Background & objective: Doxorubicin (Dox) is one of the most commonly used chemotherapeutic drugs. Drug concentrations in tumor tissue can predict the drugos efficacy better than that in serum do. This study was to detect and compare the concentration of Dox in KBv200 and KB cell xenografts in nude mice by high-performance liquid chromatography (HPLC).
Methods: Tumor models in nude mice were established with KB cells (drug-sensitive) and KBv200 cells (multidrug-resistant). Dox was injected via the tail vein. The concentration of Dox in tumor tissue was detected by HPLC at 1, 3 and 5 h after injection. A Hypersil reversed-phase BDS C18 column (250 mm x 4.6 mm, ID 5 microm) and mobile phases that were composed of acetonitrile and 0.02 mol/L KH2PO4 (1/2.4, V/V, pH 3.9) at a flow rate of 1.0 mL/min were used for setting a fluorescence detector (excitation wave length was 480 nm; emission wave length was 580 nm).
Results: Under the condition of HPLC, the calibration curve of Dox concentration in tumor tissue was linear within a range of 29.3-7 500 ng/g (r=0.9998). The limit of detection in tumor tissue was 14 ng/g. At the concentration of 3 750, 468.8 and 117.2 ng/g, extraction recovery were (99.35+/-7.65)%, (99.79+/-5.73)% and (103.67+/-6.76)%, respectively, method recovery were (91.89+/-7.03)%, (94.94+/-5.18)% and (100.83+/-5.32)%, respectively. The relative standard deviation (RSD) of the intra-day and inter-day precision were less than 4.2%. At 1, 3, 5 h after Dox injection, the concentrations of Dox were (139.32+/-54.68), (260.00+/-126.11) and (173.26+/-13.88) ng/g in KBv cell xenografts, respectively, and (385.13+/-42.55), (523.38+/-138.84) and (460.75+/-86.85) ng/g in KB cell xenografts, respectively. The Dox concentration was significantly higher in KB cell xenografts than in KBv200 cell xenografts at the same time point (P<0.05).
Conclusion: Detected by HPLC, the concentration of Dox is much lower in multidrug-resistant cell xenografts than in sensitive cell xenografts.