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Terzioğlu İ, Ventura-Hunter C, Ulbrich J, Saldívar-Guerra E, Schubert US, Guerrero-Sánchez C. Automated Parallel Dialysis for Purification of Polymers. Polymers (Basel) 2022; 14:polym14224835. [PMID: 36432962 PMCID: PMC9697721 DOI: 10.3390/polym14224835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 11/04/2022] [Accepted: 11/06/2022] [Indexed: 11/12/2022] Open
Abstract
The implementation of a dialysis method for the simultaneous purification of different polymer materials in a commercially available automated parallel synthesizer (APS) is discussed. The efficiency of this "unattended" automated parallel dialysis (APD) method was investigated by means of proton nuclear magnetic resonance (1H-NMR) measurements, which confirmed that the method enables the removal of up to 99% of the unreacted monomer derived from the synthesis of the corresponding polymers in the APS. Size-exclusion chromatography (SEC) revealed that the molar mass and molar mass distribution of the investigated polymers did not undergo significant changes after the application of the APD method. The method discussed herein can be regarded as a good alternative to the "unattended" and reliable purification of polymer libraries prepared in APS. This method may be useful for overcoming current limitations of high-throughput/-output (HT/O) synthesis of polymer libraries, where purification of the generated materials currently represents a significant constraint for establishing fully automated experimental workflows necessary to advance towards a full digitalization of research and development of new polymers for diverse applications.
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Affiliation(s)
- İpek Terzioğlu
- Laboratory of Organic and Macromolecular Chemistry (IOMC), Friedrich Schiller University Jena, Humboldtstrasse 10, 07743 Jena, Germany
| | - Carolina Ventura-Hunter
- Laboratory of Organic and Macromolecular Chemistry (IOMC), Friedrich Schiller University Jena, Humboldtstrasse 10, 07743 Jena, Germany
- Polymerization Processes Department, Centro de Investigación en Química Aplicada (CIQA), Blvd. Enrique Reyna No. 140, Saltillo 25294, Coahuila, Mexico
| | - Jens Ulbrich
- Laboratory of Organic and Macromolecular Chemistry (IOMC), Friedrich Schiller University Jena, Humboldtstrasse 10, 07743 Jena, Germany
| | - Enrique Saldívar-Guerra
- Polymerization Processes Department, Centro de Investigación en Química Aplicada (CIQA), Blvd. Enrique Reyna No. 140, Saltillo 25294, Coahuila, Mexico
| | - Ulrich S. Schubert
- Laboratory of Organic and Macromolecular Chemistry (IOMC), Friedrich Schiller University Jena, Humboldtstrasse 10, 07743 Jena, Germany
| | - Carlos Guerrero-Sánchez
- Laboratory of Organic and Macromolecular Chemistry (IOMC), Friedrich Schiller University Jena, Humboldtstrasse 10, 07743 Jena, Germany
- Correspondence:
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Bassand C, Freitag J, Benabed L, Verin J, Siepmann F, Siepmann J. PLGA implants for controlled drug release: Impact of the diameter. Eur J Pharm Biopharm 2022; 177:50-60. [PMID: 35659920 DOI: 10.1016/j.ejpb.2022.05.020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 05/24/2022] [Accepted: 05/27/2022] [Indexed: 11/17/2022]
Abstract
The aim of this study was to better understand the importance of the diameter of poly(lactic-co-glycolic acid) (PLGA)-based implants on system performance, in particular the control of drug release. Different types of ibuprofen-loaded implants were prepared by hot melt extrusion using a Leistritz Nano 16 twin-screw extruder. Drug release was measured in well agitated phosphate buffer pH7.4 bulk fluid and in agarose gels in Eppendorf tubes or transwell plates. Dynamic changes in the implants' dry & wet mass, volume, polymer molecular weight as well as inner & outer morphology were monitored using gravimetric analysis, optical macroscopy, gel permeation chromatography and scanning electron microscopy. The physical states of the drug and polymer were determined by DSC. Also pH changes in the release medium were investigated. Irrespective of the type of experimental set-up, the resulting absolute and relative drug release rates decreased with increasing implant diameter (0.7 to 2.8 mm). Bi-phasic drug release was observed in all cases from the monolithic solutions (ibuprofen was dissolved in the polymer): A zero order release phase was followed by a final, rapid drug release phase (accounting for 80-90% of the total drug dose). The decrease in the relative drug release rate with increasing system diameter can be explained by the increase in the diffusion pathway lengths to be overcome. Interestingly, also the onset of the final rapid drug release phase was delayed with increasing implant diameter. This can probably be attributed to the higher mechanical stability of thicker devices, offering more resistance to substantial entire system swelling.
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Affiliation(s)
- C Bassand
- Univ. Lille, Inserm, CHU Lille, U1008, F-59000 Lille, France
| | - J Freitag
- Univ. Lille, Inserm, CHU Lille, U1008, F-59000 Lille, France
| | - L Benabed
- Univ. Lille, Inserm, CHU Lille, U1008, F-59000 Lille, France
| | - J Verin
- Univ. Lille, Inserm, CHU Lille, U1008, F-59000 Lille, France
| | - F Siepmann
- Univ. Lille, Inserm, CHU Lille, U1008, F-59000 Lille, France
| | - J Siepmann
- Univ. Lille, Inserm, CHU Lille, U1008, F-59000 Lille, France.
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3
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Barbosa-Alfaro D, Andrés-Guerrero V, Fernandez-Bueno I, García-Gutiérrez MT, Gil-Alegre E, Molina-Martínez IT, Pastor-Jimeno JC, Herrero-Vanrell R, Bravo-Osuna I. Dexamethasone PLGA Microspheres for Sub-Tenon Administration: Influence of Sterilization and Tolerance Studies. Pharmaceutics 2021; 13:pharmaceutics13020228. [PMID: 33562155 PMCID: PMC7915986 DOI: 10.3390/pharmaceutics13020228] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 01/25/2021] [Accepted: 02/02/2021] [Indexed: 11/30/2022] Open
Abstract
Many diseases affecting the posterior segment of the eye require repeated intravitreal injections with corticosteroids in chronic treatments. The periocular administration is a less invasive route attracting considerable attention for long-term therapies. In the present work, dexamethasone-loaded poly(lactic-co-glycolic) acid (PLGA) microspheres (Dx-MS) were prepared using the oil-in-water (O/W) emulsion solvent evaporation technique. MS were characterized in terms of mean particle size and particle size distribution, external morphology, polymer integrity, drug content, and in vitro release profiles. MS were sterilized by gamma irradiation (25 kGy), and dexamethasone release profiles from sterilized and non-sterilized microspheres were compared by means of the similarity factor (f2). The mechanism of drug release before and after irradiation exposure of Dx-MS was identified using appropriate mathematical models. Dexamethasone release was sustained in vitro for 9 weeks. The evaluation of the in vivo tolerance was carried out in rabbit eyes, which received a sub-Tenon injection of 5 mg of sterilized Dx-MS (20–53 µm size containing 165.6 ± 3.6 µg Dx/mg MS) equivalent to 828 µg of Dx. No detectable increase in intraocular pressure was reported, and clinical and histological analysis of the ocular tissues showed no adverse events up to 6 weeks after the administration. According to the data presented in this work, the sub-Tenon administration of Dx-MS could be a promising alternative to successive intravitreal injections for the treatment of chronic diseases of the back of the eye.
