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Degradable Polyhydroxyalkanoates as a Basis for Drug Delivery Systems
Published in Tatiana G. Volova, Yuri S. Vinnik, Ekaterina I. Shishatskaya, Nadejda M. Markelova, Gennady E. Zaikov, Natural-Based Polymers for Biomedical Applications, 2017
Tatiana G. Volova, Yuri S. Vinnik, Ekaterina I. Shishatskaya, Nadejda M. Markelova, Gennady E. Zaikov
As a rule, in the delivery system the drug resides in the pores of the construction in the free state (Freiberg et al., 2004; Medvesky et al., 2007; Panarin et al., 2014), but it can also be conjugated to polymer molecules through the chemical bond, which influences the drug release rate (Marcucci et al., 2004). Therefore, drugs are usually conjugated to short chemical sequences, so-called linkers (Furgeson et al., 2006). The most commonly used carriers in these systems are well-studied polymers such as dextran, poly-N-vinyl pyrrolidone, poly-N-(2-hydroxypropyl) methacrylamide containing links or functional groups used to conjugate drugs. Such substances as mono- and oligo-sugars, folic acid, lectins, poly-L-lysines, and antibodies can be used as linkers (Torchilin, 2006; Panarin et al., 2014). Controlled release of the drug from the system can be achieved in different ways: breaking of the chemical bond between the polymeric carrier and the drug; diffusion through the polymer layer; drug release due to degradation (erosion) of the polymer system; release of the active agent from the swelling hydrogel system (Kim et al., 2009; Olkhov et al., 2008). Based on the administration route, DDS can be divided into surgically implanted polymer systems (plates, films, sponges, tablets, microchips) and injected implants (gels, microspheres, microcapsules, erythrocytes, liposomes, nanospheres, and nanocapsules) (Jain et al., 2005). In recent years, there has been an increasing interest in injected micro- and nano-sized polymer systems shaped as microspheres, nanotubes, nanoparticles, and various carbon nanoparticles (Kingsley et al., 2006; Dutta et al., 2007; Bordes et al., 2009).
Electroactive Polymers for Drug Delivery
Published in Inamuddin, Mohd Imran Ahamed, Rajender Boddula, Adil A. Gobouri, Electroactive Polymeric Materials, 2022
Mehdi Mogharabi-Manzari, Masoud Salehipour, Zahra Pakdin-Parizi, Shahla Rezaei, Roya Khosrokhavar, Ali Motaharian
Controlled release systems offer some benefits, such as reduced toxicity, enhanced efficacy, and improved patient convenience, and compliance (Tan et al., 2018). For example, polymer-based controlled drug delivery systems can maintain the drug concentration within the therapeutic window for a prolonged time (Figure 19.6). The flexibility and diversity in chemistry, topology, and dimension of the polymers can be used to improve the properties of the carriers including biocompatibility and biodegradability. These polymers show improved pharmacokinetics and are designed to offer unique properties as carriers including reduced toxicity and improved circulation time.
Polymers in Special Uses
Published in Manas Chanda, Plastics Technology Handbook, 2017
Controlled release refers to the use of polymers containing agents of agricultural, medicinal, or pharmaceutical activity, which are released into the environment of interest at relatively constant rates over prolonged periods [127,128]. In the agricultural field, degradable mulches to promote crop growth are composed of combinations of natural polymers (which degrade readily in the presence of soil microorganisms) and synthetic polymers. Examples are starch-graft-poly(methyl acrylate) and block copoly-mers of amylose or cellulose with polyesters. At the end of the growing season, such mulches may be plowed directly into the soil along with crop residues.
A review on the treatment of intimal hyperplasia with perivascular medical devices: role of mechanical factors and drug release kinetics
Published in Expert Review of Medical Devices, 2023
Ankur J. Raval, Jigisha K. Parikh, Meghal A. Desai
Nondegradable polymers are used to fabricate various dosage forms such as transdermal patches, coating for permanent implants, and implant devices [95]. Some polymers used for such applications include polyurethanes, silicon, polymethyl methacrylate, polyethylene vinyl acetate, and fluoropolymers. Solute diffusion primarily governs the drug release from the polymer network from these nondegradable polymeric systems. Controlled release systems can be prepared into ‘matrix’ and ‘reservoir’ kind of devices. Matrix-type devices are fabricated by blending drug and compatible polymers in a specific ratio. Generally, devices with this design elute drug under the influence of Fickian diffusion only where concentration gradient plays a dominant role along with diffusion distance, network pathways, and degree of swelling for the polymeric system. Conversely, the reservoir-type devices have a rate-limiting barrier coating over the drug-containing core. The drug release rate is mainly insensitive to concentration gradient and remains relatively constant for reservoir-type systems; however, it is influenced by the outer membrane thickness and its drug permeability.
Development of onion oil-based organo-hydrogel for drug delivery material
Published in Journal of Dispersion Science and Technology, 2023
Duygu Alpaslan, Tuba Erşen Dudu, Nahit Aktas
Controlled release; It is the delivery of the active substance within a system for an extended time, at a specified rate and in the required amount. In controlled release; the rate of release is determined by the system used, and there is a more precise and predictable rate of drug delivery. Advantages of controlled release according to classical methods, which are frequently used in drug intake; Preserving the drug level in the therapeutic rate in the blood or cells, Reducing the harmful effects due to targeting of the release to a particular cell type or tissue, Reducing the amount of the drug required, Reducing the dosage amount to improve the patient’s compliance with the recommended drug regimen; drugs with a short half-life (e.g., protein and peptide drugs), increasing the duration of efficacy; eliminating drug loss, predictable and reproducible release rates (for an extended time).[1–5]
An insight on topically applied formulations for management of various skin disorders
Published in Journal of Biomaterials Science, Polymer Edition, 2022
Amit K. Jain, Sakshi Jain, Mohammed A. S. Abourehab, Parul Mehta, Prashant Kesharwani
In recent years, the requirement for improvement of drug penetration and minimizing the adverse effects associated with drug has arisen [48]. Therefore, the development of these carrier systems has been discussed. Such systems may assist a sustained as well as controlled release thus resulting extended therapeutic value and the possible reduction of adverse effects. Figure 2 represents the drug transport through skin and advantages of delivery through nanocarriers.