Mucoadhesion and Mechanical Assessment of Oral Films

Poly(phenylalanine) and poly(3,4-dihydroxy-L-phenylalanine): Promising biomedical materials for building stimuli-responsive nanocarriers

Cancer is a serious threat to human health because of its high annual mortality rate. It has attracted significant attention in healthcare, and identifying effective strategies for the treatment and relief of cancer pain requires urgency. Drug delivery systems (DDSs) offer the advantages of excellent efficacy, low cost, and low toxicity for targeting drugs to tumor sites. In recent decades, copolymer carriers based on poly(phenylalanine) (PPhe) and poly(3,4-dihydroxy-L-phenylalanine) (PDopa) have been extensively investigated owing to their good biocompatibility, biodegradability, and controllable stimulus responsiveness, which have resulted in DDSs with loading and targeted delivery capabilities. In this review, we introduce the synthesis of PPhe and PDopa, highlighting the latest proposed synthetic routes and comparing the differences in drug delivery between PPhe and PDopa. Subsequently, we summarize the various applications of PPhe and PDopa in nanoscale-targeted DDSs, providing a comprehensive analysis of the drug release behavior based on different stimulus-responsive carriers using these two materials. In the end, we discuss the challenges and prospects of polypeptide-based DDSs in the field of cancer therapy, aiming to promote their further development to meet the growing demands for treatment.

Development and effect of orodispersible film incorporated with Biosilicate for remineralization of dental enamel subjected to cariogenic and erosive challenge

OBJECTIVES

The objective of this in vitro study was to assess the efficiency of incorporating Biosilicate particles (30 and 50 mg) into an experimental orodispersible film and its efficacy in the remineralization process of bovine dental enamel under cariogenic and erosive challenges.

METHODS

Ninety-nine intact incisors, devoid of cracks or fractures, yielding 198 samples (6 × 6 × 2 mm) via vestibular sectioning using a low-speed diamond disc under water cooling. After flattening the enamel surface with 600, 1200, and 2000 grit sandpaper, the samples were divided into two groups based on the challenges they underwent: cariogenic (0.1 M lactic acid at pH 5.0) or erosive (0.05 M citric acid solution at pH 2.3). Samples from each challenge were further categorized into 11 groups (n = 9) according to the duration of cariogenic (3, 7, and 14 days) or erosive (3, 7, and 10 days) challenge, along with positive control groups (fragments untreated with challenges and treated with different Biosilicate concentrations) and negative controls (fragments treated with artificial saliva for the same periods established for cariogenic and erosive challenges). Treatments with orodispersible films containing Biosilicate (30 and 50 mg) were administered for 2 min per day for 15 days.

RESULTS

The highest remineralizing potential was observed in samples treated with Biosilicate after 14 days of cariogenic challenge, irrespective of the concentration tested. For samples subjected to erosive challenge, erosion time did not affect Biosilicate's remineralizing potential.

CONCLUSION

Biosilicate shows promise in terms of remineralizing potential in enamel subjected to cariogenic challenge due to its ability to form hydroxycarbonapatite in mineralized tissues.

Curcumin analogue AC17-loaded dissolvable microneedles activate FOXO3 and enhance localized drug delivery for oral squamous cell carcinoma treatment

Curcumin, a polyphenol extracted from turmeric, is a potential alternative for the treatment of oral squamous cell carcinoma (OSCC) due to its remarkable anticancer activity and low systemic toxicity. To further enhance the anticancer activity and bioavailability of curcumin, we synthesized a curcumin analogue, AC17, by modifying the benzene ring and methylene group of curcumin. A soluble hyaluronic acid microneedle patch (AC17@HAMN) was developed to ensure accurate and safe delivery of AC17 to tumor tissues. The inhibitory effect of AC17 on OSCC cells was stronger than that of curcumin and some common analogues. Transcriptome sequencing showed that the target genes of AC17 were mainly concentrated in apoptosis, cell cycle and cell senescence pathways. Among them, AC17 induces cell cycle arrest and inhibits cell proliferation mainly by activating FOXO3 signaling. With good penetration and dissolution properties, microneedles can deliver AC17 directly to the tumor site and show good anti-tumor effect. Moreover, AC17@HAMN showed good biosafety. In summary, AC17@HAMN offers high efficiency, minimal invasiveness, and few adverse reactions. This microneedle patch holds great promise for potential clinical applications, especially for the treatment of OSCC.

