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Binders in Pharmaceutical Granulation
Published in Dilip M. Parikh, Handbook of Pharmaceutical Granulation Technology, 2021
Polyvinyl Alcohol is a well-established polymer in the pharmaceutical industry mainly due to its unique properties, such as excellent adhesive strength, film formation, and chemical stability (moisture and oxygen barrier properties). Its most widely used applications are tablet coating and wet granulation, but PVA also plays an important role in solubility enhancement, transdermal patches, and emulsions. This polymer is produced through the hydrolysis of polyvinyl acetate and typical pharmaceutical grades are partially hydrolyzed materials. PVA is available in a variety of viscosity grades and grades from 10 to 100 millipascal second (mPa.s) lend themselves for tablet granulation processes. PVA’s are water-soluble polymers. It is reported that they form softer granulations, which yield tablets that do not harden with age [9]. They can also be used in melt granulation applications. In addition, polyvinyl alcohol-polyethylene glycol graft copolymer was also developed as a flexible, low viscosity, peroxide-free polymer for immediate release film-forming agent. Studies have found that this graft copolymer has the superior binding performance to HPMC while the performance was comparable to PVP [10].
Principles and Methods of Ocular Pharmacokinetic Evaluation
Published in David W. Hobson, Dermal and Ocular Toxicology, 2020
The choice of vehicle for the application of a compound to the eye can severely affect the distribution, especially for topically applied drugs. Various chemicals have been used to enhance the retention of a topically applied drop on the ocular surface. Such compounds range from hydroxymethylcellulose, polyvinyl alcohol, polyvinylchloride, polyvinylpyrrolidone, and lanolin to the use of micronized materials, contact lenses soaked in the drug, and dissolving vehicles.19,38–43 Some materials have been used to increase the viscosity of the solutions and aid in the penetration of drugs into the eye through increasing the exposure time of the cornea to a higher concentration. Additionally, compounds such as EDTA are often used in ophthalmic preparations. The use of such calcium-chelating agents can enhance epithelial permeability. Calcium is a necessary ion for the maintenance of cell membrane integrity and cellular metabolism and its depletion could enhance epithelial permeability.
The human embryo: Vitrification Vitrification
Published in David K. Gardner, Ariel Weissman, Colin M. Howles, Zeev Shoham, Textbook of Assisted Reproductive Techniques, 2017
Zsolt Peter Nagy, Ching-Chien Chang, Gábor Vajta
Commonly used non-permeable cryoprotectants include monosaccharides and disaccharides, sucrose, tre- halose, glucose, and galactose (41–43). Recently, sucrose has become almost a standard component of vitrification mixtures. This is true even though nearly all comparative investigations proved the superiority of trehalose. Sucrose as well as other sugars may not have any toxic effects at low temperatures, but may compromise embryo survival when applied extensively to counterbalance embryo swelling after warming (44–46), although this effect was not always dem- onstrated (47). Several polymers were also suggested for the purpose, including polyvinylpyrrolidine, polyethylene gly- col, Ficoll, dextran and polyvinyl alcohol (48–53). However, from this group, the only widely used compound is Ficoll, predominantly in combination with ethylene glycol and sucrose (54). Various forms of protein supplementation have also been used, including egg yolk, but its optically dense appearance made microscopic manipulation rather diffi- cult. High concentrations of sera of different origins as well as serum albumin preparations (55) are common additives. In the bovine model, recombinant albumin and hyaluro- nan were also effective (56). On the other hand, the use of antifreeze proteins isolated from arctic animals (57–59) has largely been abandoned. More recently, hydroxypropyl cel- lulose was investigated as a replacement for serum-derived protein for use in cryoprotectant solutions, and results from its use have been promising (60, 61).
