key: cord-0915518-wybh3egd
authors: Rasul, Ruhisy Mohd; Tamilarasi A/P Muniandy, M.; Zakaria, Zabliza; Shah, Kifayatullah; Chee, Chin Fei; Dabbagh, Ali; Rahman, Noorsaadah Abd; Won, Tin Wui
title: A review on chitosan and its development as pulmonary particulate anti-infective and anti-cancer drug carriers
date: 2020-08-18
journal: Carbohydr Polym
DOI: 10.1016/j.carbpol.2020.116800
sha: 8212a307841f7ad90a0f469f385cb8424a68b6b5
doc_id: 915518
cord_uid: wybh3egd

Chitosan, as a biodegradable and biocompatible polymer, is characterized by anti-microbial and anti-cancer properties. It lately has received a widespread interest for use as the pulmonary particulate backbone materials of drug carrier for the treatment of infectious disease and cancer. The success of chitosan as pulmonary particulate drug carrier is a critical interplay of their mucoadhesive, permeation enhancement and site/cell-specific attributes. In the case of nanocarriers, various microencapsulation and micro-nano blending systems have been devised to equip them with an appropriate aerodynamic character to enable efficient pulmonary aerosolization and inhalation. The late COVID-19 infection is met with acute respiratory distress syndrome and cancer. Chitosan and its derivatives are found useful in combating HCoV and cancer as a function of their molecular weight, substituent type and its degree of substitution. The interest in chitosan is expected to rise in the next decade from the perspectives of drug delivery in combination with its therapeutic performance.

The human lung is a biological system consisting of a series of tissues and organs that are responsible for the process of respiration (Leslie & Wick, 2018) . Functionally, the lung is constituted of a conducting airway and a respiratory region. The conducting airway consists of nasal cavity, oral cavity and the associated sinuses, nasopharynx, oropharynx, larynx, trachea, bronchi, and bronchioles, whilst the respiratory region is divided into respiratory bronchioles, alveolar ducts, alveolar sacs and alveoli. The conducting airway conditions and conducts atmospheric air, while the respiratory region assists in the exchange of oxygen and carbon dioxide (Ruigrok, Frijlink, & Hinrichs, 2016) . The lung provides a remarkably thin interface of approximately 0.2 µm to 0.7 μm between the alveolar lumen and capillary lumen, enabling fast and effective physiological respiration when combined with its large specific surface area (Shah, Shah, & Chivate, 2012; ; Ruigrok et al., 2016) . The alveolar epithelium has type I and type II alveolar cells. Alveolar type I cell is a thin squamous cell acting as a barrier between air and internal components of the alveolar wall covering 95 % of the alveolar surfaces. Alveolar type II cell acts in the regeneration of type I and II cells, producing lung surfactant and covering 5 % of the alveolar surfaces . The alveoli surface contains brush cells and macrophages.

Inhalation is a non-invasive, organ-specific method of delivering the therapeutics to the lungs for the treatment of lung diseases (Kuzmov & Minko, 2015) . Further, the cell-and organellespecific pulmonary drug delivery can be introduced via decorating the drug carrier with specific J o u r n a l P r e -p r o o f

The most common lung diseases include asthma, pulmonary hypertension, chronic obstructive pulmonary disorder, acute respiratory distress syndrome in infants, cystic fibrosis, lung infections such as pneumonia and tuberculosis, and lung cancer (Alhajj et al., 2018; Paranjpe & Müller-Goymann, 2014) . These diseases alter the normal physiology of the lung by airways constriction, mucus thickening, fibrosis and poor blood circulation, and hence affect the deposition profile of inhaled drugs (Borghardt, Kloft, & Sharma, 2018) . In most of the pulmonary disorders, the airways are sufficiently narrowed and this results in increased deposition of inhaled drugs in the upper airway by impaction (Darquenne, 2012) . The residence time of particles in the lungs is mainly dependent on air flow rate, inhaled and exhaled volume, and end-inspiratory breath hold of patients. A deep, slow breathing allows a longer residence time and gives the inhaled particles much more time to deposit by sedimentation and diffusion especially at the peripheral lung (Löndahl et al., 2014) . The residence time in the lungs can be further increased by end-inspiratory breath holding. The alveolar deposition increases with increasing inhaled volume or penetration depth of the aerosol into the lung. Fast and shallow breath on the other hand increases the deposition of particles in the extrathoracic airways by impaction.

Lactose receives a widespread application in the development of inhalation medicine specifically with respect to dry powder aerosol (Molina, Kaialy, Chen, Commandeur, & Nokhodchi, 2018; Lee et al., 2018; Pinto, Zellnitz, Guidi, Roblegg, & Paudel, 2018; Zhou & Morton, 2012) . This is attributed to stability, better flow properties and safety of lactose in dry powder inhaler formulations (Smyth & Hickey, 2005) . The sugars such as lactose, mannitol, sorbitol and dextran are potentially applied as carriers in inhalational drug delivery (Odziomek, Sosnowski, & Gradoń, 2012) . However, lactose is the only approved carrier in dry powder inhaler formulations (Molina et al., 2018) .

The United States Food and Drug Administration (US FDA) stated two 'points to consider' in determining whether an FDA-regulated product involves the application of nanotechnology:

(I) whether a material or end product is engineered to have at least one external dimension or an internal or surface structure, in the nanoscale range (approximately 1 nm to 100 nm); or (II) whether a material or end product is engineered to exhibit properties or phenomena, including J o u r n a l P r e -p r o o f physical or chemical properties or biological effects, that are attributable to its dimension(s), even if these dimensions fall outside the nanoscale range, up to one µm (1000 nm) (Sheshala, Anuar, Abu Samah, & Wong, 2019) . With the advent of nanotechnology, the nanocarrier is recently advocated in pulmonary medicine design for the following advantages: (I) the carrier is characterized by an excessively large specific surface area that enables them to interact with the intended lung cells, (II) the carrier may be equipped with targeting ligand for cell-and organellespecific drug targeting, (III) the cellular uptake of particles by lung cells is promoted, (IV) decrease drug dosages due to lower enzymatic activity and hence reduce side effects, and (V) improve the performance of imaging techniques applied for the in vivo diagnosis of lung cancer (Alhajj et al., 2018; Smola, Vandamme, & Sokolowski, 2008) .