Self-assembly mucoadhesive beads of κ-carrageenan/sericin for indomethacin oral extended release

Oral drug administration, especially when composed of mucoadhesive delivery systems, has been a research trend due to increased residence time and contact with the mucosa, potentially increasing drug bioavailability and stability. In this context, this study aimed to develop self-assembly mucoadhesive beads composed of blends of κ-carrageenan and sericin (κ-Car/Ser) loaded with the anti-inflammatory drug indomethacin (IND). We investigated the swelling, adhesion behaviour, and mechanical/physical properties of the beads, assessing their effects on cell viability, safety and permeation characteristics in both 2D and triple-culture model. The swelling ratio of the beads indicated pH-responsiveness, with maximum water absorption at pH 6.8, and strong mucoadhesion, increasing primarily with higher polymer concentrations. The beads exhibited thermal stability and no chemical interaction with IND, showing improved mechanical properties. Furthermore, the beads remained stable during accelerated and long-term storage studies. The beads were found to be biocompatible, and IND encapsulation improved cell viability (>70 % in both models, 79 % in VN) and modified IND permeation through the models (6.3 % for F5 formulation (κ-Car 0.90 % w/v | Ser 1.2 % w/v| IND 3.0 g); 10.9 % for free IND, p < 0.05). Accordingly, κ-Car/Ser/IND beads were demonstrated to be a promising IND drug carrier to improve oral administration while mitigating the side effects of non-steroidal anti-inflammatories.

Application of hydrogel microneedles in the oral cavity

Microneedles are a transdermal drug delivery system in which the needle punctures the epithelium to deliver the drug directly to deep tissues, thus avoiding the influence of the first-pass effect of the gastrointestinal tract and minimizing the likelihood of pain induction. Hydrogel microneedles are microneedles prepared from hydrogels that have good biocompatibility, controllable mechanical properties, and controllable drug release and can be modified to achieve environmental control of drug release in vivo. The large epithelial tissue in the oral cavity is an ideal site for drug delivery via microneedles. Hydrogel microneedles can overcome mucosal hindrances to delivering drugs to deep tissues; this prevents humidity and a highly dynamic environment in the oral cavity from influencing the efficacy of the drugs and enables them to obtain better therapeutic effects. This article analyzes the materials and advantages of common hydrogel microneedles and reviews the application of hydrogel microneedles in the oral cavity.

Analysis of Key Factors for Evaluating Mucosal Adhesion Using Swine Buccal Tissue

The assessment of the mucoadhesive properties peak mucoadhesive force (Fmax) and work of mucoadhesion (Wmuc) with texture analyzers is a common in vitro method for analyzing formulation capabilities. Challenges arise in selecting and standardizing experimental conditions due to various variables influencing mucoadhesion. This complexity hampers direct product performance comparisons. In our study, we explored factors (contact force and time, probe speed and mucin in artificial saliva) impacting a model formulation's mucoadhesive capacity. Using Omcilon-A®Orabase on porcine buccal mucosa, we systematically varied experimental conditions, employing a statistical approach (Central Composite Design - CCD). Three variables (contact force, contact time, probe speed) and their interactions were assessed for their impact on Fmax and Wmuc. Results showed that contact time and force positively affected Fmax, while only contact time influenced Wmuc. In the mucin artificial saliva test, a force of 0.5 N, time of 600 s, and speed of 1 mm/s yielded optimal Fmax (0.587 N) and Wmuc (0.468 N.s). These conditions serve as a reference for comparing mucoadhesive properties of formulations for topical oral use.

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.

Semisolid extrusion 3D printing of Dolutegravir-Chitosan nanoparticles laden polymeric buccal films: personalized solution for pediatric treatment

