Table 3.

Pulmonary chitosan carriers of drugs for the treatment of cancer.

Code	Formulation and Preparation	Physicochemical Property	Aerodynamic Property	Ex Vivo / Cell Culture Performance	In Vivo Performance	Remark	Reference
F1	Paclitaxel (PTX) and quercetin (QUE) loaded nanoparticles are prepared using oleic acid-chitosan conjugate (OA-C) as the carrier by ionic crosslinking method. The aqueous dispersion of PTX-OA-C nanoparticles, QUE-OA-C nanoparticles, hydroxypropyl-β-cyclodextrin, lactose, and mannitol are spray-dried to produce the polymeric microspheres.	The particle sizes of OA-C nanoparticles, PTX-OA-C nanoparticles, QUE-OA-C nanoparticles and polymeric microspheres are 226.1 nm, 246.5 nm, 247.4 nm and 3.373 μm respectively. The polydispersity index ranges from 0.123 to 0.456 with zeta potential of 32.9 mV, 24.2 mV and 26.0 mV for OA-C nanoparticles, PTX-OA-C nanoparticles and QUE-OA-C nanoparticles respectively. A burst drug release followed by a sustained release behaviour up to 48 h are attained with polymeric microspheres in both pH 7.4 and pH 4.5 release medium.	The aerodynamic diameter of polymeric microspheres is 1.804 ± 0.022 μm, inferring from geometric particle size and tapped density profiles.	Nil	The in vivo pharmacokinetics analysis in rats depicts that the time to reach maximum plasma drug concentration, drug half-life and AUC0–t are higher with pulmonary administration of polymeric microspheres than those of combined or single intravenous administration of PTX and QUE. The clearance and peak plasma drug concentration are lower with the use of pulmonary polymeric microspheres. The tissue distribution of PTX and QUE in the lung is significantly higher than heart, liver, spleen and kidney.	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.	(Liu et al., 2017)
F2	3,4,5-tribenzyloxybenzoic acid (GAOBn) loaded gold nanoparticles stabilized by quaternized chitosan-gallic 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.	Nil	The particles exhibit a higher level of cytotoxicity (6 % cell viability) against lung cancer cells (CHAGO) and are safe (cell viability ≥ 80 %) with reference to normal fibroblast cells of skin (CRL-1947) at 20 μg/mL GAOBn. Transmission electron microscopy analysis demonstrates that particles are taken up by the lung cancer cells.	Nil	Chitosan is used to reduce and stabilize the gold nanoparticles. Chitosan is quaternized to increase its magnitude of positive charge to enhance its electrostatic interaction with the cancer cells. It is then conjugated with gallic acid as a hydrophobic moiety to increase its permeability, and with folic acid to introduce the active target element for folate receptor overexpressed on the cancer cell surfaces.	(Komenek et al., 2017)
F3	Cisplatin loaded chitosan microspheres are prepared by emulsification and ionotropic gelation method.	Spherical particles with a size of 5.20 ± 1.19 μm, Carr’s index of 28.48 %, moisture and drug contents of 4.10 % and 79.2 ± 2.9 % respectively are produced. Initial burst drug release (37 % in 1 h) followed by sustained release up to 12 h are noted.	The aerodynamic diameter of the microspheres is 2.71 μm. The fine particle fraction of the microspheres is low and can be improved through employing lactose (63 μm–90 μm) as the carrier of the microspheres.	The microspheres are cytotoxic against A549 human lung cancer cells (HOP-62).	Nil	The microspheres are characterised by a higher IC50 value when compared to free drug due to a slower drug release from the matrix thus negating the drug bioavailability.	(Menon et al., 2012)
F4	Raloxifene loaded hyaluronic acid and chitosan nanoparticles are prepared by single emulsion solvent evaporation method.	The nanoparticles are constituted of a core and surrounded by multilayers of hyaluronic acid- and chitosan-based shell. The nanoparticles are characterized by a size of 210.6 ± 4.4 nm, a polydispersity index of 0.05 ± 0.00, a zeta potential of -29.1 ± 4.5 mV and a drug encapsulation efficiency of 92 %.	Nil	The nanoparticles induce a higher level of cytotoxicity against A549 lung cancer cell line compared to liver cancer HepG2 and Huh-7 cell lines.	Nil	Hyaluronic acid and chitosan complexation is used to increase the half-life and activity of raloxifene through targeting cluster of differention-44 (CD 44) receptor. The significant suppression of A549 lung cancer cell viability is achieved via reducing their glucose uptake to diminish the bioenergetics of cancer cells and activation of apoptosis via nitric oxide level elevation.	(Almutairi et al., 2019)
