1
|
Sobiak J, Resztak M, Banasiak J, Zachwieja J, Ostalska-Nowicka D. High-performance liquid chromatography with fluorescence detection for mycophenolic acid determination in saliva samples. Pharmacol Rep 2023; 75:726-736. [PMID: 36905501 PMCID: PMC10007665 DOI: 10.1007/s43440-023-00474-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 03/01/2023] [Accepted: 03/02/2023] [Indexed: 03/12/2023]
Abstract
BACKGROUND For therapeutic drug monitoring (TDM) of mycophenolic acid (MPA), which is frequently proposed, saliva might be a suitable and easy-to-obtain biological matrix. The study aimed to validate an HPLC method with fluorescence detection for determining mycophenolic acid in saliva (sMPA) in children with nephrotic syndrome. METHODS The mobile phase was composed of methanol and tetrabutylammonium bromide with disodium hydrogen phosphate (pH 8.5) at a 48:52 ratio. To prepare the saliva samples, 100 µL of saliva, 50 µL of calibration standards, and 50 µL of levofloxacin (used as an internal standard) were mixed and evaporated to dryness at 45 °C for 2 h. The resulting dry extract was reconstituted in the mobile phase and injected into the HPLC system after centrifugation. Saliva samples from study participants were collected using Salivette® devices. RESULTS The method was linear within the range of 5-2000 ng/mL, was selective with no carry-over effect and met the acceptance criteria for within-run and between-run accuracy and precision. Saliva samples can be stored for up to 2 h at room temperature, for up to 4 h at 4 °C, and for up to 6 months at - 80 °C. MPA was stable in saliva after three freeze-thaw cycles, in dry extract for 20 h at 4 °C, and for 4 h in the autosampler at room temperature. MPA recovery from Salivette® cotton swabs was within the range of 94-105%. The sMPA concentrations in the two children with nephrotic syndrome who were treated with mycophenolate mofetil were within 5-112 ng/mL. CONCLUSIONS The sMPA determination method is specific, selective, and meets the validation requirements for analytic methods. It may be used in children with nephrotic syndrome; however further studies are required to investigate focusing on sMPA and the correlation between sMPA and total MPA and its possible contribution to MPA TDM is required.
Collapse
Affiliation(s)
- Joanna Sobiak
- Department of Physical Pharmacy and Pharmacokinetics, Poznan University of Medical Sciences, 3 Rokietnicka Street, 60-806, Poznan, Poland.
| | - Matylda Resztak
- Department of Physical Pharmacy and Pharmacokinetics, Poznan University of Medical Sciences, 3 Rokietnicka Street, 60-806, Poznan, Poland
| | - Joanna Banasiak
- Department of Physical Pharmacy and Pharmacokinetics, Poznan University of Medical Sciences, 3 Rokietnicka Street, 60-806, Poznan, Poland
| | - Jacek Zachwieja
- Department of Pediatric Nephrology and Hypertension, Poznan University of Medical Sciences, Poznan, Poland
| | - Danuta Ostalska-Nowicka
- Department of Pediatric Nephrology and Hypertension, Poznan University of Medical Sciences, Poznan, Poland
| |
Collapse
|
2
|
Sobiak J, Żero P, Zachwieja J, Ostalska-Nowicka D, Pawiński T. Limited sampling strategy to predict free mycophenolic acid area under the concentration-time curve in paediatric patients with nephrotic syndrome. Clin Exp Pharmacol Physiol 2023; 50:486-496. [PMID: 36846865 DOI: 10.1111/1440-1681.13765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 02/17/2023] [Accepted: 02/22/2023] [Indexed: 03/01/2023]
Abstract
In paediatric patients, there is no data on the recommended area under the concentration-time curve from 0 to 12 h (AUC0-12 ) for free mycophenolic acid (fMPA), which is the active form of the drug, responsible for the pharmacological effect. We decided to establish the limited sampling strategy (LSS) for fMPA for its use in MPA therapeutic monitoring in children with nephrotic syndrome treated with mycophenolate mofetil (MMF). This study included 23 children (aged 11 ± 4 years) from whom eight blood samples were collected within 12 h after MMF administration. The fMPA was determined using the high-performance liquid chromatography with fluorescence detection method. LSSs were estimated with the use of R software and bootstrap procedure. The best model was chosen based on a number of profiles with AUC predicted within ± 20% of AUC0-12 (good guess), r2 , mean prediction error (%MPE) of ±10% and mean absolute error (%MAE) of less than 25%. The fMPA AUC0-12 was 0.1669 ± 0.0697 μg h/mL and the free fraction was within 0.16%-0.81%. In total, there were 92 equations developed of which five fulfilled the acceptance criteria for %MPE, %MAE, good guess >80% and r2 > 0.900. These equations consisted of three time points: model 1 (C1 , C2 , C6 ), model 2 (C1 , C3 , C6 ), model 3 (C1 , C4 , C6 ), model 5 (C0 , C1 , C2 ), and model 6 (C1 , C2 , C9 ). Although blood sampling up to 9 h after MMF dosing is impractical, it is crucial to include C6 or C9 in LSS to assess fMPA AUCpred correctly. The most practical fMPA LSS, which fulfilled the acceptance criteria in the estimation group, was fMPA AUCpred = 0.040 + 2.220 × C0 + 1.130 × C1 + 1.742 × C2 . Further studies should define the recommended fMPA AUC0-12 value in children with nephrotic syndrome.