In this work, the semi solid extrusion 3D printing process was utilized to incorporate anti-HIV drug Dolutegravir and its nanoparticles into the buccal film (BF) that was fabricated using the developed polymer ink. The composite made of polyvinyl alcohol (PVA) and sodium alginate was processed into a 3D printing polymer ink with optimum viscosity (9587 ± 219 cP) needed for the seamless extrusion through the nozzle of the 3D printer. The formulated BFs were assessed for its physical properties like weight (0.414 ± 0.3 g), thickness (1.54 ± 0.02 mm), swelling index (18.5 ± 0.91%), and mucoadhesiveness strength (0.165 ± 0.09 N) etc, The structural integrity and the surface morphology of the developed BFs were investigated by scanning electron microscopy analysis. The chemical stability and the solid-state nature of the drug in the BFs were assessed by Fourier transform infrared and x-ray diffraction analysis respectively. Further the BFs were assessed for drug dissolutionin-vitroandex-vivo, to study the effect of polymer composition and printing condition on the dissolution profile of the drug in the simulated salivary fluid. The results demonstrated that the developed PVA based polymer ink for 3D printing utilizing pressure is a versatile approach in the context of manufacturing mucoadhesive BFs customized in terms of shape and the amount of drug loaded.

Orodispersible Films: Current Innovations and Emerging Trends

Orodispersible films (ODFs) are thin, mechanically strong, and flexible polymeric films that are designed to dissolve or disintegrate rapidly in the oral cavity for local and/or systemic drug delivery. This review examines various aspects of ODFs and their potential as a drug delivery system. Recent advancements, including the detailed exploration of formulation components, such as polymers and plasticizers, are briefed. The review highlights the versatility of preparation methods, particularly the solvent-casting production process, and novel 3D printing techniques that bring inherent flexibility. Three-dimensional printing technology not only diversifies active compounds but also enables a multilayer approach, effectively segregating incompatible drugs. The integration of nanoparticles into ODF formulations marks a significant breakthrough, thus enhancing the efficiency of oral drug delivery and broadening the scope of the drugs amenable to this route. This review also sheds light on the diverse in vitro evaluation methods utilized to characterize ODFs, ongoing clinical trials, approved marketed products, and recent patents, providing a comprehensive outlook of the evolving landscape of orodispersible drug delivery. Current patient-centric approaches involve developing ODFs with patient-friendly attributes, such as improved taste masking, ease of administration, and enhanced patient compliance, along with the personalization of ODF formulations to meet individual patient needs. Investigating novel functional excipients with the potential to enhance the permeation of high-molecular-weight polar drugs, fragile proteins, and oligonucleotides is crucial for rapid progress in the advancing domain of orodispersible drug delivery.

The Potential of Films as Transmucosal Drug Delivery Systems

Pharmaceutical films are polymeric formulations used as a delivery platform for administration of small and macromolecular drugs for local or systemic action. They can be produced by using synthetic, semi-synthetic, or natural polymers through solvent casting, electrospinning, hot-melt extrusion, and 3D printing methods, and depending on the components and the manufacturing methods used, the films allow the modulation of drug release. Moreover, they have advantages that have drawn interest in the development and evaluation of film application on the buccal, nasal, vaginal, and ocular mucosa. This review aims to provide an overview of and critically discuss the use of films as transmucosal drug delivery systems. For this, aspects such as the composition of these formulations, the theories of mucoadhesion, and the methods of production were deeply considered, and an analysis of the main transmucosal pathways for which there are examples of developed films was conducted. All of this allowed us to point out the most relevant characteristics and opportunities that deserve to be taken into account in the use of films as transmucosal drug delivery systems.

Combination therapy using multifunctional dissolvable hyaluronic acid microneedles for oral ulcers

Oral ulcers are common in the oral mucosa. Frequent occurrences of oral ulcers commonly afflict patients, seriously impacting their daily life. Treatments with good anti-inflammatory and antibacterial properties are important for promoting the healing of oral ulcers. In this study, a multifunctional, soluble hyaluronic acid (HA) microneedle (MN) patch was prepared to promote oral ulcer healing. The tip layer of the MN patch was loaded with triamcinolone acetonide (TA) and epidermal growth factor (EGF) to inhibit inflammation and promote angiogenesis. Zeolitic imidazolate framework-8 (ZIF-8) was loaded onto the base layer of the MN patch, which effectively released Zn2+ to mediate antibacterial effects. In addition, HA exerts a protective effect on the mucous membrane. Owing to these properties, the multifunctional MN patches were found to have good anti-inflammatory, antibacterial, and tissue-healing abilities, indicating that the multifunctional MN patch design successfully promoted the healing of oral ulcers.