Chitin is considered as one of the major sources of nitrogen accessible to countless living terrestrial and aquatic organisms (Elieh-Ali-Komi & Hamblin, 2016) . It is a major constituent of the exoskeleton of many arthropods like insects, spiders and crustaceans and the internal structures of other invertebrates (Brigham, 2018) . The chitin is constituted of β (1→4) linked residues of N-acetyl-2-amino-2-deoxy-D-glucose and 2-amino-2-deoxy-D-glucose (Elieh-Ali- Komi & Hamblin, 2016) . It exhibits an extremely poor aqueous solubility due to its highly crystalline characteristics which are brought about via hydrogen bonding between the acetamido moieties (Uto, Idenoue, Yamamoto, & Kadokawa, 2018; Zhu et al., 2016) . The partially deacetylated chitin is water-soluble (Muzzarelli, Muzzarelli, Cosani, & Terbojevich, 1999; Ying, Xiong, Wang, Sun, & Liu, 2011) . The lowest possible degree of deacetylation in chitin can be less than 10 % with molecular weight as high as 1-2.5 x 10 6 Da and parallel to a degree of polymerization of approximately 5000 to 10000 monomeric residues (Chawla, Kanatt, & Sharma, 2015) . Chitosan is the most important derivative obtained by N-deacetylation of chitin with hot alkali (Figure 1 ) (Antonino et al., 2017 J o u r n a l P r e -p r o o f The degree of deacetylation of chitosan ranges from 40 % to 98 % with its molecular weight ranging between 5 x 10 4 Da and 2 x 10 6 Da ( Figure 1 ) (Antonino et al., 2017; Chawla et al., 2015; Hejazi & Amiji, 2003; Mourya & Inamdar, 2008) . Deacetylation of chitin provides chitosan with free amino functional groups that are readily protonated to induce polymer solubilisation or chemically reacted and grafted to produce new chitosan derivatives with specific physicochemical and biological properties (Table 1) . N-propyl-N,N-dimethyl chitosan, N-furfuryl-N,N dimethyl chitosan, Ndiethylmethylamino chitosan. Highly positively charged. Strong film forming properties. Compatible with cations. Forms complexes with anions. Improved aqueous solubility at pH < 9. Enhanced intestinal permeation property. Improved mucoadhesive property. Biodegradable. Cytotoxic. Anti-bacterial. Anti-fungal. Potent hydroxyl radical scavenger. Avadi et al., 2004; Cano-Cebrian, Zornoza, Granero, & Polache, 2005; Ding, Xia, & Zhang, 2006; Fee et al., 2003; Guo, Liu, Chen, Ji, & Li, 2006; Guo et al., 2007; Holappa, Nevalainen, Soininen, Másson, & Järvinen, 2006; Je & Kim, 2005; Jia, Shen, & Xu, 2001; Kotze et al., 1997; Lee, Lim, & Kim, 2002; Lim & Hudson, 2004;  J o u r n a l P r e -p r o o f Rúnarsson et al., 2007; Singla & Chawla, 2001 Formyl, acetyl, propionyl, butyryl, hexanoyl, octanoyl, decanoyl, carbanoyl, succinyl, acetoxybenzoyl chitosans. Hygroscopic. Biodegradable. Amphiphatic hydrogel with excellent water-absorption and water retention abilities. Anti-cancer drug carrier. Anti-bacterial. Cyto-compatible with chondrocytes. Excellent transfection efficiency. Facilitated endocytic uptake. Guo et al., 2006; Hu et al., 2007; Lee et al., 2002; Mansouri et al., 2006; Ravi Kumar, 2000; Xiangyang et al., 2007 polyphosphoric acid to confer specific drug delivery properties (Arriagada et al., 2004; Gnavi et al., 2013; Hamman, 2010; Quiñones, Peniche, & Peniche, 2018) . Through varying its molecular weight and degree of deacetylation, the chitosan can be transformed into nanocarrier with the intended sizes and zeta potentials (Mao, Sun, & Kissel, 2010) . Chitosan is a plastic material which is mouldable into amorphous forms (Dang et al., 2017) . Its molecular chains can be compacted at nanoscale as a function of formulation and processing conditions via hydrogen J o u r n a l P r e -p r o o f bonding, electrostatic interaction and/or Van der Waals forces (Zhang, Chan, Moretti, & Uhrich, 2015) . Being polysaccharidic, chitosan is mucoadhesive and possesses viscous attribute that is essential in drug encapsulation, drug release and drug absorption kinetics modulation (Quiñones et al., 2018) . As a cationic polyelectrolyte, the chitosan has a high affinity for the negatively charged mucosal interface that is rich in sialic acid and O-sulfosaccharides (Zhang et al., 2015) .