Collapse
Affiliation(s)
- Joanna Sobiak
- Department of Physical Pharmacy and Pharmacokinetics, Poznan University of Medical Sciences, Poznań, Poland
| | - Paweł Żero
- Department of Drug Chemistry, Medical University of Warsaw, Warsaw, Poland
| | - Jacek Zachwieja
- Department of Pediatric Nephrology and Hypertension, Poznan University of Medical Sciences, Poznań, Poland
| | - Danuta Ostalska-Nowicka
- Department of Pediatric Nephrology and Hypertension, Poznan University of Medical Sciences, Poznań, Poland
| | - Tomasz Pawiński
- Department of Drug Chemistry, Medical University of Warsaw, Warsaw, Poland
| |
Collapse
|
3
|
Sobiak J, Resztak M, Zachwieja J, Ostalska-Nowicka D. Inosine monophosphate dehydrogenase activity and mycophenolate pharmacokinetics in children with nephrotic syndrome treated with mycophenolate mofetil. Clin Exp Pharmacol Physiol 2022; 49:1197-1208. [PMID: 35877984 DOI: 10.1111/1440-1681.13706] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 07/18/2022] [Accepted: 07/21/2022] [Indexed: 11/28/2022]
Abstract
Some studies have shown that the area under the concentration-time curve (AUC) of mycophenolic acid (MPA) should be higher for children with nephrotic syndrome (NS) than after renal transplantation. The pharmacodynamic aspect of MPA, the activity of inosine monophosphate dehydrogenase (IMPDH), has not been studied in children with NS. The study included 21 children (4-16 years) with NS treated with mycophenolate mofetil. MPA and its glucuronide plasma concentrations were determined using validated high-performance liquid chromatography (HPLC-UV). The separate HPLC-UV method was applied for IMPDH activity determination. The variability was expressed by the coefficient of variation (CV). IMPDH activity and MPA concentration (Ctrough ) before the morning dose amounted to 29.95 μmol·s-1 ·mol-1 AMP (range, 6.71-98.60 μmol·s-1 ·mol-1 AMP) and 1.72 μg/mL (range, 0.39-4.34 μg/mL), respectively, whereas the area under the effect-time curve from 0 to 4 h and MPA AUC0-4 were 130.36 μmol·s-1 ·mol-1 AMP∙h (range, 23.58-306.57 μmol·s-1 ·mol-1 AMP∙h) and 24.63 μg·h/mL (range, 12.21-67.48 μg·h/mL), respectively. IMPDH activity decreased concomitantly with MPA concentration increase, however, the variability of the pharmacodynamic parameters was greater than of the pharmacokinetics. The median degree of maximum IMPDH inhibition was 61%. MPA Ctrough and predicted AUC were lower than in our previous study. Only a few MPA pharmacokinetic parameters correlated with the pharmacodynamics. IMPDH activity did not correlate with children's age and did not differ between boys and girls. MPA clearance was the highest in younger children (median 10.54 L/m2 /h) and cholesterol correlated negatively with children's age (r=-0.659, p=0.003). IMPDH minimum activity and the degree of maximum IMPDH inhibition were similar to those obtained in renal transplant recipients. IMPDH activity does not undergo developmental or gender-specific regulation in children with NS. MPA underexposure might be more frequent in younger children, especially with high cholesterol and triglycerides levels due to high MPA clearance.
Collapse
Affiliation(s)
- Joanna Sobiak
- Department of Physical Pharmacy and Pharmacokinetics, Poznan University of Medical Sciences
| | - Matylda Resztak
- Department of Physical Pharmacy and Pharmacokinetics, Poznan University of Medical Sciences
| | - Jacek Zachwieja
- Department of Pediatric Nephrology and Hypertension, Poznan University of Medical Sciences
| | | |
Collapse
|
4
|
Validated Simple HPLC-UV Method for Mycophenolic Acid (MPA) Monitoring in Human Plasma. Internal Standardization: Is It Necessary? Molecules 2021; 26:molecules26237252. [PMID: 34885834 PMCID: PMC8658973 DOI: 10.3390/molecules26237252] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 11/23/2021] [Accepted: 11/26/2021] [Indexed: 11/16/2022] Open
Abstract
The aim of the work was to prepare a simple but reliable HPLC-UV method for the routine monitoring of mycophenolic acid (MPA). Sample preparation was based on plasma protein precipitation with acetonitrile. The isocratic separation of MPA and internal standard (IS) fenbufen was made on Supelcosil LC-CN column (150 × 4.6 mm, 5 µm) using a mobile phase: CH3CN:H2O:0.5M KH2PO4:H3PO4 (260:700:40:0.4, v/v). UV detection was set at 305 nm. The calibration covered the MPA concentration range: 0.1–40 µg/mL. The precision was satisfactory with RSD of 0.97–7.06% for intra-assay and of 1.92–5.15% for inter-assay. The inaccuracy was found between −5.72% and +2.96% (+15.40% at LLOQ) and between −8.82% and +5.31% (+19.00% at LLOQ) for intra- and inter-assay, respectively, fulfilling acceptance criteria. After a two-year period of successful application, the presented method has been retrospectively calibrated using the raw data disregarding the IS in the calculations. The validation and stability parameters were similar for both calculation methods. MPA concentrations were recalculated and compared in 1187 consecutive routine therapeutic drug monitoring (TDM) trough plasma samples from mycophenolate-treated patients. A high agreement (r2 = 0.9931, p < 0.0001) of the results was found. A Bland–Altman test revealed a mean bias of −0.011 μg/mL (95% CI: −0.017; −0.005) comprising −0.14% (95% Cl: −0.39; +0.11), whereas the Passing–Bablok regression was y = 0.986x + 0.014. The presented method can be recommended as an attractive analytical tool for medical (hospital) laboratories equipped with solely basic HPLC apparatus. The procedure can be further simplified by disapplying an internal standard while maintaining appropriate precision and accuracy of measurements.