Unidirectional drug release from 3D printed personalized buccal patches using FDM technology

Oromucosal delivery of active ingredients of drugs provides a superior administration route for the treatment of oral diseases, due to avoidance of the first pass effect. In the present work, in view of the characteristics of large differences between oral ulcer symptoms and different lesion sizes, dexamethasone acetate unidirectional drug release buccal patches has been prepared based on Fused Deposition Modelling (FDM). Unidirectional drug release was achieved by covering the top and side with ethyl cellulose. Polyvinyl alcohol as a drug carrier, xylitol as a plasticizer. First, the protection effect of different thicknesses of the protective layer is investigated to determine the thickness of the protective layer. Co-extrusion printing method was adapted, utilizing blank filament to regulate preparations with different areas' drug loading. The results show that co-extrusion had no significant impact on the overall patches' drug release and adhesion properties. The physicochemical properties of the patches were also characterized. Evaluation of irritation is showed that these patches do not cause irritation to the oral mucosa of rats. Pharmacodynamic evaluation results showed that the preparation could promote the reduction of ulcer area. The results showed that FDM printing is a convenient and practical approach in manufacturing buccal patches.

Oral disintegration films: applications and production methods

The use of orally disintegrating films (ODF) as a vehicle for the release of active compounds has drawn attention due to the advantages such as ease of swallowing, precise dosage, low thickness, flexibility, greater comfort and acceptability by the patient in relation to oral tablets, for do not require water for administration, it is ideal for people with difficulty in swallowing. In this review, recent advances in ODFs, their applications and production methods will be presented. The production of ODFs uses polymers, plasticizers and active compounds. Among the compounds added to the film that can affect its properties, the polymer used has a strong influence on the disintegration time and on the controlled release of active principles. Polymers used for the production of oral films must be non-toxic, have good wettability and spreadability, and may be of synthetic or natural origin. Regarding the methods used in the production of ODFs, those currently used are solvent evaporation and hot extrusion. However, one of the great challenges for the production of oral films is the scale up, from laboratory to industrial scale, as factors such as heating, mixing speed and temperatures can lead to changes in film quality. Recently, ODFs have been developed as carriers of natural compounds such as vitamins, phenolic compounds, antioxidant and antimicrobial activity. Thus, it was found that orally disintegrating films are an alternative for the release of active compounds, different from those already existing, which justifies the growing interest in this type of film.

Texture analysis – a versatile tool for pharmaceutical evaluation of solid oral dosage forms

In the past few decades, texture analysis (TA) has gained importance as a valuable method for the characterization of solid oral dosage forms. As a result, an increasing number of scientific publications describe the textural methods that evaluate the extremely diverse category of solid pharmaceutical products. Within the current work, the use of texture analysis in the characterization of solid oral dosage forms is summarised with a focus on the evaluation of intermediate and finished oral pharmaceutical products. Several texture methods are reviewed regarding the applications in mechanical characterization, and mucoadhesion testing, but also in estimating the disintegration time and in vivo specific features of oral dosage forms. As there are no pharmacopoeial standards for pharmaceutical products tested through texture analysis, and there are important differences between reported results due to different experimental conditions, the choice of testing protocol and parameters is challenging. Thereby, this work aims to guide the research scientists and quality assurance professionals involved in different stages of drug development into the selection of optimal texture methodologies depending on the product characteristics and quality control needs.

Novel Double-Layer Dissolving Microneedles for Transmucosal Sequential Delivery of Multiple Drugs in the Treatment of Oral Mucosa Diseases

The development of transmucosal drug delivery systems is a practical requirement in oral clinical practice, and controlled sequential delivery of multiple drugs is usually required. On the basis of the previous successful construction of monolayer microneedles (MNs) for transmucosal drug delivery, we designed transmucosal double-layer sequential dissolving MNs using hyaluronic acid methacryloyl (HAMA), hyaluronic acid (HA), and polyvinyl pyrrolidone (PVP). MNs have the advantages of small size, easy operation, good strength, rapid dissolution, and one-time delivery of two drugs. Morphological test results showed that the HAMA-HA-PVP MNs were small and intact in structure. The mechanical strength and mucosal insertion test results indicated the HAMA-HA-PVP MNs had appropriate strength and could penetrate the mucosal cuticle quickly to achieve transmucosal drug delivery. The in vitro and in vivo experiment results of the double-layer fluorescent dyes simulating drug release revealed that MNs had good solubility and achieved stratified release of the model drugs. The results of the in vivo and in vitro biosafety tests also indicated that the HAMA-HA-PVP MNs were biosafe materials. The therapeutic effect of drug-loaded HAMA-HA-PVP MNs in the rat oral mucosal ulcer model demonstrated that these novel HAMA-HA-PVP MNs quickly penetrated the mucosa, dissolved and effectively released the drug, and achieved sequential drug delivery. Compared to monolayer MNs, these HAMA-HA-PVP MNs can be used as double-layer drug reservoirs for controlled release, effectively releasing the drug in the MN stratification by dissolution in the presence of moisture. The need for secondary or multiple injections can be avoided, thus improving patient compliance. This drug delivery system can serve as an efficient, multipermeable, mucosal, and needle-free alternative for biomedical applications.

