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Nano Delivery of Antiviral Plant Bioactives as Cancer Therapeutics
Published in Devarajan Thangadurai, Saher Islam, Charles Oluwaseun Adetunji, Viral and Antiviral Nanomaterials, 2022
Haripriya Shanmugam, Badma Priya, Manickam Senguttuvan Swetha, Janani Semalaiyappan
Delivery of plant bioactives will be triggered by using the inherent biological stimuli existing around the tumour tissue environment. These stimuli might be the pH, enzyme, reactive-oxygen species, ATP-responsive, and redox responsive. Stimuli-responsive pH polymer are PLGA (Qu et al. 2017), poly (acrylamide) (Pafiti et al. 2016), poly (diethylaminoethyl methacrylate) (Darabi et al. 2015), poly(methacrylic acid) (Shalviri et al. 2013), poly (dimethylaminoethyl methacrylate) (Lee et al. 2011), and poly (acrylic acid) (Hu et al. 2002). Example of enzyme-responsive polymers include poly dimethylsiloxane, polyethylenimine (Onaca et al. 2009), and polyethylene glycol (Kurisawa et al. 1997). For example, pH gradient between tumour and healthy proliferative cells is responsible for the rate of release of plant bioactives. The pH of normal human tissues is 7.4, whereas that of tumour tissues would be an acidic pH below 6.5. It protects the plant bioactives against degradation during transportation. It also selectively releases the plant bioactives at the tumour site (Chen et al. 2016). The major advantage of this system of NDDS is the release of plant bioactives from nanocarrier due to the triggering factor from the tumour site. The difficulty in using endogenous stimuli-responsive NDDS is the external factor control that can be inefficient in releasing the optimum quantity of drug to the tumour site. It is also difficult in evaluating the dose, duration, and frequency of drug release by an external agent.
Two-Dimensional Nanomaterials for Drug Delivery in Regenerative Medicine
Published in Harishkumar Madhyastha, Durgesh Nandini Chauhan, Nanopharmaceuticals in Regenerative Medicine, 2022
Zahra Mohammadpour, Seyed Morteza Naghib
Delivery of the drug to the wound area is also possible through the stimuli-responsiveness of graphene-based nanosheets. In this respect, Altinbasak et al. embedded rGO into poly acrylic acid (PAA) nanofibre (PAA@rGO) and used the resulting NIR stimuli-responsive drug delivery mats in wound dressing (Altinbasak et al. 2018). The platform was activated by irradiation of NIR light as an external stimulus, and antibiotics (ampicillin and cefepime) were released on demand. The mats functioned reproducibly, and they were reusable. The interaction of antibiotics with the surface of rGO was established through non-covalent interactions. The photothermal effect of rGO was responsible for the active drug release without any sign of inflammation or bacterial foci in the superficial skin-damaged infection model. In another study, Liu demonstrated that the electrical stimulus could trigger the release of lidocaine hydrochloride based on the electrical conductivity of rGO (Liu et al. 2012). Passive release of the payload was prevented as the rGO in the rGO–PVA membrane acted as a physical barrier.
What Are Polymeric Carriers?
Published in Mesut Karahan, Synthetic Peptide Vaccine Models, 2021
Gülderen Karakuş, Dolunay Şakar Daşdan
Polyacrylic acid (PAA) is a potent adjuvant for primary and secondary immune response. PAA is the general name of synthetic high molecular weight homopolymers of acrylic acid. The solubility of PAA in water increases with a rise in temperature. It is an anionic polymer in a water solution at neutral pH. Many of the side chains have lost their protons and gained a negative charge. With its ability to absorb and retain water due to its hygroscopic nature, it is a polyelectrolyte which can be inflated to a very large extent above the original volume. It is a widely used model polymer for understanding the immunostimulatory properties of synthetic polyelectrolytes. PAA, which is not ionized at low pHs, can be associated with various non-ionic polymers {poly(ethylene oxide), poly(N-vinyl pyrrolidone), polyacrylamide} and some cellulose ethers, and may form hydrogenated interpolymer complexes.
Microneedles for transdermal drug delivery using clay-based composites
Published in Expert Opinion on Drug Delivery, 2022
Farzaneh Sabbagh, Beom Soo Kim
Carboxymethylcellulose (CMC) is a type of cellulose derivative in which a carboxymethyl group (-CH2-COOR) is bonded to a part of the hydroxyl group present in the cellulose skeleton [92]. Polar carboxyl groups make cellulose chemically reactive, soluble, and hydrophilic. However, the main disadvantage of natural polymer-based hydrogels is poor mechanical properties due to large swelling [93]. Attempts have been made to overcome these problems by using various types of grafting, developing interpenetrating polymer networks and nanofillers, or altering the structure by physically mixing with other polymers. Poly (acrylic acid) is a hydrophilic polymer due to the presence of hydrophilic -COOH groups and can absorb huge amounts of water. Therefore, poly(acrylic acid) is widely used in drug delivery systems [67].
Overview of intranasally delivered peptides: key considerations for pharmaceutical development
Published in Expert Opinion on Drug Delivery, 2018
Wisam Al Bakri, Maureen D. Donovan, Maria Cueto, Yunhui Wu, Chinedu Orekie, Zhen Yang
Polyacrylic acid derivatives have also been studied to evaluate their influence on nasal absorption. Carbopol® 934 (0.5%) has been used as a model mucoadhesive to study the nasal delivery of levonorgestrel in rats. A liposomal formulation of levonorgestrel combined with Carbopol® 934 resulted in a bioavailability of 99% compared with 26% from the liposomal preparation alone [111]. Besides the gel-forming mucoadhesive properties of Carbopol® 934, the increase in the extent of absorption of levonorgestrel was attributed to the ability of Carbopol 934 to bind with extracellular calcium ions, which resulted in a significant opening of tight junctions to facilitate transcellular transport. This mechanism was suggested based on the measured decrease in TEER across Caco-2 cell monolayers in the presence of Carbopol® 934 [112].
Functional signatures of ex-vivo dental caries onset
Published in Journal of Oral Microbiology, 2022
Dina G. Moussa, Ashok K. Sharma, Tamer A Mansour, Bruce Witthuhn, Jorge Perdigão, Joel D. Rudney, Conrado Aparicio, Andres Gomez
Scanning electron microscope (SEM) analysis was conducted to validate if ex-vivo induced lesions show structural changes similar to the clinical carious lesions at the dentin-enamel junction area for the induced incipient or/and overt lesions. Slices of sound teeth were used as a control after a mild etching, pH = 1.95, with 25% polyacrylic acid (50,000 wt.%) in H2O to remove the smear layer with minimal associated demineralization. These specifications were reached after a few pilots testing a range of different polyacrylic acid concentrations (10%–25%), different molecular weights (2000–50,000 wt.%), different application time (5, 7, 10, and 15s), and different pH (1.5–3.2).