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Affiliation(s)
- Deyanira Barbosa-Alfaro
- Innovation, Therapy and Pharmaceutical Development in Ophthalmology (InnOftal) Research Group, UCM 920415, Complutense University of Madrid, 28040 Madrid, Spain; (D.B.-A.); (V.A.-G.); (E.G.-A.); (I.T.M.-M.); (I.B.-O.)
- Departamento de Farmacia Galénica y Tecnología Alimentaria, Facultad de Farmacia, Universidad Complutense de Madrid (UCM), IdISSC, 28040 Madrid, Spain
| | - Vanessa Andrés-Guerrero
- Innovation, Therapy and Pharmaceutical Development in Ophthalmology (InnOftal) Research Group, UCM 920415, Complutense University of Madrid, 28040 Madrid, Spain; (D.B.-A.); (V.A.-G.); (E.G.-A.); (I.T.M.-M.); (I.B.-O.)
- Departamento de Farmacia Galénica y Tecnología Alimentaria, Facultad de Farmacia, Universidad Complutense de Madrid (UCM), IdISSC, 28040 Madrid, Spain
- Thematic Research Network in Ophthalmology (Oftared) Carlos III National Institute of Health, 28040 Madrid, Spain; (I.F.-B.); (J.C.P.-J.)
| | - Ivan Fernandez-Bueno
- Thematic Research Network in Ophthalmology (Oftared) Carlos III National Institute of Health, 28040 Madrid, Spain; (I.F.-B.); (J.C.P.-J.)
- Instituto Universitario de Oftalmobiología Aplicada (IOBA), Universidad de Valladolid, 47011 Valladolid, Spain;
| | | | - Esther Gil-Alegre
- Innovation, Therapy and Pharmaceutical Development in Ophthalmology (InnOftal) Research Group, UCM 920415, Complutense University of Madrid, 28040 Madrid, Spain; (D.B.-A.); (V.A.-G.); (E.G.-A.); (I.T.M.-M.); (I.B.-O.)
| | - Irene Teresa Molina-Martínez
- Innovation, Therapy and Pharmaceutical Development in Ophthalmology (InnOftal) Research Group, UCM 920415, Complutense University of Madrid, 28040 Madrid, Spain; (D.B.-A.); (V.A.-G.); (E.G.-A.); (I.T.M.-M.); (I.B.-O.)
- Departamento de Farmacia Galénica y Tecnología Alimentaria, Facultad de Farmacia, Universidad Complutense de Madrid (UCM), IdISSC, 28040 Madrid, Spain
- Thematic Research Network in Ophthalmology (Oftared) Carlos III National Institute of Health, 28040 Madrid, Spain; (I.F.-B.); (J.C.P.-J.)
| | - José Carlos Pastor-Jimeno
- Thematic Research Network in Ophthalmology (Oftared) Carlos III National Institute of Health, 28040 Madrid, Spain; (I.F.-B.); (J.C.P.-J.)
- Instituto Universitario de Oftalmobiología Aplicada (IOBA), Universidad de Valladolid, 47011 Valladolid, Spain;
- Department of Ophthalmology, Hospital Clínico Universitario of Valladolid, 47003 Valladolid, Spain
| | - Rocío Herrero-Vanrell
- Innovation, Therapy and Pharmaceutical Development in Ophthalmology (InnOftal) Research Group, UCM 920415, Complutense University of Madrid, 28040 Madrid, Spain; (D.B.-A.); (V.A.-G.); (E.G.-A.); (I.T.M.-M.); (I.B.-O.)
- Departamento de Farmacia Galénica y Tecnología Alimentaria, Facultad de Farmacia, Universidad Complutense de Madrid (UCM), IdISSC, 28040 Madrid, Spain
- Thematic Research Network in Ophthalmology (Oftared) Carlos III National Institute of Health, 28040 Madrid, Spain; (I.F.-B.); (J.C.P.-J.)
- Correspondence:
| | - Irene Bravo-Osuna
- Innovation, Therapy and Pharmaceutical Development in Ophthalmology (InnOftal) Research Group, UCM 920415, Complutense University of Madrid, 28040 Madrid, Spain; (D.B.-A.); (V.A.-G.); (E.G.-A.); (I.T.M.-M.); (I.B.-O.)
- Departamento de Farmacia Galénica y Tecnología Alimentaria, Facultad de Farmacia, Universidad Complutense de Madrid (UCM), IdISSC, 28040 Madrid, Spain
- Thematic Research Network in Ophthalmology (Oftared) Carlos III National Institute of Health, 28040 Madrid, Spain; (I.F.-B.); (J.C.P.-J.)
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4
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Andrés-Guerrero V, Bravo-Osuna I, Pastoriza P, Molina-Martinez IT, Herrero-Vanrell R. Novel technologies for the delivery of ocular therapeutics in glaucoma. J Drug Deliv Sci Technol 2017. [DOI: 10.1016/j.jddst.2017.07.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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PLGA-based monolithic filaments prepared by hot-melt extrusion: In-vitro comparative study. ANNALES PHARMACEUTIQUES FRANÇAISES 2017; 76:97-106. [PMID: 29145995 DOI: 10.1016/j.pharma.2017.09.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Revised: 08/20/2017] [Accepted: 09/17/2017] [Indexed: 01/09/2023]
Abstract
To avoid frequent drug administration, PLGA-based monolithic filament-shaped implants were prepared. In this study, the effect of different formulation variables was studied, namely: type of PLGA (PLGA 502 and PLGA 503), type of drug (the lipophilic Prednisolone acetate, PA and the hydrophilic Propranolol Hydrochloride, PH) and drug loading (10 and 30% w/w). PLGA 503-based implants showed a lower water uptake, lower mass loss and erosion, slower drug release, and better mechanical properties and elasticity (P<0.05) compared to the corresponding PLGA 502-based implants. PH-loaded implants showed a faster swelling and degradation as well as drug release (P<0.05) compared to PA-loaded implants; the former attained almost complete drug release after about 18 days, while the latter attained it after about 30 days. All the implants followed a zero-order kinetic pattern suitable for a controlled drug release. Characterization was done using SEM and DSC. This study proved the potential tailoring of the properties of PLGA-implants, prepared by hot-melt extrusion (HME), based on some formulation variables.