Collapse
|
5
|
Sobiak J, Głyda M, Malec M, Chrzanowska M. Pharmacokinetics of Mycophenolate Mofetil Metabolites in Older Patients on the Seventh Day After Renal Transplantation. Transplant Proc 2021; 53:2212-2215. [PMID: 34412913 DOI: 10.1016/j.transproceed.2021.07.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Accepted: 07/19/2021] [Indexed: 10/20/2022]
Abstract
BACKGROUND Currently, immunosuppression schemes are age-independent; however, physiological changes may alter drugs' pharmacokinetics in the older population. We compared mycophenolic acid (MPA) and its glucuronide metabolite (MPAG) pharmacokinetics among patients aged <60 and >60 years on the seventh day after renal transplantation. METHODS We included 7 and 10 renal transplant recipients, aged >60 and <60 years, respectively, treated with mycophenolate mofetil. MPA and MPAG concentrations were determined using the high-performance liquid chromatography method with ultraviolet detection (HPLC-UV). Noncompartmental pharmacokinetic analysis was performed. RESULTS In patients aged >60 years, mean MPA and MPAG concentrations before the next dose and ratio of MPAG area under the concentration-time curve (AUC0-12) to MPA AUC0-12 were higher by 1.6-fold, 1.4-fold, and 1.9-fold, respectively. Other MPAG concentrations appeared to be slightly higher (1.2- to 1.5-fold) in older patients. MPA apparent clearance was similar in both groups, whereas volume of distribution at steady state was slightly higher (1.6-fold) in patients aged >60 years. The variability of most MPA and some MPAG pharmacokinetics was greater in patients aged >60 years. The MPA AUC0-12 target was achieved in 40% and 14% of patients aged <60 and >60 years, respectively. The highest MPAG concentrations and AUC0-12 were observed for patients with the lowest glomerular filtration rate. CONCLUSIONS Higher variability of MPA and MPAG pharmacokinetic parameters, MPA AUC0-12 above the reference range, higher values of MPAG pharmacokinetics in patients with lower glomerular filtration rates, as well as lower proportion of patients achieving MPA targets all indicate the need for therapeutic drug monitoring in renal transplant recipients aged >60 years and to verify target MPA AUC0-12 for this population.
Collapse
Affiliation(s)
- J Sobiak
- Department of Physical Pharmacy and Pharmacokinetics, Poznan University of Medical Sciences, Poznań, Poland.
| | - M Głyda
- Department of Transplantology and General Surgery, Poznań District Hospital, Poznań, Poland; Department of Hepatobiliary and General Surgery, Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University, Bydgoszcz, Poland
| | - M Malec
- Department of Physical Pharmacy and Pharmacokinetics, Poznan University of Medical Sciences, Poznań, Poland
| | - M Chrzanowska
- Department of Physical Pharmacy and Pharmacokinetics, Poznan University of Medical Sciences, Poznań, Poland
| |
Collapse
|
6
|
The Evaluation of Multiple Linear Regression-Based Limited Sampling Strategies for Mycophenolic Acid in Children with Nephrotic Syndrome. Molecules 2021; 26:molecules26123723. [PMID: 34207320 PMCID: PMC8235059 DOI: 10.3390/molecules26123723] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 06/16/2021] [Accepted: 06/16/2021] [Indexed: 11/17/2022] Open
Abstract
We evaluated mycophenolic acid (MPA) limited sampling strategies (LSSs) established using multiple linear regression (MLR) in children with nephrotic syndrome treated with mycophenolate mofetil (MMF). MLR-LSS is an easy-to-determine approach of therapeutic drug monitoring (TDM). We assessed the practicability of different LSSs for the estimation of MPA exposure as well as the optimal time points for MPA TDM. The literature search returned 29 studies dated 1998–2020. We applied 53 LSSs (n = 48 for MPA, n = 5 for free MPA [fMPA]) to predict the area under the time-concentration curve (AUCpred) in 24 children with nephrotic syndrome, for whom we previously determined MPA and fMPA concentrations, and compare the results with the determined AUC (AUCtotal). Nine equations met the requirements for bias and precision ±15%. The MPA AUC in children with nephrotic syndrome was predicted the best by four time-point LSSs developed for renal transplant recipients. Out of five LSSs evaluated for fMPA, none fulfilled the ±15% criteria for bias and precision probably due to very high percentage of bound MPA (99.64%). MPA LSS for children with nephrotic syndrome should include blood samples collected 1 h, 2 h and near the second MPA maximum concentration. MPA concentrations determined with the high performance liquid chromatography after multiplying by 1.175 may be used in LSSs based on MPA concentrations determined with the immunoassay technique. MPA LSS may facilitate TDM in the case of MMF, however, more studies on fMPA LSS are required for children with nephrotic syndrome.