Buccal delivery of small molecules and biologics: Of mucoadhesive polymers, films, and nanoparticles - An update

Buccal delivery of small and large molecules is an attractive route of administration that has been studied extensively over the past few decades. This route bypasses first-pass metabolism and can be used to deliver therapeutics directly to systemic circulation. Moreover, buccal films are efficient dosage forms for drug delivery due to their simplicity, portability, and patient comfort. Films have traditionally been formulated using conventional techniques, including hot-melt extrusion and solvent casting. However, newer methods are now being exploited to improve the delivery of small molecules and biologics. This review discusses recent advances in buccal film manufacturing, using the latest technologies, such as 2D and 3D printing, electrospraying, and electrospinning. This review also focuses on the excipients used in the preparation of these films, with emphasis on mucoadhesive polymers and plasticizers. Along with advances in manufacturing technology, newer analytical tools have also been used for the assessment of permeation of the active agents across the buccal mucosa, the most critical biological barrier and limiting factor of this route. Additionally, preclinical and clinical trial challenges are discussed, and some small molecule products already on the market are explored.

Characterization of an In Vitro/Ex Vivo Mucoadhesiveness Measurement Method of PVA Films

Transmucosal drug delivery systems can be an attractive alternative to conventional oral dosage forms such as tablets. There are numerous in vitro methods to estimate the behavior of mucoadhesive dosage forms in vivo. In this work, a tensile test system was used to measure the mucoadhesion of polyvinyl alcohol films. An in vitro screening of potential influencing variables was performed on biomimetic agar/mucin gels. Among the test device-specific factors, contact time and withdrawal speed were identified as influencing parameters. In addition, influencing factors such as the sample area, which showed a linear relationship in relation to the resulting work, and the liquid addition, which led to an abrupt decrease in adhesion, could be identified. The influence of tissue preparation was investigated in ex vivo experiments on porcine small intestinal tissue. It was found that lower values of F_max and W_ad were obtained on processed and fresh tissue than on processed and thawed tissue. Film adhesion on fresh, unprocessed tissue was lowest in most of the animals tested. Comparison of ex vivo measurements on porcine small intestinal tissue with in vitro measurements on agar/mucin gels illustrates the inter- and intra-individual variability of biological tissue.

Buccal Thin Films as Potent Permeation Enhancers for Cytisine Transbuccal Delivery

Cytisine (CYT) is a powerful anti-smoking compound which could greatly benefit from transbuccal delivery because of both its unfavorable pharmacokinetics after oral administration and its intrinsic ability to permeate the buccal mucosa. This work aims to design CYT-loaded buccal thin films suitable for transbuccal drug delivery due to its capability of promoting the interaction between CYT and the buccal membrane. The solvent casting method was employed to prepare several thin films combining various excipients such as matrixing polymers, mucoadhesion agents, plasticizers and other compounds as humectants and sweeteners, component ratios and solvents. A total of 36 compositions was prepared and four of them emerged as the most promising in terms of aspect and flexibility. They all demonstrated homogeneity, thinness, low swelling degree, and controlled drug release according to the Power Law and Peppas-Sahlin mathematical models. Mainly, they proved able to interact with the ex vivo porcine buccal mucosa producing mucoadhesive effects, and act as potent permeation enhancers. In particular, Film B emerged as suitable as it produced a 10.6-fold Kp enhancement and a great Js value (52.33 μg/cm²·h^-1), even when compared to highly concentrated CYT solutions.

