Advances in Amorphous Drug Formulations, Volume II

A special issue of Pharmaceutics (ISSN 1999-4923). This special issue belongs to the section "Physical Pharmacy and Formulation".

Deadline for manuscript submissions: closed (31 October 2023) | Viewed by 21022

Special Issue Editor


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Guest Editor
Department of Pharmacy, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark
Interests: amorphous drugs and formulations; co-amorphous drug delivery; silica based drug delivery systems; functional excipients
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Special Issue Information

Dear Colleagues,

Amorphous drug delivery systems are one of the most promising technologies to tackle the issue of poor bioavailability of an increasing number of poorly soluble drugs in the development pipelines. Due to the poor physical stability of pure amorphous drugs, formulation scientists frequently use different types of excipients to stabilize the drug in its amorphous form, including different types of polymeric carriers, mesoporous materials or other low molecular weight excipients. The mechanism of stabilization has been attributed to the properties of the chosen excipient and the drug, such as drug-excipient miscibility, antiplasticization, molecular interactions, etc. However, whilst more and more products have reached the market in the past few years, the amorphous form and amorphous formulations still remain not fully understood. This Special Issue serves to capture the contemporary progress in the field of amorphous formulations, both from a fundamental understanding and their practical application.

Prof. Dr. Korbinian Löbmann
Guest Editor

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Keywords

  • poorly soluble drugs
  • high energy solids
  • amorphous form
  • relaxation
  • glass solutions
  • solid state miscibility
  • amorphous solid dispersions (ASDs)
  • polymeric carriers
  • mesoporous silica
  • co-amorphous

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Published Papers (4 papers)

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Research

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20 pages, 5263 KiB  
Article
Effect of Span 20 Feeding Zone in the Twin Screw Extruder on the Properties of Amorphous Solid Dispersion of Ritonavir
by Hengqian Wu, Zhengping Wang, Yanna Zhao, Yan Gao, Heng Zhang, Lili Wang, Zhe Wang and Jun Han
Pharmaceutics 2023, 15(2), 441; https://doi.org/10.3390/pharmaceutics15020441 - 29 Jan 2023
Cited by 2 | Viewed by 2193
Abstract
A ternary amorphous solid dispersion (ASD) system consisting of drug/polymer/surfactant is receiving increased attention to improve the oral bioavailability of poorly water-soluble drugs. The effect of polymers has been extensively studied, while the impact of surfactants has not yet to be studied to [...] Read more.
A ternary amorphous solid dispersion (ASD) system consisting of drug/polymer/surfactant is receiving increased attention to improve the oral bioavailability of poorly water-soluble drugs. The effect of polymers has been extensively studied, while the impact of surfactants has not yet to be studied to the same extent. Challenging questions to be answered are whether the surfactants should be added with the drug or separately and the resulting differences between the two operating processes. By adjusting the liquid feeding zone for Span 20 in the hot-melt twin screw extruder equipment, we investigated the effect of Span 20 on the properties of the polyvinylpyrrolidone/vinyl acetate (PVPVA)-based ASD formulations of ritonavir. We found that with the delayed feeding positions of Span 20 in the twin screw extruder, the ability of the ternary ASDs to maintain the supersaturation of the milled extrudates was observed to be significantly enhanced. Furthermore, adding surfactant after a thorough mixing of polymer and drug could decrease the molecular mobility of ternary ASD formulations. In addition, the effects of Span 20 on the complex viscosity and structure of PVPVA were also investigated. The delayed addition of Span 20 could improve the complex viscosity of PVPVA, thus leading to the drug precipitation inhibition. In conclusion, the delayed addition of Span 20 in the twin screw extruder and prolonging the mixing time of the drug and polymer may be critical to the maintenance of supersaturation. Full article
(This article belongs to the Special Issue Advances in Amorphous Drug Formulations, Volume II)
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14 pages, 9708 KiB  
Article
Structure and Glass Transition Temperature of Amorphous Dispersions of Model Pharmaceuticals with Nucleobases from Molecular Dynamics
by Ctirad Červinka and Michal Fulem
Pharmaceutics 2021, 13(8), 1253; https://doi.org/10.3390/pharmaceutics13081253 - 13 Aug 2021
Cited by 12 | Viewed by 3151
Abstract
Glass transition temperature (Tg) is an important material property, which predetermines the kinetic stability of amorphous solids. In the context of active pharmaceutical ingredients (API), there is motivation to maximize their Tg by forming amorphous mixtures with other chemicals, [...] Read more.
Glass transition temperature (Tg) is an important material property, which predetermines the kinetic stability of amorphous solids. In the context of active pharmaceutical ingredients (API), there is motivation to maximize their Tg by forming amorphous mixtures with other chemicals, labeled excipients. Molecular dynamics simulations are a natural computational tool to investigate the relationships between structure, dynamics, and cohesion of amorphous materials with an all-atom resolution. This work presents a computational study, addressing primarily the predictions of the glass transition temperatures of four selected API (carbamazepine, racemic ibuprofen, indomethacin, and naproxen) with two nucleobases (adenine and cytosine). Since the classical non-polarizable simulations fail to reach the quantitative accuracy of the predicted Tg, analyses of internal dynamics, hydrogen bonding, and cohesive forces in bulk phases of pure API and their mixtures with the nucleobases are performed to interpret the predicted trends. This manuscript reveals the method for a systematic search of beneficial pairs of API and excipients (with maximum Tg when mixed). Monitoring of transport and cohesive properties of API–excipients systems via molecular simulation will enable the design of such API formulations more efficiently in the future. Full article
(This article belongs to the Special Issue Advances in Amorphous Drug Formulations, Volume II)
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12 pages, 1056 KiB  
Article
The Influence of Drug–Polymer Solubility on Laser-Induced In Situ Drug Amorphization Using Photothermal Plasmonic Nanoparticles
by Nele-Johanna Hempel, Padryk Merkl, Matthias Manne Knopp, Ragna Berthelsen, Alexandra Teleki, Georgios A. Sotiriou and Korbinian Löbmann
Pharmaceutics 2021, 13(6), 917; https://doi.org/10.3390/pharmaceutics13060917 - 21 Jun 2021
Cited by 1 | Viewed by 3650
Abstract
In this study, laser-induced in situ amorphization (i.e., amorphization inside the final dosage form) of the model drug celecoxib (CCX) with six different polymers was investigated. The drug–polymer combinations were studied with regard to the influence of (i) the physicochemical properties of the [...] Read more.
In this study, laser-induced in situ amorphization (i.e., amorphization inside the final dosage form) of the model drug celecoxib (CCX) with six different polymers was investigated. The drug–polymer combinations were studied with regard to the influence of (i) the physicochemical properties of the polymer, e.g., the glass transition temperature (Tg) and (ii) the drug–polymer solubility on the rate and degree of in situ drug amorphization. Compacts were prepared containing 30 wt% CCX, 69.25 wt% polymer, 0.5 wt% lubricant, and 0.25 wt% plasmonic nanoparticles (PNs) and exposed to near-infrared laser radiation. Upon exposure to laser radiation, the PNs generated heat, which allowed drug dissolution into the polymer at temperatures above its Tg, yielding an amorphous solid dispersion. It was found that in situ drug amorphization was possible for drug–polymer combinations, where the temperature reached during exposure to laser radiation was above the onset temperature for a dissolution process of the drug into the polymer, i.e., TDStart. The findings of this study showed that the concept of laser-induced in situ drug amorphization is applicable to a range of polymers if the drug is soluble in the polymer and temperatures during the process are above TDStart. Full article
(This article belongs to the Special Issue Advances in Amorphous Drug Formulations, Volume II)
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Review