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Lodoso-Torrecilla I, van Gestel NAP, Diaz-Gomez L, Grosfeld EC, Laperre K, Wolke JGC, Smith BT, Arts JJ, Mikos AG, Jansen JA, Hofmann S, van den Beucken JJJP. Multimodal pore formation in calcium phosphate cements. J Biomed Mater Res A 2017; 106:500-509. [PMID: 28940662 DOI: 10.1002/jbm.a.36245] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Revised: 09/08/2017] [Accepted: 09/21/2017] [Indexed: 01/05/2023]
Abstract
Calcium phosphate cements (CPCs) are commonly used as bone substitute materials. However, their slow degradation rate and lack of macroporosity hinders new bone formation. Poly(dl-lactic-co-glycolic acid) (PLGA) incorporation is of great interest as, upon degradation, produces acidic by-products that enhance CPC degradation. Yet, new bone formation is delayed until PLGA degradation occurs a few weeks after implantation. Therefore, the aim of this study was to accelerate the early stage pore formation within CPCs in vitro. With that purpose, we incorporated the water-soluble porogen sucrose at different weight percentages (10 or 20 wt %) to CPC and CPC/PLGA composites. The results revealed that incorporation of sucrose porogens increased mass loss within the first week of in vitro degradation in groups containing sucrose compared to control groups. After week 1, a further mass loss was observed related to PLGA and CPC degradation. Macroporosity analysis confirmed that macroporosity formation is influenced by the dissolution of sucrose at an early stage and by the degradation of PLGA and CPC at a later stage. We concluded that the combination of sucrose and PLGA porogens in CPC is a promising approach to promote early stage bone tissue ingrowth and complete replacement of CPC through multimodal pore formation. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 500-509, 2018.
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Affiliation(s)
| | - Nicole A P van Gestel
- Orthopedic Biomechanics, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands.,Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Luis Diaz-Gomez
- Departamento de Farmacia y Tecnología Farmacéutica, Facultad de Farmacia, Universidade de Santiago de Compostela, Santiago de Compostela, Spain.,Department of Bioengineering, Rice University, Houston, Texas, 77030
| | | | | | - Joop G C Wolke
- Department of Biomaterials, Radboudumc, Nijmegen, The Netherlands
| | - Brandon T Smith
- Department of Bioengineering, Rice University, Houston, Texas, 77030
| | - Jacobus J Arts
- Orthopedic Biomechanics, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands.,Department of Orthopaedic Surgery, Research School CAPHRI, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Antonios G Mikos
- Department of Bioengineering, Rice University, Houston, Texas, 77030.,Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas, 77005
| | - John A Jansen
- Department of Biomaterials, Radboudumc, Nijmegen, The Netherlands
| | - Sandra Hofmann
- Orthopedic Biomechanics, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands.,Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, The Netherlands.,Institute for Biomechanics, Swiss Federal Institute of Technology Zürich (ETHZ), Zürich, Switzerland
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7
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Backofen M, Schwach G, Koechling W, Weiss T, Goepferich A. Polyanion based controlled release system for the GnRH-receptor antagonist degarelix. Eur J Pharm Sci 2017; 104:65-71. [DOI: 10.1016/j.ejps.2017.03.036] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 03/18/2017] [Accepted: 03/24/2017] [Indexed: 11/16/2022]
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8
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Pagels RF, Prud'homme RK. Polymeric nanoparticles and microparticles for the delivery of peptides, biologics, and soluble therapeutics. J Control Release 2015; 219:519-535. [PMID: 26359125 DOI: 10.1016/j.jconrel.2015.09.001] [Citation(s) in RCA: 102] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Revised: 09/02/2015] [Accepted: 09/03/2015] [Indexed: 01/10/2023]
Abstract
Biologically derived therapeutics, or biologics, are the most rapidly growing segment of the pharmaceutical marketplace. However, there are still unmet needs in improving the delivery of biologics. Injectable polymeric nanoparticles and microparticles capable of releasing proteins and peptides over time periods as long as weeks or months have been a major focus in the effort to decrease the frequency of administration. These particle systems fit broadly into two categories: those composed of hydrophilic and those composed of hydrophobic polymeric scaffolds. Here we review the factors that contribute to the slow and controlled release from each class of particle, as well as the effects of synthesis parameters and product design on the loading, encapsulation efficiency, biologic integrity, and release profile. Generally, hydrophilic scaffolds are ideal for large proteins while hydrophobic scaffolds are more appropriate for smaller biologics without secondary structure. Here we also introduce a Flash NanoPrecipitation method that has been adopted for encapsulating biologics in nanoparticles (40-200nm) at high loadings (50-75wt.%) and high encapsulation efficiencies. The hydrophilic gel interior and hydrophobic shell provide an opportunity to combine the best of both classes of injectable polymeric depots.
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Affiliation(s)
- Robert F Pagels
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, United States
| | - Robert K Prud'homme
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, United States.
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Cooper DL, Conder CM, Harirforoosh S. Nanoparticles in drug delivery: mechanism of action, formulation and clinical application towards reduction in drug-associated nephrotoxicity. Expert Opin Drug Deliv 2014; 11:1661-80. [PMID: 25054316 DOI: 10.1517/17425247.2014.938046] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
INTRODUCTION Over the past few decades, nanoparticles (NPs) have gained immeasurable interest in the field of drug delivery. Various NP formulations have been disseminated in drug development in an attempt to increase efficacy, safety and tolerability of incorporated drugs. In this context, NP formulations that increase solubility, control release, and/or affect the in vivo disposition of drugs, were developed to improve the pharmacokinetic and pharmacodynamic properties of encapsulated drugs. AREAS COVERED In this article, important properties related to NP function such as particle size, surface charge and shape are disseminated. Also, the current understanding of how NP characteristics affect particle uptake and targeted delivery is elucidated. Selected NP systems currently used in delivery of drugs in biological systems and their production methods are discussed as well. Emphasis is placed on current NP formulations that are shown to reduce drug-induced adverse renal complications. EXPERT OPINION Formulation designs utilizing NP-encapsulated drugs offer alternative pharmacotherapy options with improved safety profiles for current and emerging drugs. NPs have been shown to increase the therapeutic index of several entrapped drugs mostly by decreasing drug localization and side effects on organs. Recent studies on NP-encapsulated chemotherapeutic and antibiotic medications show enhanced therapeutic outcomes by altering drug degradation, increasing systemic circulation and/or enhancing cell specific targeting. They may also reduce the distribution of encapsulated drugs into the kidneys and attenuate drug-associated adverse renal complications. The usefulness of NP formulation in reducing the nephrotoxicity of nonsteroidal anti-inflammatory drugs is an under explored territory that deserves more attention.
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Affiliation(s)
- Dustin L Cooper
- East Tennessee State University, Gatton College of Pharmacy, Department of Pharmaceutical Sciences , Johnson City, TN 37614 , USA
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10
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Abstract
Discovery of insulin in the early 1900s initiated the research and development to improve the means of therapeutic protein delivery in patients. In the past decade, great emphasis has been placed on bringing protein and peptide therapeutics to market. Despite tremendous efforts, parenteral delivery still remains the major mode of administration for protein and peptide therapeutics. Other routes such as oral, nasal, pulmonary and buccal are considered more opportunistic rather than routine application. Improving biological half-life, stability and therapeutic efficacy is central to protein and peptide delivery. Several approaches have been tried in the past to improve protein and peptide in vitro/in vivo stability and performance. Approaches may be broadly categorized as chemical modification and colloidal delivery systems. In this review we have discussed various chemical approaches such as PEGylation, hyperglycosylation, mannosylation, and colloidal carriers including microparticles, nanoparticles, liposomes, carbon nanotubes and micelles for improving protein and peptide delivery. Recent developments on in situ thermosensitive gel-based protein and peptide delivery have also been described. This review summarizes recent developments on some currently existing approaches to improve stability, bioavailability and bioactivity of peptide and protein therapeutics following parenteral administration.
