Mucoadhesive Properties Research Articles

DESIGN, DEVELOPMENT, AND CHARACTERIZATION OF LORATADINE SUSTAINED RELEASED BUCCAL FILM: IN VITRO AND IN VIVO STUDY IN BEAGLE DOGS

Objective: The aim of this work was to develop and evaluate bucco-adhesive films of Loratadine (LTD) for sustained release use. Methods: Design of twelve different sustained released buccal film formulas using Carbopol, pectin, sodium alginate, glycerol, carboxymethyl cellulose (CMC), hydroxypropyl cellulose (HPC), Gelatin, Hydroxyethyl cellulose (HEC), and Hydroxypropyl methylcellulose (HPMC) as mucoadhesive polymers. Films were evaluated for physicochemical properties, thickness, swelling, moisture content, drug content, in vitro dissolution. The pharmacokinetic parameters of optimal formula were evaluated in beagle dogs. Results: The selected film formula (F6) showed accepted content and muco-adhesion properties. The in vitro release study showed prolonged release of drug from films over 10 h in optimal formulation. The bioavailability studies performed using beagle dogs model showed that there was 113.45% increase in the AUC0-24 of selected film compared with oral market tablets. Conclusion: Bucco-adhesive films is a promising dosage form for improving the bioavailability of loratadine.

Mucoadhesive Thiolated Hyaluronic Acid/Pluronic F127 Nanogel Formation via Thiol-Maleimide Click Reaction for Intravesical Drug Delivery.

The development of nanocarriers to prolong the residence time and enhance the permeability of chemotherapeutic drugs on bladder mucosa is important in the postsurgery treatment of superficial bladder cancers (BCs). Here, the mucoadhesive HA-SH/PF127 nanogels composed of a temperature-sensitive Pluronic F127 (PF127) core and thiolated hyaluronic acid (HA-SH) shell were prepared by the emulsification/solvent evaporation method. The nanogels were constructed through the thiol-maleimide click reaction in the HA-SH aqueous side of the oil-water interface and self-oxidized cross-linking thiols between HA-SH. The HA-SH/PF127 nanogels prepared at different thiol-to-maleimide group molar ratios, water-to-oil volume ratios, and cross-linking reaction times were characterized regarding hydrodynamic diameter (Dh) and zeta potential (ζ), and the optimal formulation was obtained. The excellent mucoadhesive properties of the HA-SH/PF127 nanogels were evaluated by using the mucin particle method. Doxorubicin (DOX) was encapsulated in the PF127 core of DOX@HA-SH/PF127 nanogels with a high loading efficiency (87.5%) and sustained release from the nanogels in artificial urine. Ex vivo studies on porcine bladder mucosa showed that the DOX@HA-SH/PF127 nanogels enhanced the penetration of the DOX into the bladder mucosa without disrupting the mucus structure or the bladder tissue. A significant dose-dependent cytotoxic effect of DOX@HA-SH/PF127 nanogels on both T24 and MB49 cells was observed. The present study demonstrates that the mucoadhesive HA-SH/PF127 nanogels are a promising intravesical drug delivery system for superficial BC therapy.

Ion-activated In Situ Gel of Gellan Gum Containing Chrysin for Nasal Administration in Parkinson's Disease.