Chitosan is able to reduce the transepithelial electrical resistance of epithelial membranes by disrupting tight junctions between the epithelial cells (Yeh et al., 2011) . It can loosen the tight junction of mucosa via the translocation of tight junction proteins from the membrane to the cytoskeleton through Protein Kinase C pathway, thereby promoting drug transport paracellularly and transcellularly (Rosenthal et al., 2012; Smith, Dornish, & Wood, 2004 . Chitosan is biodegradable and biocompatible (Rodrigues, Dionísio, López, & Grenha, 2012; Saber, Strand, & Ulfendahl, 2010) . It is known as a therapeutic polymer which possesses anti-cancer (Azuma, Osaki, Minami, & Okamoto, 2015) , anti-bacterial (Goy, Britto, & Assis, 2009; Kara, Aksoy, Yuksekdag, Hasirci, & Aksoy, 2014; Rabea, Badawy, Stevens, Smagghe, & Steurbaut, 2003) , anti-fungal (Menconi et al., 2014; Tayel et al., 2010; Verlee, Mincke, & Stevens, 2017) , antioxidative (Ngo et al., 2015) , anti-inflammatory (Azuma et al., 2015) and anti-diabetic activities (Liu, Chang, & Chiang, 2010; Ngo et al., 2015) . On this note, the potential of chitosan for use in the development of pulmonary medicine is deemed to be higher than that of lactose. With reference to cancer nanomedicine, the physicochemical attributes of the chitosan-based drug carrier such as size, shape, surface charge, surface morphology, targeting ligand availability and its nature are found to critically dictate the effectiveness of cell targeting, internalization and anti-tumour action of cancer therapeutics (Musalli et al., 2020; Wang et al., 2017) . Small, spherical and positively charged nanocarriers with reduced surface area to interrupt the cancer cell membrane and enhanced affinity for the negatively charged cancer cell surfaces favour cellular uptake. The use of a sublevel or an excessive fraction of targeting ligand translates to inadequate nanocarrier-cancer cell surface receptor interaction and poor intracellular therapeutic availability due to insufficient ligand or steric hindrance of overcrowded ligands in receptor binding. Similar findings are observed in the case of infection nanomedicine. In infectious diseases such as pulmonary tuberculosis, drug targeting at the alveolar macrophages is of paramount importance as these are the residence site of tubercle bacilli (Shah, Chan, & Wong, 2017) . The hydrophobic carrier exhibits a higher degree of opsonisation by macrophages. The 

Pulmonary infection represents one of the significant burdens to healthcare system worldwide, and this includes infection caused by bacteria (Mycobacterium tuberculosis, Pseudomonas aeruginosa, Streptococcus pneumonia), fungi (Aspergillus fumigates) and viruses (influenza virus A, influenza virus B, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)) (Brenner, McLaughlin, & Hung, 2011; Muttil, Wang, & Hickey, 2009; Wang, Wang, Ye, & Liu, 2020; Wu et al., 2020) . The infection can be fatal in immuno-compromised patients and those with underlying pulmonary dysfunctions (Merchant et al., 2016) . The infection mostly involves treatment with anti-inflammatory and anti-infective agents. Conventionally, these drugs are commonly delivered via oral or parenteral routes. The systemic administration of drugs may be accompanied by inadequate drug concentration at the site of the infected lung, rapid declination of plasma drug concentration to sub-therapeutic level and development of microbial resistance. Local drug delivery by inhalation is envisaged to resolve such hurdles. Drug delivery system development using chitosan is foreseeable to benefit from its anti-microbial activity. The chitosan is mucoadhesive (Oliverira et al., 2017) . It can bind to the lipopolysaccharides and phosphoryl groups of the bacterial cell membrane via its protonated amino moieties (Garg, Rath, & Goyal, 2015; Mohammed, Syeda, Wasan, & Wasan, 2017; Park, Saravanakumar, Kim, & Kwon, 2010) . The adhesion elicits intracellular transductions of enzymes and blockage of electron transport, membrane perforation and intracellular electron leakage which eventually destroy or prevent the growth of bacterial cells (Dutta, Tripathi, & Dutta, 2012; Pourshahab, et al., 2011; Rabea et al., 2003) . The other proposed mechanism is the binding of chitosan with microbial DNA, which leads to the inhibition of the mRNA and protein synthesis via the penetration of chitosan into the nuclei of the microorganisms (Goy et al., 2009; Sebti, Martial-Gros, Carnet-Pantiez, Grelier, & Coma, 2005) . The positively charged chitosan can also interfere with the microbial growth by selectively binding with the essential nutrients of microbes (Chen, Chung, Wang, Chen, & Li, 2002; Jia et al., 2001) . The low molecular weight chitosan with J o u r n a l P r e -p r o o f higher degrees of deacetylation and charge densities is reported to exhibit a higher level of antimicrobial activity (Goy et al., 2009; Kong, Chen, Xing, & Park, 2010; Park et al., 2010) . The negative charge on the cell surface of the gram-negative bacteria is higher than that of grampositive bacteria (Chung et al., 2004; Tayel et al., 2010) . The former is relatively hydrophilic thereby leading to more chitosan being adsorbed onto the cell surfaces and having them experiencing a higher growth inhibitory effect.

Tuberculosis is a chronic granulomatous airborne bacterial infection caused by M.

tuberculosis (Mehta, Bothiraja, Kadam, & Pawar, 2018) . This contagious infectious disease occurs through inhalation of tubercular bacilli infected droplets present in the size range of 1 μm to 5 μm, that remain suspended in the air from minutes up to several hours (Fernstrom & Goldblatt, 2013; Muttil et al., 2009 ). The small size of droplet nuclei enables them to evade bronchial defense system and reach the alveoli (Pham, Fattal, & Tsapis, 2015) . The bacterium can be engulfed by alveolar macrophages, replicated intracellularly and further infected the surrounding cells before the development of an immune response (Kinhikar et al., 2010) . The M.

tuberculosis has a tendency to infect non-phagocytic cells present in the alveolar region such as With reference to direct blending of chitosan nanoparticles with lactose based microparticles, it is found that the size, shape and specific surface area of the nanoparticles have a strong bearing on the inhalation efficiency of the nanoparticles (Alhajj et al., 2019) . Small and irregularly shaped nanoparticles with a large specific surface area tend to aggregate among themselves instead of depositing onto the microparticulate surfaces. As a result, their inhalation propensity J o u r n a l P r e -p r o o f to deep and peripheral lungs has been found to be lower than those of larger and rounder nanoparticles. Direct blending of nanoparticles with microparticles is envisaged to circumvent several drug delivery hurdles of the microencapsulated nanoparticles (Alhajj et al., 2019; Garbuzenko, Mainelis, Taratula, & Minko, 2014; Mehta, 2016) . Unlike the microencapsulated systems, the changes in nanoparticulate sizes are less likely with blending thus the sizedependent biological performances of the nanoparticles are less affected (Alhajj et al., 2019 ).

