Studies On The Quality Of Indometacin Patch

To establish a method to determine the content and related substances of indomethacin patch by HPLC. The trap-paddle method was used to determine the dissolution of patch. We used the SPSS software to calculate the dissolution parameter and studied the character of vitro dissolution. Then research on the correlation between dissolution rate in vitro and absorption rate in vivo was continued by calculating the pharmacokinetic parameter.Section one: the research on the determination of indomethacin patch's content and related substances.Liquid chromatography was performed on a C18 column(150×4.6 mm,5μm), the mobile phase consisted of methanol, water and phosphoric acid (600:400:1,v/v/v), used a flow rate of 1.0 mL·min^-1 at 40℃column temperature, and the detection wavelength was 228 nm. The linear concentration ranges of indomethacin were 10～200μg·mL^-1 and 0.5～10μg·mL^-1, respectively. The lower limit of quantification of indomethacin was 0.5 ng and the average recovery was 99.6%. The method precision was good and the method could be used for determining the content and the related substances of indomethacin patch.Section two: the research on the vitro dissolution and the correlation between dissolution rate in vitro and absorption rate in vivo. We used the trap-paddle apparatus, and 900 ml water as the sovent with a rotation speed of 100 rpm, the assay's chromatographic condition was used. The linear concentration ranges of indomethacin was 1.0～20μg·mL^-1, and the average recovery was 99.5%. The SPSS software was used to fit dissolution data with several models. The results was consistent with first lever equation, and the R2 was 0.9268. Then calculated the dissolution parameters (T50, Td), the results was satisfaction. At last, we determined the indomethacin concentration in rat skin and calculated main pharmacokinetic parameters which as follows: Compartment number=1, Weight=1, R2=0.9832. Calculated the Fraction absorption at different times with the Wagner-Nelson method. There was a significant relationship between absorption in vivo and dissolution in vitro (P<0.01).