Mucoadhesive carriers for oral drug delivery

Among the various dosage forms, oral medicine has extensive benefits including ease of administration and patients' compliance, over injectable, suppositories, ocular and nasal. Despite of extensive demand and emerging advantages, over 50% of therapeutic molecules are not available in oral form due to their physicochemical properties. More importantly, most of the biologics, proteins, peptide, and large molecular drugs are mostly available in injectable form. Conventional oral drug delivery system has limitation such as degradation and lack of stability within stomach due to presence of highly acidic gastric fluid, hinders their therapeutic efficacy and demand more frequent and higher dosing. Hence, formulation for controlled, sustained, and targeted drug delivery, need to be designed with feasibility to target the specific region of gastrointestinal (GI) tract such as stomach, small intestine, intestine lymphatic, and colon is challenging. Among various oral delivery approaches, mucoadhesive vehicles are promising and has potential for improving oral drug retention and controlled absorption to treat local diseases within the GI tract, as well systemic diseases. This review provides the overview about the challenges and opportunities to design mucoadhesive formulation for oral delivery of therapeutics in a way to target the specific region of the GI tract. Finally, we have concluded with future perspective and potential of mucoadhesive formulations for oral local and systemic delivery.

Hollow mesoporous silica nanoparticles-loaded ion-crosslinked bilayer films with excellent mechanical properties and high bioavailability for buccal delivery

Mucoadhesive buccal films (MBFs) become the most promising buccal mucosal delivery system duo to its advantageous properties, including simple preparation technique and better patient compliance. The mechanical properties and mucoadhesion of MBFs are crucial in their successful performance as well as manufacturing and administration. In this study, we prepared hollow mesoporous silica nanoparticles-loaded ion-crosslinked bilayer films (CCS-PVA-TPP-FSM@HMSNs) using carboxymethyl chitosan (CCS) and polyvinyl alcohol (PVA) for buccal delivery of furosemide (FSM). The FSM-loaded hollow mesoporous silica nanoparticles (FSM@HMSNs) were firstly characterized by SEM, TEM, and nitrogen adsorption/desorption. Then, we constructed an ion-crosslinked network using CCS and PVA employed with the solution casting method, and sodium tripolyphosphate (TPP) was used as a hydrogen bond crosslinking agent. The formulation was optimized through Box-Behnken design, where the impact of the proportion of the ingredients on the quality of the films was evaluated entirely. Herein, folding endurance, swelling, tensile strength, and adhesion force were selected as response variables. Morphology, mechanical, spectroscopic, thermal, and safety of CCS-PVA-TPP-FSM@HMSNs films were also investigated. The release and permeability behaviors of CCS-PVA-TPP-FSM@HMSNs films were evaluated by in vitro drug release, across isolated porcine buccal and TR146 cell model. The CCS-PVA-TPP-FSM@HMSNs films showed outstanding mechanical properties, suitable bioadhesion, high drug loading, significant sustained-release properties, and improved permeability. In pharmacokinetic study with golden hamster models, the relative bioavailability was increased by 191.54%, and the absolute bioavailability was 82.20%. In summary, this study provides evidence that this innovative CCS-PVA-TPP-FSM@HMSNs films could be a promising and industrialized buccal drug delivery system.

Fabrication and Characterization of Buccal Film Loaded Self-emulsifying Drug Delivery System containing Lysiphyllum strychnifolium Stem Extracts

Lysiphyllum strychnifolium has long been used as a popular herbal medicinal plant for treating fever and alcohol intoxication. This study aimed to prepare buccal film for L. strychnifolium stem extracts. These extracts were less soluble in water and were therefore loaded in self-emulsifying systems before being mixed into the film. Astilbin was selected as a chemical marker in L. strychnifolium stem extracts. Firstly, the L. strychnifolium stem extracts were entrapped in the self-emulsifying systems which were designed and optimized based on 3² factorial design. The optimal formulation was 0.60 g of surfactant-co-surfactant mixture (Tween^® 80 and polyethylene glycol 400 in the ratio of 7.5:1) and 0.40 g of caprylic/capric triglyceride. Secondly, the optimal self-emulsifying system was loaded in the polymeric film which consisted of polyvinyl alcohol blended with poloxamer 407 using glycerin as a plasticizer. The properties of the prepared buccal film were unchanged, and the film showed an amorphous state, indicating all ingredients might be completely dissolved in the film. The buccal film could be placed in direct contact with the mouth without oral mucosal irritation, and showed a smooth and homogeneous surface with a rough and compact cross-sectional morphology. Astilbin content in the buccal film was 61.39 ± 11.45 µg/cm². Astilbin was released from the buccal film while the permeation rate was low. The release mechanism was both swelling and diffusion, and followed anomalous or non-Fickian transfer. The permeability coefficient of the cumulative amount of astilbin permeated from buccal film was 1.0192 ± 0.1395 ×10^-3 cm/h. Thus, the buccal film can be prepared by using a self-emulsifying system for herbal applications and shows potential as a safe and convenient form of oral drug administration.

