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Probing the effects of experimental conditions on the character of drug-polymer phase diagrams constructed using Flory-Huggins theory. Pharm Res 2014; 32:167-79. [PMID: 25074468 DOI: 10.1007/s11095-014-1453-9] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Accepted: 07/02/2014] [Indexed: 10/25/2022]
Abstract
PURPOSE Amorphous drug-polymer solid dispersions have been found to result in improved drug dissolution rates when compared to their crystalline counterparts. However, when the drug exists in the amorphous form it will possess a higher Gibb's free energy than its associated crystalline state and can recrystallize. Drug-polymer phase diagrams constructed through the application of the Flory Huggins (F-H) theory contain a wealth of information regarding thermodynamic and kinetic stability of the amorphous drug-polymer system. This study was aimed to evaluate the effects of various experimental conditions on the solubility and miscibility detections of drug-polymer binary system. METHODS Felodipine (FD)-Polyvinylpyrrolidone (PVP) K15 (PVPK15) and FD-Polyvinylpyrrolidone/vinyl acetate (PVP/VA64) were the selected systems for this research. Physical mixtures with different drug loadings were mixed and ball milled. These samples were then processed using Differential Scanning Calorimetry (DSC) and measurements of melting point (Tend) and glass transition (Tg) were detected using heating rates of 0.5, 1.0 and 5.0°C/min. RESULTS The melting point depression data was then used to calculate the F-H interaction parameter (χ) and extrapolated to lower temperatures to complete the liquid-solid transition curves. The theoretical binodal and spinodal curves were also constructed which were used to identify regions within the phase diagram. The effects of polymer selection, DSC heating rate, time above parent polymer Tg and polymer molecular weight were investigated by identifying amorphous drug miscibility limits at pharmaceutically relevant temperatures. CONCLUSION The potential implications of these findings when applied to a non-ambient processing method such as Hot Melt Extrusion (HME) are also discussed.
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152
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Prudic A, Ji Y, Sadowski G. Thermodynamic phase behavior of API/polymer solid dispersions. Mol Pharm 2014; 11:2294-304. [PMID: 24870944 DOI: 10.1021/mp400729x] [Citation(s) in RCA: 102] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
To improve the bioavailability of poorly soluble active pharmaceutical ingredients (APIs), these materials are often integrated into a polymer matrix that acts as a carrier. The resulting mixture is called a solid dispersion. In this work, the phase behaviors of solid dispersions were investigated as a function of the API as well as of the type and molecular weight of the carrier polymer. Specifically, the solubility of artemisinin and indomethacin was measured in different poly(ethylene glycol)s (PEG 400, PEG 6000, and PEG 35000). The measured solubility data and the solubility of sulfonamides in poly(vinylpyrrolidone) (PVP) K10 and PEG 35000 were modeled using the perturbed-chain statistical associating fluid theory (PC-SAFT). The results show that PC-SAFT predictions are in a good accordance with the experimental data, and PC-SAFT can be used to predict the whole phase diagram of an API/polymer solid dispersion as a function of the kind of API and polymer and of the polymer's molecular weight. This remarkably simplifies the screening process for suitable API/polymer combinations.