Collapse
|
7
|
Sobiak J, Głyda M, Chrzanowska M. Pharmacokinetics of Enteric-Coated Mycophenolate Sodium Metabolites in Patients Over 60 Years Old Within the First Year After Renal Transplantation. Transplant Proc 2020; 53:1001-1004. [PMID: 33246587 DOI: 10.1016/j.transproceed.2020.10.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 10/01/2020] [Indexed: 01/28/2023]
Abstract
OBJECTIVE It is still unclear whether mycophenolic acid (MPA) doses should be adjusted for older patients. Therefore, we compared the pharmacokinetics of MPA, mycophenolic acid glucuronide (MPAG), and free MPA (fMPA) between older and younger renal transplant recipients. METHODS We included 12 patients <60 years and 6 patients >60 years within the first year after renal transplantation, who were receiving enteric-coated mycophenolate sodium, tacrolimus, and steroids. Blood samples were collected up to 12 hours after drug administration. RESULTS MPA and fMPA pharmacokinetics were similar for patients <60 and >60 years; however, the MPA area under the concentration-time curve from 0 to 12 hours (AUC0-12) was 1.2-fold lower in the older patients. MPAG pharmacokinetics were more than 1.5-fold higher in patients >60 years, which might be related to deteriorated renal function in older people. Moreover, the mean (MPAG AUC0-12)/(MPA AUC0-12) ratio was more than 2-fold higher in patients >60 years. The second maximal MPA concentration was more frequently observed in patients <60 years, although all patients received tacrolimus. The percentage of patients with MPA concentration before the next drug dose (Ctrough) and AUC0-12 within and below target was the same in both groups. All patients >60 years had MPA AUC0-12 >30 μg·h/mL within 22 to 114 days after transplantation. CONCLUSIONS MPA therapeutic monitoring should be recommended in enteric-coated mycophenolate sodium--treated patients >60 years because MPA AUC0-12 exceeded the recommended value in half of the studied patients.
Collapse
Affiliation(s)
- J Sobiak
- Department of Physical Pharmacy and Pharmacokinetics, Poznan University of Medical Sciences, Poznań, Poland.
| | - M Głyda
- Department of Transplantology and General Surgery, Poznań District Hospital, Poznań, Poland; Department of Hepatobiliary and General Surgery, Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University, Bydgoszcz, Poland
| | - M Chrzanowska
- Department of Physical Pharmacy and Pharmacokinetics, Poznan University of Medical Sciences, Poznań, Poland
| |
Collapse
|
8
|
The Application of Inosine 5'-Monophosphate Dehydrogenase Activity Determination in Peripheral Blood Mononuclear Cells for Monitoring Mycophenolate Mofetil Therapy in Children with Nephrotic Syndrome. Pharmaceuticals (Basel) 2020; 13:ph13080200. [PMID: 32824803 PMCID: PMC7463457 DOI: 10.3390/ph13080200] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 08/14/2020] [Accepted: 08/16/2020] [Indexed: 11/16/2022] Open
Abstract
In pediatric nephrotic syndrome, recommended mycophenolic acid (MPA) pharmacokinetics are higher than those for transplant recipients. In MPA therapeutic monitoring, inosine-5'-monophosphate dehydrogenase (IMPDH) activity may be useful. We modified the method established for renal transplant recipients and determined IMPDH activity in peripheral blood mononuclear cells (PBMCs) from healthy volunteers and children (4-16 years) with nephrotic syndrome treated with mycophenolate mofetil (MMF). From children, four blood samples were collected, and MPA concentrations were also determined. IMPDH activity was calculated using xanthosine monophosphate (XMP) normalized with adenosine monophosphate (AMP), both determined with the HPLC-UV method. The modified method was accurate, precise, and linear for AMP and XMP within 0.50-50.0 μmoL/L. Mean IMPDH activity in volunteers was 45.97 ± 6.24 µmoL·s-1·moL-1 AMP, whereas for children, the values were variable and amounted to 39.23 ± 27.40 µmoL·s-1·moL-1 AMP and 17.97 ± 15.24 µmoL·s-1·moL-1 AMP before the next MMF dose and 1 h afterward, respectively. The modified method may be applied to IMPDH activity determination in children with nephrotic syndrome treated with MMF. IMPDH activity should be determined after one thawing of PBMCs due to the change in AMP and XMP concentrations after subsequent thawing. For children, the lowest IMPDH activity was observed concomitantly with the highest MPA concentration.
Collapse
|
9
|
Sobiak J, Resztak M, Pawiński T, Żero P, Ostalska-Nowicka D, Zachwieja J, Chrzanowska M. Limited sampling strategy to predict mycophenolic acid area under the curve in pediatric patients with nephrotic syndrome: a retrospective cohort study. Eur J Clin Pharmacol 2019; 75:1249-1259. [PMID: 31172249 DOI: 10.1007/s00228-019-02701-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Accepted: 05/27/2019] [Indexed: 01/07/2023]
Abstract
PURPOSE Limited sampling strategy (LSS) is a precise and relatively convenient therapeutic drug monitoring method. We evaluated LSSs for mycophenolic acid (MPA) in children with nephrotic syndrome treated with mycophenolic mofetil (MMF) and validated the LSSs using two different approaches. METHODS We measured MPA plasma concentrations in 31 children using HPLC-UV method and received 37 MPA pharmacokinetic profiles (0-12 h). For six children, MPA profiles were estimated twice after two MMF doses. LSSs were developed using multilinear regression with STATISTICA and R software and validated using validation group and bootstrap method, respectively. RESULTS The best three time point equations included C1, C3, C6 (good guess 83%, bias - 2.78%; 95% confidence interval (CI) - 9.85-0.46); C1, C2, C6 (good guess 72%, bias 0.72%; 95% CI - 5.33-7.69); and C1, C2, C4 (good guess 72%, bias 2.05%; 95% CI - 4.92-13.01) for STATISTICA software. For R software, the best equations consisted of C1, C3, C6 (good guess 92%, bias - 2.69%; 95% CI - 27.18-33.75); C0, C1, C3 (good guess 84%, bias - 2.11%; 95% CI - 24.19-22.29); and C0, C1, C2 (good guess 84%, bias - 0.48%; 95% CI - 30.77-54.07). During validation, better results were obtained for R evaluations, i.e., bootstrap method. CONCLUSIONS The most useful equations included C0, C1, C3 and C0, C1, C2 time points; however, the most precise included C1, C3, C6 time points because of MPA enterohepatic recirculation. Better results were obtained for bootstrap validation due to greater number of patients. Validated LSS should be used only in the population for which it was developed. As there is growing evidence that underexposure of MPA is associated with insufficient treatment response, we recommend the introduction of therapeutic drug monitoring for MPA in children with nephrotic syndrome.