This study focused on creating an innovative treatment approach for Parkinson's disease (PD), a progressive neurodegenerative condition characterized by the loss of specific neurons in the brain. The research aimed to develop a nasal gel using gellan gum containing a complex of chrysin with hydroxypropyl-β-cyclodextrin (HP-β-CD) to enhance the drug's solubility and stability. The formulation process involved utilizing central composite design (CCD) to optimize the concentrations of gellan gum and HPMC E5, with viscosity and mucoadhesive strength as key factors. The resulting optimized In Situ gel comprised 0.7% w/v gellan gum and 0.6% w/v HPMC E5, exhibiting desirable viscosity levels for both sol and gel states, along with robust mucoadhesive properties. The formulated gel underwent comprehensive evaluation, including assessments for gelation, drug content, in vitro drug release, ex vivo permeation, and histopathology. The findings demonstrated superior drug release from the In Situ gel compared to standalone chrysin. Ex vivo studies revealed effective drug permeation through nasal mucosa without causing harm. Moreover, experiments on neuronal cells exposed to oxidative stress (H2O2- induced) showcased significant neuroprotection conferred by chrysin and its formulations. These treatments exhibited notable enhancements in cell viability and reduced instances of apoptosis and necrosis, compared to the control group. The formulations exhibited neuroprotective properties by mitigating oxidative damage through mechanisms, like free radical scavenging and restoration of antioxidant enzyme activity. In conclusion, this developed In situ gel formulation presents a promising novel nasal delivery system for PD therapy. By addressing challenges related to drug properties and administration route, it holds the potential to enhance treatment outcomes and improve the quality of life for individuals with Parkinson's disease.

Formulation and evaluation of mucoadhesive microspheres of metronidazole

Objective: Develop and evaluate mucoadhesive microspheres using Chitosan, Sodium alginate, and Sodium carboxymethyl cellulose (NaCMC) for sustained oral delivery of Metronidazole, aiming to improve bioavailability. Methods: Metronidazole-loaded microspheres were prepared via ionotropic gelation method with varying polymer ratios. Particle size, entrapment efficiency, swelling index, mucoadhesion (sheep mucosae), morphology (SEM), in-vitro wash-off test, drug release profile, and stability (6 months) were evaluated. Results: Chitosan content positively correlated with microsphere size. Entrapment efficiency ranged from 51.43% to 94.15%. Chitosan-based formulations, especially MTZ-7 (Chitosan:NaCMC, 3:1), displayed the highest mucoadhesion. SEM analysis revealed rough, spherical microspheres with a continuous polymeric coat. In-vitro wash-off test demonstrated prolonged residence time for Chitosan formulations. Sustained drug release was observed throughout the study, with MTZ-7 exhibiting the most desirable release profile. Stability studies showed no significant changes in drug release for selected formulations after 6 months. Conclusions: Chitosan-based microspheres, particularly MTZ-7, demonstrated superior mucoadhesive properties, sustained and controlled drug release, and desirable stability. These findings suggest the potential of Chitosan-based microspheres as a promising oral drug delivery system for Metronidazole, potentially addressing bioavailability concerns and improving therapeutic efficacy.

Mucoadhesive Polymeric Polyologels Designed for the Treatment of Periodontal and Related Diseases of the Oral Cavity.

The study objective was to design and characterise herein unreported polyologels composed of a range of diol and triol solvents and polyvinyl methyl ether-co-maleic acid (PVM/MA) and, determine their potential suitability for the treatment of periodontal and related diseases in the oral cavity using suitable in vitro methodologies. Polyologel flow and viscoelastic properties were controlled by the choice of solvent and the concentration of polymer. At equivalent polymer concentrations, polyologels prepared with glycerol (a triol) exhibited the greatest elasticity and resistance to deformation. Within the diol solvents (PEG 400, pentane 1,5-diol, propane 1,2-diol, propane 1,3-diol, and ethylene glycol), PEG 400 polyologels possessed the greatest elasticity and resistance to deformation, suggesting the importance of distance of separation between the diol groups. Using Raman spectroscopy bond formation between the polymer carbonyl group and the diol hydroxyl groups was observed. Polyologel mucoadhesion was influenced by viscoelasticity; maximum mucoadhesion was shown by glycerol polyologels at the highest polymer concentration (20% w/w). Similarly, the choice of solvent and concentration of PVM/MA affected the release of tetracycline from the polyologels. The controlled release of tetracycline for at least 10 h was observed for several polyologels, which, in combination with their excellent mucoadhesion and flow properties, offer possibilities for the clinical use of these systems to treat diseases within the oral cavity.

