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Optical Nanoprobes for Diagnosis
Published in D. Sakthi Kumar, Aswathy Ravindran Girija, Bionanotechnology in Cancer, 2023
R. G. Aswathy, D. Sakthi Kumar
Polyesters exemplify the most extensively employed class of polymers, owing to their biodegradable and biocompatible qualities. These include polylactide (PLA), polyglycolide (PGA), poly(e-caprolactone) (PCL), and poly(g-valerolactone) (PVL), and most of them are generally synthesized by ring-opening polymerization of lactide, lactide/glycolide, e-caprolactone, and gvalero-lactone, respectively. PLGA copolymer of lactide and glycolide is the Food and Drug Administration (FDA) approved polymer for drug delivery applications. Amphiphilic PLGA-b-PEG or PLA-b-PEG copolymers, comprising hydrophobic PLGA or PLA block and a hydrophilic PEG, have been used to prepare NPs, polymersomes, or micelles, where the hydrophobic part (PLGA or PLA) and hydrophilic PEG results in the formation of core and shell of nanocarriers, respectively. PEGylated NPs demonstrate the potential to be functionalized with various ligands, such as small molecules, peptides, antibodies, and aptamers conjugated to PEG chain. There have been several reports on the application of PNPs as diagnostic as well as therapeutic (theragnostic) multifunctional agents. PLGA NPs carrying various drugs (curcumin, paclitaxel, gemcitabine, 5-Fluorouracil (5FU), etc.) with different targeting moieties (folate, aptamer, peptide, transferrin, etc.) against pancreatic as well as breast cancer cells have been reported [175–178].
Spray Drying and Pharmaceutical Applications
Published in Dilip M. Parikh, Handbook of Pharmaceutical Granulation Technology, 2021
Metin Çelik, Pavan Muttil, Gülşilan Binzet, Susan C. Wendell
Two common biodegradable polymers used in microparticle formation using spray drying are polylactide (PLA) and polylactide-co-glycolide (PLGA). The efficacy of spray drying as a method for PLA and PLGA microsphere preparation was investigated using a model lipophilic drug [64]. The spray drying process parameters were tailored to each polymer and the microspheres obtained were evaluated for shape, size, drug content, and polymer influence on these characteristics. Polymer type, molecular weight, and concentration were the greatest contributing factors to these characteristics. In-vitro dissolution testing revealed different release profiles depending on the polymer type and microsphere morphology.
Organic Nanocarriers for Brain Drug Delivery
Published in Carla Vitorino, Andreia Jorge, Alberto Pais, Nanoparticles for Brain Drug Delivery, 2021
Marlene Lúcio, Carla M. Lopes, Eduarda Fernandes, Hugo Gonẹalves, Maria Elisabete C. D. Real Oliveira
Polymers are chemical compounds composed of many repeated monomers and may exist as chains or in branched form and can be from natural origin, like chitosan, alginate and other polysaccharides, or can be synthetic like poly(caprolactone) (PCL), polylactide (PLA), poly(methyl methacrylate) (PMMA), polydimethylsiloxane (PDMS), poly (2-methyl-2-oxazoline) (PMOXA), poly(N-vinylpyrrolidone) (PVP), poly(vinyl alcohol) (PVA) and PEG [112, 113]. Block copolymers are macromolecules which contain multiple adjacent blocks of chemical monomers with different structures or distributed in different sequences [112, 113]. A block copolymer, consisting of two types of monomers is called a diblock copolymer and has amphiphilic properties [112, 113]. Triblock copolymers composed of an inner hydrophobic block attached to outer hydrophilic blocks are also amphiphilic. In aqueous solution, amphiphilic block copolymers, either diblock or triblock, can self-assemble into various supramolecular polymeric structures such as micelles, rods, nanoparticles, or polymersomes (POs) [112, 113]. The final structure of the self-assembly aggregates depends on several parameters such as concentration, molecular weight, geometry of the amphiphilic block copolymers or the ratio of the different blocks [112, 113]. POs are self-assembled vesicles of amphiphilic block copolymers [112–116]. The most common polymer arrangement used in PO formation are diblock(AB) or triblock copolymers (ABA or rarely ABC, where A and C are the hydrophilic blocks and B the hydrophobic block) (Fig. 4.5) [114].
Synthetic biodegradable polyesters for implantable controlled-release devices
Published in Expert Opinion on Drug Delivery, 2022
Jinal U. Pothupitiya, Christy Zheng, W. Mark Saltzman
Polylactide (PLA) or polylactic acid is a biodegradable polyester, which is extensively used in the textile, packaging, and biomedical industries. Polylactide is synthesized from lactide monomers and polylactic acid from lactic acid. The widespread use of PLA is attributed to its relatively simple bulk production methods, high abundance, recyclability, composability, and mechanical strength (which is comparable to polystyrene). Furthermore, the long history of PLA use in implanted devices – and its well-characterized biodegradability – make it an attractive material for biomedical implants. PLA is synthesized from lactic acid or lactide, which are monomers derived from renewable resources such as corn, wheat, carbon dioxide, and rice. The polymer degrades in biological systems by hydrolysis and enzymatic activity to produce lactic acid, which is a natural metabolite in the body. PLA is generally recognized as safe; it is a component in many FDA-approved products [2,111,112].
An overview of PLGA in-situ forming implants based on solvent exchange technique: effect of formulation components and characterization
Published in Pharmaceutical Development and Technology, 2021
Tarek Metwally Ibrahim, Nagia Ahmed El-Megrab, Hanan Mohammed El-Nahas
Among the above-mentioned mechanisms, the in-situ polymer precipitation based on solvent removal or exchange is widespread. The biodegradable polymer-based ISFI delivery systems are generally liquid formulations that are transformed into gel-like or solidified depots after injection into the aqueous body fluids. The drug is dissolved or dispersed in a concentrated solution of water-insoluble biodegradable polymer and water-miscible biocompatible solvent. The solvent dissipates into the surrounding area following injection, while water penetrates the polymeric matrix. The drug is entrapped within the matrix after solidification of implants and then released by diffusion mechanism or after the implants start to biodegrade in the body (Figure 5) (Dunn et al. 1994; Vhora et al. 2021). Several formulations have been studied using various biodegradable polymers such as polylactide (PLA) (Camargo et al. 2013), PLGA (Enayati et al. 2017) or polycaprolactone (PCL) (Khodaverdi et al. 2020). Many biocompatible solvents have been mixed with these polymers such as N-methyl-2-pyrrolidone (NMP) (Patki et al. 2021), dimethyl sulfoxide (DMSO) (Wang et al. 2012) and benzyl benzoate (Wang et al. 2017).
A polymer–lipid membrane artificial cell nanocarrier containing enzyme–oxygen biotherapeutic inhibits the growth of B16F10 melanoma in 3D culture and in a mouse model
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2021
Yun Wang, Thomas Ming Swi Chang
The editorial also mentioned the problem that with intravenous administration of different drug carrier systems, the delivery efficiency was less than 1% [4]. In the present study of local injection, the nanoencapsulation efficiency of PH-TYR into the nanocarrier is 75.4% [16,17]. In the present report, by administrating this locally, most of this reached the site of injection. Analysis at the site of injection showed a small foreign body granular containing the nanocarriers with no inflammation. With time the polylactide–lipid will be biodegraded. Decreasing the molecular weight of the polylactide would increase the rate of biodegradation of the polymer. The content of PH-TYR will be metabolized like another of our enzyme–oxygen therapeutic poly-[haemoglobin–catalase–superoxide dismutase-carbonic anhydrase] that did not show any safety or immunological problem [21] and is now under development for clinical trial.