Collapse
Affiliation(s)
- Joanna Sobiak
- Department of Physical Pharmacy and Pharmacokinetics, Poznan University of Medical Sciences, 6 Święcickiego Street, 60-781, Poznan, Poland.
| | - Matylda Resztak
- Department of Physical Pharmacy and Pharmacokinetics, Poznan University of Medical Sciences, 6 Święcickiego Street, 60-781, Poznan, Poland
| | - Tomasz Pawiński
- Department of Drug Chemistry, Medical University of Warsaw, 1 Banacha Street, 02-097, Warsaw, Poland
| | - Paweł Żero
- Department of Drug Chemistry, Medical University of Warsaw, 1 Banacha Street, 02-097, Warsaw, Poland
| | - Danuta Ostalska-Nowicka
- Department of Pediatric Cardiology, Nephrology and Hypertension, Poznan University of Medical Sciences, 27/33 Szpitalna Street, 60-572, Poznan, Poland
| | - Jacek Zachwieja
- Department of Pediatric Cardiology, Nephrology and Hypertension, Poznan University of Medical Sciences, 27/33 Szpitalna Street, 60-572, Poznan, Poland
| | - Maria Chrzanowska
- Department of Physical Pharmacy and Pharmacokinetics, Poznan University of Medical Sciences, 6 Święcickiego Street, 60-781, Poznan, Poland
| |
Collapse
|
10
|
Comparison of plasma and oral fluid concentrations of mycophenolic acid and its glucuronide metabolite by LC-MS in kidney transplant patients. Eur J Clin Pharmacol 2019; 75:553-559. [DOI: 10.1007/s00228-018-02614-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Accepted: 12/18/2018] [Indexed: 10/27/2022]
|
11
|
APPROACHES TO THE DEVELOPMENT OF BIOANALYTICAL METHODS FOR DETERMINATION OF UNSTABLE SUBSTANCES IN BIOLOGICAL FLUIDS. ACTA BIOMEDICA SCIENTIFICA 2018. [DOI: 10.29413/abs.2018-3.5.16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The approaches to bioanalytical method development for determination of substances which contain unstable functional groups in the structure are described. The oxidation and the hydrolysis are main causes of the decomposition of substances in biological fluids. Phenolic hydroxyls contain drugs were selected as examples of oxidable compounds, glucuronides of drugs were selected as examples of hydrolysable compounds. Determination of mycophenolic acid, which contains one phenolic hydroxyl and metabolized by formation of glucuronides, in plasma was performed using high performance liquid chromatography with mass-spectrometry and tandem mass-spectrometry detection. Methyldopa, which contains two phenolic hydroxyls, in stabilized plasma was assayed by high performance liquid chromatography – tandem mass-spectrometry in the range of 0.02–3.00 μg/ml. Concentrations of desmethyl mebeverine acid, which contains in the structure one phenolic hydroxyl and metabolized by formation of phenolic glucuronide, was measured simultaneously with mebeverine acid in the range of 10–2000 ng/ml. The influence of the ion source conversion of glucuronides on the quantitative determination of the substances was studied in the initial part of methods development. The next, selection of anticoagulants based on the study of short-term stability and freeze/thaw stability of the analytes and back conversion of their glucuronides was performed. The combination of anticoagulant K3EDTA and the antioxidant solution containing a mixture of ascorbic acid, sodium sulfite and sodium hydrogen carbonate in the concentrations of 5.0 %, 0.2 % and 2.4 %, respectively, was used to prevent degradation of methyldopa.
Collapse
|
12
|
Managing Drug-Drug Interaction Between Ombitasvir, Paritaprevir/Ritonavir, Dasabuvir, and Mycophenolate Mofetil. Ther Drug Monit 2018; 39:305-307. [PMID: 28700519 DOI: 10.1097/ftd.0000000000000397] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
No drug-drug interaction study has been conducted to date for the combination of ombitasvir, paritaprevir/ritonavir, dasabuvir (3D), and mycophenolic acid (MPA). We here report the case of a hepatitis C virus-infected patient treated with 3D and MPA for vasculitis. In light of the threat of drug-drug interaction, the concentration of MPA was measured before, during, and 15 days after the end of the 3D treatment. Similar values were found at all 3 time points, thus indicating that there is probably no need to adapt MPA dosage to 3D.