The blending system is characterized by nanoparticles depositing onto the surfaces of the microparticles (Alhajj et al., 2019) . The nanoparticles have a high level of redispersibility. They can be detached and inhaled into the lung targets with lower risks of being captured in the core of the microencapsulated vehicle without them releasing to the lung targets.

In the case of nanoemulsion, it is delivered via the pulmonary route by means of nebulization approach (Amani, York, Chrystyn, & Clark, 2010) . Liquid dosage form such as nanoemulsion commonly exhibits a high level of dispersion and inhalation to peripheral lungs (Amani et al., 2010; Shah et al., 2017) . The alveolar macrophages are characterized by cell surface leptin receptor of mannose specificity (Filatova, Klyachko, & Kudryashova, 2018) . The chitosan is known to be able to be recognized by alveolar macrophages. The nanoemulsion droplets have been decorated with chitosan to enable drug targeting at macrophages which harbor T. bacilli (Shah et al., 2017) . The folate receptors are also expressed on the cell surfaces of activated alveolar macrophages (Jain, Mishra, & Mehra, 2013) . Decoration of nanoemulsion droplets by chitosan and folate in the form of a covalent conjugate has been found to enhance the endocytosis of particles into the macrophages and lung drug retention (Shah et al., 2017) . The dual receptor targeting is more effective than single receptor strategy, and is expected to bring about a higher degree of bacteria eradication from the macrophages and infected lung.

The derivatives of chitosan such as carboxymethyl chitosan and octanoyl chitosan have been synthesized with the aim to prepare the nanocarrier of anti-tubercular drugs (Petkar et al., 2018) .

The mono-N-carboxymethyl chitosan has been reported to be able to decrease the transepithelial electrical resistance of Caco-2 cell monolayers thereby can act as a membrane permeation enhancer (Jayakumar et al., 2010) . The acylation of chitosan using acyl chlorides and anhydrides confers organic solubility and increases the hydrophobicity of chitosan without incurring cytotoxicity. The hydrophobic octanoyl chitosan has been used to prepare crosslinker-free nanoparticles by means of double emulsion solvent evaporation technique for pulmonary J o u r n a l P r e -p r o o f delivery of rifampicin. The positively charged nanoparticles are equipped with drug release controlling ability of octanoyl derivative, and higher mucoadhesive and membrane permeation enhancement properties along with resistance to enzymatic degradation than that of plain chitosan (Ahmed & Aljaeid, 2016; Petkar et al., 2018) . The chitosan based nanoparticles are electrostatically attracted to the negatively charged sialic acid present on the surfaces of lung alveolar macrophages. An enhancement in the binding affinity between the nanoparticles and the macrophages leads to a greater extent in uptake of drug and nanoparticles by the alveolar macrophages harboring the T. bacilli (Rawal et al., 2017) . Both passive membrane adhesion and active receptor binding of nanoparticles are promotable with the use of particulate carrier characterized by positive surface charges.

Cystic fibrosis is an inherited autosomal recessive disease of the lung characterized by the production of viscid mucus which leads to the dysfunction of lung microorganism clearance system (Garbuzenko et al., 2019) . The chronic inflammation and bacterial infection specifically by P. aeruginosa result in respiratory failure of the cystic fibrosis patients (Ng, Flight, & Smith, 2014) . Tobramycin, aztreonam and colistimethate, a prodrug of colistin, are available as inhalational products that represent a valuable alternative to solution for injection or oral therapy.

Phase 2b trial of levofloxacin inhalation solution demonstrates that the sputum content of P.

aeruginosa is reduced with the lung function improved in cystic fibrosis patients (Gaspar et al., 2015; Stockmann, Sherwin, Ampofo, & Spigarelli, 2014) . The inhaled formulations with an aerodynamic diameter of 1 µm to 5 µm are suitable for deep lung deposition, but particles of 1 µm to 5 µm are also favorably phagocytosed by the resident macrophages. This poses toxicity to macrophages and could have reduced the availability of drug at the intended target site. The inhaled microparticles are designed with the ability to swell upon hydration following their deposition in the lung epithelial lining fluid in order to bypass macrophage uptake (Chaubey & Mishra, 2014) . Chitosan as a swellable biopolymer, on this note, have been effectively utilized in the development of inhalable dosage forms for cystic fibrosis treatment (Table 2) J o u r n a l P r e -p r o o f

The global incidence of cancer rises to 18.1 million newly diagnosed cases, with 9.6 million deaths in 2018 (Bray et al., 2018) . Lung cancer is one of the major causes in worldwide cancer related mortalities (Wang et al., 2017) . It is histologically divided into small cell lung carcinoma and non-small cell lung carcinoma representing 96 % of the cases, and mesothelioma, carcinoid, and sarcoma (Alhajj et al., 2018) . 