Chitosan surface modification modulates the mucoadhesive, permeation and anti-angiogenic properties of gellan gum/bevacizumab nanoparticles

Bevacizumab (BVZ) was the first monoclonal antibody approved by the FDA and has shown an essential advance in the antitumor therapy of colorectal cancer (CRC), however, the systemic action of BVZ administered intravenously can trigger several adverse effects. The working hypothesis of the study was to promote the modulation of the mucoadhesion properties and permeability of the BVZ through the formation of nanoparticles (NPs) with gellan gum (GG) with subsequent surface modification with chitosan (CS). NPs comprising BVZ and GG were synthesized through polyelectrolyte complexation, yielding spherical nanosized particles with an average diameter of 264.0 ± 2.75 nm and 314.0 ± 0.01 nm, polydispersity index of 0.182 ± 0.01 e 0.288 ± 0.01, and encapsulation efficiency of 29.36 ± 0.67 e 60.35 ± 0.27 mV, for NPs without (NP_BVZ) and with surface modification (NP_BVZ + CS). The results showed a good ability of nanoparticles with surface modification to modulate the NPs biological properties.

Enhancing Mucoadhesive Properties of Gelatin through Chemical Modification with Unsaturated Anhydrides.

Gelatin is a water-soluble natural polyampholyte with poor mucoadhesive properties. It has traditionally been used as a major ingredient in many pharmaceuticals, including soft and hard capsules, suppositories, tissue engineering, and regenerative medicine. The mucoadhesive properties of gelatin can be improved by modifying it through conjugation with specific adhesive unsaturated groups. In this study, gelatin was modified by reacting with crotonic, itaconic, and methacrylic anhydrides in varying molar ratios to yield crotonoylated-, itaconoylated-, and methacryloylated gelatins (abbreviated as Gel-CA, Gel-IA, and Gel-MA, respectively). The successful synthesis was confirmed using 1H NMR, FTIR spectroscopies, and colorimetric TNBSA assay. The effect of chemical modification on the isoelectric point was studied through viscosity and electrophoretic mobility measurements. The evolution of the storage (G') and loss (G'') moduli was employed to determine thermoreversible gelation points of modified and unmodified gelatins. The safety of modified gelatin derivatives was assessed with an in vivo slug mucosal irritation test (SMIT) and an in vitro MTT assay utilizing human pulmonary fibroblasts cell line. Two different model dosage forms, such as physical gels and spray-dried microparticles, were prepared and their mucoadhesive properties were evaluated using a flow-through technique with fluorescent detection and a tensile test with ex vivo porcine vaginal tissues and sheep nasal mucosa. Gelatins modified with unsaturated groups exhibited superior mucoadhesive properties compared to native gelatin. The enhanced ability of gelatin modified with these unsaturated functional groups is due to the formation of covalent bonds with cysteine-rich subdomains present in the mucin via thiol-ene click Michael-type addition reactions occurring under physiologically relevant conditions.

Nanoparticles of Thiolated Xanthan Gum for the Oral Delivery of Miconazole Nitrate: In Vitro and In Vivo Evaluation.

The objective of this research was to develop a mucoadhesive delivery system that improves permeation for the administration of poorly absorbed oral medications. Thiolation of xanthan gum (XGM) was carried out by esterification with mercaptobutyric acid. Fourier-transformed infrared spectroscopy was used to confirm thiol-derivatization. Using Ellman's technique, it was revealed that the xanthan-mercaptobutyric acid conjugate had 4.7 mM of thiol groups in 2 mg/mL of polymeric solution. Using mucosa of sheep intestine, the mucoadhesive properties of XGM and thiolated xanthan gum (TXGM) nanoparticles were investigated and we found that TXGM had a longer bioadhesion time than XGM. The disulfide link that forms between mucus and thiolated XGM explains why it has better mucoadhesive properties than XGM. A study on in vitro miconazole (MCZ) release using phosphate buffer (pH 6.8) found that TXGM nanoparticles released MCZ more steadily than MCZ dispersion did. A 1-fold increase in the permeation of MCZ was observed from nanoparticles using albino rat intestine compared to MCZ. Albino rats were used to test the pharmacokinetics of MCZ, and the results showed a 4.5-fold increase in bioavailability. In conclusion, the thiolation of XGM enhances its bioavailability, controlled release of MCZ for a long period of time, and mucoadhesive activity.

