethylammonium lactate, which significantly affects retention, shortening analysis time and having a positive impact on the symmetry of resulting chromatographic peaks. The method shows linearity between 2.5 and 100 microg/mL, high repeatability [0.39 and 0.42% for diosmin and hesperidin, respectively] and accuracy of 96 to 102% for both the assayed compounds. Intraday and interday precision of the new method were less than RSD% 1, 2. The limit of detection of the assayed compounds is 2.5 and 1.2 microg/mL for diosmin and hesperidin, respectively. The method was tested on several pharmaceutical products available in Poland

The Influence of Incudostapedial Joint Separation on the Middle Ear Transfer Function

OBJECTIVES: One of the risks in middle ear surgery is high frequency hearing loss. It is believed that manipulations on the middle ear ossicles with the instruments may cause overstimulation of the inner ear and damage of the hear cells. Controversy arises whether temporary separation of the ossicles has any impact on middle ear transfer function and hearing threshold after surgery. The aim of the study is to evaluate the influence of incudostapedial joint (ISJ) separation on middle ear function in an experimental model. METHODS: With the use of single point laser Doppler vibrometer (LDV) stapes velocity in the intact chain and after ISJ separation was measured in 5 fresh human cadaver temporal bones. RESULTS: In all cases there was a decrease in stapes velocity after ISJ separation. Mead stapes velocity was reduced for 1 dB in 800 Hz to 9 dB in frequencies above 1,000 Hz. The decrease of velocity was greater in higher frequencies. CONCLUSION: Separation of the ISJ does not reduce significantly the middle ear function.