Tamarind seed polysaccharide-guar gum buccal films loaded with resveratrol-bovine serum albumin nanoparticles: Preparation, characterization, and mucoadhesiveness assessment.

Mucoadhesive films based on tamarind seed polysaccharide and guar gum (TSP-GG) were formulated for buccal delivery of resveratrol. Resveratrol-bovine serum albumin nanoparticles (Res-BSA) were prepared and dispersed in TSP-GG to improve its buccal mucoadhesiveness. The impregnation of Res-BSA induced the dense internal structures of TSP-GG and improved its strength and rigidity. Structural characterization showed that resveratrol existed in an amorphous state in the films containing Res-BSA, and hydrogen bonding was formed between Res-BSA and the film matrices. The films containing Res-BSA exhibited good uniformity in thickness, weight, and resveratrol content, and their surface pH was near neutral, ranging between 6.78 and 7.09. Increasing Res-BSA content reduced the water contact angle of TSP-GG (from 75.9° to 59.6°). The swelling and erosion studies indicated the favorable hydration capacity and erosion resistance of the films containing Res-BSA. Additionally, the addition of Res-BSA imparted enhanced ex vivo mucoadhesive force, in the range of 1.53 N to 1.98 N, and extended ex vivo residence time, between 17.9 h and 18.9 h, to TSP-GG. The current study implied that the composite systems of TSP-GG and Res-BSA may be a novel platform for buccal mucosal delivery of resveratrol.

Enhancing Antifungal Treatment of Candida albicans with Hypericin-Loaded Nanostructured Lipid Carriers in Hydrogels: Characterization, In Vitro, and In Vivo Photodynamic Evaluation.

BACKGROUND: Vulvovaginal candidiasis (VVC) is a worldwide public health problem caused predominantly by the opportunistic polymorphic fungus Candida albicans, whose pathogenicity is associated with its morphological adaptability. To potentiate the treatment of C. albicans-induced VVC by an alternative method as photodynamic therapy (PDT), hypericin (Hy), a potent photosensitizer compound was incorporated into a nanostructured lipid carrier (NLC) and dispersed in hydrogel (HG). METHODS: After preparation of the sonication process, an NLC loaded with Hy was dispersed in HG based on Poloxamer 407 and chitosan obtaining Hy.NLC-HG. This hydrogel system was physically and chemically characterized and its in vitro and in vivo photodynamic and antifungal effects were evaluated. RESULTS: Through scanning electron microscopy, it was possible to observe a hydrogel system with a porous polymeric matrix and irregular microcavities. The Hy.NLC-HG system showed mucoadhesive properties (0.45 ± 0.08 N) and a satisfactory injectability (15.74 ± 4.75 N.mm), which indicates that it can be easily applied in the vaginal canal, in addition to a controlled and sustained Hy release profile from the NLC-HG of 28.55 ± 0.15% after 720 min. The in vitro antibiofilm assay significantly reduced the viability of C. albicans (p < 0.001) by 1.2 log10 for Hy.NLC-HG/PDT and 1.9 log10 for PS/PDT, Hy.NLC/PDT, and free RB/PDT, compared to the PBS/PDT negative control. The in vivo antifungal evaluation showed that animals treated with the vaginal cream (non-PDT) and the PDT-mediated Hy.NLC-HG system showed a significant difference of p < 0.001 in the number of C. albicans colonies (log) in the vaginal canal, compared to the inoculation control group. CONCLUSIONS: Thus, we demonstrate the pharmaceutical, antifungal, and photodynamic potential of hydrogel systems for Hy vaginal administration.

Biopolymer from Water Kefir as a Potential Clean-Label Ingredient for Health Applications: Evaluation of New Properties.

The present work aimed to characterize the exopolysaccharide obtained from water kefir grains (EPSwk), a symbiotic association of probiotic microorganisms. New findings of the technological, mechanical, and biological properties of the sample were studied. The EPSwk polymer presented an Mw of 6.35 × 105 Da. The biopolymer also showed microcrystalline structure and characteristic thermal stability with maximum thermal degradation at 250 °C. The analysis of the monosaccharides of the EPSwk by gas chromatography demonstrated that the material is composed of glucose units (98 mol%). Additionally, EPSwk exhibited excellent emulsifying properties, film-forming ability, a low photodegradation rate (3.8%), and good mucoadhesive properties (adhesion Fmax of 1.065 N). EPSwk presented cytocompatibility and antibacterial activity against Escherichia coli and Staphylococcus aureus. The results of this study expand the potential application of the exopolysaccharide from water kefir as a potential clean-label raw material for pharmaceutical, biomedical, and cosmetic applications.