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Vijayaraghavan M, Stolnik S, Howdle SM, Illum L. Suitability of polymer materials for production of pulmonary microparticles using a PGSS supercritical fluid technique: preparation of microparticles using PEG, fatty acids and physical or chemicals blends of PEG and fatty acids. Int J Pharm 2012. [PMID: 23178217 DOI: 10.1016/j.ijpharm.2012.10.040] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The production of microparticles using a supercritical carbon dioxide based PGSS technique (CriticalMix™) has been exploited to develop blended systems targeted at pulmonary delivery. Hence, PEG based polymers of different molecular weights (1000-6000 Da) were blended in situ with fatty acids (stearic, palmitic or myristic acid) or with commercially available PEG-stearates. The effect of the different thermodynamic properties of the polymers was evaluated by characterising the microparticles produced in terms of their melting temperature by conventional DSC and in the presence of high pressure CO(2) using a high pressure variable volume view cell. The microparticles produced were also assessed by SEM and particle size distribution. It is well known that as the molecular weight of the PEG chains increases, so does the viscosity of the melt and this leads to an increase in the particle size. In the paper we show that blending with myristic acid provides optimal control of particle size when the blend is sprayed from scCO(2) leading to high yields in the optimal aerodynamic size range of 2-5 μm for the deep lung delivery. The highest yield and smallest particles (~5 μm) were produced with a blend of PEG 3000 and myristic acid (1:1) whereas the batches containing palmitic acid and stearic acid showed lower yields and larger particle sizes.
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Affiliation(s)
- Meera Vijayaraghavan
- School of Pharmacy, University of Nottingham, University Park, Nottingham NG7 2RD, UK
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12
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Hu L, Zhang H, Song W. An overview of preparation and evaluation sustained-release injectable microspheres. J Microencapsul 2012; 30:369-82. [DOI: 10.3109/02652048.2012.742158] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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13
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Teng L, Jiang C, Sun F, Li C, Teng L, Meng Q, Lee RJ, Li Y. Long-acting formulation of a new muscarinic receptor antagonist for the treatment of overactive bladder. J Microencapsul 2012; 30:116-23. [PMID: 22861176 DOI: 10.3109/02652048.2012.704950] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
A new muscarinic receptor antagonist, 5-hydroxymethyl tolterodine (5-HMT), was successfully encapsulated into PLGA microspheres. With an increase of PLGA concentration from 15% to 40%, encapsulation efficiency of 5-HMT increased from 55.39% to 76.32%, and the particle size of microsphere increased from 34.33 to 70.48 µm. Increasing the homogenisation speed from 850 to 2300 rpm, the particle size was reduced about 65%.The in vitro and in vivo studies in beagle dogs show that the release profile of 5-HMT-loaded microspheres (5-HMT MS) prepared with 503H is characterised by a low initial burst followed by slow release that lasted for 2 weeks. A C(max) of 1.617 ± 0.392 ng/mL was found on the sixth day. When evaluated for inhibition of the carbachol-induced contraction of rat urinary bladder, 5-HMT MS showed a much longer and more potent effect than tolterodine tablets. The mean urination time of the rats in the 5-HMT MS group was significantly decreased (p < 0.05 or p < 0.01) to less than 2 weeks.
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Affiliation(s)
- Lesheng Teng
- College of Life Science, Jilin University, Changchun, China
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14
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Checa-Casalengua P, Jiang C, Bravo-Osuna I, Tucker BA, Molina-Martínez IT, Young MJ, Herrero-Vanrell R. Preservation of biological activity of glial cell line-derived neurotrophic factor (GDNF) after microencapsulation and sterilization by gamma irradiation. Int J Pharm 2012; 436:545-54. [PMID: 22828071 DOI: 10.1016/j.ijpharm.2012.07.019] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2012] [Revised: 07/10/2012] [Accepted: 07/12/2012] [Indexed: 11/25/2022]
Abstract
A main issue in controlled delivery of biotechnological products from injectable biodegradable microspheres is to preserve their integrity and functional activity after the microencapsulation process and final sterilization. The present experimental work tested different technological approaches to maintain the biological activity of an encapsulated biotechnological product within PLGA [poly (lactic-co-glycolic acid)] microspheres (MS) after their sterilization by gamma irradiation. GDNF (glial cell line-derived neurotrophic factor), useful in the treatment of several neurodegenerative diseases, was chosen as a labile model protein. In the particular case of optic nerve degeneration, GDNF has been demonstrated to improve the damaged retinal ganglion cells (RGC) survival. GDNF was encapsulated in its molecular state by the water-in-oil-in-water (W/O/W) technique or as solid according to the solid-in-oil-in-water (S/O/W) method. Based on the S/O/W technique, GDNF was included in the PLGA microspheres alone (S/O/W 1) or in combination with an antioxidant (vitamin E, Vit E) (S/O/W 2). Microspheres were sterilized by gamma-irradiation (dose of 25 kGy) at room and low (-78 °C) temperatures. Functional activity of GDNF released from the different microspheres was evaluated both before and after sterilization in their potential target cells (retinal cells). Although none of the systems proposed achieved with the goal of totally retain the structural stability of the GDNF-dimer, the protein released from the S/O/W 2 microspheres was clearly the most biologically active, showing significantly less retinal cell death than that released from either W/O/W or S/O/W 1 particles, even in low amounts of the neurotrophic factor. According to the results presented in this work, the biological activity of biotechnological products after microencapsulation and sterilization can be further preserved by the inclusion of the active molecule in its solid state in combination with antioxidants and using low temperature (-78 °C) during gamma irradiation exposure.
