6-Maleimidohexanoic acid-grafted chitosan: A new generation mucoadhesive polymer.

This study aims to synthesize and evaluate a new generation mucoadhesive polymer, 6-maleimidohexanoic acid-grafted chitosan; MHA-CS, for transmucosal drug delivery compared with a well-known mucoadhesive polymer, Cys-CS. The successful synthesis was confirmed by nuclear magnetic resonance (NMR) spectroscopy and Fourier transform infrared (FT-IR) spectroscopy. Gel permeation chromatography (GPC) was used to determine the molecular weight of the synthesized polymer. The quantity of maleimide on the polymer chain as well as the mucoadhesive properties and biocompatibility of the synthesized polymers were also assessed. The results revealed that the synthesized MHA-CS demonstrated excellent mucoadhesive properties which is superior to CS and Cys-CS. The maleimide content bound to synthesized polymer was 466 µmol per gram of the polymer. The cytotoxicity test assured the low toxicity of the synthesized polymer on the normal human gingival fibroblast cells. These data support the potential of MHA-CS as a novel material for developing mucoadhesive drug delivery system with enhanced mucoadhesive properties.

Apoptosis Induction and Antimigratory Activity of Andrographolide Analog (3A.1)-Incorporated Self-Assembled Nanoparticles in Cancer Cells.

Andrographolide analog, namely 19-tert-butyldiphenylsilyl-8,17-epoxy andrographolide (or 3A.1) has been reported to be a potential anticancer agent for several types of cancer. Due to its poor aqueous solubility, 3A.1 was incorporated within self-assembly polymeric nanoparticles made of naphthyl-grafted succinyl chitosan (NSC), octyl-grafted succinyl chitosan (OSC), and benzyl-grafted succinyl chitosan (BSC). These 3A.1-loaded nanoparticles were nanosized (< 200 nm) and spherical in shape with a negative surface charge. 3A.1-loaded nanoparticles were produced using a dropping method, which 40% initial drug adding exhibited the highest entrapment efficiency. The release of 3A.1 from the 3A.1-loaded nanoparticles displayed a delayed release pattern. Under acidic conditions (pH 1.2), there was no free drug release. After the pH was adjusted to 6.8, a high cumulative 3A.1 release was obtained which was dependent on the hydrophobic moieties. These 3A.1-loaded pH-sensitive nanoparticles proved to be beneficial for specifically delivering anticancer drugs to the targeted colon cancer sites. In vitro anticancer activity against HT-29 found that the 3A.1-loaded nanoparticles had significantly lower IC50 than that of the free drug and promoted apoptosis. Additionally, in vitro wound-healing migration on HN-22 revealed that free 3A.1 and the 3A.1-loaded nanoparticles inhibited cell motility compared with untreated cells. These pH-sensitive amphiphilic chitosan nanoparticles may be promising nanocarriers for oral anticancer drug delivery to colorectal cancer cells. Graphical abstract ᅟ.

Development of Microemulsions and Microemulgels for Enhancing Transdermal Delivery of Kaempferia parviflora Extract.

The purpose of this research was to develop microemulsions (ME) and microemulgels (MG) for enhancing transdermal delivery of Kaempferia parviflora (KP) extract. The methoxyflavones were used as markers. Various formulations of ME and MG containing 10% w/v KP extract were prepared, and the in vitro skin permeation and deposition were investigated. The potential ME system containing oleic acid (5% w/v), Tween 20 (20% w/v), PG (40% w/v), and water (35% w/v) was successfully formulated. ME with 10% w/v limonene (ME-L10%) showed higher methoxyflavones flux than ME-L5%, ME-L1%, ME without limonene, and KP extract in water, respectively. ME-L10% was selected for adding a gelling agent to form microemulgels (MG-L10%). However, the high viscosity of the gel formulation might control the diffusion of the compound from gel layer into the skin. Therefore, the liquid formulation provided potential ME droplets to deliver KP extract through the skin. Limonene also plays an effective role on the skin permeation, in which the histological image of the skin treated with ME-L10% exhibited larger space of each flattened keratinocyte layer in the stratum corneum compared to the skin treated with KP extract in water. Moreover, ME-L10% showed good stability. Therefore, ME-L10% was a potential formulation for improving transdermal delivery of KP extract.

