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Kafle P, Sanghavi R, Khasbaatar A, Punjani S, Davies DW, Diao Y. Drastic Modulation of Molecular Packing and Intrinsic Dissolution Rates by Meniscus-Guided Coating of Extremely Confined Pharmaceutical Thin Films. ACS Appl Mater Interfaces 2021; 13:56519-56529. [PMID: 34783517 DOI: 10.1021/acsami.1c08398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Nanosizing has emerged as one of the most effective formulation strategies for enhancement of dissolution properties of active pharmaceutical ingredients (APIs). In addition to enhancing the specific area of the dissolving solids, nanosizing can also capture and stabilize the metastable form of the API, which can further enhance the solubility by drastic modulation of surface energies. Herein, we employ meniscus-guided coating to fabricate nanothin films of three APIs that show anticancer properties and are poorly soluble:10-HCPT, SN-38, and amonafide. By modulating the coating speed, we systematically deposited the APIs in films ranging from ∼200 nm thickness to extreme confinement of ∼10 nm (<10 molecular layers). In all three APIs, we observe a general order-to-disorder transition with semicrystalline (10-HCPT and amonafide) or amorphous (SN-38) form of API solids trapped in thin films when the thickness decreases below a critical value of ∼25-30 nm. The existence of a critical thickness highlights the importance of nanoconfinement in tuning molecular packing. In the case of 10-HCPT, we demonstrate that the disordered form of the API occurs largely due to lack of incorporation of water molecules in thinner films below the critical thickness, thereby disrupting the three-dimensional hydrogen-bonded network held by water molecules. We further developed a dissolution model that predicts variation of the intrinsic dissolution rate (IDR) with API film thickness, which also closely matched with experimental results. We achieved drastic improvement in the IDR of ∼240% in 10-HCPT by decreasing film thickness alone. Further leveraging the order-to-disorder transition led to 2570% modulation of the IDR for amonafide. Our work demonstrates, for the first time, opportunities to largely modulate API dissolution by precisely controlling the dimensionality of thin films.
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Affiliation(s)
- Prapti Kafle
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, United States
| | - Rishabh Sanghavi
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, United States
| | - Azzaya Khasbaatar
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, United States
| | - Samdisha Punjani
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, United States
| | - Daniel W Davies
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, United States
| | - Ying Diao
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, United States
- Beckman Institute, Molecular Science and Engineering, University of Illinois at Urbana-Champaign, 405 N Mathews Avenue, Urbana, Illinois 61801, United States
- Materials Research Laboratory, University of Illinois at Urbana-Champaign, 104 South Goodwin Avenue MC-230, Urbana, Illinois 61801, United States
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Cho YJ, Aziz H. Root Causes of the Limited Electroluminescence Stability of Organic Light-Emitting Devices Made by Solution-Coating. ACS Appl Mater Interfaces 2018; 10:18113-18122. [PMID: 29733188 DOI: 10.1021/acsami.8b00926] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Although organic electroluminescent materials have long promised the prospect of making organic light emitting devices (OLEDs) via low-cost solution-coating techniques, the electroluminescence stability of devices made by such techniques continues to be rather limited making them unsuitable for commercialization. The root causes of the lower stability of OLEDs made by solution-coating versus the more conventional vacuum-deposition remain unknown. In this work, we investigate and compare between solution-coated and vacuum-deposited materials under prolonged excitation, using the archetypical host material 4,4'-bis( N-carbazolyl)-1,1'-biphenyl as a model OLED material. Results show that solution-coated films are more susceptible to degradation by excitons in comparison to their vacuum-deposited counterparts, resulting in a faster decrease in their luminescent quantum yield. The degradation rate also depends on the choice of solvent that was used in the solution-coating process. Results also show that the decrease in quantum yield is caused by exciton-induced chemical decomposition in the material as well as some possible molecular reorganization or aggregation, both of which are induced by excitons and proceed more quickly in case of solution-coated films. The faster degradation in the solution-coated films appears to originate primarily from their different morphological makeup and not due to chemical impurities. The findings uncover what appears to be one of the fundamental root causes of the lower stability of solution-coated OLEDs in general.
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Affiliation(s)
- Yong Joo Cho
- Department of Electrical & Computer Engineering, and Waterloo Institute for Nanotechnology (WIN) , University of Waterloo , 200 University Avenue West , Waterloo , Ontario N2G 3G1 , Canada
| | - Hany Aziz
- Department of Electrical & Computer Engineering, and Waterloo Institute for Nanotechnology (WIN) , University of Waterloo , 200 University Avenue West , Waterloo , Ontario N2G 3G1 , Canada
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