Antiviral and antibacterial potential of electrosprayed PVA/PLGA nanoparticles loaded with chlorogenic acid for the management of coronavirus and Pseudomonas aeruginosa lung infection
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2023
Asmaa Saleh, Dalia H. Abdelkader, Thanaa A. El-Masry, Duaa Eliwa, Badriyah Alotaibi, Walaa A. Negm, Engy Elekhnawy
Polyvinyl alcohol (PVA) is a non-toxic polymer approved for use in several devices, including contact lenses and artificial organs [16]. PVA is valuable for drug delivery formulations intended for alternate administration routes because of its advantages, biocompatibility and bioadhesiveness [18]. Furthermore, PVA's high water solubility offers additional advantages over conventional or complex drug preparation techniques, allowing safe preparation methods that do not harm pharmaceuticals during formulation [16]. Due to its biodegradability and biocompatibility, poly lactic-co-glycolic acid (PLG) has been widely utilized in multiple nanotechnology pharmaceutical applications. It has been approved by FDA [19,20]. Notably, few studies have investigated PVA/PLGA nano-formulations. For example, Panda et al. discussed the in vitro pharmaceutical characterization of PVA/PLGA nanofibres [21].
Dry powder formulation of azithromycin for COVID-19 therapeutics
Published in Journal of Microencapsulation, 2023
Stefanie Ho Yi Chan, Khalid Sheikh, Mohammed Gulrez Zariwala, Satyanarayana Somavarapu
Azithromycin dihydrate-loaded 50:50 poly(lactic-co-glycolic acid) (PLGA) nanoparticles were prepared by double emulsion method. 100 mg of PLGA and 10 mg of azithromycin dihydrate were dissolved in 10 ml of dichloromethane (DCM). 1 ml of 2% polyvinyl alcohol (PVA) solution was then added. This solution was emulsified for two minutes using a homogeniser (IKA Ultra-Turrax T-25 Digital Homogeniser) with 24,000 rpm to form the primary emulsion. This primary emulsion was added into 25 ml of the 0.5% PVA solution (for azithromycin only formulation) or 12.5 ml of 0.5% PVA solution and 12.5 ml of 0.1% chitosan oligosaccharide lactate solution (for azithromycin and chitosan formulation), and then emulsified by a homogeniser for five minutes. This secondary emulsion was then homogenised with a diluted (0.1%) PVA solution for a further five minutes. The emulsion was then left to stir at a temperature range of 40 °C – 45 °C for up to four hours to remove the solvent. Blank nanoparticles were prepared under the same conditions but with absence of the drug. For optimisation purposes, three different types of chitosan, i.e., chitooligosaccharide (CO), chitosan hydrochloride (CH), chitosan oligosaccharide lactate (COL), were used; and COL was chosen to be used in the formulations presented in this study.
Pharmaceutical, biomedical and ophthalmic applications of biodegradable polymers (BDPs): literature and patent review
Published in Pharmaceutical Development and Technology, 2022
Barzan Osi, Mouhamad Khoder, Ali A. Al-Kinani, Raid G. Alany
Polyvinyl Alcohol (PVA) is a synthetic, biodegradable, biocompatible and non-toxic polymer that has been widely used in ophthalmic drug delivery system (Jiang et al. 2011). PVA has excellent film-forming and mucoadhesive properties. PVA hydrogels can be made of PVA, or of blends of PVA with other polymers like gelatine (Santos et al. 2019). Gelatine is a natural polymer that is well-tolerated on ocular administration and has good mucoadhesive properties (Rashid et al. 2019). However, its unfavourable mechanical properties limit its potential application as a biomaterial. To overcome this limitation and improve the functional properties of gelatine, it is essential to modify it through physical or chemical methods, such as blending, cross-linking, and grafting (Rashid et al. 2019). Taking this into an advantage, Jain et al. formulated biosynthetic PVA–gelatine ocular inserts loaded with ciprofloxacin. Compared with eyedrops, the inserts showed superior mechanical, mucoadhesive and biocompatible properties, suggesting the PVA–gelatine polymeric blends as a promising material for antibiotic prolonged-release ocular inserts (Jain et al. 2011). Additionally, Terreni and co-workers were used PVA in combination with other mucoadhesive polymers to prepare hybrid nanomicelle-polymer inserts for improved delivery of cyclosporine A to the surface of the eye. The results were promising as the system demonstrated prolonged precorneal residence compared with eyedrops Ikervis® with no ocular adverse effects when tested in the rabbit eye (Terreni et al. 2021).