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Affiliation(s)
- P Checa-Casalengua
- Dep. of Pharmacy and Pharmaceutical Technology, School of Pharmacy, Avd. Complutense s/n, Complutense University, Madrid 28040, Spain
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Habraken WJEM, Wolke JGC, Mikos AG, Jansen JA. PLGA microsphere/calcium phosphate cement composites for tissue engineering: in vitro release and degradation characteristics. JOURNAL OF BIOMATERIALS SCIENCE-POLYMER EDITION 2012; 19:1171-88. [DOI: 10.1163/156856208785540136] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Affiliation(s)
- W. J. E. M. Habraken
- a Department of Periodontology and Biomaterials, College of Dental Science, Radboud University Nijmegen Medical Center, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands
| | - J. G. C. Wolke
- b Department of Periodontology and Biomaterials, College of Dental Science, Radboud University Nijmegen Medical Center, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands
| | - A. G. Mikos
- c Department of Bioengineering, Rice University, Houston, TX, USA
| | - J. A. Jansen
- d Department of Periodontology and Biomaterials, College of Dental Science, Radboud University Nijmegen Medical Center, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands
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Habraken WJEM, Wolke JGC, Mikos AG, Jansen JA. Injectable PLGA microsphere/calcium phosphate cements: physical properties and degradation characteristics. JOURNAL OF BIOMATERIALS SCIENCE-POLYMER EDITION 2012; 17:1057-74. [PMID: 17094642 DOI: 10.1163/156856206778366004] [Citation(s) in RCA: 153] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Calcium phosphate (CaP) cements show an excellent biocompatibility and often have a high mechanical strength, but in general degrade relatively slow. To increase degradation rates, macropores can be introduced into the cement, e.g., by the inclusion of biodegradable microspheres into the cement. The aim of this research is to develop an injectable PLGA microsphere/CaP cement with sufficient setting/cohesive properties and good mechanical and physical properties. PLGA microspheres were prepared using a water-in-oil-in-water double-emulsion technique. The CaP-cement used was Calcibon, a commercially available hydroxyapatite-based cement. 10:90 and 20:80 dry wt% PLGA microsphere/CaP cylindrical scaffolds were prepared as well as microporous cement (reference material). Injectability, setting time, cohesive properties and porosity were determined. Also, a 12-week degradation study in PBS (37 degree C) was performed. Results showed that injectability decreased with an increase in PLGA microsphere content. Initial and final setting time of the PLGA/CaP samples was higher than the microporous sample. Porosity of the different formulations was 40.8% (microporous), 60.2% (10:90) and 69.3% (20:80). The degradation study showed distinct mass loss and a pH decrease of the surrounding medium starting from week 6 with the 10:90 and 20:80 formulations, indicating PLGA erosion. Compression strength of the PLGA microsphere/CaP samples decreased siginificantly in time, the microporous sample remained constant. After 12 weeks both PLGA/CaP samples showed a structure of spherical micropores and had a compressive strength of 12.2 MPa (10:90) and 4.3 MPa (20:80). Signs of cement degradation were also found with the 20:80 formulation. In conclusion, all physical parameters were well within workable ranges with both 10:90 and 20:80 PLGA microsphere/CaP cements. After 12 weeks the PLGA was totally degraded and a highly porous, but strong scaffold remained.
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Affiliation(s)
- W J E M Habraken
- Department of Periodontology and Biomaterials, College of Dental Science, Radboud University Nijmegen Medical Centre, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands
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Levato R, Mateos-Timoneda MA, Planell JA. Preparation of biodegradable polylactide microparticles via a biocompatible procedure. Macromol Biosci 2012; 12:557-66. [PMID: 22362713 DOI: 10.1002/mabi.201100383] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2011] [Revised: 12/16/2011] [Indexed: 11/06/2022]
Abstract
PLA MPs are prepared via a novel and toxic-chemical-free fabrication route using ethyl lactate, a green solvent and FDA-approved aroma. MPs are obtained by a solution jet break-up and solvent displacement method. Adjusting flow parameters allows the tuning of MPs size between 60 and 180 µm, with reduced polydispersity. Morphological analysis shows microporous particles with Janus-like surface. A fluorophore is successfully loaded into the MPs during their formation step. This versatile green solvent-based procedure is proven to be suitable for drug encapsulation and delivery applications. The method may be extended to different droplet generation techniques.
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Affiliation(s)
- Riccardo Levato
- Institute for Bioengineering of Catalonia (IBEC) and CIBER en Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Edifici Helix, C/Baldiri Reixac 15-21, 08028 Barcelona, Spain
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Wang T, Gao L, Quan D. Multivesicular liposome (MVL) sustained delivery of a novel synthetic cationic GnRH antagonist for prostate cancer treatment. J Pharm Pharmacol 2011; 63:904-10. [DOI: 10.1111/j.2042-7158.2011.01295.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Abstract
Objectives
Multivesicular liposomes (MVLs) are often used as an appropriate carrier for delivering peptides due to high drug loading, relative stability and extended-release behaviour. However, when cationic amphipathic peptides are involved, some challenges may be encountered, including instability of multiple emulsions due to interaction between peptides and lipid membranes (electrostatic and hydrophobic interaction). LXT-101, a cationic amphipathic peptide, is a novel antagonist of gonadotropin-releasing hormone (GnRH) for prostate cancer treatment. The purpose of the current research was to explore simple methods of determining the interaction between peptide and lipid bilayer and to prepare MVLs of LXT-101 (DepoLXT-101) by the modified DepoFoam technique.
Methods
The anionic surfactants were added in the process of DepoLXT-101 preparation in order to minimize the effect of instability resulting from cationic peptides.
Key findings
DepoLXT-101 was obtained with good efficiency and reproduction. The integrity of encapsulated peptide was maintained as shown by RP-HPLC. DepoLXT-101 particles were characterized by morphology and particle size distribution and in-vitro release was also investigated. The release behaviour in vitro in medium of sodium chloride at 37°C showed that 70–90% of LXT-101 was released slowly from MVLparticles over 11 days. According to the fitting results of Ritgar-Pepps model, the in-vitro release of DepoLXT-101 was mainly governed by Fick's diffusion.
Conclusions
The data obtained from in-vivo study indicated that a sustained anticancer effect can be achieved over a 7-day period with subcutaneous administration of DepoLXT-101 in rats.
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Affiliation(s)
- Tao Wang
- Beijing Institute of Pharmacology and Toxicology Beijing, China
| | - Lijun Gao
- Beijing Institute of Pharmacology and Toxicology Beijing, China
| | - Dongqin Quan
- Beijing Institute of Pharmacology and Toxicology Beijing, China
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Mashak A, Mobedi H, Ziaee F, Nekoomanesh M. The effect of aliphatic esters on the formation and degradation behavior of PLGA-based in situ forming system. Polym Bull (Berl) 2010. [DOI: 10.1007/s00289-010-0386-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Chaudhari KR, Shah N, Patel H, Murthy R. Preparation of porous PLGA microspheres with thermoreversible gel to modulate drug release profile of water-soluble drug: bleomycin sulphate. J Microencapsul 2010; 27:303-13. [PMID: 20128747 DOI: 10.3109/02652040903191818] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Bleomycin sulphate-loaded porous microspheres were prepared using modified solvent evaporation method (w/o/w) using PLGA50:50 as a polymeric system. The prepared microspheres were incorporated in pluronic (F127) based thermoreversible gel to develop a depot formulation. Various process parameters as solvent evaporation temperature and formulation parameters such as surfactant concentration, volume of internal and external phase and drug-to-polymer ratio were optimized for enhancing percentage drug entrapment, percentage drug loading and desired release profile by controlling size and porosity of the microspheres. Microspheres were characterized for particle size, zeta potential, surface morphology, percentage drug loading and in vitro drug release study after incorporated in gel. The formulated microspheres were porous in nature and showed biphasic in vitro drug release profile. The microspheres incorporated in pluronic (F127) gel showed sustained release up to 1 week and may be useful for treatment of squamous cell carcinoma with better therapeutic effect.
