Antifungal activity of nanocapsule suspensions containing tea tree oil on the growth of Trichophyton rubrum.

The aim of this study was to evaluate, for the first time, the antifungal efficacy of nanocapsules and nanoemulsions containing Melaleuca alternifolia essential oil (tea tree oil) in an onychomycosis model. The antifungal activity of nanostructured formulations was evaluated against Trichophyton rubrum in two different in vitro models of dermatophyte nail infection. First, nail powder was infected with T. rubrum in a 96-well plate and then treated with the formulations. After 7 and 14 days, cell viability was verified. The plate counts for the samples were 2.37, 1.45 and 1.0 log CFU mL(-1) (emulsion, nanoemulsion containing tea tree oil and nanocapsules containing tea tree oil, respectively). A second model employed nails fragments which were infected with the microorganism and treated with the formulations. The diameter of fungal colony was measured. The areas obtained were 2.88 ± 2.08 mm(2), 14.59 ± 2.01 mm(2), 40.98 ± 2.76 mm(2) and 38.72 ± 1.22 mm(2) for the nanocapsules containing tea tree oil, nanoemulsion containing tea tree oil, emulsion and untreated nail, respectively. Nail infection models demonstrated the ability of the formulations to reduce T. rubrum growth, with the inclusion of oil in nanocapsules being most efficient.

Determination of aliskiren in tablet dosage forms by a validated stability-indicating RP-LC method.

A reversed-phase liquid chromatography (RP-LC) method is validated for the determination of aliskiren in tablet dosage form. The LC method is carried out on a Waters XBridge C(18) column (150 × 4.6 mm i.d.), maintained at 25°C. The mobile phase consisted of acetonitrile:water (95:5, v/v)/phosphoric acid (25 mM, pH 3.0) (40:60, v/v), run at a flow rate of 1.0 mL/min, with photodiode array detector set at 229 nm. The chromatographic separation is obtained with aliskiren retention time of 3.68 min, and it is linear in the range of 10-300 µg/mL (r = 0.9999). The limits of detection and quantitation are 2.38 and 7.93 µg/mL, respectively. The specificity and stability-indicating capability of the method are proven through degradation studies, which also showed that there is no interference of the formulation excipients, showing that peak is free from any coeluting peak. The method showed adequate precision, with a relative standard deviation (RSD) values lower than 0.92%. Good values of accuracy were also obtained, with a mean value of 99.55%. Experimental design is used during validation to calculate method robustness. The proposed method is applied for the analysis of the tablet dosage forms, contributing to improve the quality control and to assure the therapeutic efficacy.

Simple and reliable HPLC analysis of fexofenadine hydrochloride in tablets and its application to dissolution studies.

A simple RP-HPLC method using a PDA detector was developed and validated for the analysis and dissolution studies of fexofenadine hydrochloride (FEX) in dosage forms. Mobile phase: triethylamine phosphate 1%, pH 3.2: acetonitrile(ACN):methanol (50:30:20), 210 nm detection, C18 Phenomenex& column. The method was validated regarding accuracy/precision (RSD < 1%), linearity (r2 = 0.9999), and robustness. The method was applied to the determination of the drug in commercial tablet preparations and proved to be fast and reliable for quantification and it was also used for the comparison of dissolution profiles of FEX tablets. When we used the factor f2 as a comparison parameter, all the medium didn't present difference in the formulations, but just in the HCI 0.1 M the formulations showed similar results for the parameters f1/f2 andDE allowing to affirm that the two formulations are similar and with the same performance in vivo.