Nebulization of a polyelectrolyte-drug system for systemic hypertension treatment.

Hypertension is a chronic pathology where blood pressure levels are continuously high, causing cardiac, renal, cerebral, and vascular damage leading to early morbi-mortality. This illness is the main risk factor for cardiovascular diseases and the main cause of atrial fibrillation. Atenolol (AT) is a ß-1 blocker drug useful for antihypertension and antiarrhythmic treatments. However, this drug possesses low oral bioavailability associated to its low permeability and extensive hepatic first-pass metabolism. To solve the conventional AT-administration problems, oral controlled-release and transdermal delivery have been reported. In this work, an alternative AT inhalatory system administered by nebulization is presented. This system is based on an ionic complex between acidic groups of alginic acid and cationic groups of AT (AA-AT), which was obtained by spray-drying. Pharmaceutical and biopharmaceutical properties for AA-AT inhalatory administration using a jet nebulizer were investigated. The aerodynamic performance (assayed at different cup-nebulizer loadings) of the nebulized system demonstrated that around 40% of the formulation would deposit in the respiratory membrane, with mass median aerodynamic diameters of 3.4-3.6 µm. The AT carried in the AA-AT system was released adequately by ionic exchange in saline solution by permeation through a cellulose membrane. The presence of AA as polyelectrolyte conferred mucoadhesive properties to the ionic complex. Even at high relative AA-AT concentrations, no cytotoxic effect was detected in A-549 cell line. Finally, the preliminary pharmacokinetic assay in the in vivo model confirmed that AT was absorbed from the lung to the systemic circulation, with a greater plasmatic AUC compared to the pure drug (around 50% higher). Then, the system and the nebulization administration demonstrated potential for drug cardiac targeting.

Cyclodextrin as Functional Carrier in Development of Mucoadhesive Tablets Containing Polygoni cuspidati Extract with Potential for Dental Applications.

Polygoni cuspidati root is a resveratrol-rich source with anti-inflammatory, angiogenic and neuroprotective effects. The raw material was standardized for the content of resveratrol, for which there is a special justification for administration within the oral mucosa. To improve the solubility of resveratrol and to assure its high content in plant material, an ultrasound-assisted extraction method was applied. The addition of cyclodextrin was found to increase the extraction efficiency of resveratrol (from 13 to 297 µg per 1 g of plant material in case of 50% ethanol extracts) and enhanced its antioxidant activity as compared to pure Polygoni cuspidati extract/resveratrol. Cyclodextrin plays the role of a functional extract regarding technological properties (increasing the extraction of resveratrol from the extract, improving mucoadhesive properties). Therefore, the aim of this study was to develop mucoadhesive tablets containing combinations of the Polygoni cuspidati extract with a cyclodextrin carrier for buccal delivery. The tests sequentially included extract preparation and characterization of its physical and biological properties and then formulation studies with a broad description of the prototype properties. The test results indicate that cyclodextrin increases the efficiency of resveratrol extraction from Polygoni cuspidati rhizome, which is a rich source of resveratrol, and its extract enclosed in a mucoadhesive tablet guarantees prolonged action at the site of administration.

Impact of uncharged and charged stabilizers on in vitro drug performances of clarithromycin nanocrystals.

The purpose of this study was to evaluate the effect of charge on the in vitro drug performances of clarithromycin nanocrystals. To prepare different charges of nanocrystals, media milling was employed with the use of different stabilizing systems. The uncharged nanocrystals were prepared from poloxamer 407. The negatively and positively charged nanocrystals were stabilized using a combination of poloxamer 407 with sodium lauryl sulfate (SLS) and cetyltrimethylammonium bromide (CTAB), respectively. After production, the particle size of the negatively and positively charged nanocrystals was smaller than that of the uncharged one. The similar particle size of variously charged clarithromycin nanocrystals was selected to determine the in vitro drug performances. Dissolution profiles of the variously charged nanocrystals were similar; however, kinetic saturation solubility profiles were different. The positively charged nanocrystals showed higher mucoadhesiveness than the uncharged and the negatively charged nanocrystals. For drug permeation through NCI-N87 and Caco-2 cell monolayers, both charged nanocrystals showed a higher drug transport than the uncharged nanocrystals. It could be concluded that incorporating charge into clarithromycin nanocrystal formulations affected the particle size reduction process as well as the nanocrystal performances. Therefore, the surface charge is one of the crucial factors for the development of nanocrystal formulations.