Nanocrystals based mucosal delivery system: Research Advances

Nanocrystal technology is a new way to increase the solubility and bioavailability of poorly soluble drugs. As an intermediate preparation technology, nanocrystals are widely used in drug delivery for oral, venous, percutneous and inhalation administration, which exhibits a broad application prospect. By referring to the domestic anforeign literatures, this paper mainly reviews the preparation methods of nanocrystals for poorly soluble natural products and its application in the mucosal delivery for skin, eye, oral cavity and nasal cavity. This can provide the reference for the research and development of nanocrystal technology in natural product preparations.

Oral Films with Addition Mushroom (Agaricus bisporus) as a Source of Active Compounds

The purpose of this study was to develop oral films (OFs) based on agar-agar with the incorporation of mushroom powder (MP) as a source of phenolic compounds. To this end, three different OFs were produced using different concentrations of MP, containing sorbitol and agar-agar. The OFs were characterized based on visual assessment, mass, thickness, moisture content, folding endurance, surface pH, contact angle, and phenolic compound content, scanning electron microscopy, X-ray diffraction, and FTIR, as well as an assessment of their antioxidant capacity. In general, all the OFs showed film-forming capacity after the incorporation of MP, although their mass, thickness, moisture content, and folding endurance differed significantly. The surface pH value remained close to neutrality (∼6.7), regardless of MP concentration. The incorporation of MP increased the crystallinity of the OFs in comparison to that of the agar-based film, but all the OFs showed similar FTIR spectra. The oral films containing 2 g of MP showed antioxidant capacity by ABTS^●+ and FRAP of 3.68±0.23 and 14.61±0.66 mMol ET/g OF, respectively, and total phenolic content of 3.55±0.27 µmol GAE/g OF. Thus, oral films offer an innovative source of delivery of active compounds, and their consumption does not cause oral mucosal irritation.

A novel versatile flow-donor chamber as biorelevant ex-vivo test assessing oral mucoadhesive formulations

Oral transmucosal drug delivery is a non-invasive administration route for rapid therapeutic onset and greater bioavailability avoiding the first-pass metabolism. Mucoadhesive formulations are advantageous as they may retain the drug at the administration site. Proper equipment to assess mucoadhesive properties and corresponding drug absorption is fundamental for the development of novel drug delivery systems. Here we developed a new flow-through donor chamber for well-established diffusion cells, and we tested the effects on drug and formulation retention in situ of adding mucoadhesive polymers or mesoporous silica particles to a reference formulation. Mesoporous silica particles are of particular interest as they may be used to encapsulate and retain drug molecules. Compared to other ex-vivo methods described in literature for assessing mucoadhesive performance and transmucosal drug delivery, this new donor chamber provides several advantages: i) it reflects physiological conditions better as a realistic saliva flow can be provided over the administration site, ii) it is versatile since it can be mounted on any kind of vertical diffusion cell allowing simultaneous detection of drug retention at the administration site and drug permeation through the tissue, and iii) it enables optical quantification of formulations residence time aided by image processing. This new flow-through donor diffusion cell set-up proved sensitive to differentiate a reference formulation from one where 20 %(w/w) Carbomer was added (to further improve the mucoadhesive properties), with respect to both drug and formulation residence times. We also found that mesoporous silica particles, investigated as particles only and mixed together with the reference formulation, gave very similar drug and formulation retention to what we observed with the mucoadhesive Carbomer. However, after some time (>30 min) it became obvious that the tablet excipients in the reference formulation promote particle retention on the mucosa. This work provides a new simple and versatile biorelevant test for the evaluation of oral mucoadhesive formulations and paves the way for further studies on mesoporous silica particles as valuable excipients for enhancing oral mucoadhesion.

