Quantification of entrapment efficiency of Tetramethylpyrazine long-circulating liposomes

Objective To establish a method for determination of the entrapment efficiency of Tetramethylpyrazine long-circulating liposomes.Methods The Tetramethylpyrazine long-circulating liposomes and free Tetramethylpyrazine were separated by Sephadex G-50 chromatography,and quantified by HPLC.Results The Tetramethylpyrazine longcirculating liposomes and free Tetramethylpyrazine were well separated by Sephadex G-50 chromatography;it was found that the excipients in the liposome did not interfere with the assay.Tetramethylpyrazine had a good linearity over the range of 1.09-43.60 μg/mL(r = 0.9994,n = 6).Conclusion This method is simple,accurate and sensitive for the quality control of the Tetramethylpyrazine long-circulating liposomes,and can provide evaluation and control for the quality of Tetramethylpyrazine long circulating liposomes.