A technological comparison of freeze-dried poly-ɛ-caprolactone (PCL) and poly (lactic-co-glycolic acid) (PLGA) nanoparticles loaded with clozapine for nose-to-brain delivery

Clozapine (CZP) is an atypical antipsychotic, the most effective for the treatment of resistant schizophrenia. With the aim of overcome the limitations of current dosage forms (tablets or suspensions) and routes of administration (oral and intramuscular), this research project proposes nanocarrier systems for intranasal (IN) administration of CZP. In particular, the systems have been developed for the direct nose-to-brain (N2B) route, which allows the direct delivery of the drug to the central nervous system (CNS), bypassing the blood-brain barrier (BBB). This study focusses on the development and investigation of two distinct types of lyophilized polymeric nanoparticles (NPs) consisting of poly- ɛ -caprolactone (PCL) or poly (lactic-co-glycolic acid) (PLGA). The lyophilized formulations were cryoprotected with 5 % (w/v) d-maltose for PLGA-NPs and 25 % (w/v) d-maltose for PCL-NPs. The NPs showed a size of approximately 200 nm, suitable for reuptake from the olfactory nerve to reach the brain directly after the IN administration. In vitro release studies performed in artificial cerebrospinal fluid (aCSF) and simulated nasal fluid (SNF) showed that PLGA NPs released 100 % of the drug in 4 days in SNF, while in aCSF they released about 80 % in 20 days. On the contrary, PCL-NPs released the entire amount of drug within 24 h in both fluids. Furthermore, preliminary in vitro mucoadhesion studies were performed on NPs in liquid form (suspensions) to compare the possible variation in their mucoadhesive properties with respect to powdered NPs, which were tested directly on pig nasal mucosa tissue, where permeability was also assessed. CZP-loaded NPs showed some interactions with mucin in vitro, but no ex-vivo mucoadhesiveness was demonstrated. Furthermore, the results of permeation indicated that the use of CZP-PCL-NPs did not increase the effective permeation of CZP into the mucosa; however, a faster onset of permeation compared to free CZP and a controlled profile were demonstrated. Toxicity studies on primary human olfactory mucosa cells extracted from volunteer patients and on MDCKII cells were also done. Finally, stability studies were carried out under different conditions: suspensions stored at 4 and 25 °C for 3 months, in SNF at 35 °C and in aCSF at 37 °C; dry powders were instead stored at 25 °C with 50 % relative humidity for 8 months. All the results demonstrated a greater stability of NPs in powder form and the absence of aggregation phenomena under artificial physiological conditions.

Smart mucoadhesive 3-D network hydrogels for use in localized impregnated anticancer drug delivery

Recently, bioactive dietary fibers (DFs) have been explored for various benefits to human health because of their therapeutic activities. Role of DF psyllium (arabinoxylan (Ax)) has been established for curing colon cancer. Herein, methotrexate (MXT), an anti-neoplastic agent, was impregnated into network hydrogels developed from DF psyllium, through graft copolymerization reactions for its sustained colon-specific drug delivery (DD). Copolymers were characterized through SEM, AFM, FTIR, C13-NMR and TGA analysis. Smart hydrogels demonstrated antioxidant (39.40 ± 0.78% free radical scavenging in the DPPH assay), biocompatible (1.16 ± 0.22% hemolysis value in blood-polymer interactions), and mucoadhesive (7.0 ± 0.1 mN detachment force from the mucous membrane) properties. Sustained diffusion of MXT in colonic conditions occurred with a Fickian mechanism, and release profile obeyed the Korsmeyer-Peppas kinetic model. Overall, findings suggested the suitability of DF psyllium-based DD carriers for colon with enhanced potential.

