ABSTRACT
The apparent degradation rate constant of fluticasone propionate (FLT) in 0.1 M NaOH:methanol=1:1 at 37 ℃ was previously reported to be 0.169 ± 0.003 h?1, and four degradation products (products 1–4) were observed in the solution. The aims of the present study were to assess the degradation rates of FLT in other alkaline solutions and clarify the chemical structures of the four degradation products in order to obtain basic data for designing an enema for inflammatory bowel disease. The apparent degradation rate constants in 0.05 M NaOH and 0.1 M NaOH:CH3CN=1:1 were 0.472 ± 0.013 h?1 and 0.154 ± 0.000 h?1 (n=3), respectively. The chemical structures of products 1–4 in 0.1 M NaOH:methanol=1:1 were revealed by nuclear magnetic resonance (NMR) and mass spectrometry data. The chemical structure of products 2 was that the 17-position of the thioester moiety of FLT was substituted by a carboxylic acid. The degradation product in 0.1 M NaOH:CH3CN=1:1 was found to be product 2 based on 1H NMR data. The degradation product in 0.05 M NaOH was considered to be product 2 based on the retention time of HPLC. These results are useful for detecting the degradation products of FLT by enzymes of the intestinal bacterial flora in the large intestine after dosing FLT as an enema.
ABSTRACT
The apparent degradation rate constant of fluticasone propionate (FLT) in 0.1 M NaOH:methanol=1:1 at 37 ℃ was previously reported to be 0.169 ± 0.003 h?1, and four degradation products (products 1–4) were observed in the solution. The aims of the present study were to assess the degradation rates of FLT in other alkaline solutions and clarify the chemical structures of the four degradation products in order to obtain basic data for designing an enema for inflammatory bowel disease. The apparent degradation rate constants in 0.05 M NaOH and 0.1 M NaOH:CH3CN=1:1 were 0.472 ± 0.013 h?1 and 0.154 ± 0.000 h?1 (n=3), respectively. The chemical structures of products 1–4 in 0.1 M NaOH:methanol=1:1 were revealed by nuclear magnetic resonance (NMR) and mass spectrometry data. The chemical structure of products 2 was that the 17-position of the thioester moiety of FLT was substituted by a carboxylic acid. The degradation product in 0.1 M NaOH:CH3CN=1:1 was found to be product 2 based on 1H NMR data. The degradation product in 0.05 M NaOH was considered to be product 2 based on the retention time of HPLC. These results are useful for detecting the degradation products of FLT by enzymes of the intestinal bacterial flora in the large intestine after dosing FLT as an enema.
ABSTRACT
Differential first derivative (ΔD1) method is developed for the quantitative analysis of cefquinome sulphate (CS) in bulk and dosage form. The method is based on measuring the ΔD1 of CS in alkaline solutions against its neutral aqueous solutions as blanks. The proposed method is sensitive and highly specific, since the interference of the excipients or impurities is nullified. Beer’s law was obeyed over the concentration range 4-20 μg/mL with a limit of detection and limit of quantification 1.5 μg/mL and 4.8 μg/mL respectively.