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33 pages, 3236 KiB  
Review
Recent Advances in Amorphous Solid Dispersions: Preformulation, Formulation Strategies, Technological Advancements and Characterization
by Srushti Tambe, Divya Jain, Sai Kishore Meruva, Gopinath Rongala, Abhishek Juluri, Girish Nihalani, Hemanth Kumar Mamidi, Pavan Kumar Nukala and Pradeep Kumar Bolla
Pharmaceutics 2022, 14(10), 2203; https://doi.org/10.3390/pharmaceutics14102203 - 16 Oct 2022
Cited by 55 | Viewed by 10851
Abstract
Amorphous solid dispersions (ASDs) are among the most popular and widely studied solubility enhancement techniques. Since their inception in the early 1960s, the formulation development of ASDs has undergone tremendous progress. For instance, the method of preparing ASDs evolved from solvent-based approaches to [...] Read more.
Amorphous solid dispersions (ASDs) are among the most popular and widely studied solubility enhancement techniques. Since their inception in the early 1960s, the formulation development of ASDs has undergone tremendous progress. For instance, the method of preparing ASDs evolved from solvent-based approaches to solvent-free methods such as hot melt extrusion and Kinetisol®. The formulation approaches have advanced from employing a single polymeric carrier to multiple carriers with plasticizers to improve the stability and performance of ASDs. Major excipient manufacturers recognized the potential of ASDs and began introducing specialty excipients ideal for formulating ASDs. In addition to traditional techniques such as differential scanning calorimeter (DSC) and X-ray crystallography, recent innovations such as nano-tomography, transmission electron microscopy (TEM), atomic force microscopy (AFM), and X-ray microscopy support a better understanding of the microstructure of ASDs. The purpose of this review is to highlight the recent advancements in the field of ASDs with respect to formulation approaches, methods of preparation, and advanced characterization techniques Full article
(This article belongs to the Special Issue Advances in Amorphous Drug Formulations, Volume II)
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