W/O/W Microemulsions for Nasal Delivery of Hydrophilic Compounds: A Preliminary Study

The administration of hydrophilic therapeutics has always been a great challenge because of their low bioavailability after administration. For this purpose, W/O/W microemulsion resulted to be a potential successful strategy for the delivery of hydrophilic compounds, interesting for the nasal mucosal therapy. Herein, an optimized biphasic W/O microemulsion was designed, through a preliminary screening, and it was inverted in a triphasic W/O/W microemulsion, intended for the nasal administration. In order to enhance the mucosal retention, surface modification of the biphasic W/O microemulsion was performed adding didodecyldimethylammonium bromide, and then converting the system into a cationic triphasic W/O/W microemulsion. The developed samples were characterized in terms of droplet size, polydispersity, zeta potential, pH and osmolality. The physical long-term stability was analyzed storing samples at accelerated conditions (40 ± 2 °C and 75 ± 5 % RH) for 6 months in a constant climate chamber, following ICH guidelines Q1A (R2). In order to verify the potential retention on the nasal mucosa, the two triphasic systems were analyzed in terms of mucoadhesive properties, measuring the in vitro interaction with mucin over time. Furthermore, fluorescein sodium salt was selected as a model hydrophilic drug to be encapsulated into the inner core of the two triphasic W/O/W microemulsions, and its release was analyzed compared to the free probe solution. The cytocompatibility of the two platforms was assessed on two cell lines, human fibroblasts HFF1 and Calu-3 cell lines, chosen as pre-clinical models for nasal and bronchial/tracheal airway epithelium.

Hyaluronic Acid-Conjugated Thermoresponsive Polymer-Based Bioformulation Enhanced Wound Healing and Gut Barrier Repair of a TNBS-Induced Colitis Injury Ex Vivo Model in a Dynamic Perfusion Device.

Impairment of intestinal epithelium is a typical feature of inflammatory bowel disease (IBD) that causes leakage of bacteria and antigens from the intestinal lumen and thus results in persistent immune activation. Hence, healing and regeneration of the damaged gut mucosa is a promising therapeutic approach to achieve deep remission in IBD. Currently, available systemic therapies have moderate effects and are often associated with numerous side effects and malignancies. In this study, we aimed to develop a topical therapy by chemically conjugating a temperature-responsive polymer, i.e., poly(N-isopropylacrylamide), along with hyaluronic acid to obtain a sprayable therapeutic formulation that upon colon instillation adheres to the damaged gut mucosa due to its temperature-induced phase transition and mucoadhesive properties. An ex vivo adhesion experiment demonstrates that this therapeutic formulation forms a thin physical coating on the mucosal lining at a physiological temperature within 5 min. Physicochemical characterization of (P(NIPAM-co-NTBAM)-HA) established this formulation to be biocompatible, hemo-compatible, and non-immunogenic. Prednisolone was encapsulated within the polymer formulation to achieve maximum therapeutic efficacy in the case of IBD-like conditions as assessed in a custom-fabricated perfusion-based ex vivo model system. Histological analysis suggests that the prednisolone-encapsulated polymer formulation nearly restored the mucosal architecture after 2,4,6-trinitrobenzenesulfonic acid-induced damage. Furthermore, a significant (p ≤ 0.001) increase in mRNA levels of Muc-2 and ZO-1 in treated groups further confirmed the mucosal epithelial barrier restoration.