Mucoadhesive maleimide-functionalised liposomes for drug delivery to urinary bladder.

Intravesical drug administration is used to deliver chemotherapeutic agents via a catheter to treat bladder cancer. The major limitation of this treatment is poor retention of the drug in the bladder due to periodic urine voiding. In this work, maleimide-functionalised PEGylated liposomes (PEG-Mal) were explored as mucoadhesive vehicles for drug delivery to the urinary bladder. The retention of these liposomes on freshly excised porcine bladder mucosa in vitro was compared with conventional liposomes, PEGylated liposomes, two controls (dextran and chitosan), and evaluated through Wash Out50 (WO50) values. PEG-Mal liposomes exhibited greater retention on mucosal surfaces compared to other liposomes. The penetration abilities of conventional, PEG-Mal-functionalised and PEGylated liposomal dispersions with encapsulated fluorescein sodium into the bladder mucosa ex vivo were assessed using a fluorescence microscopy technique. PEGylated liposomes were found to be more mucosa-penetrating compared to other liposomes. All liposomes were loaded with fluorescein sodium salt as a model drug and the in vitro release kinetics was evaluated. Longer drug release was observed from PEG-Mal liposomes.

Chitosan-based self-assembled nanocarriers coordinated to cisplatin for cancer treatment.

Polymeric nanocarriers were prepared via a dialysis method using three chitosan derivatives, N-benzyl-N,O-succinyl chitosan (BSCT), N-naphthyl-N,O-succinyl chitosan (NSCT), and N-octyl-N-O-succinyl chitosan (OSCT) and were coordinated to cisplatin. The nanocarrier properties and cytotoxicity on the human carcinoma cells, HN22 (head and neck), were investigated. In addition, intracellular cisplatin accumulation, apoptosis induction and toxicity on renal cells were also evaluated. The findings revealed that the succinyl groups of the polymers were perfectly deprotonated and bound with cisplatin by co-ordinate bonds at pH 8.5. Among the derivatives, BSCT exhibited the highest cisplatin loading and release in simulated physiological medium. The cytotoxicities on HN22 cells of cisplatin-loaded BSCT nanocarriers were lower than that of free cisplatin, however, they presented a greater percentage of early apoptosis in HN22 cells and could decrease cisplatin induced renal cell death. In conclusion, the BSCT self-assembly nanocarrier might be a cisplatin carrier for sustained release, which provides prolonged antitumour treatment and reduced nephrotoxicity.

Development of Chitosan-Based pH-Sensitive Polymeric Micelles Containing Curcumin for Colon-Targeted Drug Delivery.

pH-sensitive N-naphthyl-N,O-succinyl chitosan (NSCS) and N-octyl-N,O-succinyl chitosan (OSCS) polymeric micelles carriers have been developed to incorporate curcumin (CUR) for colon-targeted drug delivery. The physical entrapment methods (dialysis, co-solvent evaporation, dropping, and O/W emulsion) were applied. The CUR-loaded micelles prepared by the dialysis method presented the highest loading capacity. Increasing initial amount of CUR from 5 to 40 wt% to polymer resulted in the increase in loading capacity of the polymeric micelles. Among the hydrophobic cores, there were no significant differences in the loading capacity of CUR-loaded micelles. The particle sizes of all CUR-loaded micelles were in the range of 120-338 nm. The morphology of the micelles changed after being contacted with medium with different pH values, confirming the pH-responsive properties of the micelles. The release characteristics of curcumin from all CUR-loaded micelles were pH-dependent. The percent cumulative release of curcumin from all CUR-loaded micelles in simulated gastric fluid (SGF) was limited to about 20%. However, the release amount was significantly increased after contacted with simulated intestinal fluid (SIF) (50-55%) and simulated colonic fluid (SCF) (60-70%). The released amount in SIF and SCF was significantly greater than the release of CUR from CUR powder. CUR-loaded NSCS exhibited the highest anti-cancer activity against HT-29 colorectal cancer cells. The stability studies indicated that all CUR-loaded micelles were stable for at least 90 days. Therefore, the colon targeted, pH-sensitive NSCS micelles may have potential to be a prospective candidate for curcumin delivery to the colon.