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Affiliation(s)
- Kiran R Chaudhari
- Maharaja Sayajirao University of Baroda, Drug Delivery Research Laboratory, Ctr Relevance and Excellence NDDS, Department of Pharmaceutics, Baroda, India
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Habraken W, Liao H, Zhang Z, Wolke J, Grijpma D, Mikos A, Feijen J, Jansen J. In vivo degradation of calcium phosphate cement incorporated into biodegradable microspheres. Acta Biomater 2010; 6:2200-11. [PMID: 20026289 DOI: 10.1016/j.actbio.2009.12.028] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2009] [Revised: 12/11/2009] [Accepted: 12/14/2009] [Indexed: 10/20/2022]
Abstract
In this study we have investigated the influence of the mechanism of microsphere degradation or erosion on the in vivo degradation of microsphere/calcium phosphate cement composites (microsphere CPCs) used in tissue engineering. Microspheres composed of poly(lactic-co-glycolic acid) (PLGA), gelatin and poly(trimethylene carbonate) (PTMC) were used as the model and the resulting microsphere CPCs were implanted subcutaneously for 4, 8 or 12weeks in the back of New Zealand white rabbits. Besides degradation, the soft tissue response to these formulations was evaluated. After retrieval, specimens were analyzed by physicochemical characterization and histological analysis. The results showed that all microsphere CPCs exhibited microsphere degradation after 12weeks of subcutaneous implantation, which was accompanied by decreasing compression strength. The PLGA microspheres exhibited bulk erosion simultaneously throughout the whole composite, whereas the gelatin type B microspheres were degradated from the outside to the center of the composite. High molecular weight PTMC microspheres exhibited surface erosion resulting in decreasing microsphere size. Furthermore, all composites showed a similar tissue response, with decreasing capsule thickness over time and a persistent moderate inflammatory response at the implant interface. In conclusion, microsphere CPCs can be used to generate porous scaffolds in an in vivo environment after degradation of microspheres by various degradation/erosion mechanisms.
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Su ZX, Shi YN, Teng LS, Li X, Wang LX, Meng QF, Teng LR, Li YX. Biodegradable poly(D, L-lactide-co-glycolide) (PLGA) microspheres for sustained release of risperidone: Zero-order release formulation. Pharm Dev Technol 2010; 16:377-84. [DOI: 10.3109/10837451003739297] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Abstract
The growth of prostate cancer cells is hormone dependent in the majority of patients with the disease. Lowering testosterone either surgically or medically (usually with a gonadotropin releasing hormone (GnRH) agonist) is the standard of care in patients with metastatic prostate cancer. Degarelix is a new GnRH antagonist for the treatment of patients with prostate cancer. In contrast to GnRH agonists, the development of GnRH antagonists was hindered for a long time owing to histamine-releasing activity and lack of potency and water solubility. Recently, however, degarelix has been approved by the FDA for the treatment of advanced prostate cancer. This review summarizes the preclinical and clinical data available for degarelix and describes its potential role in the market of prostate cancer therapeutics.
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Affiliation(s)
- Christian Doehn
- Department of Urology, University of Lübeck Medical School, Ratzeburger Allee 160, Lübeck, Germany.
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Anderson J. Degarelix: a novel gonadotropin-releasing hormone blocker for the treatment of prostate cancer. Future Oncol 2009; 5:433-43. [PMID: 19450172 DOI: 10.2217/fon.09.24] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Androgen deprivation therapy with gonadotropin releasing-hormone (GnRH) receptor agonists provides the mainstay of endocrine treatment for advanced prostate cancer. Although effective, GnRH agonists induce an initial testosterone surge, which can cause painful and potentially dangerous clinical flare. Degarelix is a novel GnRH receptor blocker that provides immediate, profound and sustained testosterone reduction, without an initial surge. In a Phase III trial, degarelix and leuprolide showed similar long-term efficacy in maintaining testosterone levels of 0.5 ng/ml or less over 1 year, and induced significantly faster testosterone and prostate-specific antigen suppression. Degarelix was well tolerated; the most common side effects were mild/moderate injection-site reactions and hot flashes. Findings to date suggest that degarelix may make an important contribution to the treatment of prostate cancer.
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Affiliation(s)
- John Anderson
- Department of Urology, Royal Hallamshire Hospital, Glossop Road, Sheffield, UK.
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Doehn C, Sommerauer M, Jocham D. Degarelix and its therapeutic potential in the treatment of prostate cancer. Clin Interv Aging 2009; 4:215-23. [PMID: 19503784 PMCID: PMC2685243 DOI: 10.2147/cia.s3503] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Degarelix is a gonadotropin-releasing hormone (GnRH) antagonist for the treatment of patients with prostate cancer in whom hormonal therapy is indicated. Two phase II trials and one phase III have been published as full papers in the literature. In the dose-finding phase II studies an initial dose of 240 mg degarelix sc followed by a monthly injection of 80 mg or 160 mg degarelix sc was sufficient to keep testosterone levels < or = 0.5 ng/ml. In a phase III trial it was demonstrated that degarelix was not inferior (in terms of testosterone suppression and prostate-specific antigen [PSA] decline) compared to standard hormonal therapy, ie, a GnRH agonist such as leuprolide. In fact, degarelix was associated with a faster testosterone suppression and PSA decline than leuprolide. Adverse events such as injection site reactions (40% vs <1%) and chills (4% vs 0%) were more commonly associated with degarelix. Also, degarelix is currently only available as one-month depot whereas in daily practice three-month depots (of GnRH agonists) are the preferred regimen. However, degarelix was recently approved by the US Food and Drug Administration for the treatment of advanced prostate cancer.
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Affiliation(s)
- Christian Doehn
- Department of Urology, University of Lübeck Medical School, Lübeck, Germany.
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Su Z, Sun F, Shi Y, Jiang C, Meng Q, Teng L, Li Y. Effects of Formulation Parameters on Encapsulation Efficiency and Release Behavior of Risperidone Poly(D,L-lactide-co-glycolide) Microsphere. Chem Pharm Bull (Tokyo) 2009; 57:1251-6. [DOI: 10.1248/cpb.57.1251] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
| | | | - Yanan Shi
- College of Life Science, Jilin University
| | | | | | | | - Youxin Li
- College of Life Science, Jilin University
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Gittelman M, Pommerville PJ, Persson BE, Jensen JK, Olesen TK. A 1-year, open label, randomized phase II dose finding study of degarelix for the treatment of prostate cancer in North America. J Urol 2008; 180:1986-92. [PMID: 18801505 DOI: 10.1016/j.juro.2008.07.033] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2008] [Indexed: 11/17/2022]
Abstract
PURPOSE Degarelix is a gonadotropin-releasing hormone receptor antagonist (blocker) with rapid onset of action suppressing gonadotropins, testosterone and prostate specific antigen in prostate cancer. In the present open label, randomized study in North America we evaluated the efficacy and safety of a starting dose of 200 mg degarelix followed by monthly injections of 60 or 80 mg during 1 year of prostate cancer treatment. MATERIALS AND METHODS A total of 127 patients (median age 76 years, range 47 to 93) with histologically confirmed prostate cancer were enrolled in the study. Efficacy was assessed by measuring serum testosterone and prostate specific antigen. RESULTS Median baseline testosterone and prostate specific antigen levels were 4.13 ng/ml (P25-P75 3.03-5.11) and 13.4 ng/ml (P25-P75 6.80-25.7), respectively. The starting dose induced a rapid suppression of testosterone in that 88% of the patients had testosterone levels of 0.5 ng/ml or less 1 month after the injection. For patients who had testosterone levels of 0.5 ng/ml or less after 1 month, 93% and 98% of those receiving maintenance doses of 60 and 80 mg, respectively, had testosterone levels that were consistently 0.5 ng/ml or less at all monthly measurements from 1 month to 1 year. No evidence of testosterone surge was detected. In both groups prostate specific antigen decreased by 96% after 1 year and median time to 90% reduction in prostate specific antigen was 56 days. Six patients (5%) withdrew from the study due to adverse events. CONCLUSIONS Degarelix treatment for 1 year resulted in a fast, profound and sustained suppression of testosterone and prostate specific antigen with no evidence of testosterone surge. Degarelix was well tolerated.
