Functional Polymers for Controlled Drug Release

A special issue of Pharmaceutics (ISSN 1999-4923).

Deadline for manuscript submissions: closed (31 July 2019) | Viewed by 50797

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Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, Cosenza, Italy
Interests: stimuli-responsive drug delivery systems; munti-functional hydrogels; antioxidant polymers
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Dear Colleagues,

In the last decade, high-performing functional polymers for specific uses, including stimuli-responsive materials, molecularly imprinted polymers, mucoadhesive materials, carriers for the delivery of high MW drugs, and gene-delivery have emerged as one of the most significant trends in the area of nanotechnology. In this regard, polymeric devices that are able to undergo morphological modifications in response to an external stimulus (pH, redox balance, temperature, magnetic field, and light) represent an innovative field in the delivery of therapeutics. Additionally, in an effort to further improve delivery device performance, a combination of two or more signals have recently been developed by incorporating different stimulus responsive elements into the same polymeric network with the aim to improve the situ-controlled delivery of bioactive compounds. These smart polymeric materials lead to superior in vitro and/or in vivo therapeutic efficacy, with programmed site-specific features and remarkable potential for targeted therapy. Specifically, the correlation between the physical features and the situ-controlled delivery of bioactive compounds represents an important aspect worthy of investigation. This Special Issue welcomes any topics regarding recent progress in the synthesis and characterization of innovative functional polymers suitable to be employed as drug carriers in the pharmaceutical and biomedical fields.

Prof. Umile Gianfranco Spizzirri
Guest Editor

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Keywords

  • Functional polymer
  • Drug delivery
  • External stimulus
  • Site-specific release

Published Papers (10 papers)

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Editorial

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3 pages, 188 KiB  
Editorial
Functional Polymers for Controlled Drug Release
by Umile Gianfranco Spizzirri
Pharmaceutics 2020, 12(2), 135; https://doi.org/10.3390/pharmaceutics12020135 - 5 Feb 2020
Cited by 3 | Viewed by 1943
Abstract
In the last decade, the pharmaceutical application of hydrophilic materials has emerged as one of the most significant trends in the biomedical and pharmaceutical areas [...] Full article
(This article belongs to the Special Issue Functional Polymers for Controlled Drug Release)