Development and evaluation of N-naphthyl-N,O-succinyl chitosan micelles containing clotrimazole for oral candidiasis treatment.

Clotrimazole (CZ)-loaded N-naphthyl-N,O-succinyl chitosan (NSCS) micelles have been developed as an alternative for oral candidiasis treatment. NSCS was synthesized by reductive N-amination and N,O-succinylation. CZ was incorporated into the micelles using various methods, including the dropping method, the dialysis method, and the O/W emulsion method. The size and morphology of the CZ-loaded micelles were characterized using dynamic light scattering measurements (DLS) and a transmission electron microscope (TEM), respectively. The drug entrapment efficiency, loading capacity, release characteristics, and antifungal activity against Candida albicans were also evaluated. The CZ-loaded micelles prepared using different methods differed in the size of micelles. The micelles ranged in size from 120 nm to 173 nm. The micelles prepared via the O/W emulsion method offered the highest percentage entrapment efficiency and loading capacity. The CZ released from the CZ-loaded micelles at much faster rate compared to CZ powder. The CZ-loaded NSCS micelles can significantly hinder the growth of Candida cells after contact. These CZ-loaded NSCS micelles offer great antifungal activity and might be further developed to be a promising candidate for oral candidiasis treatment.

Fabrication and Evaluation of Nanostructured Herbal Oil/Hydroxypropyl-ß-Cyclodextrin/Polyvinylpyrrolidone Mats for Denture Stomatitis Prevention and Treatment.

This work aims to develop the herbal oil-incorporated nanostructure mats with antifungal activity for the prevention and treatment of Candida-associated denture stomatitis. The nanofiber mats loaded with betel oil or clove oil were fabricated via electrospinning process. The morphologies and physicochemical properties of the herbal oil loaded nanofiber mats were examined using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), and mechanical testing. The release characteristic, antifungal activity, and cytotoxicity were also investigated. The SEM images confirmed the homogeneous and smooth nanoscale fibers. The addition of the herbal oil into the nanofiber mats reduced the fiber diameters. The DSC and FT-IR results confirmed the presence of the oil in the nanofiber mats. The herbal oils can be released from the mats in a very fast manner and inhibit the growth of candida cells within only few minutes after contact. These nanofiber mats may be beneficial for the prevention and treatment of denture stomatitis.

Maleimide-bearing nanogels as novel mucoadhesive materials for drug delivery.

Novel maleimide-functionalised nanogels have been synthesised via the polymerisation of 2,5-dimethylfuran-protected 3-maleimidoethyl butylacrylate in the presence of presynthesised poly(N-vinylpyrrolidone) (PVP) nanogel scaffolds using surfactant-free emulsion polymerisation techniques. The protected maleimide nanogels were subsequently deprotected to generate the reactive maleimide group via a retro-Diels-Alder reaction. These activated nanogels were found to exhibit excellent mucoadhesive properties on ex vivo conjunctival tissue when compared to the known mucoadhesive chitosan. In order to determine the viability of the materials as drug carriers, nanogels were loaded with a model drug compound and the in vitro release kinetics were analysed. The nanogels could sustain the release of a model drug compound over several hours owing to the swellable hydrophilic nanogel structure, exhibiting first order release kinetics. As a consequence, these findings support the potential of these maleimide-bearing nanogels as a novel platform for sustained drug delivery.

Fabrication of mucoadhesive chitosan coated polyvinylpyrrolidone/cyclodextrin/clotrimazole sandwich patches for oral candidiasis.

This study aims to fabricate clotrimazole (CZ)-composite sandwich nanofibers using electrospinning. The CZ-loaded polyvinylpyrrolidone (PVP)/hydroxypropyl-ß-cyclodextrin (HPßCD) fiber was coated with chitosan-cysteine (CS-SH)/polyvinyl alcohol (PVA) to increase the mucoadhesive properties and to achieve a sustained release of the drug from the nanofibers. The nanofibers were characterized using scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy and X-ray diffractometry (XRD). The nanofibers mechanical and mucoadhesive properties, drug release, antifungal activity and cytotoxicity were also assessed. The fibers were in the nanoscale with good mucoadhesive properties. The XRPD revealed a molecular dispersion of amorphous CZ in the nanofibers. The initial fast release of CZ from the nanofibers was achieved. Moreover, the sandwich nanofibers coated for longer times resulted in slower release rates compared with the shorter coating times. The CZ-loaded nanofibers killed the Candida significantly faster than the commercial CZ lozenges at 5, 15 and 30 min and were safe for a 2-h incubation. Therefore, these nanofibers may be promising candidates for the treatment of oral candidiasis.

