Isolation and identification of the C6-hydroxy and C20-hydroxy metabolites and glucuronide conjugate of methylprednisolone by preparative high-performance liquid chromatography from urine of patients receiving high-dose pulse therapy

Donor Genotype and Intragraft Expression of CYP3A5 Reflect the Response to Steroid Treatment During Acute Renal Allograft Rejection

BACKGROUND

Glucocorticoid (GC)-refractory acute rejection (AR) is a risk factor for inferior renal allograft outcome. We investigated genetic predisposition to the response to steroid treatment of acute allograft rejection.

METHODS

Single nucleotide polymorphisms of genes involved in GC signaling (GR, GLCCI1) and drug metabolism and transport (CYP3A5, ABCB1, and PXR) were analyzed in kidney transplant recipients (1995-2005, Leiden cohort, n = 153) treated with methylprednisolone. Significant associations were verified in a second cohort (Berlin cohort, n = 66).

RESULTS

Patients who received a CYP3A5*1 allele expressing allograft had a lower risk of resistance to methylprednisolone during AR (odds ratio, 0.29; 95% confidence interval, 0.11-0.79; P = 0.016 in combined cohorts analysis). No differences were observed for GC signaling or other drug metabolism/transport-related genes. Both before transplantation (n = 69) and at time of AR (n = 88), tissue CYP3A5 mRNA expression was significantly higher in CYP3A5*1 allele expressing donor kidneys than in CYP3A5*3/*3 allografts (P < 0.00001). Moreover, steroid-responsive patients (n = 64) expressed significantly higher intragraft CYP3A5 mRNA levels compared to steroid-refractory patients (n = 42) in AR (P = 0.006).

CONCLUSIONS

CYP3A5 protein expression was detected in tubular epithelial cells and inflammatory cells within the grafts. Our findings show that steroid resistance during AR is associated with donor genotype and intragraft expression levels of CYP3A5.

Management of Multiple Sclerosis in the Breastfeeding Mother

Multiple Sclerosis (MS) is an autoimmune neurological disease characterized by inflammation of the brain and spinal cord. Relapsing-Remitting MS is characterized by acute attacks followed by remission. Treatment is aimed at halting these attacks; therapy may last for months to years. Because MS disproportionately affects females and commonly begins during the childbearing years, clinicians treat pregnant or nursing MS patients. The intent of this review is to perform an in-depth analysis into the safety of drugs used in breastfeeding women with MS. This paper is composed of several drugs used in the treatment of MS and current research regarding their safety in breastfeeding including immunomodulators, immunosuppressants, monoclonal antibodies, corticosteroids, and drugs used for symptomatic treatment. Typically, some medications are large polar molecules which often do not pass into the milk in clinically relevant amounts. For this reason, interferon beta is likely safe for the infant when given to a breastfeeding mother. However, other drugs with particularly dangerous side effects may not be recommended. While treatment options are available and some data from clinical studies does exist, there continues to be a need for investigation and ongoing review of the medications used in breastfeeding mothers.

Urinary profile of methylprednisolone and its metabolites after oral and topical administrations

Methylprednisolone (MP) is prohibited in sports competitions when administered by systemic routes; however its use by topical administration is allowed. Therefore, analytical approaches to distinguish between these different administration pathways are required. A reporting level of 30ng/mL was established for this purpose. However, the suitability of that reporting level for MP is not known. In the present work, excretion profiles of MP and different metabolites after oral and topical administrations have been compared. A method for the quantification of MP and the qualitative detection of fifteen previously reported metabolites has been validated. The method involved an enzymatic hydrolysis, liquid-liquid extraction and analysis by liquid chromatography coupled to tandem mass spectrometry. The method was found to be linear, selective, precise and accurate. The high sensitivity (limit of detection 0.1ng/mL) and linear range (0.1-250ng/mL) achieved allowed for the quantification of MP at both the low concentrations present after topical administration and the high concentrations detected after oral intake. The method was applied to samples collected after oral (4 or 40mg) and topical administration (10mg of MP aceponate/day for 5 consecutive days) to healthy volunteers. After oral administration, MP and all metabolites were detected in urines collected up to at least 36h. Only MP and five metabolites were detected in samples obtained after topical treatment. As expected, concentrations of MP after topical administration were well below current reporting level (30ng/mL), however 3 out of 4 samples in range 8-24h after the low oral dose (4mg) were also below that concentration. Taking into account metabolites detected after both administration routes, metabolites 16β,17α,21-trihydroxy-6α-methylpregna-1,4-diene-3,11,20-trione (M8) and 17α,20α,21-trihydroxy-6α-methylpregna-1,4-diene-3,11-dione (M11) are best markers to differentiate between topical and oral administrations. Their signals after topical administration were lower than those obtained in the first 48h after all oral doses.