Formulation, Development and In-vitro Evaluation of Alendronate Buccal Tablets

The aim of this work was to develop Alendronate mucoadhesive buccal tablets. Buccal tablets of Alendronate are designed to release drug at mucosal site for extended period of time without wash out of drug by saliva. Sodium alginate, Ethyl cellulose and Carbopol were selected as mucoadhesive polymers on the basis of their matrix forming properties. The objective of the study is to improve the bioavailability of Alendronate buccal tablets. In present study, an attempt was made to design mucoadhesive buccal tablets containing Alendronate, Sodium alginate, Ethyl cellulose and Carbopol using as polymers. The tablets were prepared by direct compression method. The formulations were evaluated for hardness, thickness, friability, weight variation, drug content estimation, surface pH determination, swelling index, in vitro drug release. The obtained results of various evaluation parameters are described in post compression studies. The results of in vitro release study were in full support of swelling study. In vitro release data of optimized formula F11 fitted into various release kinetic models to study the release mechanism. All the prepared tablets were stable at different temperature and shows good mucoadhesive properties.

Development of Mucoadhesive Buccal Films Containing Triamcinolone Acetonide by using Co-solvent Systems

This work aimed to develop mucoadhesive buccal films containing triamcinolone acetonide (TA), which shows local anti-inflammatory activity. A thin film layer was formulated from polyvinyl alcohol (PVA) by the solvent casting method. The solubility of TA and the ability of the co-solvents to produce films were evaluated. The optimal co-solvents were chosen to prepare the film. Pharmaceutical properties of the film, including uniformity of weight, thickness, mechanical property, wetting time, mucoadhesion, TA content, and release, were evaluated. Furthermore, the cytotoxicity and scratch assay were assessed for the in vitro cell line. Among the co-solvents, the system consisted of ethanol, distilled water, and an individual plasticizer (glycerin and polyethylene glycol 400 (PEG 400)), which showed promising co-solvents for TA solubility and film formation. The films were clear and colorless, with a smooth surface and good mechanical properties. PEG 400-contained film formulation had higher mechanical properties and faster wetting time than glycerin. Both films had similar mucoadhesive properties, although the TA content differed slightly, and a rapid release of TA from the films was observed. However, PEG 400-contained film offered a slightly faster TA release than glycerin. The films were non-toxic to gingival fibroblast cells. However, they decreased the cell growth and migration compared to the control. According to this research, co-solvents increased TA solubility and produced good characteristic buccal mucoadhesive films containing TA. Keywords: Triamcinolone acetonide, Co-solvents, Film, Mucoadhesive property

Preparation and Evaluation of Ketoprofen Loaded Mucoadhesive Microspheres

The aim of the present study was to prepare and evaluate Ketoprofen loaded microspheres fabricated with sodium alginate and Carbopol 934 by ion gelation method which enhances the drug residence time into the stomach by adhering to the mucus layer of and control the rate of drug release for longer period of time. Ketoprofen is a nonsteroidal anti-inflammatory drug (NSAID) that is commonly used for its analgesic, anti-inflammatory, and antipyretic (fever-reducing) properties. It belongs to the propionic acid class of NSAIDs and is available in various formulations, including oral tablets, capsules, topical gels, creams, and as an injectable solution. In present study ketoprofen incorporates in mucoadhesive drug delivery system for utilizing its controlled drug delivery up to 12 hrs. In present study prepared microspheres were evaluated for- particle size, entrapment efficiency, percentage yield, morphology, mucoadhesive property, in-vitro drug release property.
 Keywords: Mucoadhesive microspheres, NSAID, ion gelation method, ketoprofen