F5	POXylated strawberry-like gold-coated magnetite nanocomposites and ibuprofen are encapsulated into a chitosan matrix using the supercritical assisted spray drying technique to produce a nano-in-micro drug delivery system.	Nanocomposites with a diameter of 50 nm–200 nm are encapsulated in spherical particles having a volume-weighted mean diameter varying from 2.0 μm to 2.9 μm and a span value of 0.8 to 0.9 suitable for deep lung deposition. The drug release propensity is higher at pH 6.8 than pH 7.4.	The particles are characterized by a mass median aerodynamic diameter of approximately 1.5 μm, an emitted fraction above 96 % and a fine particle fraction of 55 %.	Nil	Nil	The higher drug release at pH 6.8 than pH 7.4 is attributed to chitosan, having a pKa value of 6.5, is characterized by partially protonated amine moieties at pH 6.8 leading to particle swelling and thus a faster drug release. The aerosolisation and inhalation of particles exceed the majority of commercial dry powder inhalation formulations.	(Silva et al., 2017)
F6	Docetaxel loaded glutaraldehyde-crosslinked chitosan microspheres are prepared using a water-in-oil emulsification method.	The microspheres are spherical with smooth surface and a size of 9.6 ± 0.8 μm, a drug encapsulation efficiency and drug loading of 88.1 ± 3.5 % and 18.7 ± 1.2 % respectively. Only 23 % of drugs are released from the microspheres in the first 12 h of dissolution.	Nil	Nil	The microspheres deliver docetaxel mainly to lung following intravenous injection to mice and the concentration of drug in lung is significantly higher than other tissues (heart, liver, spleen, kidney and uterus/ovaries) and plasma.	The chitosan microspheres possess suitable physicochemical properties for lung administration and pharmacokinetics behaviour as drug delivery system to minimize the exposure of healthy tissues while increasing the accumulation of therapeutic at target sites.	(Wang et al., 2014)
F7	Gemcitabine loaded surface-tailored chitosan/polyethylene glycol nanoparticles are prepared using ionic gelation method. The nanoparticles encapsulated with gemcitabine are tethered with folic acid.	The particle size and zeta potential of gemcitabine loaded chitosan nanoparticles are 157.2 ± 7.68 nm and 29.3 ± 1.91 mV respectively, whereas gemcitabine loaded surface-tailored polyethylene glycol and folate-polyethylene glycol chitosan nanoparticles are characterized by a size of 165.3 ± 11.0 nm and a zeta potential of 25.1 ± 1.8 mv, and a size of 184.3 ± 12.5 nm and a zeta potential of 21.1 ± 1.18 mV respectively. The drug encapsulation efficiency of gemcitabine loaded, gemcitabine loaded polyethylene glycol, gemcitabine folate-polyethylene glycol chitosan nanoparticles are 40.8 ± 1.5 %, 37.2 ± 2.2 % and 39.6 ± 2.7 % respectively. The extents of drug released from the nanoparticles over 10 days are nearly 87 % (gemcitabine loaded polyethylene glycol chitosan nanoparticles) and 85 % (gemcitabine loaded folate-polyethylene glycol chitosan nanoparticles) at pH 5.8 and nearly 79 % (gemcitabine loaded polyethylene glycol chitosan nanoparticles) and 75.3 % (gemcitabine loaded folate-polyethylene glycol chitosan nanoparticles) at pH 7.4. The nanoparticles exhibit a slow and sustained drug release profile.	Nil	The higher cellular binding with eventual uptake and cytotoxicity are observed with gemcitabine loaded folate-polyethylene glycol chitosan nanoparticles, presumably facilitated by folate receptor-mediated endocytosis in lung epithelial cancer cell lines (A549 cell).	