Similar to anti-tubercular drugs (Table 2) , the chitosan based particulate carriers of anticancer drugs are developed by means of ionic gelation, emulsification and/or spray drying methods (Table 3) . Further, nanoprecipitation and chemical vapor deposition are adopted to produce chitosan nanoparticles containing lipid or carbon based composition. Microparticles or microencapsulated nanoparticles are produced to elicit aerodynamic behavior required for pulmonary inhalation (Liu et al., 2017; Rosière et al., 2018; Silva et al., 2017) . Targeting ligand such as folate and hyaluronic acid, and permeation enhancer such as gallic acid are introduced to the backbone of chitosan for the purpose of raising the affinity of carrier with cancer target and cellular permeabilisation (Almutairi, Abd-Rabou, & Mohamed, 2019; Rosière et al., 2018) .

Quercetin can be used as the p-glycoprotein inhibitor, along with the drug to reduce drug efflux from the cancer cells (Liu et al., 2017) . The particle sizes of the carrier for targeting lung tumor are within the range of 50 nm to 9.6 µm ( Table 3) The chitosan, specifically the oligosaccharide variants, exhibits anti-cancer activity (Chokraadjaroen et al., 2017; Gibot et al., 2015; Oberemko et al., 2019; Rafael et al., 2019) . Its anti-cancer mechanism is generally not known, but it is presumably associated with its electrostatic charges, changes in membrane permeability of cancer cells, regulation of expression of tumor factor such as metalloproteinase-9 and/or vascular endothelial growth factor, and proapoptotic effects. The significance of positive charges of chitosan in combating cancer growth is reflected by quaternized chitosan derivatives being more selective and potent as a cancer therapeutic than the native chitosan (Chokraadjaroen et al., 2017) . (Table 3) . Aerodynamic characterization and in vivo examination of the functionality of these particles through natural inhalation is required to elucidate their actual possible therapeutic performance.

The nanoparticles are prone to exhalation and susceptible to mucociliary transport (Lee, Loo, Traini, & Young, 2015b). With diameters larger than 200 nm, they have shown to induce non-specific scavenging by monocytes and reticuloendothelial system (Wang et al., 2017) with phagocytosis by the alveolar macrophages (Patel, Gupta, & Ahsan, 2015) . The conversion of nanoparticles into microparticulate system larger than 6 µm mass median aerodynamic diameter translates to particle deposition at the upper airways and elimination by mucociliary clearance in the epithelia tissue (Dabbagh, Abu Kasim, Yeong, Wong, & Abdul Rahman, 2018) . Particles with mass median aerodynamic diameter of 1 µm to 5 µm, though are accumulated in the narrower airways and evade mucociliary clearance, have their fraction between 2 µm and 3 µm prone to be recognized and eliminated by the resident alveolar macrophages (Lee et al., 2015a) .

In order to circumvent the above hurdles for the purpose of efficient drug delivery to lung cancer cells, it has been suggested to encapsulate nanocarriers with particle sizes of less than 200 nm into the microparticles with mass median aerodynamic diameters ranging from 3 µm to 5 µm (Dabbagh et al., 2018) .

J o u r n a l P r e -p r o o f The polymeric microspheres act as a platform to deliver the nanoparticles to lungs, with mannitol and lactose serving as disintegrant to release the nanoparticles at the target site. The OA-C nanoparticles, PTX-OA-C nanoparticles and QUE-OA-C nanoparticles are adopted to promote cellular drug uptake via nanogeometry of particles and permeation enhancement property of oleic acid.

The tissue distribution of PTX and QUE in the lung is significantly higher than heart, liver, spleen and kidney.

F2 3,4,5tribenzyloxybenzoic acid (GAOBn) loaded gold nanoparticles stabilized by quaternized chitosangallic acid-folic acid as a cancer-targeting drug delivery system are prepared by chemical reduction method consisting of two major steps: reduction and stabilization processes.

Spherical particles with a size of 33 ± 9 nm, a size distribution of 0.276 ± 0.050 and a zeta potential of 25.9 ± 0.4 mV are produced. size distribution (length in a range of 110-980 nm, an average inner diameter of 0.7 to 1.5 nm, and an outer diameter of 5 to 8 nm corresponding to 4 to 7 graphene shells).

The coat composition of CS-MWCNT nanohybrid is evident from chemical analysis, Raman spectroscopy and thermogravimetric evaluation. The coat content is about 20 %.

The release of methotrexate from nanohybrid follows a pH-responsive behaviour with higher and faster release in acidic (pH 5.50) against neutral (pH 7.4) environments.

(non-small cell lung cancer derived from the lymph node) and MRC-5 cells (fibroblast derived from normal lung tissue). It exhibits a high biocompatibility .

The drug loaded CS-MWCNT is highly selective in killing of cancer cells. They are found to possess equal or even more activity on cancer cells than free drugs. The H1299 cells viability is reduced by 15 % when free drug is used in treatment, while the drug loaded CS-MWCNT significantly increases the amount of cell healthy MRC-5 cells. This system is successful at reducing side effects of methotrexate to normal tissues and cells.

Chitosan and its derivatives are excellent backbone materials of nano and microparticulate carriers for pulmonary delivery of anti-infective and anti-cancer drugs, with respect to their biodegradability, biocompatibility, mucoadhesive, anti-microbial, anti-tumour, and permeation enhancement properties. They have been investigated for their suitability of use as the pulmonary particulate carrier lately, deviating from the conventional application of lactose as the main drug carrier. The exploitation of chitosan and derivatives is relatively recent, and requires in depth analysis including in vitro aerodynamic characterisation and in vivo examination of the pharmacokinetics and functionality of these particles through natural inhalation to relate to the actual therapeutic performance.