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Affiliation(s)
- Marc Gittelman
- Department of Urology, South Florida Medical Research, Aventura, Florida, USA.
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Van Poppel H, Tombal B, de la Rosette JJ, Persson BE, Jensen JK, Kold Olesen T. Degarelix: a novel gonadotropin-releasing hormone (GnRH) receptor blocker--results from a 1-yr, multicentre, randomised, phase 2 dosage-finding study in the treatment of prostate cancer. Eur Urol 2008; 54:805-13. [PMID: 18538469 DOI: 10.1016/j.eururo.2008.04.065] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2007] [Accepted: 04/24/2008] [Indexed: 12/18/2022]
Abstract
BACKGROUND Degarelix is a gonadotropin-releasing hormone antagonist (GnRH receptor blocker) with immediate onset of action, suppressing gonadotropins, testosterone, and prostate-specific antigen (PSA) in prostate cancer. OBJECTIVE To determine the efficacy and safety of initial doses of 200 mg or 240 mg of degarelix and thereafter monthly subcutaneous maintenance doses of 80 mg, 120 mg, or 160 mg of degarelix for the treatment of prostate cancer. DESIGN, SETTING, AND PARTICIPANTS The 1-yr study was of open-label, randomised design and involved 187 patients (range: 52-93 yr, median: 72 yr) with histologically confirmed adenocarcinoma of the prostate and a baseline PSA >2 ng/ml. RESULTS AND LIMITATIONS At baseline, median serum testosterone was 4.13 ng/ml (range: P25-P75, 3.37-5.19 ng/ml) and PSA was 27.6 ng/ml (range: P25-P75, 11.9-55.0 ng/ml). On day 3, 88% and 92% of patients in the groups to whom 200-mg and 240-mg initial doses of degarelix were administered, respectively, had testosterone levels < or =0.5 ng/ml. For patients with testosterone levels < or =0.5 ng/ml at 1 mo, the testosterone levels remained < or =0.5 ng/ml until the end of the study in 100% of the patients treated with a monthly maintenance dosage of 160 mg of degarelix. No evidence of testosterone surge was detected. PSA decreased by 97-98% after 1 yr and the median time to 90% reduction in PSA was 8 wk in all but one patient (from the 80-mg dosage treatment group at the initial 200-mg dose of degarelix). Thirteen patients (6%) withdrew from the study due to adverse events, largely related to androgen deprivation. CONCLUSIONS Degarelix treatment for 1 yr resulted in a fast, profound, and sustained suppression of testosterone and PSA, with no evidence of testosterone surge. Degarelix was well tolerated.
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De Spiegeleer B, Vergote V, Pezeshki A, Peremans K, Burvenich C. Impurity profiling quality control testing of synthetic peptides using liquid chromatography-photodiode array-fluorescence and liquid chromatography-electrospray ionization-mass spectrometry: The obestatin case. Anal Biochem 2008; 376:229-34. [DOI: 10.1016/j.ab.2008.02.014] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2007] [Revised: 02/18/2008] [Accepted: 02/19/2008] [Indexed: 10/22/2022]
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Abstract
This review covers recent developments in the area of particle engineering via spray drying. The last decade has seen a shift from empirical formulation efforts to an engineering approach based on a better understanding of particle formation in the spray drying process. Microparticles with nanoscale substructures can now be designed and their functionality has contributed significantly to stability and efficacy of the particulate dosage form. The review provides concepts and a theoretical framework for particle design calculations. It reviews experimental research into parameters that influence particle formation. A classification based on dimensionless numbers is presented that can be used to estimate how excipient properties in combination with process parameters influence the morphology of the engineered particles. A wide range of pharmaceutical application examples—low density particles, composite particles, microencapsulation, and glass stabilization—is discussed, with specific emphasis on the underlying particle formation mechanisms and design concepts.
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Habraken WJEM, Wolke JGC, Jansen JA. Ceramic composites as matrices and scaffolds for drug delivery in tissue engineering. Adv Drug Deliv Rev 2007; 59:234-48. [PMID: 17478007 DOI: 10.1016/j.addr.2007.03.011] [Citation(s) in RCA: 285] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2007] [Accepted: 03/28/2007] [Indexed: 10/23/2022]
Abstract
Ceramic composites and scaffolds are popular implant materials in the field of dentistry, orthopedics and plastic surgery. For bone tissue engineering especially CaP-ceramics or cements and bioactive glass are suitable implant materials due to their osteoconductive properties. In this review the applicability of these ceramics but also of ceramic/polymer composites for bone tissue engineering is discussed, and in particular their use as drug delivery systems. Overall, the high density and slow biodegradability of ceramics is not beneficial for tissue engineering purposes. To address these issues, macroporosity can be introduced often in combination with osteoinductive growth factors and cells. Ceramics are good carriers for drugs, in which release patterns are strongly dependent on the chemical consistency of the ceramic, type of drug and drug loading. Biodegradable polymers like polylactic acid, gelatin or chitosan are used as matrices for ceramic particles or as adjuvant to calcium phosphate cements. The use of these polymers can introduce a tailored biodegradation/drug release to the ceramic material.
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Affiliation(s)
- W J E M Habraken
- Department of Periodontology and Biomaterials, Radboud University Nijmegen Medical Center, Nijmegen, The Netherlands
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Princivalle M, Broqua P, White R, Meyer J, Mayer G, Elliott L, Bjarnason K, Haigh R, Yea C. Rapid suppression of plasma testosterone levels and tumor growth in the dunning rat model treated with degarelix, a new gonadotropin-releasing hormone antagonist. J Pharmacol Exp Ther 2006; 320:1113-8. [PMID: 17179469 DOI: 10.1124/jpet.106.112326] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Degarelix (FE 200486) is a member of a new class of water-soluble (>50 mg/ml) gonadotropin-releasing hormone (GnRH) antagonists in clinical development for prostate cancer. Upon subcutaneous administration, degarelix forms a gel that results in a sustained release of the compound into the circulation, immediately blocking GnRH receptors in the pituitary and inducing a fast and sustained suppression of gonadotrophin secretion in rats and primates. One of the few animal models of prostate adenocarcinoma is the Dunning R-3327H rat carcinoma transplanted into Copenhagen rats. The growth of the Dunning tumor can be inhibited by various treatments reported to be effective in the clinic, such as GnRH superagonists, antiandrogens, 5-alphareductase inhibitors, tyrosine kinase inhibitors, and surgical castration. We report in this study that degarelix produces a fast and sustained suppression of the pituitary gonadal axis in rats and a similar inhibition of tumor growth compared with surgical castration in the Dunning R-3327H rat carcinoma model. First, degarelix as been compared with d-Trp(6)-luteinizing hormone-releasing hormone and surgical castration on a short-term study (2 months); and second, degarelix has been compared with leuprolide and surgical castration on a long-term study (12 months). In both studies, degarelix demonstrated a sustained inhibition of tumor growth at least comparable with surgical castration. These data provide a convincing profile of degarelix as a potential candidate for the clinical management of sex steroid-dependent pathologies, such as prostate cancer, where long-term reversible chemical castration is required.
