Simple method for the determination of rosiglitazone in human plasma using a commercially available internal standard

Quantification of rosiglitazone in rat plasma and tissues via LC-MS/MS - method development, validation, and its application in pharmacokinetic and tissue distribution studies

A bioanalytical method for the quantification of rosiglitazone on rat plasma and tissues (adipose tissue, heart, brain, bone, and kidney) using liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) was developed and validated. Chromatographic separation was achieved on Gemini C₁₈ column (50mm x 4.6mm, 3μm) using mobile phase consists of 10mM ammonium formate (pH 4.0) and acetonitrile (10:90, v/v) at a flow rate of 0.8 mL/min and injection volume of 10μL (Internal standard - Pioglitazone). LC-MS detection was performed with multiple reaction monitoring mode (MRM) using target ions at m/z→358.0 and m/z → 357.67 for rosiglitazone and pioglitazone (IS) respectively. The calibration curve showed a good correlation coefficient (r² ) over the concentration range of 1-10000 ng/mL. The mean percentage recoveries of rosiglitazone were found to be over the range of 92.54-96.64 % with detection and lower quantification limit of 0.6 ng/mL and 1.0 ng/mL, respectively. The developed method was validated as per USFDA guidelines and successfully utilized to measure rosiglitazone in plasma and tissue samples. Further, the developed method can be utilized for validating specific organ targeting delivery systems of rosiglitazone in addition to conventional dosage forms.

Effect of albumin on transplacental transfer and distribution of rosiglitazone and glyburide

OBJECTIVE

The aims of this investigation were (i) to determine the rate and extent of rosiglitazone transfer across term human placenta, and (ii) to determine the effect of human serum albumin (HSA) on rosiglitazone and glyburide transfer and distribution.

METHODS

These aims were achieved by utilizing the technique of dual perfusion of placental lobule (DPPL). Each hypoglycemic drug was coperfused with the marker compound antipyrine (AP). In each experiment, the [3H]-isotope of the hypoglycemic drug and the [14C]-isotope of AP were added to enhance the detection limits of each drug. Human serum albumin (HSA) was added to both the maternal and fetal circuits in the experiments in which it was investigated.

RESULTS

Transplacental transfer of rosiglitazone and glyburide from the maternal to fetal circuits in media devoid of HSA was similar. However, the addition of HSA to the maternal and fetal circuits had different effects on the transfer and distribution of the two drugs, though their binding to HSA (99.8%) was almost identical. HSA increased the maternal (M) to fetal (F) transfer of rosiglitazone, as revealed by an increase in its F/M concentration ratio from 0.17 +/- 0.01 (in the absence of albumin) to 0.33 +/- 0.07 (p < 0.001). Moreover, the addition of albumin decreased the amount of rosiglitazone retained by placental tissue from 539 +/- 148 to 60 +/- 8 ng/g (p < 0.001). Conversely, the addition of HSA to the perfusion media resulted in a decrease in glyburide transfer, as revealed by the change of its F/M concentration ratio from 0.09 +/- 0.02 (in the absence of albumin) to 0.03 +/- 0.01 (p < 0.01). However, similar to rosiglitazone, glyburide retention by the tissue decreased from 103 +/- 26 to 19 +/- 6 ng/g (p < 0.001).

CONCLUSIONS

These data indicate that the binding of the two drugs to albumin, though similar, is only one of the factors that could affect their placental transfer and distribution.

Interactions among peroxisome proliferator activated receptor-gamma, insulin signaling pathways, and steroidogenic acute regulatory protein in human ovarian cells

CONTEXT AND OBJECTIVE

Peroxisome proliferator activated receptor-gamma (PPAR-gamma) agonists thiazolidinediones (TZDs) are thought to ameliorate hyperandrogenism in polycystic ovary syndrome by reducing hyperinsulinemia. However, TZDs also exhibit direct effects in the human ovary. We examined interactions among PPAR-gamma, insulin signaling pathways, and steroidogenic acute regulatory (StAR) protein in human ovarian cells.