Infection with SARS-CoV-2 brings about coronavirus disease that leads to acute respiratory distress syndrome, and the patients with cancer appear to be more likely to be diagnosed with COVID-19 (Sidaway, 2020) . The late innovations of chitosan have found the therapeutic uses of this biopolymer to combat coronavirus related diseases and cancer. N-(2-hydroxypropyl)-3trimethylammonium chitosan chloride with an average molecular weight of 250 kDa and degree of substitution between 50 % and 80 % have been shown to exert a strong interaction with the recombinant ectodomain of the S protein of HCoV, thus blocking S protein-host cellular interaction and virus infection (Milewska et al., 2016) . Chito-oligosaccharides (molecular weight = 1000 to 12000 Da, degree of deacetylation = 65 to 70 %), prepared via electrical discharge plasma treatment of chitosan in the liquid state, induce apoptotic death in MCF-7 breast cancer cells (Chokradjaroen et al., 2018) . The chito-oligosaccharides have also been found to be effective in killing of PC3 (prostate cancer cells), A549 (lung cancer cells) and HepG2

(hepatoma cells) with lower molecular weights being more effective than larger molecular weight counterparts. The late findings of chitosan and derivatives as therapeutic molecules to treat infection and cancer are envisaged to initiate an intense research interest combining the drug delivery as well as drug discovery attributes of this biomaterials. Their structural-activity relationships in association with coronavirus disease and lung cancer treatment are of great interest from the therapeutic and drug delivery performance viewpoints at molecular levels.

J o u r n a l P r e -p r o o f

Inhalable particulate drug delivery systems for lung cancer therapy: Nanoparticles, microparticles, nanocomposites and nanoaggregates

Recent advances on chitosan-based micro-and nanoparticles in drug delivery

Preparation, characterization, and potential application of chitosan, chitosan derivatives, and chitosan metal nanoparticles in pharmaceutical drug delivery. Drug Design

Lung cancer: active therapeutic targeting and inhalational nanoproduct design

Critical physicochemical attributes of chitosan nanoparticles admixed

microparticles in pulmonary inhalation

Raloxifene-encapsulated hyaluronic acid-decorated chitosan nanoparticles selectively induce apoptosis in lung cancer cells

Evaluation of a Nanoemulsion-Based Formulation for Respiratory Delivery of Budesonide by Nebulizers

Preparation and characterization of chitosan obtained from shells of shrimp (Litopenaeus vannamei Boone)

Cisplatin-based adjuvant chemotherapy in patients with completely resected non-small-cell lung cancer

Diethylmethyl chitosan as an antimicrobial agent: Synthesis, characterization and antibacterial effects

Anticancer and anti-inflammatory properties of chitin and chitosan oligosaccharides

Fungicidal and insecticidal activity of O-acyl chitosan derivatives

Chemically modified chitosans as enzyme inhibitors

Bio-inspired synthesis of chitosan/copper oxide nanocomposite using rutin and their anti-proliferative activity in human lung cancer cells

Inhaled Therapy in Respiratory Disease: The Complex Interplay of Pulmonary Kinetic Processes

Global cancer statistics 2018: GLOBOCAN estimates of incidence and mortality worldwide for 36 cancers in 185 countries

Previous lung diseases and lung cancer risk: A systematic review and meta-analysis

Biopolymers: Biodegradable alternatives to traditional plastics

Intestinal Absorption Enhancement Via the Paracellular Route by Fatty Acids, Chitosans and Others: A Target for Drug Delivery

Alveolar epithelium in lung toxicology

Mannose-conjugated chitosan nanoparticles loaded with rifampicin for the treatment of visceral leishmaniasis

Polysaccharides

Antibacterial properties of chitosan in waterborne pathogen

Synthesis and anti-metastasis activities of norcantharidin-conjugated carboxymethyl chitosan as a novel drug delivery system

Relationship between antibacterial activity of chitosan and surface characteristics of cell wall

Enhanced degradation of chitosan by applying plasma treatment in combination with oxidizing agents for potential use as an anticancer agent

Cytotoxicity against cancer cells of chitosan oligosaccharides prepared from chitosan powder degraded by electrical discharge plasma

Combining carbon nanotubes and chitosan for the vectorization of methotrexate to lung cancer cells

Critical influential parameters in particle-based pulmonary delivery of chemotherapeutics

Water-soluble chitosan-derived sustainable materials: towards filaments, aerogels, microspheres, and plastics

Aerosol Deposition in Health and Disease

Development and evaluation of chitosan nanoparticles based dry powder inhalation formulations of prothionamide

Synthesis of metallic nanoparticles protected with N,N,N-trimethyl chitosan chloride via a relatively weak affinity

Progress in antimicrobial activities of chitin, chitosan and its oligosaccharides: A systematic study needs for food applications

Chitin and Chitosan: Production and Application of Versatile Biomedical Nanomaterials

Correlation of SEC/MALLS with ultracentrifuge and viscometric data for chitosans

Aerobiology and Its Role in the Transmission of Infectious Diseases

Targeted delivery of antituberculosis drugs to macrophages: targeting mannose receptors

In vivo evaluation of an oral delivery system for P-gp substrates based on thiolated chitosan

Biological obstacles for identifying in vitro-in vivo correlations of orally inhaled formulations

Inhalation treatment of cystic fibrosis with lumacaftor and ivacaftor co-delivered by nanostructured lipid carriers

Inhalation treatment of lung cancer: the influence of composition, size and shape of nanocarriers on their lung accumulation and retention

Inhalable chitosan nanoparticles as antitubercular drug carriers for an effective treatment of tuberculosis

Optimization of levofloxacin-loaded crosslinked chitosan microspheres for inhaled aerosol therapy

Cremophor EL: the drawbacks and advantages of vehicle selection for drug formulation

Mycobacterium tuberculosis: Success through dormancy

Anticancer properties of chitosan on human melanoma are cell line dependent

The use of chitosan-based scaffolds to enhance regeneration in the nervous system

A review of the antimicrobial activity of chitosan

A proposed definition of the activity of surface sites on lactose carriers for dry powder inhalation

Hydroxyl radicals scavenging activity of Nsubstituted chitosan and quaternized chitosan

