Bioanalysis of INCB000928 in hemodialysate: prevention of nonspecific binding and validation of surrogate matrices

To develop and validate a bioanalytical method for the quantification of INCB000928 in hemodialysate. Blank dialysate and phosphate-buffered saline were compared with hemodialysate for surrogate matrix selection. Direct addition of internal standard without analyte extraction and a high-performance LC–MS/MS were used for analysis. INCB000928 in hemodialysate exhibited strong nonspecific binding to polypropylene containers. In the presence of 10% isopropyl alcohol, the loss of INCB000928 was fully recovered, regardless of pre- or post-addition of the solvent. Blank dialysate and phosphate-buffered saline were determined to be appropriate surrogate matrices by using a three-way cross-comparison and were subsequently validated in the quantitative analysis of INCB000928 in hemodialysate. Fibrodysplasia ossificans progressiva (FOP) is a very rare disease characterized by congenital malformation of the great toes and progressive heterotopic ossification. The genetic cause of FOP is mutation in the gene . INCB000928 is a novel and orally available drug that inhibits ALK2 protein activity and has been shown to prevent ossification in a laboratory mouse model of FOP. Patients with end-stage renal disease who undergo hemodialysis may require a different dose of INCB000928. This study showed that INCB000928 was heavily adsorbed by the container wall, resulting in underestimated drug levels in hemodialysate. We present a method to accurately measure INCB000928 levels in hemodialysate by using isopropyl alcohol as an antiadsorption agent and cost-effective surrogate matrix. Isopropyl alcohol 10% fully prevents nonspecific binding of INCB000928 in hemodialysate, with pre- or post-addition of the solvent. Blank dialysate or phosphate-buffered saline is a suitable surrogate matrix for hemodialysate for quantitative analysis of INCB000928.