RP-HPLC method.

A simple, rapid and accurate RP-HPLC method was developed for the determination of doxofylline and photolytic degradation product. The method showed a linear response for concentrations in the range of 1-200 g/ml using acetonitrile: formic acid (90: 10); pH-3.0 as the mobile phase with detection at 274 nm and a flow rate of 1 ml/min and retention time 2.9 min. The method was statistically validated for accuracy, precision, linearity, ruggedness, robustness, forced degradation, solution stability and selectivity. Quantitative and recovery studies of the dosage form were also carried out and analyzed; the % RSD from recovery studies was found to be less than 1. Due to simplicity, rapidity and accuracy of the method, we believe that the method will be useful for routine quality control analysis. The hydrolytic degradation product as well as pathway was characterized by LC-MS/MS.
RESULT AND DISCUSSION:
A sensitive, selective, precise and accurate high
performance liquid chromatographic method of analysis of
doxofylline in both as bulk drug and in formulation was
developed and validated. The mobile phase consisted of
acetonitril: 0.05M formic Acid (90: 10v/v); pH-3.0. The
detection wavelength was 274nm. This system was found to
give the sharp peak for doxofylline (RT-2.9). The method
was validated as per ICH guideline (table 1). Stability
indicating assay method in which hydrolytic stress
condition was used for quantitative estimation of
doxofylline in tablet formulation and identification of
hydrolytic degradation product The separation of drug
from its degradation product were optimized by varying the
ratio &/or nature of organic modifier. Finally method was
developed using same mobile phase composed of
acetonitrile: formic acid (90: 10); pH-3.0, in that both drug
and degradation product showing good elution RT-2.9
(Doxofylline) and RT-3.68 (Hydrolytic degradation
product) and m/e-229 (fig 4). The hydrolytic degradation
product and pure drug were identified by LC-MS/MS in
order to establish hydrolytic degradation pathway (fig 5 and
6).

A reverse phase HPLC method was successfully developed and validated for concurrent assessment of omeprazole and aspirin for bulk and pharmaceutical formulation. The method was developed employing a reversed phase C 18 column. A optimized mobile phase having a composition of acetonitrile-methanol (20:80 v/v) was used. The experiment was carried out at flow rate of 0.6 ml/min and wavelength of 233 nm. Retention times for omeprazole and aspirin were found at 2.667 and 1.720 min respectively. Across a concentration span of 10-50 µg/ml and 5-25 µg/ml the method was linear for aspirin and omeprazole, respectively. The proposed method have potential for the regular quality scrutiny of this combination in bulk and pharmaceutical dosage form.

Aim:  To developing, stability indicating validating bioanalytical method for the estimation of Levosulpiride and Rabeprazole Sodium by RP-HPLC method which is expected to be accurate, precise, linear, stable and selective Methods of measuring drugs in biologic media are increasingly important problems related to bioavailability and bioequivalence, new drug development, drug abuse, clinical pharmacokinetics, and drug research are highly dependent on accurately measured drugs in biological fluids.
Method: to development of New Bioanalytical method for estimation in combined oral solid formulation of Levosulpiride and Rabeprazole Sodium. Stationary phase Hibra C18(250×4.6 mm i.d.,5µ) column at wavelength of 240nm. Using 10mM ammonium acetate is mobile phase in an isocratic elution mode at a flow ratio 0.8ml/min.
Result: the retention time of Levosulpiride and Rabeprazole Sodium were 9.92 and 4.27min respectively and internal standard RT was 12.04min, therefore no interference between internal standard and drug peaks. Quantitation was achieved with UV detect in at 240nm based on peak areas with linearity concentration ranges 0.024-2.4 µg/ml for levosulpiride, 0.024-1.24 µg/ml for rabeprazole sodium (R2 value 0.9985 and 0.9993). The LOD’s were 0.003µg/ml, LOQ’s found to be 0.009µg/ml and 0.01µg/ml respectively.
Conclusion: the developed method for the estimation of Levosulpiride and Rabeprazole in plasma is rugged, rapid, sensitive, precise, selective and linear and is therefore, can be employed for a bioequivalence study to evaluate its applicability further.

                  Key words: levosulpiride, rabeprazole, amisulpiride, RP-HPLC.

The objective of the work was to study the degradation behavior of rizatriptan benzoate under different ICH recommended stress
conditions by HPLC, and to establish a validated stability indicating LC assay method. Rizatriptan benzoate was subjected to stress conditions
of hydrolysis and oxidation decomposition. Extensive degradation was found to occur in acidic medium. Mild degradation was observed in
alkaline and oxidative conditions. Rizatriptan benzoate was stable to photolytic and thermal stress conditions. Successful separation of drug
from degradation products formed under stress conditions was achieved on a Perfectsil (C18, 250 mm × 4.6 mm, 5.0 μ) and 0.01 M Phosphate
buffer : methanol (80:20 v/v) as the mobile phase at a flow rate of 1.0 mL /min at ambient temperature and detected at 225 nm. pH of buffer
is adjusted 5.0 with 85 % of otho phosphoric acid. Characterization of the degradent product was separately. The molecular weight of impurity
product was found to be 188.