Antifungal properties of Schiff bases of chitosan, N-substituted chitosan and quaternized chitosan

Chitosan based polyelectrolyte complexes as potential carrier materials in drug delivery systems

A simple rheological method for the in vitro assessment of mucin-polymer bioadhesive bond strength

Chitosan-based gastrointestinal delivery systems

Synthesis of Novel Quaternary Chitosan Derivatives via N -Chloroacyl-6-O -triphenylmethylchitosans

Effect of Zeta Potential on the Properties of Nano -Drug Delivery Systems -A Review (Part 2)

Self-aggregation and antibacterial activity of N-acylated chitosan

A new approach to chemically modified chitosan sulfates and study of their influences on the inhibition of Escherichia coli and Staphylococcus aureus growth. Reactive and Functional Polymers

Proteoglycan form and function: A comprehensive nomenclature of proteoglycans

Targeted drug delivery to macrophages

Novel carboxymethyl derivatives of chitin and chitosan materials and their biomedical applications

Water-soluble chitosan derivatives as a BACE1 inhibitor

Synthesis and antibacterial activities of quaternary ammonium salt of chitosan

Synthesis and surface modification of polyurethanes with chitosan for antibacterial properties

Sulfation of chitosan oligomers enhances their anti-adipogenic effect in 3T3-L1 adipocytes

Chitosan-thioglycolic acid conjugate: a new scaffold material for tissue engineering?

Potential role for ESAT6 in dissemination of M. tuberculosis via human lung epithelial cells

Antioxidant and antimutagenic activity of N-(2-carboxyethyl)chitosan

Nanogold-Gallate Chitosan-Targeted Pulmonary Delivery for Treatment of Lung Cancer

Antimicrobial properties of chitosan and mode of action: A state of the art review

N-trimethyl chitosan chloride as a potential absorption enhancer across mucosal surfaces: In vitro evaluation in intestinal epithelial cells (Caco-2)

Oral insulin delivery: the potential of thiolated chitosan-insulin tablets on non-diabetic rats

Synthesis and antimicrobial activity of a water-soluble chitosan derivative with a fiber-reactive group

Paclitaxel and quercetin nanoparticles co-loaded in microspheres to prolong retention time for pulmonary drug delivery

Chitosan Reduces Gluconeogenesis and Increases Glucose Uptake in Skeletal Muscle in Streptozotocin-Induced Diabetic Rats

Measurement techniques for respiratory tract deposition of airborne nanoparticles: a critical review

Preparation and in vitro evaluation of thiolated chitosan microparticles

Nanocarrier-based systems for targeted and site specific therapeutic delivery

Characterization of folate-chitosan-DNA nanoparticles for gene therapy

Chitosan-based formulations for delivery of DNA and siRNA

Dry Powder Inhalers: A focus on advancements in novel drug delivery systems

Potential of dry powder inhalers for tuberculosis therapy: facts, fidelity and future

Effect of Chitosan on Salmonella Typhimurium in Broiler Chickens

Development of chitosan-based dry powder inhalation system of cisplatin for lung cancer

A new era of pulmonary delivery of nano-antimicrobial therapeutics to treat chronic pulmonary infections

HTCC: Broad range inhibitor of coronavrius entry

An overview of chitosan nanoparticles and its application in non-parenteral drug delivery

In vitro investigation of influences of chitosan nanoparticles on fluorescein permeation into alveolar macrophages

Agglomerated novel spray-dried lactose-leucine tailored as a carrier to enhance the aerosolization performance of salbutamol sulfate from DPI formulations

Biological Activities of Carbohydrate-Branched Chitosan Derivatives

Chitosan-modifications and applications: Opportunities galore. Reactive and Functional Polymers

Inhalable nanoparticulate powders for respiratory delivery

Folate-induced nanostructural changes of oligochitosan nanoparticles and their fate of cellular J o u r n a l P r e -p r o o f internalization by melanoma

Inhaled Drug Delivery for Tuberculosis Therapy

6-Oxychitins, novel hyaluronan-like regiospecifically carboxylated chitins

Pulmonary complications of cystic fibrosis

Biological effects of chitosan and its derivatives

Regioselective syntheses of sulfated polysaccharides: specific anti-HIV-1 activity of novel chitin sulfates

Physicochemical effects of lactose microcarrier on inhalation performance of rifampicin in polymeric nanoparticles

Physicochemical and in vitro cytotoxic properties of chitosan from mushroom species (Boletus bovinus and Laccaria laccata)

Conception, preparation and properties of functional carrier particles for pulmonary drug delivery

Microparticles prepared with 50-190 kDa chitosan as promising non-toxic carriers for pulmonary delivery of isoniazid

Development of Novel Chitosan Microcapsules for Pulmonary Delivery of Dapsone: Characterization, Aerosol Performance, and In Vivo Toxicity Evaluation

Erlotinib loaded chitosan nanoparticles: Formulation, physicochemical characterization and cytotoxic potential

Nanoparticle-mediated pulmonary drug delivery: A review

Targeted delivery of low molecular drugs using chitosan and its derivatives

Particle engineering to enhance or lessen uptake by alveolar macrophages and to influence therapeutic outcomes

Radiotherapy in small-cell lung cancer: Where should it go? Lung Cancer

Development of Novel Octanoyl Chitosan Nanoparticles for Improved Rifampicin Pulmonary Delivery: Optimization by Factorial Design

Pulmonary drug delivery systems for tuberculosis treatment

Formulation strategy and use of excipients in pulmonary drug delivery

Assessment of Dry Powder Inhaler Carrier Targeted Design: A Comparative Case Study of Diverse Anomeric Compositions and Physical Properties of Lactose

Sulfated chitosan as tear substitute with no antimicrobial activity

Preparation and characterization of spray dried inhalable powders containing chitosan nanoparticles for pulmonary delivery of isoniazid