Collapse
|
13
|
Bahram M, Mojarrad S, Moghtader M. Simultaneous kinetic–spectrophotometric determination of mycophenolate mofetil and mycophenolic acid based on complexation with Fe(III) using chemometric techniques. JOURNAL OF THE IRANIAN CHEMICAL SOCIETY 2018. [DOI: 10.1007/s13738-017-1276-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
|
14
|
Sobiak J, Resztak M, Ostalska-Nowicka D, Zachwieja J, Gąsiorowska K, Piechanowska W, Chrzanowska M. Monitoring of mycophenolate mofetil metabolites in children with nephrotic syndrome and the proposed novel target values of pharmacokinetic parameters. Eur J Pharm Sci 2015; 77:189-96. [PMID: 26102431 DOI: 10.1016/j.ejps.2015.06.017] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2015] [Revised: 05/22/2015] [Accepted: 06/19/2015] [Indexed: 11/30/2022]
Abstract
The aim of the study was to estimate target values of mycophenolate mofetil (MMF) pharmacokinetic parameters in children with proteinuric glomerulopathies by calculating the pharmacokinetic parameters of MMF metabolites (mycophenolic acid [MPA], free MPA [fMPA] and MPA glucuronide [MPAG]) and assessing their relation to proteinuria recurrence. One hundred and sixty-eight blood samples were collected from children, aged 3-18 years, diagnosed with nephrotic syndrome or lupus nephritis. MMF metabolites concentrations were examined before drug administration (Ctrough) and up to 12h afterward employing high-performance liquid chromatography. Dose-normalized MPA Ctrough and area under the concentration-time curve from 0 to 12h (AUC12) were within 0.29-6.47 μg/mL/600 mg/m(2) and 9.97-105.52 μg h/mL/600 mg/m(2), respectively. MPA Ctrough was twofold lower (p=0.024) in children with proteinuria recurrence. MPA, fMPA and MPAG concentrations correlated positively to respective AUC12. It may be suggested MMF metabolites monitoring in children with proteinuric glomerulopathies is justified by MPA Ctrough<2 μg/mL in patients at risk of the proteinuria recurrence. Such a recurrence is most probably caused by not sufficient MPA concentration during proteinuric glomerulopathies treatment. MPA Ctrough>3 μg/mL may be considered as an efficient one to avoid proteinuria recurrence. Finally, MPA target AUC12 should exceed 60 μg h/mL to ensure the safe and effective treatment in children with nephrotic syndrome, however, the upper limit is still to be established.
Collapse
Affiliation(s)
- Joanna Sobiak
- Department of Physical Pharmacy and Pharmacokinetics, Poznan University of Medical Sciences, 6 Swiecickiego Street, 60-781 Poznan, Poland.
| | - Matylda Resztak
- Department of Physical Pharmacy and Pharmacokinetics, Poznan University of Medical Sciences, 6 Swiecickiego Street, 60-781 Poznan, Poland
| | - Danuta Ostalska-Nowicka
- Department of Pediatric Cardiology and Nephrology, Poznan University of Medical Sciences, 27/33 Szpitalna Street, 60-572 Poznan, Poland
| | - Jacek Zachwieja
- Department of Pediatric Cardiology and Nephrology, Poznan University of Medical Sciences, 27/33 Szpitalna Street, 60-572 Poznan, Poland
| | - Karolina Gąsiorowska
- Department of Physical Pharmacy and Pharmacokinetics, Poznan University of Medical Sciences, 6 Swiecickiego Street, 60-781 Poznan, Poland
| | - Wiktoria Piechanowska
- Department of Physical Pharmacy and Pharmacokinetics, Poznan University of Medical Sciences, 6 Swiecickiego Street, 60-781 Poznan, Poland
| | - Maria Chrzanowska
- Department of Physical Pharmacy and Pharmacokinetics, Poznan University of Medical Sciences, 6 Swiecickiego Street, 60-781 Poznan, Poland
| |
Collapse
|
15
|
Pharmacokinetics of mycophenolate sodium co-administered with tacrolimus in the first year after renal transplantation. Eur J Drug Metab Pharmacokinet 2015; 41:331-8. [PMID: 25663618 PMCID: PMC4954842 DOI: 10.1007/s13318-015-0262-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Accepted: 01/28/2015] [Indexed: 01/03/2023]
Abstract
We assessed the relations between MPA, free MPA (fMPA) and MPA glucuronide (MPAG) pharmacokinetics and the clinical condition of renal transplant recipients treated with EC-MPS and tacrolimus (Tac) in the first post-transplant year. In 18 adult patients blood samples were collected up to 12 h after EC-MPS oral administration. EC-MPS metabolites' plasma concentrations were determined using validated HPLC methods. All patients reached MPA area under the time-concentration curve (AUC0-12) above 30 µg h/mL. Most of the MPA, fMPA and all MPAG concentrations correlated significantly with respective AUC0-12 values. Some fMPA and all MPAG pharmacokinetic parameters correlated negatively with creatinine clearance and positively with creatinine concentration, whereas no such correlation was observed for MPA. Lower hemoglobin concentrations were observed in patients with higher MPA or fMPA C 0. The significant correlations between MPA C 3 as well as MPA C 4 and MPA AUC0-4 and MPA AUC0-12 may be of importance in further studies including larger number of patients in regard to establishing LSS. In patients treated with EC-MPS and Tac, monitoring MPA C 0 may be important, as too high MPA C 0 may contribute to anemia onset. In EC-MPS treated patients, MPAG concentration is related to renal function as MPAG pharmacokinetics were higher in patients with renal impairment.
Collapse
|
16
|
Chen H, Chen B. Clinical mycophenolic acid monitoring in liver transplant recipients. World J Gastroenterol 2014; 20:10715-10728. [PMID: 25152575 PMCID: PMC4138452 DOI: 10.3748/wjg.v20.i31.10715] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Revised: 06/03/2014] [Accepted: 06/26/2014] [Indexed: 02/06/2023] Open
Abstract
In liver transplantation, the efficacy of mycophenolate mofetil (MMF) has been confirmed in clinical trials and studies. However, therapeutic drug monitoring for mycophenolic acid (MPA) has not been fully accepted in liver transplantation as no long-term prospective study of concentration controlled vs fixed-dose prescribing of MMF has been done. This review addressed MPA measurement, pharmacokinetic variability and reasons of this variation, exposure related to acute rejection and MMF-associated side effects in liver transplant recipients. Limited sampling strategies to predict MPA area under the concentration-time curve have also been described, and the value of clinical use needs to be investigated in future. The published data suggested that a fixed-dosage MMF regimen might not be suitable and monitoring of MPA exposure seems helpful in various clinical settings of liver transplantation.