Research

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11 pages, 3377 KiB  
Article
Preparation of Lutein-Loaded PVA/Sodium Alginate Nanofibers and Investigation of Its Release Behavior
by Xinxu Han, Peipei Huo, Zhongfeng Ding, Parveen Kumar and Bo Liu
Pharmaceutics 2019, 11(9), 449; https://doi.org/10.3390/pharmaceutics11090449 - 2 Sep 2019
Cited by 48 | Viewed by 5368
Abstract
This investigation aims to study the characteristics and release properties of lutein-loaded polyvinyl alcohol/sodium alginate (PVA/SA) nanofibers prepared by electrospinning. In order to increase PVA/SA nanofibers’ water-resistant ability for potential biomedical applications, the electrospun PVA/SA nanofibers were cross-linked with a mixture of glutaraldehyde [...] Read more.
This investigation aims to study the characteristics and release properties of lutein-loaded polyvinyl alcohol/sodium alginate (PVA/SA) nanofibers prepared by electrospinning. In order to increase PVA/SA nanofibers’ water-resistant ability for potential biomedical applications, the electrospun PVA/SA nanofibers were cross-linked with a mixture of glutaraldehyde and saturated boric acid solution at room temperature. The nanofibers were characterized using scanning electron microscopy (SEM) and X-ray diffractometer (XRD). Disintegration time and contact angle measurements testified the hydrophilicity change of the nanofibers before and after cross-linking. The lutein release from the nanofibers after cross-linking was measured by an ultraviolet absorption spectrophotometer, which showed sustained release up to 48 h and followed anomalous (non-Fickian) release mechanism as indicated by diffusion exponent value obtained from the Korsmeyer–Peppas equation. The results indicated that the prepared lutein-loaded PVA/SA nanofibers have great potential as a controlled release system. Full article
(This article belongs to the Special Issue Functional Polymers for Controlled Drug Release)
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19 pages, 3169 KiB  
Article
Film Dressings Based on Hydrogels: Simultaneous and Sustained-Release of Bioactive Compounds with Wound Healing Properties
by Fabian Ávila-Salas, Adolfo Marican, Soledad Pinochet, Gustavo Carreño, Oscar Valdés, Bernardo Venegas, Wendy Donoso, Gustavo Cabrera-Barjas, Sekar Vijayakumar and Esteban F. Durán-Lara
Pharmaceutics 2019, 11(9), 447; https://doi.org/10.3390/pharmaceutics11090447 - 2 Sep 2019
Cited by 31 | Viewed by 4794
Abstract
This research proposes the rational modeling, synthesis and evaluation of film dressing hydrogels based on polyvinyl alcohol crosslinked with 20 different kinds of dicarboxylic acids. These formulations would allow the sustained release of simultaneous bioactive compounds including allantoin, resveratrol, dexpanthenol and caffeic acid [...] Read more.
This research proposes the rational modeling, synthesis and evaluation of film dressing hydrogels based on polyvinyl alcohol crosslinked with 20 different kinds of dicarboxylic acids. These formulations would allow the sustained release of simultaneous bioactive compounds including allantoin, resveratrol, dexpanthenol and caffeic acid as a multi-target therapy in wound healing. Interaction energy calculations and molecular dynamics simulation studies allowed evaluating the intermolecular affinity of the above bioactive compounds by hydrogels crosslinked with the different dicarboxylic acids. According to the computational results, the hydrogels crosslinked with succinic, aspartic, maleic and malic acids were selected as the best candidates to be synthesized and evaluated experimentally. These four crosslinked hydrogels were prepared and characterized by FTIR, mechanical properties, SEM and equilibrium swelling ratio. The sustained release of the bioactive compounds from the film dressing was investigated in vitro and in vivo. The in vitro results indicate a good release profile for all four analyzed bioactive compounds. More importantly, in vivo experiments suggest that prepared formulations could considerably accelerate the healing rate of artificial wounds in rats. The histological studies show that these formulations help to successfully reconstruct and thicken epidermis during 14 days of wound healing. Moreover, the four film dressings developed and exhibited excellent biocompatibility. In conclusion, the novel film dressings based on hydrogels rationally designed with combinatorial and sustained release therapy could have significant promise as dressing materials for skin wound healing. Full article
(This article belongs to the Special Issue Functional Polymers for Controlled Drug Release)
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17 pages, 4422 KiB  
Article
