Formulation and in vitro evaluation of xanthan gum-based bilayered mucoadhesive buccal patches of zolmitriptan

Evaluation of polymer combinations in vaginal mucoadhesive tablets for the extended release of acyclovir

Genital herpes, caused by herpes simplex virus type 2 (HSV-2), affects nearly 500 million people, mostly women. Since the main route of transmission is sexual contact, the development of an acyclovir extended-release vaginal microbicide would be a suitable tool for the prevention of virus transmission. In this work, we evaluated the potential of three polymers with different characteristics (chitosan, xanthan gum and ethyl cellulose) for obtaining acyclovir extended-release vaginal tablets. By combining the polymers, certain useful synergies were observed to modify their mucoadhesive capacity and control drug release. In the swelling studies, it observed that a polyelectrolyte complex with more moderate swelling and sustained gelation was formed between chitosan and xanthan gum exclusively in acidic medium (simulated vaginal fluid). This complex allowed prolonging the mucoadhesion of the tablets in ex vivo studies performed with vaginal mucosa, which would translate into better retention in the vagina after administration. In addition, the combination of chitosan and xanthan gum allowed obtaining a controlled release of acyclovir for 5 days, regardless of the pH of the medium, which would guarantee that drug release continues even in the presence of seminal fluid.

A Comprehensive Review of Xanthan Gum-Based Oral Drug Delivery Systems

Xanthan gum (XG) is an exopolysaccharide synthesized by the aerobic fermentation of simple sugars using Xanthomonas bacteria. It comprises a cellulosic backbone with a trisaccharide side chain connected to alternative glucose residues in the main backbone through α (1→3) linkage. XG dissolves readily in cold and hot water to produce a viscous solution that behaves like a pseudoplastic fluid. It shows excellent resistance to enzymatic degradation and great stability throughout a broad temperature, pH, or salt concentration range. Additionally, XG is nontoxic, biocompatible, and biodegradable, making it a suitable carrier for drug delivery. Furthermore, the carboxylic functions of pyruvate and glucuronic acid offer a considerable opportunity for chemical modification to meet the desired criteria for a specific application. Therefore, XG or its derivatives in conjunction with other polymers have frequently been studied as matrices for tablets, nanoparticles, microparticles, and hydrogels. This review primarily focuses on the applications of XG in various oral delivery systems over the past decade, including sustained-release formulations, gastroretentive dosage forms, and colon-targeted drug delivery. Source, production methods, and physicochemical properties relevant to drug delivery applications of XG have also been discussed.

Madhuca indica oil-entrapped buoyant galactomannan hydrogel microspheres for controlling epileptic seizures

A stable Madhuca indica oil-in-water nanoemulsion (99-210 nm, zeta potential: > - 30 mV) was produced employing Tween 20 (surfactant) and Transcutol P (co-surfactant) (3:1). The nanoemulsion (oil: Smix = 3:7, 5:5, and 7:3) were subsequently incorporated into oxcarbazepine-loaded carboxymethylxanthan gum (DS = 1.23) dispersion. The hydrogel microspheres were formed using the ionic gelation process. Higher oil concentration had a considerable impact on particle size, drug entrapment efficiency, and buoyancy. The maximum 92 % drug entrapment efficiency was achieved with the microspheres having oil: Smix ratio 5:5. FESEM study revealed that the microspheres were spherical in shape and had an orange peel-like surface roughness. FTIR analysis revealed a hydrogen bonding interaction between drug and polymer. Thermal and x-ray examinations revealed the transformation of crystalline oxcarbazepine into an amorphous form. The microspheres had a buoyancy period of 7.5 h with corresponding release of around 83 % drug in 8 h in simulated stomach fluid, governed by supercase-II transport mechanism. In vivo neurobehavioral studies on PTZ-induced rats demonstrated that the microspheres outperformed drug suspension in terms of rotarod retention, number of crossings, and rearing activity in open field. Thus, Madhuca indica oil-in-water nanoemulsion-entrapped carboxymethyl xanthan gum microspheres appeared to be useful for monitoring oxcarbazepine release and managing epileptic seizures.

