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Special Issue "Advances in Amorphous Drug Formulations, Volume II"

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

Deadline for manuscript submissions: 31 October 2023 | Viewed by 10550

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Prof. Dr. Korbinian Löbmann

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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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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

Published Papers (4 papers)

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Research

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Open AccessArticle

Effect of Span 20 Feeding Zone in the Twin Screw Extruder on the Properties of Amorphous Solid Dispersion of Ritonavir

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Pharmaceutics 2023, 15(2), 441; https://doi.org/10.3390/pharmaceutics15020441 - 29 Jan 2023

Viewed by 1066

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 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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Open AccessArticle

Structure and Glass Transition Temperature of Amorphous Dispersions of Model Pharmaceuticals with Nucleobases from Molecular Dynamics

Ctirad Červinka

and

Michal Fulem

Pharmaceutics 2021, 13(8), 1253; https://doi.org/10.3390/pharmaceutics13081253 - 13 Aug 2021

Cited by 5 | Viewed by 1781

Abstract

Glass transition temperature (T_g) 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 T_g 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 T_g, 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 T_g 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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Open AccessArticle

The Influence of Drug–Polymer Solubility on Laser-Induced In Situ Drug Amorphization Using Photothermal Plasmonic Nanoparticles

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Pharmaceutics 2021, 13(6), 917; https://doi.org/10.3390/pharmaceutics13060917 - 21 Jun 2021

Cited by 1 | Viewed by 2572

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 polymer, e.g., the glass transition temperature (T_g) 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 T_g, 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., T_DStart. 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 T_DStart. Full article

(This article belongs to the Special Issue Advances in Amorphous Drug Formulations, Volume II)

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Recent Advances in Amorphous Solid Dispersions: Preformulation, Formulation Strategies, Technological Advancements and Characterization

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Pharmaceutics 2022, 14(10), 2203; https://doi.org/10.3390/pharmaceutics14102203 - 16 Oct 2022

Cited by 14 | Viewed by 4428

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 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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Special Issue "Advances in Amorphous Drug Formulations, Volume II"

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