Enhanced Delivery of Imatinib into Vaginal Mucosa via a New Positively Charged Nanocrystal-Loaded in Situ Hydrogel Formulation for Treatment of Cervical Cancer.

The present study was carried out to investigate the potential of cationic functionalization on imatinib nanocrystals to improve the mucoadhesiveness and, thus, delivery to the lesion of cervicovaginal tumors. Amino-group-functionalized imatinib nanocrystals (NC@PDA-NH2) were prepared with near-spheroid shape, nanoscale size distribution, positive zeta potential, and relatively high drug content with the aid of the polydopamine-coating technique. Efficient interaction between NC@PDA-NH2 and mucin was proven by mucin adsorption which was related to the positive zeta-potential value of NC@PDA-NH2 and the change in the size distribution on mixing of NC@PDA-NH2 and mucin. Cellular uptake, growth inhibition, and apoptosis induction in cervicovaginal cancer-related cells demonstrated the superiority of NC@PDA-NH2 over unmodified nanocrystals. For practical intravaginal administration, NC@PDA-NH2 was dispersed in Pluronic F127-based thermosensitive in situ hydrogel, which showed suitable gelation temperature and sustained-release profiles. In comparison with unmodified nanocrystals, NC@PDA-NH2 exhibited extended residence on ex vivo murine vaginal mucosa, prolonged in vivo intravaginal residence, and enhanced inhibition on the growth of murine orthotopic cervicovaginal model tumors indicated by smaller tumor size, longer median survival time, and more intratumor apoptosis with negligible mucosal toxicity. In conclusion, cationic functionalization endowed NC@PDA-NH2 significant mucoadhesiveness and, thus, good potential against cervicovaginal cancer via intravaginal administration.

In Vitro Evaluation of Hybrid Cooperative Complexes of Hyaluronic Acid as a Potential New Ophthalmic Treatment.

PURPOSE: The purpose of this in vitro study was to assess the potential benefits of eye drops based on hybrid cooperative complexes (HCCs) obtained from high and low molecular weight hyaluronic acid (HA). METHODS: Rheological measurements were performed to adjust the HCC concentration toward optimal resistance to drainage from the ocular surface. The viscosity and mucoadhesion profiles of the optimized preparation were derived. Primary porcine corneal epithelial cells were used for biological studies. Cells were exposed to dehydration after being pretreated with the HCC solution, and protection from desiccation was evaluated using cell viability assays. Time-lapse experiments were carried out to evaluate the ability of the HCC preparation to promote corneal wound healing. The characterization studies were performed in comparison with a control HA solution representative of commercial HA-based products. RESULTS: The HCC formulation is able to deliver twice the amount of biopolymer compared with conventional products while avoiding discomfort due to excessive viscosity. The viscosity and mucoadhesion profiles allowed the authors to predict the longer in vivo retention and, therefore, an improved HCC formulation bioavailability. The new preparation also proved superior in protecting porcine corneal epithelial cells from desiccation and in hastening corneal cell wound repair in vitro. CONCLUSIONS: The results suggest that the developed formulation may be a promising topical ophthalmic medical treatment.

Evaluation of the mucoadhesive properties of chitosan nanoparticles prepared using different chitosan to tripolyphosphate (CS:TPP) ratios.

