Stability-indicating RP-HPLC method development and validation for duloxetine hydrochloride in tablets.

This paper describes the development of a stability-indicating RP-HPLC method for duloxetine hydrochloride (DLX) in the presence of its degradation products generated from forced decomposition studies. The drug substance was found to be susceptible to stress conditions of acid, base, oxidation, wet heat, dry heat, and photodegradation. The drug was found to be stable to the dry heat condition attempted. Successful separation of the drug from the degradation products formed under stress conditions was achieved on a Phenomenex C18 column (250 x 4.6 mm id, 5 microm particle size) using acetonitrile-methanol-0.032 M ammonium acetate buffer (55 + 05 + 40, v/v/v) as the mobile phase at a flow rate of 1.0 mL/min at 40 degrees C temperature. Quantification was achieved with photodiode array detection at 290 nm over the concentration range 0.2-5 microg/mL with mean recovery of 101.048 +/- 0.53% for DLX by the RP-HPLC method. Statistical analysis proved the method is repeatable, specific, and accurate for estimation of DLX. Because the method could effectively separate the drug from its degradation products, it can be used as a stability-indicating method.

Development and validation of reversed-phase column high-performance liquid chromatographic and first-derivative UV spectrophotometric methods for estimation of voriconazole in oral suspension powder.

This research paper describes validated reversed-phase high-performance column liquid chromatographic (RP-HPLC) and first-derivative UV spectrophotometric methods for the estimation of voriconazole (VOR) in oral suspension powder. The RP-HPLC separation was achieved on Phenomenex C18 column (250 x 4.6 mm id, 5 microm particle size) using water-acetonitrile (40 + 60, v/v; pH adjusted to 4.5 +/- 0.02 with acetic acid) as the mobile phase at a flow rate of 1.4 mL/min and ambient temperature. Quantification was achieved with photodiode array detection at 255 nm over the concentration range of 0.1-1 microg/mL with mean recovery of 99.49 +/- 0.83% for VOR by the RP-HPLC method. Quantification was achieved with UV detection at 266 nm over the concentration range of 8-20 microg/mL with mean recovery of 99.74 +/- 0.664% for VOR by the first-derivative UV spectrophotometric method. These methods are simple, precise, and sensitive, and they are applicable for the determination of VOR in oral suspension powder.

Development and validation of column high-performance liquid chromatographic and derivative spectrophotometric methods for determination of levofloxacin and ornidazole in combined dosage forms.

The manuscript describes validated reversed-phase column high-performance liquid chromatographic (RP-HPLC) and first-derivative UV spectrophotometric methods for the estimation of levofloxacin (LFX) and ornidazole (ORNI) in combined dosage forms. The RP-HPLC separation was achieved on a Phenomenex C18 column (250 mm x 4.6 mm id, 5 microm) using KH2PO4 buffer (pH 6.8)-methanol-acetonitrile (70 + 15 + 15, v/v/v) mobile phase at a flow rate of 1.5 mL/min and ambient temperature (25 +/- 2 degrees C). Quantification was achieved with photodiode array detection at 295 nm over the concentration range of 1-10 microg/mL for both LFX and ORNI, with mean recovery of 101.7 +/- 0.23 and 99.23 +/- 1.57%, respectively, by the RP-HPLC method. The derivative spectrophotometric method was based on the determination of both the drugs at their respective zero crossing point (ZCP). The first-order derivative spectra were obtained at N = 1 (scaling factor), Deltalambda = 2.0 nm (wavelength interval), and the determinations were made at 310 nm (ZCP of ORNI) for LFX and 295 nm (ZCP of LFX) for ORNI over the concentration range of 2-40 microg/mL for both LFX and ORNI. Mean recovery was 99.46 +/- 0.96 and 100.9 +/- 0.72%, respectively, by the first-derivative UV spectrophotometric method. Standard and sample solutions were prepared with methanol as the solvent in both of the methods. These methods were found to be simple, accurate, precise, and sensitive and were applicable for the simultaneous determination of LFX and ORNI in combined dosage forms.

Development and validation of a visible absorption densitometry method for quantitation of conessine in Holarrhena antidysenterica (Kurchi).

A selective, precise, and accurate high-performance thin-layer chromatographic (HPTLC) method has been proposed for the analysis of conessine in Holarrhena antidysenterica. The method involves visible densitometric evaluation of conessine resolving it by HPTLC on aluminium-based silica gel plates. For visible densitometric evaluation, peak areas were recorded at 520 nm after the resolved bands were derivatized with Dragendorff's reagent and then sprayed with a 10% solution of aqueous sodium nitrite which resulted in reddish brown color. The correlation between the concentration and area was found to be linear within the range of 10 to 60 ng/spot. The method was validated for precision (interday and intraday), repeatability, and accuracy. Mean recovery for conessine was 98.34-100.25%. The method was applied for the quantitation of conessine in Kurchi. The proposed HPTLC method was found to be precise, specific, sensitive, and accurate and can be used for routine analysis of Kurchi.