Delivery of RNAi therapeutics to airways-From bench to bedside

Chitosan based self-assembled nanoparticles in drug delivery

Chitosan as antimicrobial agent: Applications and mode of action

Production of chitosan-oligosaccharides by the chitin-hydrolytic system of Trichoderma harzianum and their antimicrobial and anticancer effects

Formation and characterization of chitosan-polylacticacidpolyethylene glycol-gelatin nanoparticles: A novel biosystem for controlled drug delivery

Increased exposure of anionic phospholipids on the surface of tumor blood vessels

A review of chitin and chitosan applications. Reactive and Functional Polymers

Rifampicin loaded chitosan nanoparticle dry powder presents an improved therapeutic approach for alveolar tuberculosis

Nano-and microstructured model carrier surfaces to alter dry powder inhaler performance

Biocompatibility of chitosan carriers with application in drug delivery

Mucoadhesive thiolated chitosans as platforms for oral controlled drug delivery: synthesis and in vitro evaluation

The effect of chitosan on transcellular and paracellular mechanisms in the J o u r n a l P r e -p r o o f intestinal epithelial barrier

New folate-grafted chitosan derivative to improve delivery of paclitaxel-loaded solid lipid nanoparticles for lung tumor therapy by inhalation

Nanodelivery in airway diseases: Challenges and therapeutic applications

Pulmonary drug delivery: From generating aerosols to overcoming biological barriers-therapeutic possibilities and technological challenges

Pulmonary administration of small interfering RNA: The route to go

Antibacterial activity of methylated chitosan and chitooligomer derivatives: Synthesis and structure activity relationships

Use of the biodegradable polymer chitosan as a vehicle for applying drugs to the inner ear

Extracellular barriers in respiratory gene therapy

Chemically modified chitin and chitosan as biomaterials

Chitosan polymer as bioactive coating and film against Aspergillus niger contamination

Controlled drug delivery vehicles for cancer treatment and their performance

Critical physicochemical and biological attributes for pulmonary delivery of rifampicin by nebulization technique in tuberculosis treatment

Pulmonary Drug Delivery: A promising approach

In vitro drug dissolution/permeation testing of nanocarriers for skin application: a comprehensive review

COVID-19 and cancer: what we know so far

Supercritical CO2-assisted spray drying of strawberry-like gold-coated magnetite nanocomposites in chitosan powders for inhalation

Chitosan: some pharmaceutical and biological aspects -an update

Involvement of protein kinase C in chitosan glutamate-mediated tight junction disruption

Effect of chitosan on epithelial cell tight junctions

Nanocarriers as pulmonary drug delivery systems to treat and to diagnose respiratory and non respiratory diseases

Carriers in drug powder delivery

New old challenges in tuberculosis: Potentially effective nanotechnologies in drug delivery

Development of levofloxacin inhalation solution to treat Pseudomonas aeruginosa in patients with cystic fibrosis

Biodegradable alginate-chitosan hollow nanospheres for codelivery of doxorubicin and paclitaxel for the effect of human lung cancer A549 Cells

Inhibition of microbial pathogens by fungal chitosan

Understanding dissolution process of chitin crystal in ionic liquids: theoretical study

Recent developments in antibacterial and antifungal chitosan and its derivatives

Preparation and anticoagulant activity of a low-molecular-weight sulfated chitosan

Development and characterization of folic acid-conjugated chitosan nanoparticles for targeted and controlled delivery of gemcitabinein lung cancer therapeutics

Docetaxel-loaded chitosan microspheres as a lung targeted drug delivery system: In vitro and in vivo evaluation

A review of the 2019 Novel Coronavirus (COVID-19) based on current evidence

The synergy of 6-O-sulfation and N-or 3-Osulfation of chitosan is required for efficient inhibition of P-selectin-mediated human melanoma A375 cell adhesion

Advances in spray drying technology for nanoparticle formation

A new coronavirus associated with human respiratory disease in China

Genipincrosslinked carboxymethyl chitosan nanogel for lung-targeted delivery of isoniazid and rifampin

Preparation and characterization of N-succinyl-N′-octyl chitosan micelles as doxorubicin carriers for effective anti-tumor activity

Inhalable microparticles containing isoniazid and rifabutin target macrophages and "stimulate the phagocyte" to achieve high efficacy

Pulmonary drug delivery by powder aerosols

Inhaled nanoparticles-A current review

Mechanism and consequence of chitosan-mediated reversible epithelial tight junction opening

Preparation and Characterization of Doripenem-Loaded Microparticles for Pulmonary Delivery

Preparation, water solubility and antioxidant activity of branched-chain chitosan derivatives

Aerosol delivery of siRNA to the lungs. part 1: Rationale for gene delivery systems

Hydrophobically modified chitosan nanoliposomes for intestinal J o u r n a l P r e -p r o o f drug delivery

The influence of carrier morphology on drug delivery by dry powder inhalers

Lactose as a carrier in dry powder formulations: The influence of surface characteristics on drug delivery

Chitosan modification and pharmaceutical/biomedical applications

FT Raman investigation of novel chitosan sulfates exhibiting osteogenic capacity

Designing polymers with sugarbased advantages for bioactive delivery applications

Drug-lactose binding aspects in adhesive mixtures: Controlling performance in dry powder inhaler formulations by altering lactose carrier surfaces

Adhesion dynamics, morphology, and organization of 3T3 fibroblast on chitosan and its derivative: The effect of O-carboxymethylation

Materials for Green Electronics, Biological Devices, and Energy Applications

The authors wish to express their heart-felt gratitude to Universiti Teknologi MARA (0141903), and Ministry of Higher Education of Malaysia (LRGS-NanoMITe RU029-2014) for fund and facility support.J o u r n a l P r e -p r o o f