Microparticles and multi-unit systems for advanced drug delivery

Microparticles have unique benefits in the formulation of multiparticulate and multi-unit type pharmaceutical dosage forms allowing improved drug safety and efficacy with favorable pharmacokinetics and patient centricity. On the other hand, the above advantages are served by high and well reproducible quality attributes of the medicinal product where even flexible design and controlled processability offer success as well as possible longer product life-cycle for the manufacturers. Moreover, the specific demands of patients can be taken into account, including simplified dosing regimens, flexible dosage, drug combinations, palatability, and ease of swallowing.In the more than 70 years since the first modified-release formulation appeared on the market, many new formulations have been marketed and many publications have appeared in the literature. More unique and newer pharmaceutical technologies and excipients have become available for producing tailor-made particles with micrometer dimensions and beyond. All these have contributed to the fact that the sub-units (e.g. minitablets, pellets, microspheres) that make up a multiparticulate system can vary widely in composition and properties. Some units have mucoadhesive properties and others can float to contribute to a suitable release profile that can be designed for the multiparticulate formula as a whole. Nowadays, there are some available formulations on the market, which are able to release the active substance even for several months (3 or 6 months depending on the type of treatment).In this review, the latest developments in technologies that have been used for a long time are presented, as well as innovative solutions such as the applicability of 3D printing to produce subunits of multiparticulate systems. Furthermore, the diversity of multiparticulate systems, different routes of administration are also presented, touching the ones which are capable of carrying the active substance as well as the relevant, commercially available multiparticle-based medical devices. The versatility in size from 1 µm and multiplicity of formulation technologies promise a solid foundation for the future applications of dosage form design and development.

Preparation and Characterization of Novel Polyelectrolyte Liposomes Using Chitosan Succinate Layered over Chitosomes: A Potential Strategy for Colon Cancer Treatment.

Chitosan succinate is distinguished by its ability to shield the loaded drug from the acidic environment, localize and keep the drug at the colon site, and release the drug over an extended time at basic pH. The current study attempts to develop polyelectrolyte liposomes (PEL), using chitosan and chitosan succinate (CSSC), as a carrier for liposomal-assisted colon target delivery of 5 fluorouracil (5FU). The central composite design was used to obtain an optimized formulation of 5FU-chitosomes. The chitosan-coated liposomes (chitosomes) were prepared by thin lipid film hydration technique. After that, the optimized formulation was coated with CSSC, which has several carboxylic (COOH) groups that produce an anionic charge that interacts with the cation NH2 in chitosan. The prepared 5FU-chitosomes formulations were evaluated for entrapment efficiency % (EE%), particle size, and in vitro drug release. The optimized 5FU-chitosomes formulation was examined for particle size, zeta potential, in vitro release, and mucoadhesive properties in comparison with the equivalent 5FU-liposomes and 5FU-PEL. The prepared 5FU-chitosomes exhibited high EE%, small particle size, low polydispersity index, and prolonged drug release. PEL significantly limited the drug release at acidic pH due to the deprotonation of carboxylate ions in CSSC, which resulted in strong repulsive forces, significant swelling, and prolonged drug release. According to a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay, PEL treatment significantly decreased the viability of HT-29 cells. When compared to 5FU-liposome and 5FU-chitosome, the in vivo pharmacokinetics characteristics of 5FU-PEL significantly (p < 0.05) improved. The findings show that PEL enhances 5FU permeability, which permits high drug concentrations to enter cells and inhibits the growth of colon cancer cells. Based on the current research, PEL may be used as a liposomal-assisted colon-specific delivery.

