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Feturi FG, Weinstock M, Zhao W, Zhang W, Schnider JT, Erbas VE, Oksuz S, Plock JA, Rohan L, Spiess AM, Ferreira LM, Solari MG, Venkataramanan R, Gorantla VS. Mycophenolic Acid for Topical Immunosuppression in Vascularized Composite Allotransplantation: Optimizing Formulation and Preliminary Evaluation of Bioavailability and Pharmacokinetics. Front Surg 2018; 5:20. [PMID: 29868602 PMCID: PMC5954844 DOI: 10.3389/fsurg.2018.00020] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2017] [Accepted: 02/19/2018] [Indexed: 12/21/2022] Open
Abstract
Mycophenolic acid (MPA), is the active form of the ester prodrug mycophenolate mofetil (MMF). MMF is an FDA approved immunosuppressive drug that has been successfully used in systemic therapy in combination with other agents for the prevention of acute rejection (AR) following solid organ transplantation (SOT) as well as in vascularized composite allotransplantation (VCA). Systemic use of MMF is associated with gastrointestinal adverse effects. Topical delivery of the prodrug could thus provide graft-targeted immunosuppression while minimizing systemic drug exposure. Our goal was to develop a topical formulation of MPA with optimal in vitro/in vivo characteristics such as release, permeation, and tissue bioavailability to enable safety and efficacy evaluation in clinical VCA. Permeation studies were performed with a solution of MPA (10 mg/ml). In vitro release and permeation studies were performed for different semisolid formulations (Aladerm, Lipoderm, emollient, and VersaBase) of MPA (1% w/w) using a Franz Diffusion Cell System (FDCS). In vivo pharmacokinetic characterization of MPA release from Lipoderm was performed in rats. MPA in solution exhibited a steady state flux (3.8 ± 0.1 µg/cm2/h) and permeability (1.1 × 10−7 ± 3.2 × 10−9 cm/s). MPA in Lipoderm exhibited a steady state flux of 1.12 ± 0.24 µg/cm2/h, and permeability of 6.2 × 10−09 ± 1.3 × 10−9 cm/s across the biomimetic membrane. The cumulative release of MPA from Lipoderm, showed a linear single-phase profile with a R2 of 0.969. In vivo studies with MPA in Lipoderm showed markedly higher local tissue MPA levels and lower systemic MPA exposure as compared to values obtained after intravenous delivery of the same dose of drug (p < 0.05). We successfully developed for the first time, a topical formulation of MPA in Lipoderm with optimal in vitro/in vivo permeability characteristics and no undesirable local or systemic adverse effects in vivo. Our study provides key preliminary groundwork for translational efficacy studies of topical MPA in pre-clinical large animal VCA models and for effectiveness evaluation in patients receiving VCA.
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Affiliation(s)
- Firuz G Feturi
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, PA, United States
| | - Matthias Weinstock
- Disciplina de Cirurgia Plástica, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Wenchen Zhao
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, PA, United States
| | - Wei Zhang
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, PA, United States.,Magee-Womens Research Institute, Pittsburgh, PA, United States
| | - Jonas T Schnider
- Division of Plastic and Hand Surgery, University Hospital Zurich, Zurich, Switzerland
| | - Vasil E Erbas
- Department of Plastic Surgery, Medicalpark Gaziantep Hastanesi, Gaziantep, Turkey
| | - Sinan Oksuz
- Department of Plastic Reconstructive and Aesthetic Surgery, Gulhane Medical School, Ankara, Turkey
| | - Jan A Plock
- Division of Plastic and Hand Surgery, University Hospital Zurich, Zurich, Switzerland
| | - Lisa Rohan
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, PA, United States.,Magee-Womens Research Institute, Pittsburgh, PA, United States
| | - Alexander M Spiess
- Department of Plastic and Reconstructive Surgery, School of Medicine, University of Pittsburgh, Pittsburgh, PA, United States
| | - Lydia M Ferreira
- Disciplina de Cirurgia Plástica, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Mario G Solari
- Department of Plastic and Reconstructive Surgery, School of Medicine, University of Pittsburgh, Pittsburgh, PA, United States
| | - Raman Venkataramanan
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, PA, United States.,McGowan Institute for Regenerative Medicine, Pittsburgh, PA, United States
| | - Vijay S Gorantla
- Department of Plastic and Reconstructive Surgery, School of Medicine, University of Pittsburgh, Pittsburgh, PA, United States.,McGowan Institute for Regenerative Medicine, Pittsburgh, PA, United States.,Wake Forest Institute for Regenerative Medicine, Wake Forest Baptist Medical Center, Winston-Salem, NC, United States
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Tredger JM, Brown NW, Dhawan A. Calcineurin inhibitor sparing in paediatric solid organ transplantation : managing the efficacy/toxicity conundrum. Drugs 2008; 68:1385-414. [PMID: 18578558 DOI: 10.2165/00003495-200868100-00004] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Despite their efficacy, the calcineurin inhibitors (CNIs) ciclosporin and tacrolimus carry a risk of debilitating adverse effects, especially nephrotoxicity, that affect the long-term outcome and survival of children who are given organ transplants. Simple reduction in dosage of CNI has little or no long-term benefit on their adverse effects, and complete withdrawal without threatening graft outcome may only be possible after liver transplantation. Until the last decade, the only option was to increase corticosteroid and/or azathioprine doses, which imposed additional long-term hazards. Considered here are the emerging generation of new agents offering an opportunity for improving long-term graft survival, minimizing CNI-related adverse events and ensuring patient well-being.A holistic, multifaceted strategy may need to be considered - initial selection and optimized use and monitoring of immunosuppressant regimens, early recognition of indicators of patient and graft dysfunction, and, where applicable, early introduction of CNI-sparing regimens facilitating CNI withdrawal. The evidence reviewed here supports these approaches but remains far from definitive in paediatric solid organ transplantation. Because de novo immunosuppression uses CNI in more than 93% of patients, reduction of CNI-related adverse effects has focused on CNI sparing or withdrawal.A recurring theme where sirolimus and mycophenolate mofetil have been used for this purpose is the importance of their early introduction to limit CNI damage and provide long-term benefit: for example, long-term renal function critically reflects that at 1 year post-transplant. While mycophenolic acid shows advantages over sirolimus in preserving renal function because the latter is associated with proteinuria, sirolimus appears the more potent immunosuppressant but also impairs early wound healing. The use of CNI-free immunosuppressant regimens with depleting or non-depleting antibodies plus sirolimus and mycophenolic acid needs much wider investigation to achieve acceptable rejection rates and conserve renal function. The adverse effects of the alternative immunosuppressants, particularly the dyslipidaemia associated with sirolimus, needs to be minimized to avoid replacing one set of adverse effects (from CNIs) with another. While we can only conjecture that judicious combinations with the second generation of novel immunosuppressants currently in development will provide these solutions, a rationale of low-dose therapy with multiple immunosuppressants acting by complementary mechanisms seems to hold the promise for efficacy with minimal toxicity until the vision of tolerance achieves reality.
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Affiliation(s)
- J Michael Tredger
- Institute of Liver Studies, King's College Hospital and King's College London School of Medicine, London, UK.
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