A sensitive and specific precursor ion scanning approach in liquid chromatography/electrospray ionization tandem mass spectrometry to detect methylprednisolone acetate and its metabolites in rat urine

A new, simple, sensitive and specific liquid chromatography/electrospray ionization tandem mass spectrometric (LC/ESI-MS/MS) method in precursor ion scanning (PIS) mode has been developed for the rapid detection of methylprednisolone acetate (MPA) and its metabolites in rat urine. A suitable product ion specific for methylprednisolone (MP) and MPA was selected after a fragmentation study on 20 (cortico)steroids at different collision energies (5-40 eV). Urine samples were simply treated with acetonitrile then dried in a SpeedVac system. The method was validated and compared with other PIS methods for detecting corticosteroids in human urine. It was more sensitive, with limit of detection (LOD) and lower limit of quantitation (LLOQ), respectively, of 5 and 10 ng mL(-1). The method was applied for the analysis of rat urine collected before and after (24, 48, 72 h) intra-articular (IA) injection of a marketed formulation of MPA (Depo-Medrol(R)). MS/MS acquisitions were taken at different collision energies for the precursor ions of interest, detected in PIS mode, to verify the MP-related structure. Six different metabolites were detected in rat urine, and their chemical structures were assigned with a computational study.

A rapid and sensitive LC-ESI-MS/MS method for detection and quantitation of methylprednisolone and methylprednisolone acetate in rat plasma after intra-articular administration

A rapid, sensitive and specific liquid chromatography-electrospray-tandem mass spectrometric (LC-ESI-MS/MS) method for the simultaneous detection and quantitation of methylprednisolone acetate (MPA) and methylprednisolone (MP) in rat plasma, using a triple-stage quadrupole, has been developed and validated. MP-D(2) was used as internal standard (IS) and acetonitrile was added to plasma samples for protein precipitation. After extraction with dichloromethane, the analytes were separated on a C-12 reversed-phase column by isocratic elution (6min at a flow rate 0.2mLmin(-1)) with water containing 0.01% formic acid (A) and acetonitrile (B) (50:50, v/v). Quantitation was performed in positive ion multiple reaction monitoring (MRM) mode by applying the following precursor-to-product ion transitions: MPA m/z 417-->135+161+253; MP m/z 375-->135+161+253; IS m/z 377-->135+161+253. The method, validated over the concentration range 6-600ngmL(-1), has been shown to meet the current requirements of bioananalytical validation, providing satisfactory results in terms of linearity, recovery, intra-day and inter-day precision and accuracy. The lower limit of quantitation (LLOQ) was 6ngmL(-1) for both the analytes (0.080 and 0.072pmol injected for MP and MPA, respectively). The method was successfully applied to monitor the plasma levels of MPA and MP following intra-articular (IA) injections of a low MPA (Depo-Medrol((R))) dose in rats.