Mucoadhesive molecules such as chitosan, can allow targeting of a particular tissue to prolong residence time and subsequently improve bioavailability. The purpose of this study was to investigate chitosan-tripolyphosphate (CS:TPP) nanoparticles and to evaluate the interaction between nanoparticles of different CS:TPP ratios with mucin using viscosity, particle size analysis and ζ-potential. For all CS:TPP ratios examined, a minimum value of viscosity was reached for a 3:1 CS:TPP ratio, however chitosan nanoparticles at this ratio were not stable (<+30 mV), whereas a CS:TPP ratio of 4:1 displayed the strongest interaction. This suggests a minimum CS:TPP ratio of 4:1 is required to produce stable nanoparticles able to form strong interactions, which is consistent with a greater mucin binding efficiencies at CS:TPP ratios of 4:1 and higher, which were quantified using a colorimetric assay. Further analysis of similar systems could lead potentially to tuneable chitosan nanoparticles for specific applications.

Multifunctional Tannic Acid/Silver Nanoparticle-Based Mucoadhesive Hydrogel for Improved Local Treatment of HSV Infection: In Vitro and In Vivo Studies.

Mucoadhesive gelling systems with tannic acid modified silver nanoparticles were developed for effective treatment of herpes virus infections. To increase nanoparticle residence time after local application, semi solid formulations designed from generally regarded as safe (GRAS) excipients were investigated for their rheological and mechanical properties followed with ex vivo mucoadhesive behavior to the porcine vaginal mucosa. Particular effort was made to evaluate the activity of nanoparticle-based hydrogels toward herpes simplex virus (HSV) type 1 and 2 infection in vitro in immortal human keratinocyte cell line and in vivo using murine model of HSV-2 genital infection. The effect of infectivity was determined by real time quantitative polymerase chain reaction, plaque assay, inactivation, attachment, penetration and cell-to-cell assessments. All analyzed nanoparticle-based hydrogels exhibited pseudoplastic and thixotropic properties. Viscosity and mechanical measurements of hydrogels were found to correlate with the mucoadhesive properties. The results confirmed the ability of nanoparticle-based hydrogels to affect viral attachment, impede penetration and cell-to-cell transmission, although profound differences in the activity evoked by tested preparations toward HSV-1 and HSV-2 were noted. In addition, these findings demonstrated the in vivo potential of tannic acid modified silver nanoparticle-based hydrogels for vaginal treatment of HSV-2 genital infection.

Chitosan Loaded into a Hydrogel Delivery System as a Strategy to Treat Vaginal Co-Infection.

Polymeric hydrogels are common dosage forms designed for the topical administration of antimicrobial drugs to treat vaginal infections. One of the major advantages of using chitosan in these formulations is related to the intrinsic and broad antimicrobial activity exerted on bacteria and fungi by this natural polymer. Most vaginal yeast infections are caused by the pathogenic fungus Candida albicans. However, despite the anti-Candida activity towards and strains susceptibility to low molecular weight chitosan being documented, no information is available regarding the antimicrobial efficacy of mixed hydrogels in which chitosan is dispersed in a polymeric matrix. Therefore, the aim of the study is to evaluate the anti-Candida activity against eight different albicans and non-albicans strains of a mixed hydroxypropyl methylcellulose (HPMC)/chitosan hydrogel. Importantly, chitosan was dispersed in HPMC matrix either assembled in nanoparticles or in a monomolecular state to eventually correlate any variation in terms of rheological and mucoadhesive properties, as well as anti-Candida activity, with the chitosan form. Hydrogels containing 1% w/w chitosan, either as free polymer chain or assembled in nanoparticles, showed an improved mucoadhesiveness and an anti-Candida effect against all tested albicans and non-albicans strains. Overall, the results demonstrate the feasibility of preparing HPMC/CS mixed hydrogels intended for the prevention and treatment of Candida infections after vaginal administration.

Molecular and biopharmaceutical investigation of alginate-inulin synbiotic coencapsulation of probiotic to target the colon.

