Development of immobilized TiO2 photocatalysts for solar photocatalytic degradation of organic pollutants
is a technological need. In the present study, Degussa P-25 TiO2 photocatalyst was coated on pretreated
pebbles and the photoactivity of TiO2/pebbles is reported for the first time. Three types of pebbles, i.e., black
(B), red (R), and white (W), and a mixture (M) having equal proportions of B, R, and W, were chosen. The
pretreatment of pebbles constituted washing with deionized water or leaching with EDTA solution. Coating
of TiO2 on the pretreated pebbles was carried out as per the previously made titania powder (PMTP) method.
X-ray powder diffractograms (XRD) of powdered pebbles and analysis for various metals in washings and
leachates using an inductively coupled plasma-optical emission spectrometer (ICP-OES) and an atomic
absorption spectrophotometer (AAS) were carried out. Solar photocatalytic decolorization of reactive black
5 (RB5) and some other reactive dyes was tested using TiO2/pebbles in an open dish method. The percent
decolorization of RB5 using TiO2/white washed pebbles (TiO2/WW) and TiO2/white leached pebbles (TiO2/WL) was 59% and 99%, respectively, at the end of 5 h of exposure to sunlight. In contrast, less than 28%
decolorization was found with all the other TiO2/pebble systems. On the basis of the apparent first-order rate
constants, the TiO2/WL was found 63−81 times more efficient when compared to the lowest efficiency TiO2/black leached (TiO2/BL) pebbles. The difference in photoactivity of various TiO2/pebble systems was
rationalized in terms of interaction between metal oxides/ions native to pebbles and illuminated TiO2.
Objective: This study was designed to conduct forced degradation and validation studies for determination the benzalkonium chloride (BKC) as major homologues form in azelastine hydrochloride pharmaceutical ophthalmic formulation by a novel stability indicating reverse phase high-performance liquid chromatographic method (RP-HPLC).Methods: Forced degradation study and validation were carried out with a analytical approach of reverse phase chromatographic analysis with C18, cosmosil (250mm x 4.6mm i.d. x 5µm) column using mobile phase consisting acetonitrile -buffer of pH 5.0 with 5N NaOH (45:55 %v/v) at a flow rate of 1.5 ml per minute. Column temperature was maintained at 25°C and detection wavelength was 210nm.By using these chromatographic conditions of method, two major homologues of benzalkonium chloride were separated without any interference of drug components and exciepients.Results: Forced degradation studies were carried out as per ICH guidelines and established a stability indicating property of a method .The method was found linear in concentration range 40µg/ml to 60µg/ml (50µg/ml±20%), correlation coefficient was found 0.999. The recovery was found to be 99.2%, 100.7% and 101.4% at ±30% of target concentration. The %RSD for method precision and intermediate precision were found 0.28% and 0.30 % respectively. The method was found specific, selective, precise, accurate, linear, robust and stability indicating for quantification benzalkonium chloride in azelastine pharmaceutical ophthalmic formulation.
Conclusion:The method has been found successful for determination of BKC pharmaceutical formulation and validated for all the parameters of validation and found within the acceptance criteria as per ICH guideline Q2R1.
A novel, sensitive, specific, accurate and reproducible reverse phase high performance liquid chromatographic analytical method (RP-HPLC) was developed and validated for estimation of total benzalkonium chloride (BKC) content as a preservative in azelastine hydrochloride pharmaceutical ophthalmic formulation. The reversed phase HPLC method was used with C18, cosmosil (250 mm × 4.6mm i.d. × 5μm) column. The mobile phase was used as a combination of acetonitrile and buffer (adjusted to pH 5.0 with 5N NaOH) in the ratio of 45:55 % v/v, mobile phase was pumped at a constant flow rate of 1.5 ml per minute. The quantification of benzalkonium chloride was carried out with UV detection at 210 nm and column oven temperature was 25°C. By using these chromatographic conditions of method, four homologues of benzalkonium chloride were separated without any interference of any drug product components. The obtained results were found linear in concentration range 40μg/ml to 60μg/ml (50μg/ml ± 20%), correlation coefficient of calibration curve of regression data was 0.999 value. Recovery was found to be 99.0%, 100.4% and 101.1% at ± 30% of theoretical target concentration. The %RSD for method precision, instrument precision were found 0.28% and % 0.10% respectively. The method has been statistically validated as per international council for harmonization guideline Q2R1 and found within the acceptance criteria. So that the method was found specific, linear, precise and accurate for quantification of total benzalkonium chloride content as a preservative in azelastine hydrochloride pharmaceutical ophthalmic formulation.
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