Retinol-Containing Graft Copolymers for Delivery of Skin-Curing Agents
by Justyna Odrobińska, Katarzyna Niesyto, Karol Erfurt, Agnieszka Siewniak, Anna Mielańczyk and Dorota Neugebauer
Pharmaceutics 2019, 11(8), 378; https://doi.org/10.3390/pharmaceutics11080378 - 2 Aug 2019
Cited by 9 | Viewed by 3989
Abstract
The new polymeric systems for delivery in cosmetology applications were prepared using self-assembling amphiphilic graft copolymers. The synthesis based on “click” chemistry reaction included grafting of azide-functionalized polyethylene glycol (PEG-N3) onto multifunctional polymethacrylates containing alkyne units. The latter ones were obtained [...] Read more.
The new polymeric systems for delivery in cosmetology applications were prepared using self-assembling amphiphilic graft copolymers. The synthesis based on “click” chemistry reaction included grafting of azide-functionalized polyethylene glycol (PEG-N3) onto multifunctional polymethacrylates containing alkyne units. The latter ones were obtained via atom transfer radical polymerization (ATRP) of alkyne-functionalized monomers, e.g., ester of hexynoic acid and 2-hydroxyethyl methacrylate (AlHEMA) with methyl methacrylate (MMA), using bromoester-modified retinol (RETBr) as the initiator. Varying the content of alkyne moieties adjusted by initial monomer ratios of AlHEMA/MMA was advantageous for the achievement of a well-defined grafting degree. The designed amphiphilic graft copolymers P((HEMA-graft-PEG)-co-MMA), showing tendency to micellization in aqueous solution at room temperature, were encapsulated with arbutin (ARB) or vitamin C (VitC) with high efficiencies (>50%). In vitro experiments carried out in the phosphate-buffered saline solution (PBS) at pH 7.4 indicated the maximum release of ARB after at least 20 min and VitC within 10 min. The fast release of the selected antioxidants and skin-lightening agents by these micellar systems is satisfactory for applications in cosmetology, where they can be used as the components of masks, creams, and wraps. Full article
(This article belongs to the Special Issue Functional Polymers for Controlled Drug Release)
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17 pages, 11682 KiB  
Article
Use of nPSi-βCD Composite Microparticles for the Controlled Release of Caffeic Acid and Pinocembrin, Two Main Polyphenolic Compounds Found in a Chilean Propolis
by Dina Guzmán-Oyarzo, Tanya Plaza, Gonzalo Recio-Sánchez, Dulcineia S. P. Abdalla, Luis A. Salazar and Jacobo Hernández-Montelongo
Pharmaceutics 2019, 11(6), 289; https://doi.org/10.3390/pharmaceutics11060289 - 19 Jun 2019
Cited by 11 | Viewed by 3897
Abstract
Propolis is widely recognized for its various therapeutic properties. These are attributed to its rich composition in polyphenols, which exhibit multiple biological properties (e.g., antioxidant, anti-inflammatory, anti-angiogenic). Despite its multiple benefits, oral administration of polyphenols results in low bioavailability at the action site. [...] Read more.
Propolis is widely recognized for its various therapeutic properties. These are attributed to its rich composition in polyphenols, which exhibit multiple biological properties (e.g., antioxidant, anti-inflammatory, anti-angiogenic). Despite its multiple benefits, oral administration of polyphenols results in low bioavailability at the action site. An alternative to face this problem is the use of biomaterials at nano-micro scale due to its high versatility as carriers and delivery systems of various drugs and biomolecules. The aim of this work is to determine if nPSi-βCD microparticles are a suitable material for the load and controlled release of caffeic acid (CA) and pinocembrin (Pin), two of the main components of a Chilean propolis with anti-atherogenic and anti-angiogenic activity. Polyphenols and nPSi-βCD microparticles cytocompatibility studies were carried out with human umbilical vein endothelial cells (HUVECs). Results from physicochemical characterization demonstrated nPSi-βCD microparticles successfully retained and controlled release CA and Pin. Furthermore, nPSi-βCD microparticles presented cytocompatibility with HUVECs culture at concentrations of 0.25 mg/mL. These results suggest that nPSi-βCD microparticles could safely be used as an alternate oral delivery system to improve controlled release and bioavailability of CA or Pin—and eventually other polyphenols—thus enhancing its therapeutic effect for the treatment of different diseases. Full article
(This article belongs to the Special Issue Functional Polymers for Controlled Drug Release)
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13 pages, 2543 KiB  
Article
Thermally-Responsive Loading and Release of Elastin-Like Polypeptides from Contact Lenses