Colon targeting, as a site-specific delivery for oral formulation, remains a major challenge, especially for sensitive bioactive components such as therapeutic forms of phages, live attenuated virus and prebiotics-probiotics association. Synbiotics could be used to protect encapsulated probiotics during the gastrointestinal tract and control their release in the colon. To achieve these goals, effective prebiotics, such as inulin, could be combined with alginate - the most exploited polymer used for probiotic encapsulation - in the form of beads. This work aimed to study the biopharmaceutical behaviour of alginate beads (A) and inulin-alginate beads of different inulin concentrations (5 or 20%) in 2% alginate (AI5, AI20). Beads were loaded with three probiotic strains (Pediococcus acidilactici Ul5, Lactobacillus reuteri and Lactobacillus salivarius). Dissolution of beads was studied by USP4 under conditions simulating the gastrointestinal condition. The survival rates of the bacterial strains were measured by a specific qPCR bacterial count. Mucoadhesiveness of beads was studied by an ex vivo method using intestinal mucosa. To understand the behaviour of each formulation, the ultrastructure of the polymeric network was studied using scanning electron microscopy (SEM). Molecular interactions between alginate and inulin were studied by Fourier transform infra-red spectroscopy (FTIR). Dissolution results suggested that the presence of inulin in beads provided more protection for the tested bacterial strains against the acidic pH. AI5 was the most effective formulation to deliver probiotics to the colon simulation conditions. FTIR and SEM investigations explained the differences in behaviour of each formula. The developed symbiotic form provided a promising matrix for the development of colonic controlled release systems.

Novel Spray Dried Glycerol 2-Phosphate Cross-Linked Chitosan Microparticulate Vaginal Delivery System-Development, Characterization and Cytotoxicity Studies.

Chitosan microparticulate delivery systems containing clotrimazole were prepared by a spray drying technique using glycerol 2-phosphate as an ion cross-linker. The impact of a cross-linking ratio on microparticle characteristics was evaluated. Drug-free and drug-loaded unmodified or ion cross-linked chitosan microparticles were examined for the in vitro cytotoxicity in VK2/E6E7 human vaginal epithelial cells. The presence of glycerol 2-phosphate influenced drug loading and encapsulation efficacy in chitosan microparticles. By increasing the cross-linking ratio, the microparticles with lower diameter, moisture content and smoother surface were observed. Mucoadhesive studies displayed that all formulations possessed mucoadhesive properties. The in vitro release profile of clotrimazole was found to alter considerably by changing the glycerol 2-phosphate/chitosan ratio. Results from cytotoxicity studies showed occurrence of apoptotic cells in the presence of chitosan and ion cross-linked chitosan microparticles, followed by a loss of membrane potential suggesting that cell death might go through the mitochondrial apoptotic pathway.

Optimization of hyaluronan-based eye drop formulations.

Hyaluronan (HA) is frequently incorporated in eye drops to extend the pre-corneal residence time, due to its viscosifying and mucoadhesive properties. Hydrodynamic and rheological evaluations of commercial products are first accomplished revealing molecular weights varying from about 360 to about 1200kDa and viscosity values in the range 3.7-24.2mPa s. The latter suggest that most products could be optimized towards resistance to drainage from the ocular surface. Then, a study aiming to maximize the viscosity and mucoadhesiveness of HA-based preparations is performed. The effect of polymer chain length and concentration is investigated. For the whole range of molecular weights encountered in commercial products, the concentration maximizing performance is identified. Such concentration varies from 0.3 (wt%) for a 1100kDa HA up to 1.0 (wt%) for a 250kDa HA, which is 3-fold higher than the highest concentration on the market. The viscosity and mucoadhesion profiles of optimized formulations are superior than commercial products, especially under conditions simulating in vivo blinking. Thus longer retention on the corneal epithelium can be predicted. An enhanced capacity to protect corneal porcine epithelial cells from dehydration is also demonstrated in vitro. Overall, the results predict formulations with improved efficacy.

Effect of non-cross-linked calcium on characteristics, swelling behaviour, drug release and mucoadhesiveness of calcium alginate beads.

In this study, ibuprofen-loaded calcium alginate beads (CABs) with varying amounts of non-cross-linked calcium (NCL-Ca) were prepared using different washing methods. The influence of NCL-Ca on beads properties was investigated. Increasing the number or duration of washes led to significant decreases in the amount of NCL-Ca whereas the impact of the volume of washes was not significant. Approximately 70% of the initial amount of Ca(2+) was NCL-Ca which was removable by washing while only 30% was cross-linked (CL-Ca). Ca(2+) release from the CABs was bimodal; NCL-Ca was burst-released followed by a slower release of CL-Ca. Washing methods and the amount of NCL-Ca had significant influences on the encapsulation efficiency, beads weight, beads swelling, drug release profile and the mucoadhesiveness of CABs. This study highlighted the importance of washing methods and the amount of NCL-Ca to establish CABs properties and understand their behaviour in the simulated intestinal fluids (SIFs).

