ABSTRACT
OBJECTIVE: To prepare epalrestat (EP) solid dispersion by holt-melt extrusion (HME) technique in order to enhance its dissolution rate. METHODS: Optimal formula was obtained by screening the carrier type and drug proportion. The dispersion state of EP in the solid dispersion and physical mixture were studied with differential X-ray diffraction (X-RD), Fourier transform infrared spectroscopy (FT-IR) and differential scanning calorimetry (DSC) analysis techniques. RESULTS: Poloxamer 188 was selected as the carrier with the optimal ratio of Poloxamer188 to EP of 1∶3. The final solid powder product was homogeneous dispersion in light yellow color without any agglomerate. CONCLUSION: The carrier of EP solid dispersion has significant impact on the dissolution behavior and state of EP. Using Poloxamer 188 as the carrier, holt-melt extrusion is an effective technology for improving the in vitro dissolution of EP.
ABSTRACT
OBJECTIVE: To establish a new method for determination of the main active ingredient and its isomer in commercially available calcitriol capsules by reverse phase-high performance liquid chromatography-diode array detector (RP-HPLC-DAD). METHODS: The chromatographic separation was performed on a Symmetry C18 column (4.6 mm × 250 mm, 5 μm) with gradient elution of water-acetonitrile-methanol. The mass spectrometer was equipped with diode array detector. Using Chem Station chromatography workstation, the main ingredient and its isomer in commercially available calcitriol capsules were analyzed. RESULTS The linear ranges of calcitriol and its isomer were 0.171 4 - 1.36 and 0.161 3 - 1.28 μg·mL-1, the detection limits were 39.75 and 40.90 ng·mL-1 and the limits of quantification were 141.6 and 136.4 ng·mL-1, respectively. The specificity of the method was good, the RSD values of the precision and stability tests were less than 1.2%, and the recoveries were greater than 98%. The average contents of calcitriol capsules from three manufacturers were 72.71%, 80.35%, and 78.18%, respectively. CONCLUSION: The method is simple, rapid, accurate, and easy to be popularized, which is suitable for the determination of calcitriol and trans-calcitriol in calcitriol capsules.