Monterrubio C, Paco S, Vila-Ubach M, Rodríguez E, Glisoni R, Lavarino C, Schaiquevich P, Sosnik A, Mora J, Carcaboso AM. Combined Microdialysis-Tumor Homogenate Method for the Study of the Steady State Compartmental Distribution of a Hydrophobic Anticancer Drug in Patient-Derived Xenografts.
Pharm Res 2015;
32:2889-900. [PMID:
25773723 DOI:
10.1007/s11095-015-1671-9]
[Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Accepted: 03/06/2015] [Indexed: 12/12/2022]
Abstract
PURPOSE
To develop a reproducible microdialysis-tumor homogenate method for the study of the intratumor distribution of a highly hydrophobic anticancer drug (SN-38; 7-ethyl-10-hydroxycamptothecin) in neuroblastoma patient-derived xenografts.
METHODS
We studied the nonspecific binding of SN-38 to the microdialysis tubing in the presence of 2-hydroxypropyl-beta-cyclodextrin (HPBCD) in the perfusate. We calibrated the microdialysis probes by the zero flow rate (ZFR) method and calculated the enhancement factor (f = extrapolated SN-38 concentration at the ZFR / SN-38 concentration in the dialysed solution) of HPBCD. We characterized the extravasation of HPBCD to tumors engrafted in mice. In vivo microdialysis and terminal homogenate data at the steady state (subcutaneous pump infusions) were used to calculate the volume of distribution of unbound SN-38 (Vu,tumor) in neuroblastoma.
RESULTS
HPBCD (10% w/v) in the perfusate prevented the nonspecific binding of SN-38 to the microdialysis probe and enhanced SN-38 recovery (f = 1.86). The extravasation of HPBCD in the tumor during microdialysis was lower than 1%. Vu,tumor values were above 3 mL/g tumor for both neuroblastoma models and suggested efficient cellular penetration of SN-38.
CONCLUSIONS
The method contributes to overcome the limitations of the microdialysis technique in hydrophobic drugs and provides a powerful tool to characterize compartmental anticancer drug distribution in xenografts.
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