MATERIALS AND METHODS

Mixed human ovarian tissue culture that contained granulosa, theca, and stromal cells, and a culture of purified granulosa cells obtained during in vitro fertilization, were established as previously described. Cells were cultured in the presence or absence of insulin, with or without 25 or 50 microm rosiglitazone or pioglitazone. Expression of PPAR-gamma, insulin receptor, or insulin receptor substrate (IRS)-1 in both cell systems and of the StAR protein in granulosa cells was measured using immunoprecipitation and immunoblotting.

RESULTS

Rosiglitazone stimulated expression of PPAR-gamma, insulin receptor alpha- and beta-subunits, and IRS-1 up to 168% (P < 0.05), 679% (P < 0.006), 290% (P < 0.037), and 323% (P < 0.01) of baseline, respectively. Pioglitazone stimulated expression of PPAR-gamma, insulin receptor alpha- and beta-subunits, and IRS-1 up to 222% (P < 0.01), 362% (P < 0.001), 402% (P < 0.029), and 492% (P < 0.03), respectively. Insulin alone stimulated expression of PPAR-gamma, alpha-subunit and beta-subunit of insulin receptor, and IRS-1 up to 174% (P < 0.001), 692% (P < 0.014), 275% (P < 0.024), and 431% (P < 0.01), respectively. In purified granulosa cell culture, rosiglitazone stimulated expression of StAR protein up to 540% (P < 0.007), and pioglitazone stimulated expression of StAR protein up to 670% (P < 0.007). Insulin alone stimulated expression of StAR protein up to 600% (P < 0.012).

CONCLUSIONS

Insulin and TZDs independently stimulate expression of PPAR-gamma, insulin receptor, IRS-1, and StAR protein in human ovarian cells. Thus, PPAR-gamma, insulin receptor with its signaling pathways, and StAR protein constitute a novel human ovarian regulatory system with complex interactions among its components.

Placental transfer of rosiglitazone in the ex vivo human perfusion model

OBJECTIVE

The objective of the study was to determine transplacental passage of rosiglitazone (Avandia) using the ex vivo human placental model.

STUDY DESIGN

Perfusion studies were performed on 10 placentas from term, uncomplicated deliveries. Concentrations typical for an 8-mg oral dose (216 to 692 ng/mL) as well as 2- to 3-fold increased concentrations were tested (734 to 1261 ng/mL). Transfer of rosiglitazone was assessed and accumulation was determined using the 14C-antipyrine reference method.

RESULTS

The clearance index for low and high concentrations were 0.14 +/- 0.04 and 0.20 +/- 0.08, suggesting that the drug passes through the placenta at a relatively low rate. Fetal accumulation occurred in only 1 of 5 placentas at 16.4 ng/mL (5%) for the 8-mg dose and in 2 of 5 placentas ranging from 0 to 74 ng/mL (5% to 8%) at higher concentrations.

CONCLUSION

There is minimal transfer and fetal accumulation of rosiglitazone according to the ex vivo human perfusion model.

Solid-phase extraction coupled with liquid chromatography–tandem mass spectrometry for determination of trace rosiglitazone in urine

This project evaluated solid-phase extraction (SPE) combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS) to determine the trace amount of rosiglitazone in human urine. The analytical performance of four modes of LC-MS and tandem MS operation (atmospheric pressure chemical ionization (APCI), electrospray ionization (ESI), positive and negative ionization) was compared for two mass spectrometers, a triple-quadrupole and a quadrupole ion trap instrument. Rosiglitazone was extracted from urine using a SPE cartridge of 50mg C8 sorbent and acetonitrile used as the eluting solvent. Samples were then separated on a RP18 column interfaced with a tandem mass spectrometer. The recovery of rosiglitazone was greater than 91.2%. The urine assay combining SPE and LC-APCI-MS/MS of triple-quadrupole was proved a very selective and sensitive method for determination of trace rosiglitazone. The assay was linear over a wide range, with a lower limit of quantification of 0.1 ng/mL using 1 mL of urine. The intra- and inter-day precisions were <9.8% and <7.9%, respectively, and the accuracies were in the range 91.0-103.6%. The rosiglitazone concentration profile in human urine was also determined. The results of this study reveal the adequacy of SPE-LC-APCI-MS/MS method for analyzing rosiglitazone from diabetic patients' urines. The concentrations of rosiglitazone were detected to range from 760 to 164 pg/mL.