Mucosal drug delivery and 3D printing technologies: A focus on special patient populations

In the last decade, additive manufacturing (AM) technologies have revolutionized how healthcare provision is envisioned. The rapid evolution of these technologies has already created a momentum in the effort to address unmet personalized needs in large patient groups, especially those belonging to sensitive subgroup populations (e.g., paediatric, geriatric, visually impaired). At the same time, AM technologies have become a salient ally to overcome defined health challenges in drug formulation development by addressing not only the requirement of personalized therapy, but also problems related to lowering non-specific drug distribution and the risk of adverse reactions, enhancing drug absorption and bioavailability, as well as ease of administration and patient compliance. To this end, mucoadhesive drug delivery systems fabricated with the support of AM technologies provide competitive advantages over conventional dosage forms, aiming to entice innovation in drug formulation with special focus on sensitive patient populations.

Sensing technologies and experimental platforms for the characterization of advanced oral drug delivery systems

Complex and miniaturized oral drug delivery systems are being developed rapidly for targeted, controlled drug release and improved bioavailability. Standard analytical techniques are widely used to characterize i) drug carrier and active pharmaceutical ingredients before loading into a delivery device (to ensure the solid form), and ii) the entire drug delivery system during the development process. However, in light of the complexity and the size of some of these systems, standard techniques as well as novel sensing technologies and experimental platforms need to be used in tandem. These technologies and platforms are discussed in this review, with a special focus on passive delivery systems in size range from a few 100 µm to a few mm. Challenges associated with characterizing these systems and evaluating their effect on oral drug delivery in the preclinical phase are also discussed.

Interaction of mucin with viologen and acetate derivatives of calix[4]resorcinols

The mucus layer acts as a selective diffusion barrier that has an important effect on the efficiency of drug delivery systems in the human body. In this regard, currently the drug nanocarriers of various sizes and compositions are being widely developed to study their mucoadhesive properties i.e., the ability to interact with mucin. However, the effective interaction of drug composition with mucin does not guarantee the success due to the fact that there is a further barrier in the form of epithelial cells retained by calcium ions under the mucus layer. In this work, the interaction of mucin (porcine gastric mucin) with calixarenes is considered for the first time. The study of interaction between calixarenes, mucin and calcium ions by a complex of physicochemical methods showed that effective interaction with mucin requires cationic fragments, and binding with calcium is realized due to anionic fragments in the calixarene structure. Therefore, the combination of different chemical groups in the structure of drug nanocarrier plays an important role in successful mucosal drug delivery. Taking into account the wide possibilities of synthetic modification of the macrocyclic platform, calixarenes can find the application in the drug delivery across mucous barriers.

In vitro evaluation of adhesion and mechanical properties of oral thin films

Oral drug delivery is often challenged with enzymatic degradation of drug molecules in the gastrointestinal tract and high first-pass metabolism, resulting in low bioavailability. Delivery of drug molecules via the oral cavity mucosa is considered a viable option to enhance bioavailability. One of the relatively new dosage forms for transmucosal drug delivery is the oral thin film (OTF) with mucoadhesive properties that offers several advantages over conventional dosage forms, including faster dissolution, higher patient compliance, and extended oral retention by reduced salivary washout. Mucoadhesive OTFs should have sufficient muco-adhesiveness as well as suitable mechanical properties for their best performance, thus such characterization is critical in the successful design and development of OTFs. However, there is currently no FDA or USP-recommended analytical procedure or standard available for evaluating adhesiveness and mechanical properties of mucoadhesive OTFs. Therefore, we aimed to develop a fast and reliable in vitro method capable of differentiating various OTFs in terms of their adhesive strengths using a texture analyzer. We found that an in vitro gel substrate composed of 4% w/v gellan gum and 2% w/v glycerin could be used to discriminate between the adhesive features of the tested film samples. Also, our studies show that the adhesion test parameters of 0.96 N target force, probe speed of 0.1 mm/s, holding time of 15 s, and conditioning medium volume of 200 μL while using the said substrate could successfully differentiate between the adhesion strength of the OTF samples. We further examined the film samples for their physicomechanical properties to obtain a tangible and practical range of mechanical values for pharmaceutical OTFs using the puncture test and folding endurance test. We found a breaking factor above 34.5 N/mm, elongation to puncture less than 5.55% and folding endurance of at least 50 folds can be used as a starting point when designing and manufacturing OTFs.