OXP And CYPZ Lab Analysis
In order to carry out a detailed stability study of OXP and CYPZ in combination, it is essential to have a single stability-indicating assay method which can separate both drugs along with all of their degradation products from each other. Therefore, a RP-HPLC method was developed and optimized.
Optimization of the chromatographic conditions
In this study, the different experimental parameters were carefully studied and optimized in order to improve the performance and system suitability parameters of the chromatographic separation.
The effect of different column types (packing material) on the separation of OXP and CYPZ from their degradation peaks was studied. The column Zorbax SB-C18 (250 x 4.6 mm) was chosen as it resolved the intact …show more content…
On the other hand, the peak area of CYPZ was decreased by 24.4%. CYPZ degradation products peaks appeared at 2.91, 3.16 and 5.63 minutes and they were well resolved from OXP and CYPZ peaks.
Neutral hydrolysis
OXP was found to be stable under neutral condition and its peak area remained unchanged. CYPZ peak area decreased by 21.8 %, its degradation peak appeared at 2.91 minutes which is completely resolved from the neighboring peaks of OXP and CYPZ.
Oxidative degradation
By heating OXP with H2O2 for 30 min at 70°C, its peak area didn’t change. When CYPZ was subjected to oxidative degradation, its peak area declined by 23.3 %, its oxidation product peaks appeared at 4.82 and 7.48 minutes and with a good resolution from other peaks (Fig. 5a).
Dry heat degradation
Dry heat degraded samples showed no additional peaks in HPLC chromatogram. No significant degradation was observed in standard that were left 8h in oven at 60 °C.
Photolytic degradation
When a mixture of OXP and CYPZ standard solutions was exposed to UV radiation for 8 hours, CYPZ peak area was decreased by 8.3%. Very small degradation peaks appeared at 5.47, 5.75 and 8.59 while OXP showed a little decline in peak area with % degradation
Optimization of the chromatographic conditions
In this study, the different experimental parameters were carefully studied and optimized in order to improve the performance and system suitability parameters of the chromatographic separation.
The effect of different column types (packing material) on the separation of OXP and CYPZ from their degradation peaks was studied. The column Zorbax SB-C18 (250 x 4.6 mm) was chosen as it resolved the intact …show more content…
On the other hand, the peak area of CYPZ was decreased by 24.4%. CYPZ degradation products peaks appeared at 2.91, 3.16 and 5.63 minutes and they were well resolved from OXP and CYPZ peaks.
Neutral hydrolysis
OXP was found to be stable under neutral condition and its peak area remained unchanged. CYPZ peak area decreased by 21.8 %, its degradation peak appeared at 2.91 minutes which is completely resolved from the neighboring peaks of OXP and CYPZ.
Oxidative degradation
By heating OXP with H2O2 for 30 min at 70°C, its peak area didn’t change. When CYPZ was subjected to oxidative degradation, its peak area declined by 23.3 %, its oxidation product peaks appeared at 4.82 and 7.48 minutes and with a good resolution from other peaks (Fig. 5a).
Dry heat degradation
Dry heat degraded samples showed no additional peaks in HPLC chromatogram. No significant degradation was observed in standard that were left 8h in oven at 60 °C.
Photolytic degradation
When a mixture of OXP and CYPZ standard solutions was exposed to UV radiation for 8 hours, CYPZ peak area was decreased by 8.3%. Very small degradation peaks appeared at 5.47, 5.75 and 8.59 while OXP showed a little decline in peak area with % degradation