On the mucoadhesive properties of synthetic and natural polyampholytes

HypothesisThe mucoadhesive characteristics of amphoteric polymers (also known as polyampholytes) can vary and are influenced by factors such as the solution's pH and its relative position against their isoelectric point (pHIEP). Whilst the literature contains numerous reports on mucoadhesive properties of either cationic or anionic polymers, very little is known about these characteristics for polyampholytes ExperimentsHere, two amphoteric polymers were synthesized by reaction of linear polyethylene imine (l-PEI) with succinic or phthalic anhydride and their mucoadhesive properties were compared to bovine serum albumin (BSA), selected as a natural polyampholyte. Interactions between these polymers and porcine gastric mucin were studied using turbidimetric titration and isothermal titration calorimetry across a wide range of pHs. Model tablets were designed, coated with these polymers and tested to evaluate their adhesion to porcine gastric mucosa at different pHs. Moreover, a retention study using fluorescein isothiocyanate (FITC)-labelled polyampholytes deposited onto mucosal surfaces was also conducted FindingsAll these studies indicated the importance of solution pH and its relative position against pHIEP in the mucoadhesive properties of polyampholytes. Both synthetic and natural polyampholytes exhibited strong interactions with mucin and good mucoadhesive properties at pH < pHIEP.

Multiresponsive Core-Shell Microgels Functionalized by Nitrilotriacetic Acid.

Stimuli-responsive microgels with ionizable functional groups offer versatile applications, e.g., by the uptake of oppositely charged metal ions or guest molecules such as drugs, dyes, or proteins. Furthermore, the incorporation of carboxylic groups enhances mucoadhesive properties, crucial for various drug delivery applications. In this work, we successfully synthesized poly{N-vinylcaprolactam-2,2'-[(5-acrylamido-1-carboxypentyl)azanediyl]diacetic acid} [p(VCL/NTAaa)] microgels containing varying amounts of nitrilotriacetic acid (NTA) using precipitation polymerization. We performed fundamental characterization by infrared (IR) spectroscopy and dynamic and electrophoretic light scattering. Despite their potential multiresponsiveness, prior studies on NTA-functionalized microgels lack in-depth analysis of their stimuli-responsive behavior. This work addresses this gap by assessing the microgel responsiveness to temperature, ionic strength, and pH. Morphological investigations were performed via NMR relaxometry, nanoscale imaging (AFM and SEM), and reaction calorimetry. Finally, we explored the potential application of the microgels by conducting cytocompatibility experiments and demonstrating the immobilization of the model protein cytochromec in the microgels.

Evaluation of drug release, mucoadhesive and viscoelastic performances of Netildex gel versus an antibiotic‐steroid combination system

Purpose: The poor bioavailability and therapeutic response exhibited by conventional antibiotic‐steroid ophthalmic solutions due to rapid precorneal elimination of the drug may be overcome using a gel systems. Netildex gel is a preservative‐free product based on netilmicin and dexamethasone indicated for the treatment of inflammatory ocular conditions of the anterior segment and ocular adnexa including post‐cataract surgery. The current investigation evaluated the in vitro drug release, viscosity and mucoadhesion profile of Netildex gel in comparison to a gel matrix with regard to steroid and antibiotic delivery.Methods: In vitro drug release was assessed using Franz‐type diffusion cells, under sink condition, exploiting a simulated tear solution (STS) as dissolution medium and a regenerated cellulose membrane. Evaluation of mucoadhesive and viscoelastic properties were performed by texture analyzer TA‐XT2 and rheometer.Results: The dexamethasone and netilmicin release curves in Netildex gel exhibited a better sustained and controlled pattern over an extended time period (48 h) with respect to another gel system containing anti‐inflammatory and antibiotic drugs. The results were expressed as cumulative percentage of drug release and the antibiotics‐release kinetics from the polymeric matrix, evaluated by different mathematical models. The determination of detachment force demonstrated a significant mucoadhesive strength of Netildex gel compared to mucin. Moreover, rheological analysis of Netildex gel highlighted a strong pseudo‐plastic behaviour under shear strain due to its formulation features.Conclusions: Overall, Netildex gel exhibits a sustained and controlled drug release of both dexamethasone and netilmicin from polymeric matrix thanks to its viscoelastic and mucoadhesive properties allowing to prolong drug residence time on the ocular surface. These data support the reduced administration frequency while maintaining the same efficacy and simultaneously favouring patients' compliance [1].Reference1. Mencucci R. et al. Adv Ther (2022) 39: 5474–5486.