Lysozyme-immobilized electrospun PAMA/PVA and PSSA-MA/PVA ion-exchange nanofiber for wound healing.

This research was aimed to develop the lysozyme immobilized ion-exchange nanofiber mats for wound healing. To promote the healing process, the PSSA-MA/PVA and PAMA ion-exchange nanofiber mats were fabricated to mimic the extracellular matrix structure using electrospinning process followed by thermally crosslinked. Lysozyme was immobilized on the ion-exchane nanofibers by an adsorption method. The ion-exchange nanofibers were investigated using SEM, FTIR and XRPD. Moreover, the lysozyme-immobilized ion-exchange nanofibers were further investigated for lysozyme content and activity, lysozyme release and wound healing activity. The fiber diameters of the mats were in the nanometer range. Lysozyme was gradually absorbed into the PSSA-MA/PVA nanofiber with higher extend than that is absorbed on the PAMA/PVA nanofiber and exhibited higher activity than lysozyme-immobilized PAMA/PVA nanofiber. The total contents of lysozyme on the PSSA-MA/PVA and PAMA/PVA nanofiber were 648 and 166 µg/g, respectively. FTIR and lysozyme activity results confirmed the presence of lysozyme on the nanofiber mats. The lysozyme was released from the PSSA-MA/PVA and PAMA/PVA nanofiber in the same manner. The lysozyme-immobilized PSSA-MA/PVA nanofiber mats and lysozyme-immobilized PAMA/PVA nanofiber mats exhibited significantly faster healing rate than gauze and similar to the commercial antibacterial gauze dressing. These results suggest that these nanofiber mats could provide the promising candidate for wound healing application.

Fabrication of a novel scaffold of clotrimazole-microemulsion-containing nanofibers using an electrospinning process for oral candidiasis applications.

Clotrimazole (CZ)-loaded microemulsion-containing nanofiber mats were developed as an alternative for oral candidiasis applications. The microemulsion was composed of oleic acid (O), Tween 80 (T80), and a co-surfactant such as benzyl alcohol (BzOH), ethyl alcohol (EtOH) or isopropyl alcohol (IPA). The nanofiber mats were obtained by electrospinning a blended solution of a CZ-loaded microemulsion and a mixed polymer solution of 2% (w/v) chitosan (CS) and 10% (w/v) polyvinyl alcohol (PVA) at a weight ratio of 30:70. The nanofiber mats were characterized using various analytical techniques. The entrapment efficiency, drug release, antifungal activity and cytotoxicity were investigated. The average diameter of the nanofiber mats was in the range of 105.91-125.56 nm. The differential scanning calorimetry (DSC) and powder X-ray diffractometry (PXRD) results revealed the amorphous state of the CZ-loaded microemulsions incorporated into the nanofiber mats. The entrapment efficiency of CZ in the mats was approximately 72.58-98.10%, depended on the microemulsion formulation. The release experiment demonstrated different CZ release characteristics from nanofiber mats prepared using different CZ-loaded microemulsions. The extent of drug release from the fiber mats at 4h was approximately 64.81-74.15%. The release kinetics appeared to follow Higuchi's model. In comparison with CZ lozenges (10mg), the nanofiber mats exhibited more rapid killing activity. Moreover, the nanofiber mats demonstrated desirable mucoadhesive properties and were safe for 2h. Therefore, the nanofiber mats have the potential to be promising candidates for oral candidiasis applications.

Fast-acting clotrimazole composited PVP/HPßCD nanofibers for oral candidiasis application.