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Affiliation(s)
- Anke Prudic
- Department of Biochemical and Chemical Engineering, Laboratory of Thermodynamics, TU Dortmund , Emil-Figge-Str. 70, D-44227 Dortmund, Germany
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153
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Pajula K, Wittoek L, Lehto VP, Ketolainen J, Korhonen O. Phase Separation in Coamorphous Systems: in Silico Prediction and the Experimental Challenge of Detection. Mol Pharm 2014; 11:2271-9. [DOI: 10.1021/mp400712m] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Katja Pajula
- School
of Pharmacy, University of Eastern Finland, POB 1627, FI-70211 Kuopio, Finland
| | - Lieke Wittoek
- Department of Pharmaceutical
Analysis, Faculty of Pharmaceutical Sciences, Ghent University, Harelbekestraat
72, 9000 Ghent, Belgium
| | - Vesa-Pekka Lehto
- Department of Applied Physics, University of Eastern Finland, POB 1627, FI-70211 Kuopio, Finland
| | - Jarkko Ketolainen
- School
of Pharmacy, University of Eastern Finland, POB 1627, FI-70211 Kuopio, Finland
| | - Ossi Korhonen
- School
of Pharmacy, University of Eastern Finland, POB 1627, FI-70211 Kuopio, Finland
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154
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Jackson NE, Chen LX, Ratner MA. Solubility of Nonelectrolytes: A First-Principles Computational Approach. J Phys Chem B 2014; 118:5194-202. [DOI: 10.1021/jp5024197] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Nicholas E. Jackson
- Department
of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
| | - Lin X. Chen
- Department
of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
- Chemical
Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Mark A. Ratner
- Department
of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
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155
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Grohganz H, Priemel PA, Löbmann K, Nielsen LH, Laitinen R, Mullertz A, Van den Mooter G, Rades T. Refining stability and dissolution rate of amorphous drug formulations. Expert Opin Drug Deliv 2014; 11:977-89. [DOI: 10.1517/17425247.2014.911728] [Citation(s) in RCA: 98] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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156
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Laitinen R, Priemel PA, Surwase S, Graeser K, Strachan CJ, Grohganz H, Rades T. Theoretical Considerations in Developing Amorphous Solid Dispersions. ADVANCES IN DELIVERY SCIENCE AND TECHNOLOGY 2014. [DOI: 10.1007/978-1-4939-1598-9_2] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
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157
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Brown C, DiNunzio J, Eglesia M, Forster S, Lamm M, Lowinger M, Marsac P, McKelvey C, Meyer R, Schenck L, Terife G, Troup G, Smith-Goettler B, Starbuck C. Hot-Melt Extrusion for Solid Dispersions: Composition and Design Considerations. ADVANCES IN DELIVERY SCIENCE AND TECHNOLOGY 2014. [DOI: 10.1007/978-1-4939-1598-9_6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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158
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Li Y, Pang H, Guo Z, Lin L, Dong Y, Li G, Lu M, Wu C. Interactions between drugs and polymers influencing hot melt extrusion. J Pharm Pharmacol 2013; 66:148-66. [DOI: 10.1111/jphp.12183] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Accepted: 10/15/2013] [Indexed: 11/30/2022]
Abstract
Abstract
Objectives
Hot melt extrusion (HME) as a technique for producing amorphous solid dispersion (ASD) has been widely used in pharmaceutical research. The biggest challenge for the application of HME is the thermal degradation of drug, poor physical stability of ASD and precipitation of drug during dissolution. Interactions between drugs and polymers may play an important role in overcoming these barriers. In this review, influence of drug–polymer interactions on HME and the methods for characterizing the drug–polymer interactions were reviewed.
Key findings
Strong drug–polymer interactions, especially ionic interactions and hydrogen bonds, are helpful to improving the thermal stability of drug during HME, enhancing the physical stability of ASD during storage and maintaining supersaturated solution after dissolution in gastrointestinal tract. The interactions can be quantitatively and qualitatively characterized by many analysing methods.
Conclusions
As many factors collectively determine the properties of HME products, drug–polymer interactions play an extremely important role. However, the action mechanisms of drug–polymer interactions need intensive investigation to provide more useful information for optimizing the formulation and the process parameters of HME.