Buccal adhesive nanofibers containing human growth hormone for oral mucositis.

Due to a lack of proper drug carriers to deliver treatments for mucositis, many cancer patients suffer from oral mucositis caused by chemotherapy and radiotherapy. We prepared a double-layered electrospun nanofibrous sheets composed of Eudragit and chitosan to accelerate the healing rate of oral mucous ulcer. Human growth hormone (hGH) and Eudragit in a mixture of dimethylacetamide and ethanol were co-electrospun to nanofibrous sheets. The electrospun fibrous mat was subsequently layered with chitosan by a dip-coating method. Chitosan-layered sheets showed attenuated mass erosion while uncoated sheets were instantly melted at the physiological condition. The released hGH was trapped on the chitosan layer by the ionic interaction between positively charged chitosan and negatively charged hGH, and a large number of entrapped proteins remained on the SIS membrane due to the muco-adhesive properties of chitosan. hGH-incorporated sheets significantly increased proliferation of human dermal fibroblasts. In vivo study employing oral ulcers in dogs, the ulcers dressed with chitosan-layered sheets showed enhanced wound recovery and the chitosan layers on the sheet greatly assisted prolonged recovery. Therefore, chitosan-layered Eudragit nanofibrous sheets can be potentially applied to developing muco-adhesive wound dressing materials with pH-dependent drug release by adjusting the thickness of chitosan sheath on the sheets. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1396-1406, 2016.

Thiolated silicone oil: synthesis, gelling and mucoadhesive properties.

The aim of this study was the development of novel thiolated silicone oils and their evaluation with regard to gelling and mucoadhesive properties. A thiol coupling of 220 ± 14 and 127 ± 33 µmol/g polymer for 3-mercaptopropionic acid (MPA)- and cysteine-coupled silicone oil was determined, respectively. The dynamic viscosity of MPA-silicone raised significantly (p<0.000001) after oxidation with iodine to a maximum of 523-fold within 1h. During tensile studies, MPA-silicone showed both the highest results for total work of adhesion (TWA) and maximum detachment force (MDF) with a 3.8- and 3.4-fold increase, respectively, compared to the control. As far as the residence time on small intestinal mucosa is concerned, both silicone conjugates were detectable in almost the same quantities for up to 8h with 56.9 ± 3.3 and 47.8 ± 8.9% of the initially applied conjugated silicone oil. Thiolated silicone oils can be regarded superior in comparison to commonly used silicone oils due to a prolonged retention time in the small intestine as site of action. Gelling and mucoadhesive features are advantageous for antiflatulent as well as mucoprotective biomaterials. Thus, these novel thiomers seem promising for an upgrade of currently available products for the treatment of dyspepsia, reflux oesophagitis and even inflammatory bowel diseases such as ulcerative colitis or Crohn's disease.

Effective mucoadhesive liposomal delivery system for risedronate: preparation and in vitro/in vivo characterization.

In this work, we aimed to develop chitosan-coated mucoadhesive liposomes containing risedronate to improve intestinal drug absorption. Liposomes containing risedronate were prepared with 1,2-distearoryl-sn-glycero-3-phosphocholine and distearoryl-sn-glycero-3-[phospho-rac-(1-glycerol)] using the freeze-drying method, with subsequent coating of the anionic surfaces of the liposomes with chitosan. The in vitro characteristics of the chitosan-coated liposomes were investigated, including their stability, mucoadhesiveness, and Caco-2 cell permeability. This formulation was stable in simulated gastric and intestinal fluids, with the percentage of drug remaining in the liposomes being more than 90% after 24 hours of incubation. Chitosan-coated liposomes also showed strong mucoadhesive properties, implying potential electrostatic interaction with the mucous layer in the gastrointestinal tract. Compared with the untreated drug, chitosan-coated liposomes significantly enhanced the cellular uptake of risedronate, resulting in an approximately 2.1-2.6-fold increase in Caco-2 cells. Further, the chitosan-coated liposomes increased the oral exposure of risedronate by three-fold in rats. Taken together, the results of this study suggest that chitosan-coated liposomes containing risedronate should be effective for improving the bioavailability of risedronate.