PURPOSE: This study investigates fabrication of clotrimazole (CZ)-composited electrospun Polyvinylpyrrolidone/Hydroxypropyl-ß-cyclodextrin (PVP/HPßCD) blended nanofiber mats for oral candidiasis applications. METHODS: PVP/HPßCD blended nanofiber mats containing clotrimazole were electrospun and characterized using SEM, DSC and XRPD. The solvent system ethanol: water: benzyl alcohol (EtOH:H2O:BzOH) with a 70:20:10 ratio was optimal for the electrospinning process. Various amounts of CZ were loaded into the nanofiber mats. The nanofiber mats was further investigated for drug release, antifungal activity and cytotoxicity. RESULTS: The fiber diameters in the mats were in the nanometer range. The DSC and XRPD revealed a molecular dispersion of amorphous CZ in the nanofiber mats. The loading capacity increased when CZ content was raised. A fast dissolved and released of CZ from the nanofibers mat was achieved. The ability of the CZ-loaded nanofiber mats to kill the Candida depended on the amount of CZ in the mats; moreover, the CZ-loaded nanofibers killed the Candida significantly faster than the CZ powder and lozenges with low cytotoxicity. CONCLUSIONS: CZ-loaded nanofiber mats were successfully electrospun. They exhibited rapid antifungal activity in vitro relative to CZ powder and lozenges. Further in vivo studies are needed to investigate for their application in oral candidiasis.

Encapsulation of plai oil/2-hydroxypropyl-ß-cyclodextrin inclusion complexes in polyvinylpyrrolidone (PVP) electrospun nanofibers for topical application.

The aim of this study was to prepare electrospun polyvinylpyrrolidone (PVP)/2-hydroxypropyl-ß-cyclodextrin (HPßCD) nanofiber mats and to incorporate plai oil (Zingiber Cassumunar Roxb.). The plai oil with 10, 20 and 30% wt to polymer were incorporated in the PVP/HPßCD solution and electrospun to obtain nanofibers. The morphology and structure of the PVP and PVP/HPßCD nanofiber mats with and without the plai oil were analyzed using scanning electron microscopy (SEM). The thermal behaviors of the nanofiber mats were characterized using differential scanning calorimeter (DSC). Terpinen-4-ol was used as a marker of the plai oil. The amount of plai oil remaining in the PVP/HPßCD nanofiber mats was determined using gas chromatography-mass spectoscopy (GC-MS). The SEM images revealed that all of the fibers were smooth. The average diameter of fibers was 212-450 nm, and decreased with the increasing of plai oil content. The release characteristics of plai oil from the fiber showed the fast release followed by a sustained release over the experimental time of 24 h. The release rate ranged was in the order of 10% > 20% ∼ 30% plai oil within 24 h. Electrospun fibers with 20% plai oil loading provided the controlled release and also showed the highest plai oil content. Hence, this electrospun nanofiber has a potential for use as an alternative topical application.

Development and characterization of propranolol selective molecular imprinted polymer composite electrospun nanofiber membrane.

Propranolol (PPL) imprinted microspheres (MIP) were successfully prepared via oil/water polymerization using a methyl methacrylate (MMA) monomer, PLL template, and divinylbenzene (DVB) cross-linker and favorably incorporated in a Eudragit-RS100 nanofiber membrane. A non-PPL imprinted polymer (NIP), without a template, was used as a control. The morphology and particle size of the beads were investigated using scanning electron microscopy. The results revealed that both MIP and NIP had a spherical shape with a micron size of approximately 50-100 µm depending on the amounts of DVB and PPL used. NIP2 (MMA/DVB, 75:2.5) and MIP8 (PPL/MMA/DVB, 0.8:75:2.5) were selected for reloading of PPL, and the result indicated that increasing the ratio of PPL to polymer beads resulted in increase PPL reloading (>80%). A total of 10-50% NIP2 or MIP8 was incorporated into a 40% (w/v) Eudragit-RS100 fiber membrane using an electrospinning technique. PPL could be bound to the 50% MIP8 composite fiber membrane with a higher extent and at a higher rate than the control (NIP2). Furthermore, the MIP8 composite fiber membrane showed higher selectivity to PPL than the other ß-blockers (atenolol, metoprolol, and timolol). Thus, the MIP8 composite fiber membrane can be further developed for various applications in pharmaceutical and other affinity separation fields.