by Wan Wang, Changrim Lee, Martha Pastuszka, Gordon W. Laurie and J. Andrew MacKay
Pharmaceutics 2019, 11(5), 221; https://doi.org/10.3390/pharmaceutics11050221 - 7 May 2019
Cited by 10 | Viewed by 5881
Abstract
Contact lenses are widely prescribed for vision correction, and as such they are an attractive platform for drug delivery to the anterior segment of the eye. This manuscript explores a novel strategy to drive the reversible adsorption of peptide-based therapeutics using commercially available [...] Read more.
Contact lenses are widely prescribed for vision correction, and as such they are an attractive platform for drug delivery to the anterior segment of the eye. This manuscript explores a novel strategy to drive the reversible adsorption of peptide-based therapeutics using commercially available contact lenses. To accomplish this, thermo-sensitive elastin-like polypeptides (ELPs) alone or tagged with a candidate ocular therapeutic were characterized. For the first time, this manuscript demonstrates that Proclear CompatiblesTM contact lenses are a suitable platform for ELP adsorption. Two rhodamine-labelled ELPs, V96 (thermo-sensitive) and S96 (thermo-insensitive), were employed to test temperature-dependent association to the contact lenses. During long-term release into solution, ELP coacervation significantly modulated the release profile whereby more than 80% of loaded V96 retained with a terminal half-life of ~4 months, which was only 1–4 days under solubilizing conditions. A selected ocular therapeutic candidate lacritin-V96 fusion (LV96), either free or lens-bound LV96, was successfully transferred to HCE-T cells. These data suggest that ELPs may be useful to control loading or release from certain formulations of contact lenses and present a potential for this platform to deliver a biologically active peptide to the ocular surface via contact lenses. Full article
(This article belongs to the Special Issue Functional Polymers for Controlled Drug Release)
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24 pages, 6373 KiB  
Article
Modulation of the Release of a Non-Interacting Low Solubility Drug from Chitosan Pellets Using Different Pellet Size, Composition and Numerical Optimization
by Ioannis Partheniadis, Paraskevi Gkogkou, Nikolaos Kantiranis and Ioannis Nikolakakis
Pharmaceutics 2019, 11(4), 175; https://doi.org/10.3390/pharmaceutics11040175 - 10 Apr 2019
Cited by 14 | Viewed by 3729
Abstract
Two size classes of piroxicam (PXC) pellets (mini (380–550 μm) and conventional (700–1200 μm)) were prepared using extrusion/spheronization and medium viscosity chitosan (CHS). Mixture experimental design and numerical optimization were applied to distinguish formulations producing high sphericity pellets with fast or extended release. [...] Read more.
Two size classes of piroxicam (PXC) pellets (mini (380–550 μm) and conventional (700–1200 μm)) were prepared using extrusion/spheronization and medium viscosity chitosan (CHS). Mixture experimental design and numerical optimization were applied to distinguish formulations producing high sphericity pellets with fast or extended release. High CHS content required greater wetting liquid volume for pellet formation and the diameter decreased linearly with volume. Sphericity increased with CHS for low-to-medium drug content. Application of PXRD showed that the drug was a mixture of form II and I. Crystallinity decreased due to processing and was significant at 5% drug content. Raman spectroscopy showed no interactions. At pH 1.2, the dissolved CHS increased ‘apparent’ drug solubility up to 0.24 mg/mL while, at pH 5.6, the suspended CHS increased ‘apparent’ solubility to 0.16 mg/mL. Release at pH 1.2 was fast for formulations with intermediate CHS and drug levels. At pH 5.6, conventional pellets showed incomplete release while mini pellets with a CHS/drug ratio ≥2 and up to 21.25% drug, showed an extended release that was completed within 8 h. Numerical optimization provided optimal formulations for fast release at pH 1.2 with drug levels up to 40% as well as for extended release formulations with drug levels of 5% and 10%. The Weibull model described the release kinetics indicating complex or combined release (parameter ‘b’ > 0.75) for release at pH 1.2, and normal diffusion for the mini pellets at pH 5.6 (‘b’ from 0.63 to 0.73). The above results were attributed mainly to the different pellet sizes and the extensive dissolution/erosion of the gel matrix was observed at pH 1.2 but not at pH 5.6. Full article
(This article belongs to the Special Issue Functional Polymers for Controlled Drug Release)
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Review

