Liquid chromatography and tandem mass spectrometry method for quantitative determination of pioglitazone and its metabolite 5-hydroxy pioglitazone in human plasma

Quantitative measurement of pioglitazone in neoplastic and normal tissues by AP-MALDI mass spectrometry imaging

Pioglitazone is a Peroxisome Proliferator-Activated Receptor (PPAR) agonist of the thiazolidinedione class of compounds with promising anticancer activity. An innovative quantitative mass spectrometry imaging (MSI) method and a HPLC-UV method were developed and validated to investigate its distribution in tumor and liver tissues. The MSI method is based on stable isotope normalization and resulted highly specific and sensitive (0.2 pmol/spot). The correct identification of the drug ion signal is confirmed by MS/MS analysis on tissue. The method shows an optimal lateral resolution (25 μm) relying on the ionization efficiency and fine laser diameter of the atmospheric pressure MALDI source. The HPLC-UV method is simple and straightforward involving quick protein precipitation and shows good sensitivity (50ng/sample) using a small starting volume of biological sample. Thus, it is applicable to samples obtained from both preclinical models and clinical surgical procedures. MSI and HPLC-UV assays were validated assessing linearity, intra- and inter-day precision and accuracy, limit of quantification, selectivity and recovery. These are the first methods developed and validated for the analysis of pioglitazone in tissues, and they were applied successfully to myxoid liposarcoma xenograft-bearing mice, which received clinically relevant drug doses. Pioglitazone was measured by either method in sections of tumor and liver 2, 6 and 24 h post-treatment. Drug distribution was relatively homogeneous.

Development and validation of a sensitive LC-MS/MS method for pioglitazone: application towards pharmacokinetic and tissue distribution study in rats

In the present study, a sensitive LC-MS/MS method was developed and validated to measure pioglitazone (PGZ) concentrations in rat plasma and tissues. The chromatographic separation was achieved by using a YMC Pro C₁₈ column (100 mm × 4.6 mm, 3μ) with a mobile phase consisting of formic acid (0.1% v/v) and acetonitrile (5 : 95) at a flow rate of 0.7 mL min⁻¹ and injection volume of 10 μL (IS: rosiglitazone). Mass spectrometric detection was done using triple quadrupole mass spectrometry using the ESI interface operating in a positive ionization mode. The developed method was validated over a linearity range of 1–500 ng mL⁻¹ with detection and a lower quantification limit of 0.5 ng mL⁻¹ and 1 ng mL⁻¹. The method accuracy ranged from 95.89–98.78% (inter-day) & 93.39–97.68% (intra-day) with a precision range of 6.09–8.12% for inter-day & 7.55–9.87% for intra-day, respectively. The PGZ shows the highest C_max of 495.03 ng mL⁻¹ in plasma and the lowest C_max, 24.50 ± 2.71 ng mL⁻¹ in bone. The maximum T_max of 5.00 ± 0.49 h was observed in bone and a minimum of 1.01 ± 0.05 h in plasma. The AUC_{(0–24 h and 0–∞)} values are highest in plasma (1056.58 ± 65.78 & 1069.38 ± 77.50 ng h⁻¹ mL⁻¹) and lowest in brain (166.93 ± 15.70 &167.12 ± 16.77 ng h⁻¹ mL⁻¹), and the T_1/2 was highest in plasma (5.62 ± 0.74 h) and lowest in kidney (2.78 ± 0.19). The developed method was successfully used to measure the PGZ pharmacokinetic and tissue distribution. Further, the developed method could be utilized for validating target organ (adipose tissue) specific delivery of PGZ (nano-formulations) in addition to conventional dosage forms.

The developed method was investigated for target and off-target distribution of pioglitazone and could be applied to validate the site-specific delivery systems.