Use of liquid chromatography-diode-array detection and mass spectrometry for rapid product identification in biotechnological synthesis of a hydroxyprogesterone

In exploratory scale biotechnological process development, the product must be rapidly identified although a reference compound may not always be available. LC-diode-array detection and MS were used for this purpose in a process producing 9alpha-hydroxyprogesterone from progesterone as substrate. The electrospray ionization mass spectrometer was combined with an ion trap mass spectrometer for the second generation MS. The preliminary identification, which could be carried out within the course of a day, confirmed that the product was a hydroxyprogesterone. The final identification step, which was much more material intensive and hence time consuming, involved a two-step preparative separation to yield quantities necessary for definitive product identification based on 1H- and 13C NMR.

High-performance liquid-chromatographic-atmospheric-pressure chemical-ionization ion-trap mass-spectrometric identification of isomeric C6-hydroxy and C20-hydroxy metabolites of methylprednisolone in the urine of patients receiving high-dose pulse therapy

Fourteen metabolites of methylprednisolone have been analysed by gradient-elution high-performance liquid chromatography coupled with tandem mass spectrometry (LC-MS-MS). The compounds were separated on a Cp Spherisorb 5 microm ODS column connected to a guard column packed with pellicular reversed phase. The mobile phase was an acetonitrile- 1.0% aqueous acetic acid gradient at a flow rate of 1.5 mL min(-1) The analysis gave a complete picture of parent drug, prodrugs and metabolites, and the alpha/beta stereochemistry was resolved. The short (1-2 h) elimination half-life of methylprednisolone is explained by extensive metabolism. The overall picture of the metabolic pathways of methylprednisolone is apparently simple-reduction of the C20 carbonyl group and further oxidation of the C20,C21 side chain (into C21COOH and C20COOH), in competition with or in addition to oxidation at the C6 position.

High-performance liquid chromatography analysis, preliminary pharmacokinetics, metabolism and renal excretion of methylprednisolone with its C6 and C20 hydroxy metabolites in multiple sclerosis patients receiving high-dose pulse therapy

A gradient eluent HPLC analysis in human plasma and urine was developed and validated for methylprednisolone (MP), its prodrug methylprednisolone-21-hemisuccinate (MPS) with the metabolites 6beta-hydroxy-6alpha-methylprednisolone (MPA), 20-hydroxymethylprednisolone (MPC), 6beta-hydroxy-20alpha-hydroxymethylprednisolone (MPB), 6beta-hydroxy-20beta-hydroxymethylprednisolone (MPE), 20-carboxymethylprednisolone (MPD), methylprednisolone-glucuronide (MPF) and 21-carboxymethylprednisolone (MPX). The column was Cp Spherisorb C8 5 microm, 250 mm x 4.6 mm I.D. (Chrompack, Bergen op Zoom, The Netherlands) with a guard column 75 mm x 2.1 mm, packed with pellicular reversed-phase. The eluent was a mixture of acetonitrile and 0.067 M KH2PO4 buffer, pH 4.5. At t=O, the eluent consisted of 2% acetonitrile and 98% buffer (v/v). Over the following 35 min the eluent changed linearly until it attained a composition of 50% acetonitrile and 50% buffer (v/v). At 37 min (t=37) the eluent was changed over 5 min to the initial composition, followed by equilibration over 3 min. The flow-rate was 1.5 ml/min and UV detection was achieved at 248 nm. Preliminary pharmacokinetic data were obtained from one patient who showed illustrative plasma concentration-time curves and renal excretion-time profiles after a short-lasting infusion (0.5 h) of 1 g of methylprednisolone hemisuccinate. The half-life of prodrug methylprednisolone-21-hemisuccinate (MPS) was 0.3 h, that of metabolite MPX (21-carboxy MP) was 0.4 h and that of the parent drug methylprednisolone (MP) was 1.4 h. The half-lives of the metabolites are almost similar (4 h). The main compounds in the urine are methylprednisolone hemisuccinate (prodrug, 15.0%), methylprednisolone (parent drug, 14.6%), metabolite MPD (20-carboxy, 11.7%), and metabolite MPB (13.2%). The renal clearance values of metabolites MPB, MPC and MPD are approximately 500 ml/min, that of MP is 100 ml/min.