Development and Validation of Simple RP-HPLC Method for Intracellular Determination of Fluconazole Concentration and Its Application to the Study of Candida albicans Azole Resistance

Table 2

Stability of FLC assay in C. albicans biological matrix.

Nominal concentration (ng/mL)	Room temperature for 4 h	Stored at −80°C for 4 months	Three freeze and thaw cycles	Autosampler at 18°C for 48 h
250
Mean ± SD	249 ± 7	254 ± 7	234 ± 4	236 ± 4
RSD, %	2.7	2.82	1.8	1.6
RE, %	−0.24	1.6	−6.32	−5.68
QC-S/QC-R, %	99.76	99.82	103.84	103.40
8000
Mean ± SD	8041 ± 70	8035 ± 55	8166 ± 35.38	8162 ± 86
RSD, %	0.68	0.86	0.31	1.05
RE, %	0.44	0.51	2.08	2.02
QC-S/QC-R, %	99.92	99.91	102.50	100.58

Mean and SD representation for standard samples for each of the mentioned analytes. QC-S/QC-R, %: QC-S, samples exposed at room temperature for 4 h or stored at −80°C for 4 months or undergoing three freeze-thaw cycles or kept in an autosampler at 18°C for 48 h, and QC-R, reference samples, respectively.