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Marine Polysaccharides in Pharmaceutical Applications
Published in Se-Kwon Kim, Marine Biochemistry, 2023
Riyasree Paul, Sourav Kabiraj, Sreejan Manna, Sougata Jana
Chawla et al. have investigated the efficacy of alginate-based mucoadhesive microbeads for delivering naproxen sodium. Emulsification method was employed to synthesize calcium chloride cross-linked alginate microbeads. Eudragit S-100 was used to coat the developed microbeads. The core microbeads showed an enhanced mucoadhesive property in respect to coated microbeads. The uncoated microspheres exhibited pH-dependent sustained drug release following Higuchi kinetics, where s the coated microspheres demonstrated Korsmeyer-Peppas kinetics (Chawla et al. 2012). Alginate-gellan gum based microspheres were synthesized for oral delivery of aceclofenac by Jana et al. The average size of the microparticles was reported between 270 and 490 μm. An in vitro drug release study revealed a sustained release of aceclofenac over 6 hours following Korsemeyer-Peppas kinetics. An in vivo study performed on a rabbit model revealed sustained absorption of drug with an excellent anti-inflammatory effect (Jana et al. 2013). Another study conducted by Jana et al. reported the development of alginate and locust bean gum based interpenetrating polymeric network (IPN) microspheres for oral delivery of aceclofenac. The ionic gelation technique was employed to develop calcium ion cross-linked microspheres. An in vitro study revealed sustained release of aceclofenac over 8 hours in pH 6.8 phosphate buffer. An increased polymer concentration has decreased the aceclofenac release percentage, as shown in Figure 5.3. Pharmacodynamic analysis exhibited a sustained anti-inflammatory effect after oral administration (Jana et al. 2015).
Nanomedicines for Ocular NSAIDs: State-of-the-Art Update of the Safety on Drug Delivery
Published in Lajos P. Balogh, Nano-Enabled Medical Applications, 2020
Joana R. Campos, Joana Araújo, Elisabet Gonzalez-Mira, Maria A. Egea, Elena Sanchez-Lopez, Marta Espina, Selma B. Souto, Maria L. Garcia, Eliana B. Souto
Many authors have tested the use of microparticles as drug carriers over the last decades. Posterior segment diseases such as proliferative vitreoretinopathy, age-related macular degeneration, diabetic retinopathy, uveitis, macular oedema, cytomegalovirus, glaucoma, and retinitis pigmentosa have been treated with drug-loaded microspheres with a relatively high rate of success [199]. Addo et al. observed that the use of tetracaine-loaded microparticles enhanced the anaesthetic effect of the drug in rabbits, in comparison with a commercialized ophthalmic solution [200]. Other authors have studied the hypothesis that mucoadhesive microparticles may offer a means for slow drug release from the particles that remain adherent to the ocular surface for an extended period of time. Sensoy et al. showed the utility of mucoadhesive polymers for the preparation of bioadhesive microspheres loaded with sulphacetamide for the treatment of keratitis in rabbits [201]. Choy et al. observed that the use of a mucoadhesion promoter such as polyethyleneglycol (PEG) increased the microparticles’ retention time on the ocular surface of rabbits [202, 203].
Pharmaceutical and Methodological Aspects of Microparticles
Published in Neville Willmott, John Daly, Microspheres and Regional Cancer Therapy, 2020
Yan Chen, Mark A. Burton, Bruce N. Gray
Microparticle properties are of importance in determining their disposition in the body as well as therapeutic effects of the incorporated drug. Characterization of particles is an important step in optimization of design and development of drug carrier systems. This section considers factors that influence the in vivo performance of microspheres and microcapsules.
Novel formulations for topical delivery of tranexamic acid: assessing the need of epidermal targeting for hyperpigmentation disorders
Published in Expert Opinion on Drug Delivery, 2023
Piyush Verma, Khushwant S. Yadav
Microparticles are the micro-sized polymeric particulate drug delivery systems, in which different drugs can be encapsulated. Control drug delivery via topical route can be achieved by using microparticles formulated using biodegradable polymers such as poly(lactic-co-glycolic acid) (PLGA) and chitosan [46,47]. Microparticles are being exploited for formulating sustained release systems for topical delivery [48]. Ming-Hsi Huang et al. prepared tranexamic-acid-loaded charged PLGA polymer-based microparticles for studying the release of the molecule [38]. A double emulsion solvent evaporation process was used by them for the preparation of particles. For inducing charge on microparticles, they used quaternary ammonium compound (cetyltrimethylammonium bromide). Prepared microparticles were spherical in shape. It was found that charged polymeric microparticle had longer and better release as compared to uncharged polymeric microparticles. Release was fastest in alkaline media because of PLGA because of faster degradation of PLGA in alkaline environment.
The utility of platelet activation biomarkers in thrombotic microangiopathies
Published in Platelets, 2022
Mohammad Al-Tamimi, Jianlin Qiao, Elizabeth E. Gardiner
Plasma levels of PMPs were significantly elevated in TTP and HUS patients compared to healthy controls [32,55,56,75]. Microparticles can be measured by flow cytometry, and while they are not routinely measured in clinical laboratories, they bear surface markers, which can provide information about their origin and level of reactivity. Microparticles can be derived from a number of activated cell types, but like sGPVI, CD41-bearing microparticles in plasma are a direct and selective measure of platelet activation in a patient. Active calpain was associated with PMPs in plasma from TTP patients [77], and P-selectin expression was significantly elevated in microparticles from TTP plasma, while significant levels of PMPs were positive for Stx2 and C3 and C9 complement factors in HUS patients [32,56,75]. Clinical improvement was accompanied by normalization of PMP levels and platelet count, and a correlation between PMPs and platelet number was found [55,56]. Accordingly, PMPs were proposed as a diagnostic and prognostic biomarker of thrombosis in TTP patients [32,55]. PMPs were increased in allogeneic SCT patients with or without TMA at 4 and 2 weeks, respectively, post-transplantation [41] (Table II).
Platelet phenotype and function in the absence of splenic sequestration (Review)
Published in Platelets, 2021
Sarah Luu, Ian J. Woolley, Robert K. Andrews
As aforementioned, microparticles are thought to also play a role in the risk of thromboembolism post-splenectomy. Microparticles are small vesicles commonly derived from platelets and erythrocytes in the human and have a well-described key role in coagulation [39]. Evidence suggests that the spleen plays a role in regulating circulating microparticles [64]. In the setting of splenectomy, there appears to be increased levels of erythrocyte- and platelet-derived microparticles as shown in ITP and thalassemia splenectomized cohorts [65–68]. Microparticles are also increased in individuals with pulmonary hypertension [39,65]. Murine studies have also demonstrated increased circulating microparticles post-splenectomy [69]. Further studies particularly amongst individuals, splenectomized for trauma or benign causes (e.g. splenic cysts) would further validate these claims.