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Affiliation(s)
- Yongcheng Li
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, China
| | - Huishi Pang
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, China
| | - Zhefei Guo
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, China
| | - Ling Lin
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, China
| | - Yixuan Dong
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, China
| | - Ge Li
- Research and Development Center of Pharmaceutical Engineering, Sun Yat-sen University, Guangzhou, China
| | - Ming Lu
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, China
| | - Chuangbin Wu
- School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, China
- Research and Development Center of Pharmaceutical Engineering, Sun Yat-sen University, Guangzhou, China
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159
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Tian Y, Caron V, Jones DS, Healy AM, Andrews GP. Using Flory-Huggins phase diagrams as a pre-formulation tool for the production of amorphous solid dispersions: a comparison between hot-melt extrusion and spray drying. ACTA ACUST UNITED AC 2013; 66:256-74. [PMID: 24192445 DOI: 10.1111/jphp.12141] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2013] [Accepted: 08/06/2013] [Indexed: 11/28/2022]
Abstract
OBJECTIVES Amorphous drug forms provide a useful method of enhancing the dissolution performance of poorly water-soluble drugs; however, they are inherently unstable. In this article, we have used Flory-Huggins theory to predict drug solubility and miscibility in polymer candidates, and used this information to compare spray drying and melt extrusion as processes to manufacture solid dispersions. METHOD Solid dispersions were prepared using two different techniques (hot-melt extrusion and spray drying), and characterised using a combination of thermal (thermogravimetric analysis and differential scanning calorimetry), spectroscopic (Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction methods. KEY FINDINGS Spray drying permitted generation of amorphous solid dispersions across a wider drug concentration than melt extrusion. Melt extrusion provided sufficient energy for more intimate mixing to be achieved between drug and polymer, which may improve physical stability. It was also confirmed that stronger drug-polymer interactions might be generated through melt extrusion. Remixing and dissolution of recrystallised felodipine into the polymeric matrices did occur during the modulated differential scanning calorimetry analysis, but the complementary information provided from FTIR confirms that all freshly prepared spray-dried samples were amorphous with the existence of amorphous drug domains within high drug-loaded samples. CONCLUSION Using temperature-composition phase diagrams to probe the relevance of temperature and drug composition in specific polymer candidates facilitates polymer screening for the purpose of formulating solid dispersions.
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Affiliation(s)
- Yiwei Tian
- The Drug Delivery and Biomaterials Group, School of Pharmacy, Medical Biology Centre, Queen's University, Belfast, UK
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160
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Aw MS, Kurian M, Losic D. Polymeric micelles for multidrug delivery and combination therapy. Chemistry 2013; 19:12586-601. [PMID: 23943229 DOI: 10.1002/chem.201302097] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The use of conventional therapy based on a single therapeutic agent is not optimal to treat human diseases. The concept called "combination therapy", based on simultaneous administration of multiple therapeutics is recognized as a more efficient solution. Interestingly, this concept has been in use since ancient times in traditional herbal remedies with drug combinations, despite mechanisms of these therapeutics not fully comprehended by scientists. This idea has been recently re-enacted in modern scenarios with the introduction of polymeric micelles loaded with several drugs as multidrug nanocarriers. This Concept article presents current research and developments on the application of polymeric micelles for multidrug delivery and combination therapy. The principles of micelle formation, their structure, and the developments and concept of multidrug delivery are introduced, followed by discussion on recent advances of multidrug delivery concepts directed towards targeted drug delivery and cancer, gene, and RNA therapies. The advantages of various polymeric micelles designed for different applications, and new developments combined with diagnostics and imaging are elucidated. A compilation work from our group based on multidrug-loaded micelles as carriers in drug-releasing implants for local delivery systems based on titania nanotubes is summarized. Finally, an overview of recent developments and prospective outlook for future trends in this field is given.