The half-life of gemcitabine increases from 0.45 ± 0.04 h (free drug) to 3.89 ± 0.13 h and 4.05 ± 0.23 h, respectively with respect to gemcitabine loaded polyethylene glycol chitosan nanoparticles and gemcitabine loaded folate-polyethylene glycol chitosan nanoparticles. The free gemcitabine is not detectable in plasma 12 h post-administration by lateral tail vein route, whereas gemcitabine shielded with a nanoparticulate system is found up to 12 h. A greater quantity of gemcitabine is found in tumour tissues followed by liver and kidney when it is delivered in the form of polyethylene glycol (11.67 ± 1.73 %) and folate-polyethylene glycol (31.33 ± 1.73 %) chitosan nanoparticles after 8 h. The incorporation of gemcitabine into nanoparticles will shield the drug from being metabolized in systemic circulation, and sustain its release from the matrix. Coupling with the use of folate, the drug targeting property of the nanoparticles is enhanced.	Gemcitabine loaded into folate-polyethylene glycol chitosan nanoparticles show a marked cytotoxicity against the A549 lung epithelial cancer cells, and A549 cell-bearing mice.	(Wang et al., 2017)
F8	Paclitaxel loaded solid lipid nanoparticles are prepared by using nanoprecipitation method. The nanoparticles are then coated with folate grafted copolymer of polyethylene glycol and chitosan derivative which is N-[(2-hydroxy-3-trimethyl ammonium) propyl] chitosan chloride.	The nanoparticles are spherical in shape with encapsulation efficiency, mean diameter and zeta potential of about 100 %, 250 nm and +32 mV respectively. Cumulative drug release from the nanoparticles is about 50 % within 3 days of dissolution. After a first burst release of 13 % of drug within 7 h, the drug release rate remains constant, with approximately 15 % of drug released every 24 h.	Nil	The nanoparticles enter, or at least bind to two folate receptor-expressing cancer cell lines namely HeLa and M109-HiFR. The HeLa cells are significantly more sensitive to nanoparticles than M109-HiFR cells. The nanoparticles grafted with folate are almost five times more active than the folate-free nanoparticles in M109-HiFR cells and almost three times more active in HeLa cells.	Inhaled folate-grafted nanoparticles exhibit 7-fold and 32-fold increase in pulmonary drug concentrations compared to inhaled taxol following 1 h and 6 h of administration. These nanoparticles are able to reach and penetrate M109-HiFR murine lung carcinoma cell subline in vivo.	The nanoparticles demonstrate a favourable pharmacokinetics profile, with pulmonary exposure to drug prolonged up to 6 h with limited systemic distribution.	(Rosière et al., 2018)
F9	Alginate coated chitosan hollow nanospheres of paclitaxel and doxorubicin are prepared. The paclitaxel is loaded into the nanoscale hollow structure via adsorption process. The positively charged doxorubicin is coated onto the surface of negatively charged hollow nanospheres via electrostatic adsorption.	The drug loadings of paclitaxel and doxorubicin in nanospheres are 18.4 ± 1.32 % and 74.2 ± 3.24 % respectively. The paclitaxel loaded nanospheres show a weakly crystalline diffraction pattern, whereas the doxorubicin loaded nanospheres do not display any crystalline diffraction pattern in comparison to physical mixture and pure drug.	Nil	The drug-free nanospheres are non-toxic, whereas the drug loaded nanospheres are cytotoxic against A549 lung cancer cells and induce apoptosis.	Nil	Co-delivery of paclitaxel and doxorubicin can effectively inhibit cell proliferation and promote cell apoptosis due to the nanoscale effect of particles and the synergistic effect of combined drugs.	(Tao et al., 2018)
F10	A hybrid system composed of multi-walled carbon nanotubes (MWCNT) coated with chitosan is produced as a pH-responsive carrier of methotrexate. MWCNT are synthesized by fixed-bed chemical vapour deposition method. The fabrication of chitosan-MWCNT (CS-MWCNT) nanohybrid is achieved via precipitation technique.	The use of fix-bed chemical vapour deposition method produces well defined MWCNT with a narrow size distribution (length in a range of 110−980 nm, an average inner diameter of 0.7–1.5 nm, and an outer diameter of 5–8 nm corresponding to 4–7 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.	Nil	Drug-free CS-MWCNT does not affect the viability of H1299 cells (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 death up to 44 %.	Nil	The CS-MWCNT nanohybrid can selectively deliver the drug to H1299 lung cancer cells with negligible toxicity to healthy MRC-5 cells. This system is successful at reducing side effects of methotrexate to normal tissues and cells.	(Cirillo et al., 2019)