Collapse
|
17
|
Upadhyay V, Trivedi V, Shah G, Yadav M, Shrivastav PS. Determination of mycophenolic acid in human plasma by ultra performance liquid chromatography tandem mass spectrometry. J Pharm Anal 2013; 4:205-216. [PMID: 29403884 PMCID: PMC5761118 DOI: 10.1016/j.jpha.2013.06.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Accepted: 06/03/2013] [Indexed: 11/16/2022] Open
Abstract
A simple, sensitive and high throughput ultra performance liquid chromatography tandem mass spectrometry method has been developed for the determination of mycophenolic acid in human plasma. The method involved simple protein precipitation of MPA along with its deuterated analog as an internal standard (IS) from 50 µL of human plasma. The chromatographic analysis was done on Acquity UPLC C18 (100 mm×2.1 mm, 1.7 µm) column under isocratic conditions using acetonitrile and 10 mM ammonium formate, pH 3.00 (75:25, v/v) as the mobile phase. A triple quadrupole mass spectrometer operating in the positive ionization mode was used for quantitation. In-source conversion of mycophenolic glucuronide metabolite to the parent drug was selectively controlled by suitable optimization of cone voltage, cone gas flow and desolvation temperature. The method was validated over a wide concentration range of 15-15000 ng/mL. The mean extraction recovery for the analyte and IS was >95%. Matrix effect expressed as matrix factors ranged from 0.97 to 1.02. The method was successfully applied to support a bioequivalence study of 500 mg mycophenolate mofetil tablet in 72 healthy subjects.
Collapse
Affiliation(s)
- Vivek Upadhyay
- Chemistry Department, Kadi Sarva Vishwavidyalaya, Gandhinagar 382015, India
| | - Vikas Trivedi
- Chemistry Department, Kadi Sarva Vishwavidyalaya, Gandhinagar 382015, India
| | - Gaurang Shah
- Chemistry Department, Kadi Sarva Vishwavidyalaya, Gandhinagar 382015, India
| | - Manish Yadav
- Chemistry Department, Kadi Sarva Vishwavidyalaya, Gandhinagar 382015, India
| | - Pranav S. Shrivastav
- Chemistry Department, Kadi Sarva Vishwavidyalaya, Gandhinagar 382015, India
- Department of Chemistry, School of Sciences, Gujarat University, Navrangpura, Ahmedabad 380009, India
- Corresponding author at: Department of Chemistry, School of Sciences, Gujarat University, Navrangpura, Ahmedabad 380009, India. Tel.: +91 079 2630 0969; fax: +91 079 2630 8545.
| |
Collapse
|
18
|
Look M, Stern E, Wang QA, DiPlacido LD, Kashgarian M, Craft J, Fahmy TM. Nanogel-based delivery of mycophenolic acid ameliorates systemic lupus erythematosus in mice. J Clin Invest 2013; 123:1741-9. [PMID: 23454752 DOI: 10.1172/jci65907] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2012] [Accepted: 01/03/2013] [Indexed: 02/02/2023] Open
Abstract
The ability to selectively inactivate immune cells with immunosuppressants is a much sought-after modality for the treatment of systemic lupus erythematosus and autoimmunity in general. Here, we designed and tested a novel nanogel drug delivery vehicle for the immunosuppressant mycophenolic acid (MPA). Treatment with MPA-loaded nanogels increased the median survival time (MST) of lupus-prone NZB/W F1 mice by 3 months with prophylactic use (MST was 50 weeks versus 38 weeks without treatment), and by 2 months when administered after the development of severe renal damage (MST after proteinuria onset was 12.5 weeks versus 4 weeks without treatment). Equivalent and greater doses of MPA administered in buffer were not efficacious. Nanogels had enhanced biodistribution to organs and association with immune cells. CD4-targeted nanogels yielded similar therapeutic results compared with nontargeted formulations, with protection from glomerulonephritis and decreases in IFN-γ-positive CD4 T cells. DCs that internalized nanogels helped mediate immunosuppression, as they had reduced production of inflammatory cytokines such as IFN-γ and IL-12. Our results demonstrate efficacy of nanogel-based lupus therapy and implicate a mechanism by which immunosuppression is enhanced, in part, by the targeting of antigen-presenting cells.