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Affiliation(s)
- Moom Sinn Aw
- School of Chemical Engineering, The University of Adelaide, SA 5005 (Australia)
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161
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Liu J, Cao F, Zhang C, Ping Q. Use of polymer combinations in the preparation of solid dispersions of a thermally unstable drug by hot-melt extrusion. Acta Pharm Sin B 2013. [DOI: 10.1016/j.apsb.2013.06.007] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
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162
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Song Y, Wang L, Yang P, Wenslow RM, Tan B, Zhang H, Deng Z. Physicochemical Characterization of Felodipine-Kollidon VA64 Amorphous Solid Dispersions Prepared by Hot-Melt Extrusion. J Pharm Sci 2013; 102:1915-1923. [DOI: 10.1002/jps.23538] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2012] [Revised: 02/05/2013] [Accepted: 03/18/2013] [Indexed: 11/11/2022]
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163
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Thakral S, Thakral NK. Prediction of drug-polymer miscibility through the use of solubility parameter based Flory-Huggins interaction parameter and the experimental validation: PEG as model polymer. J Pharm Sci 2013; 102:2254-63. [PMID: 23649486 DOI: 10.1002/jps.23583] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2013] [Revised: 04/11/2013] [Accepted: 04/12/2013] [Indexed: 11/09/2022]
Abstract
Important consideration for developing physically stable solid dispersion is miscibility of drug in carrier matrix. It is possible to predict thermodynamics of binary system through free energy calculations based on Flory-Huggins interaction parameter (χ(dp)). In present study, PEG 6000 as model polymer and dataset comprising commonly used drugs/excipients was selected. The three-dimensional solubility parameter based on group contribution method was utilized for systemic calculation of χ(dp) of the polymer with each compound in data set. On the basis of the values of χ(dp), it was possible to categorize all the compounds into three distinct categories, Types I and II: compounds predicted to be miscible and immiscible respectively with the polymer in all proportions and Type III: compounds expected to exhibit composition dependent miscibility behavior. The Bagley plot showed that majority of points for Type I fall in a region, which can approximately be delimited by a circle. Experimental verification through thermal analysis revealed that though it was possible to predict correctly miscibility behavior of Type II class compounds, distinction between Types I and III was less evident. Hence, solubility parameter based χ(dp) may be used as an initial tool for fast screening of immiscible combination of polymer and drug.
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Affiliation(s)
- Seema Thakral
- Department of Pharmaceutics, University of Minnesota, Minneapolis, Minnesota 55455, USA.
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164
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Caron V, Hu Y, Tajber L, Erxleben A, Corrigan OI, McArdle P, Healy AM. Amorphous solid dispersions of sulfonamide/Soluplus® and sulfonamide/PVP prepared by ball milling. AAPS PharmSciTech 2013; 14:464-74. [PMID: 23389838 DOI: 10.1208/s12249-013-9931-7] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Accepted: 01/29/2013] [Indexed: 11/30/2022] Open
Abstract
The aim of this paper is to investigate the physicochemical properties of binary amorphous dispersions of poorly soluble sulfonamide/polymeric excipient prepared by ball milling. The sulfonamides selected were sulfathiazole (STZ), sulfadimidine (SDM), sulfamerazine (SMZ) and sulfadiazine (SDZ). The excipients were polyvinylpyrrolidone (PVP) and polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol graft co-polymer, commercially known as Soluplus®. Co-milled systems were characterised by powder X-ray diffraction and differential scanning calorimetry. PVP was shown to form amorphous dispersions over a wider composition range than Soluplus® for the four sulfonamides tested. Moreover, amorphous dispersions made with PVP were homogeneous [single glass transition (Tg)], while amorphous dispersions made from Soluplus® were heterogeneous (two Tgs). This behaviour is consistent with the fact that all the sulfonamides tested presented a lower solubility in Soluplus® than in PVP, as evidenced by Flory-Huggins parameters determined. Amorphous dispersions of SDM with Soluplus® could be produced even though SDM does not amorphise alone upon milling and Soluplus® presents Tg at a lower temperature than SDM. Amorphous dispersions of SMZ could be prepared with a lower excipient concentration compared to STZ, SDM and SDZ, which may reflect the one-dimensional H-bonding network in SMZ compared to the 2D or 3D H-bonding network found in the other sulfonamides. Stability tests (60% RH/25°C) revealed that dispersions made with Soluplus® remained dry and powdery compared to those made with PVP that formed a sticky paste in less than 2 weeks, indicating a possible advantage of using Soluplus® in terms of increased physical stability under high humidity storage conditions.
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