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22 pages, 3321 KiB  
Review
Silk Fibroin as a Functional Biomaterial for Drug and Gene Delivery
by Mhd Anas Tomeh, Roja Hadianamrei and Xiubo Zhao
Pharmaceutics 2019, 11(10), 494; https://doi.org/10.3390/pharmaceutics11100494 - 26 Sep 2019
Cited by 128 | Viewed by 7214
Abstract
Silk is a natural polymer with unique physicochemical and mechanical properties which makes it a desirable biomaterial for biomedical and pharmaceutical applications. Silk fibroin (SF) has been widely used for preparation of drug delivery systems due to its biocompatibility, controllable degradability and tunable [...] Read more.
Silk is a natural polymer with unique physicochemical and mechanical properties which makes it a desirable biomaterial for biomedical and pharmaceutical applications. Silk fibroin (SF) has been widely used for preparation of drug delivery systems due to its biocompatibility, controllable degradability and tunable drug release properties. SF-based drug delivery systems can encapsulate and stabilize various small molecule drugs as well as large biological drugs such as proteins and DNA to enhance their shelf lives and control the release to enhance their circulation time in the blood and thus the duration of action. Understanding the properties of SF and the potential ways of manipulating its structure to modify its physicochemical and mechanical properties allows for preparation of modulated drug delivery systems with desirable efficacies. This review will discuss the properties of SF material and summarize the recent advances of SF-based drug and gene delivery systems. Furthermore, conjugation of the SF to other biomolecules or polymers for tissue-specific drug delivery will also be discussed. Full article
(This article belongs to the Special Issue Functional Polymers for Controlled Drug Release)
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51 pages, 4297 KiB  
Review
Injectable Hydrogels for Cancer Therapy over the Last Decade
by Giuseppe Cirillo, Umile Gianfranco Spizzirri, Manuela Curcio, Fiore Pasquale Nicoletta and Francesca Iemma
Pharmaceutics 2019, 11(9), 486; https://doi.org/10.3390/pharmaceutics11090486 - 19 Sep 2019
Cited by 67 | Viewed by 9025
Abstract
The interest in injectable hydrogels for cancer treatment has been significantly growing over the last decade, due to the availability of a wide range of starting polymer structures with tailored features and high chemical versatility. Many research groups are working on the development [...] Read more.
The interest in injectable hydrogels for cancer treatment has been significantly growing over the last decade, due to the availability of a wide range of starting polymer structures with tailored features and high chemical versatility. Many research groups are working on the development of highly engineered injectable delivery vehicle systems suitable for combined chemo-and radio-therapy, as well as thermal and photo-thermal ablation, with the aim of finding out effective solutions to overcome the current obstacles of conventional therapeutic protocols. Within this work, we have reviewed and discussed the most recent injectable hydrogel systems, focusing on the structure and properties of the starting polymers, which are mainly classified into natural or synthetic sources. Moreover, mapping the research landscape of the fabrication strategies, the main outcome of each system is discussed in light of possible clinical applications. Full article
(This article belongs to the Special Issue Functional Polymers for Controlled Drug Release)
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17 pages, 4221 KiB  
Review
Ionic Polymethacrylate Based Delivery Systems: Effect of Carrier Topology and Drug Loading
by Dorota Neugebauer, Anna Mielańczyk, Rafał Bielas, Justyna Odrobińska, Maria Kupczak and Katarzyna Niesyto
Pharmaceutics 2019, 11(7), 337; https://doi.org/10.3390/pharmaceutics11070337 - 15 Jul 2019
Cited by 10 | Viewed by 4129
Abstract
The presented drug delivery polymeric systems (DDS), i.e., conjugates and self-assemblies, based on grafted and star-shaped polymethacrylates have been studied for the last few years in our group. This minireview is focused on the relationship of polymer structure to drug conjugation/entrapment efficiency and [...] Read more.
The presented drug delivery polymeric systems (DDS), i.e., conjugates and self-assemblies, based on grafted and star-shaped polymethacrylates have been studied for the last few years in our group. This minireview is focused on the relationship of polymer structure to drug conjugation/entrapment efficiency and release capability. Both graft and linear polymers containing trimethylammonium groups showed the ability to release the pharmaceutical anions by ionic exchange, but in aqueous solution they were also self-assembled into nanoparticles with encapsulated nonionic drugs. Star-shaped polymers functionalized with ionizable amine/carboxylic groups were investigated for drug conjugation via ketimine/amide linkers. However, only the conjugates of polybases were water-soluble, giving opportunity for release studies, whereas the self-assembling polyacidic stars were encapsulated with the model drugs. Depending on the type of drug loading in the polymer matrix, their release rates were ordered as follows: Physical ≥ ionic > covalent. The studies indicated that the well-defined ionic polymethacrylates, including poly(ionic liquid)s, are advantageous for designing macromolecular carriers due to the variety of structural parameters, which are efficient for tuning of drug loading and release behavior in respect to the specific drug interactions. Full article
(This article belongs to the Special Issue Functional Polymers for Controlled Drug Release)
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