Collapse
Affiliation(s)
- Michael Look
- Department of Biomedical Engineering, Yale University, New Haven, Connecticut, USA
| | | | | | | | | | | | | |
Collapse
|
19
|
Ahmed H, Elbarbry F, Clark B. Mixed Micellar Electrokinetic Chromatographic Analysis of Colistin, Polypeptide Antibiotic, Using Laser-Induced Fluorescence Detection. ACTA ACUST UNITED AC 2012. [DOI: 10.4236/ajac.2012.33031] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
20
|
Protić A, Zivanovic L, Radišić M, Lušević M. IMPURITY PROFILING OF MYCOPHENOLATE MOFETIL WITH THE ASSISSTANCE OF DESIRABILITY FUNCTION IN METHOD DEVELOPMENT. J LIQ CHROMATOGR R T 2011. [DOI: 10.1080/10826076.2011.569809] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Ana Protić
- a Faculty of Pharmacy, Department of Drug Analysis , University of Belgrade , Belgrade, Serbia
| | - Ljiljana Zivanovic
- a Faculty of Pharmacy, Department of Drug Analysis , University of Belgrade , Belgrade, Serbia
| | - Marina Radišić
- b Faculty of Technology and Metallurgy, Department of Analytical Chemistry , University of Belgrade , Belgrade, Serbia
| | - Mila Lušević
- b Faculty of Technology and Metallurgy, Department of Analytical Chemistry , University of Belgrade , Belgrade, Serbia
| |
Collapse
|
21
|
Gao JW, Peng ZH, Li XY, Sun B, Guo YK, Liu GL. simultaneous determination of mycophenolic acid and its metabolites by HPLC and pharmacokinetic studies in rat plasma and bile. Arch Pharm Res 2011; 34:59-69. [DOI: 10.1007/s12272-011-0107-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2010] [Revised: 07/02/2010] [Accepted: 07/05/2010] [Indexed: 11/29/2022]
|
22
|
Tett SE, Saint-Marcoux F, Staatz CE, Brunet M, Vinks AA, Miura M, Marquet P, Kuypers DR, van Gelder T, Cattaneo D. Mycophenolate, clinical pharmacokinetics, formulations, and methods for assessing drug exposure. Transplant Rev (Orlando) 2011; 25:47-57. [DOI: 10.1016/j.trre.2010.06.001] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2010] [Revised: 05/26/2010] [Accepted: 06/07/2010] [Indexed: 10/18/2022]
|
23
|
Delavenne X, Juthier L, Pons B, Mariat C, Basset T. UPLC MS/MS method for quantification of mycophenolic acid and metabolites in human plasma: Application to pharmacokinetic study. Clin Chim Acta 2010; 412:59-65. [PMID: 20937266 DOI: 10.1016/j.cca.2010.09.041] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2010] [Revised: 09/10/2010] [Accepted: 09/10/2010] [Indexed: 11/25/2022]
Abstract
BACKGROUND We described the development and full validation of a rapid, high throughput sensible and accurate UPLC method using tandem mass spectrometry detection for mycophenolate acid (MPA) and its metabolites, MPA glucuronide (MPAG) and acyl MPA glucuronide (AcMPAG) concentration determination with MPA-D3 as internal standard in human plasma. METHODS Plasma pretreatment involved a one-step protein precipitation with acetonitrile. The separation was performed by reverse-phase chromatography on a Waters BEH HSST3 100 mm*2.1 mm*1.8 μm column. The multiple reaction monitoring transitions used for quantification were m/z 321.04→303.02 for MPA, 524.09→303.02 for AcMPAG and MPAG and 324.03→306.04 for MPA-D3 in the electrospray positive ionization mode. RESULTS The method was linear over the concentration range of 0.1-20mg/L for MPA and AcMPAG and 1-200mg/L for MPAG respectively. The intra- and inter-day precision values were below 14% and accuracy was from 94.0 to 103.3% at all quality control levels. The lower LOQ was 0.1 mg/L for MPA and AcMPAG, 1 mg/L for MPAG. CONCLUSION Sample analysis time was reduced to 7 min including sample preparation. The present method was successfully applied to a pharmacokinetic study following oral administration of enterocoated sodium mycophenolate in de novo renal transplantation.
Collapse
Affiliation(s)
- Xavier Delavenne
- Laboratory of Pharmacology and Toxicology, University Hospital, F-42055 Saint-Etienne, France.
| | | | | | | | | |
Collapse
|
24
|
Elbarbry F, Attia A, Shoker A. Validation of a new HPLC method for determination of midazolam and its metabolites: Application to determine its pharmacokinetics in human and measure hepatic CYP3A activity in rabbits. J Pharm Biomed Anal 2009; 50:987-93. [DOI: 10.1016/j.jpba.2009.07.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2009] [Revised: 07/03/2009] [Accepted: 07/03/2009] [Indexed: 10/20/2022]
|
25
|
Živanović L, Protić A, Zečević M, Jocić B, Kostić M. Multicriteria optimization methodology in development of HPLC separation of mycophenolic acid and mycophenolic acid glucuronide in human urine and plasma. J Pharm Biomed Anal 2009; 50:640-8. [DOI: 10.1016/j.jpba.2008.09.052] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2008] [Revised: 09/29/2008] [Accepted: 09/30/2008] [Indexed: 11/28/2022]
|
26
|
Determination of total, free and saliva mycophenolic acid with a LC-MS/MS method: application to pharmacokinetic study in healthy volunteers and renal transplant patients. J Pharm Biomed Anal 2009; 50:515-21. [PMID: 19574013 DOI: 10.1016/j.jpba.2009.05.030] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2009] [Revised: 05/24/2009] [Accepted: 05/26/2009] [Indexed: 12/21/2022]
Abstract
Mycophenolic acid (MPA) is the active moiety of mycophenoate mofetil (MMF), an ester prodrug widely used as an immunosuppressant. Therapeutic drug monitoring (TDM) of MPA is becoming mandatory for transplant patients received MMF therapy in the routine clinical practice because of large individual variability, dose-related toxicity and the risk of acute rejection. In this study, a rapid, sensitive and selective LC-MS/MS method was developed and validated for the quantitative analysis of total and free MPA in plasma and in saliva that uses one identical liquid chromatographic and mass spectrometric condition. Following protein precipitation for total and saliva MPA, and ultrafiltration for free MPA, chromatographic separation was performed on an Allure PFP Propyl analytical column (100 x 2.1 mm, 5 microm, RESTEK Co., Bellefonte, PA, USA) with 0.1% formic acid in acetonitrile and 0.1% formic acid in water (45:55, v/v) as the mobile phases. The compounds were quantified by positive electrospray ionization tandem mass spectrometry. Selectivity, linearity, accuracy, precision, recovery, matrix effect, and saliva stability were evaluated during method validation. The validated method was applied to a pharmacokinetic study of MPA after an oral administration of a single 1000 mg of MMF to eight healthy male volunteers and 750 mg bid of MMF to nine renal transplant patients.
Collapse
|