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Affiliation(s)
- Marc Princivalle
- Ferring Research Ltd., Chilworth Science Park, 1 Venture Rd., Southampton SO16 7NP, UK.
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Williams HE, Huxley J, Claybourn M, Booth J, Hobbs M, Meehan E, Clark B. The effect of γ-irradiation and polymer composition on the stability of PLG polymer and microspheres. Polym Degrad Stab 2006. [DOI: 10.1016/j.polymdegradstab.2006.01.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Du L, Cheng J, Chi Q, Qie J, Liu Y, Mei X. Biodegradable PLGA Microspheres as a Sustained Release System for a New Luteinizing Hormone-Releasing Hormone (LHRH) Antagonist. Chem Pharm Bull (Tokyo) 2006; 54:1259-65. [PMID: 16946531 DOI: 10.1248/cpb.54.1259] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A sustained release poly(DL-lactide-co-glycolide) (PLGA) microsphere delivery system to treat prostate cancer for a luteinizing hormone-releasing hormone (LHRH) antagonists, LXT-101 was prepared and evaluated in the paper. LXT-101 microspheres were prepared from PLGA by three methods: (1) double-emulsion solvent extraction/evaporation technique, (2) single-emulsion solvent extraction/evaporation technique, and (3) S/O/O (solid-in-oil-in-oil) method. The microspheres were investigated on drug loading, particle size, surface morphology and in vitro release profiles. An accelerated release approach was also established in order to expedite the evaluation periods. The in vivo evaluation of the microspheres was made by monitoring testosterone levels after subcutaneous administration to rats. The LXT-101 PLGA microspheres showed smooth and round surfaces according to a scanning electron microscopic investigation, and average particle size of ca. 30 mum according to laser diffractometry. The drug encapsulation efficiency of microspheres was influenced by LA/GA ratio of PLGA, salt concentrations, solvent mixture and preparation methods. Moreover, LA/GA ratio of PLGA, different preparation methods and different peptide stabilizers affected in vitro release of drugs. In vivo study, the testosterone levels were suppressed to castration up to 42 d as for the 7.5 mg/kg dose. And in vivo performance of LXT-101 microspheres was dose-dependent. The weights of rat sexual organs decreased and histopathological appearance of testes had little changes after 4-month microspheres therapy. This also testified that LXT-101 sustained release microspheres could exert the efficacy to suppress the testosterone level to castration with little toxicity. In conclusion, the PLGA microspheres could be a well sustained release system for LXT-101.
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Affiliation(s)
- Lina Du
- Department of Pharmaceutical Chemistry, Beijing Institute of Pharmacology and Toxicology
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Rosca ID, Watari F, Uo M. Microparticle formation and its mechanism in single and double emulsion solvent evaporation. J Control Release 2005; 99:271-80. [PMID: 15380636 DOI: 10.1016/j.jconrel.2004.07.007] [Citation(s) in RCA: 200] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2004] [Accepted: 07/06/2004] [Indexed: 11/27/2022]
Abstract
The emulsification is the first step of the emulsification solvent evaporation method and has been extensively investigated. On the contrary the second step, the solvent transport out from the emulsion droplets that determine the particle morphology and with great influence on the microparticles encapsulation and release behavior has been scarcely studied. This study investigates the mechanism of the solvent elimination from the emulsion droplets and its influence on the particle morphology, encapsulation and release behavior. Usually, the solvent is highly volatile that makes the solvent elimination process very fast thus difficult to observe. In order to observe in detail the microparticle formation, the initial emulsion was monitored by optical microscope under controlled solvent evaporation conditions. The results from the optical microscopic observations corroborated with laser diffractometry analysis showed that in single emulsion formulations, spherical microparticles are formed by accelerated solvent elimination due to the combined effects of high solvent volatility and polymer precipitation. The solvent expulsion accompanied by important shrinkage generates on the microparticle surface a thin layer of nanoparticles attested by scanning electron microscopy and laser diffractometry. During the intense solvent elimination, the encapsulated substance is drained, affecting the loading efficiency. Furthermore, it will concentrate towards the microparticle surface contributing to the initial burst release. In double emulsion formulations, microparticles with different morphologies are generated due to the presence of the aqueous-phase microdroplets inside the emulsion droplet. During the solvent elimination, these microdroplets generally coalesce under the pressure of the precipitating polymer. Depending mainly on the polymer concentration and emulsification energies, the final microparticles will be a mixture of honeycomb, capsule or plain structure. During the shrinkage due to the incompressibility of the inner microdroplets, the precipitating polymer wall around them may break forming holes through which the encapsulated substance is partly expulsed. Through these holes, the encapsulated substance is further partitioning with the external aqueous phase during solvent evaporation and contributes to the initial burst release during the application.
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Affiliation(s)
- Iosif Daniel Rosca
- Department of Polymer Science, Faculty of Industrial Chemistry, Polytechnic University of Bucharest, Calea Victoriei, 149, Sector 1, Bucharest, Romania.
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Schwach G, Oudry N, Giliberto JP, Broqua P, Lück M, Lindner H, Gurny R. Biodegradable PLGA microparticles for sustained release of a new GnRH antagonist: part II. In vivo performance. Eur J Pharm Biopharm 2004; 57:441-6. [PMID: 15093591 DOI: 10.1016/j.ejpb.2004.01.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2002] [Revised: 08/27/2003] [Accepted: 01/29/2004] [Indexed: 10/26/2022]
Abstract
Poly (DL-lactide-co-glycolide) microparticles (MP) containing a highly potent peptidic gonadotropin releasing hormone antagonist (degarelix) of interest in the prostate cancer indication were screened for biological performance. Efficacy was tested in a castrated male rat model at 3 doses (0.4, 1.0 and 1.5 mg/kg) and assessed as inhibition of luteinizing hormone (LH) secretion. When increasing the dose, onset of inhibition was faster, inhibition was more intense, and duration of action was prolonged. The MP type was also highly influent. If spray-dried and microextrusion particles exhibited comparable potencies, double emulsion microspheres were significantly less potent, both for onset and duration of inhibition. Interestingly, for the latter type it was found that the degarelix fraction released upon reconstitution in the solution for injection was significantly lower (max 0.3%), in comparison to spray-dried MP (max 2%) or microextrusion (max 4%). With the three types of particles, increasing peptide content was detrimental for duration of action, but only little difference was noticed between particles based on different polymers. At 1.5 mg/kg, LH inhibition was achieved over 36 days with spray-dried MP based on 75/25 lactate/glycolate copolymer. This was superior by 1 week to the performance of unformulated degarelix given at the same dose.
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