Review on emerging trends and challenges in the modification of xanthan gum for various applications

This review explores the realm of structural modifications and broad spectrum of their potential applications, with a special focus on the synthesis of xanthan gum derivatives through graft copolymerization methods. It delves into the creation of these derivatives by attaching functional groups (-OH and -COOH) to xanthan gum, utilizing a variety of initiators for grafting, and examining their diverse applications, especially in the areas of food packaging, pharmaceuticals, wastewater treatment, and antimicrobial activities. Xanthan gum is a biocompatible, biodegradable, less toxic, bioactive, and cost-effective natural polymer derived from Xanthomonas species. The native properties of xanthan gum can be improved by cross-linking, grafting, curing, blending, and various modification techniques. Grafted xanthan gum has excellent biodegradability, metal binding, dye adsorption, immunological properties, and wound healing ability. Owing to its remarkable properties, such as biocompatibility and its ability to form gels resembling the extracellular matrix of tissues, modified xanthan gum finds extensive utility across biomedicine, engineering, and the food industry. Furthermore, the review also covers various modified derivatives of xanthan gum that exhibit excellent biodegradability, metal binding, dye adsorption, immunological properties, and wound healing abilities. These applications could serve as important resources for a wide range of industries in future product development.

Development and In Vitro Evaluation of Aceclofenac Buccal Film

AIM

This study aimed to formulate and characterize aceclofenac buccal film formulations made of different polymers and evaluate the effects of polymer type on buccal film properties.

MATERIALS AND METHODS

Five polymer types, namely hydroxypropyl methylcellulose (HPMC), sodium carboxymethylcellulose (SCMC), polyvinyl alcohol (PVA), Eudragit S100, and Eudragit SR100, were used to prepare aceclofenac buccal film formulation either separately or combined by solvent-casting method. These formulations were evaluated in terms of physical appearance, folding test, film weight and thickness, drug content, percentage of elongation, moisture uptake, water vapor permeability, and in vitro drug release.

RESULTS

The addition of Eudragit polymer in most of the produced buccal films was unacceptable with low folding endurance. However, the dissolution profile of buccal films made from PVA and Eudragit SR100 provided a controlled drug release profile.

CONCLUSION

Buccal films can be formulated using different polymers either individually or in combination to obtain the drug release profile required to achieve a desired treatment goal. Furthermore, the property of the buccal films depends on the type and concentration of the polymer used.

Novel tetrahydrocurcumin integrated mucoadhesive nanocomposite κ-carrageenan/xanthan gum sponges: a strategy for effective local treatment of oral cancerous and precancerous lesions

Oral cancer is one of the leading causes of death worldwide. Oral precancerous lesions (OPL) are the precursors of oral cancer, with varying degrees of progression. Tetrahydrocurcumin (THC) is a major metabolite of curcumin with superior anticancer properties against various types of cancer. However, THC's clinical outcome is limited by its poor aqueous solubility. Herein, we developed novel mucoadhesive biopolymer-based composite sponges for buccal delivery of THC, exploiting nanotechnology and mucoadhesion for efficient prevention and treatment of oral cancer. Firstly, THC-nanocrystals (THC-NC) were formulated and characterized for subsequent loading into mucoadhesive composite sponges. The anticancer activity of THC-NC was assessed on a human tongue squamous carcinoma cell line (SCC-4). Finally, the chemopreventive activity of THC-NC loaded sponges (THC-NC-S) was examined in DMBA-induced hamster OPL. The selected THC-NC exhibited a particle size of 532.68 ± 13.20 nm and a zeta potential of -46.08 ± 1.12 mV. Moreover, THC-NC enhanced the anticancer effect against SCC-4 with an IC50 value of 80 µg/mL. THC-NC-S exhibited good mucoadhesion properties (0.24 ± 0.02 N) with sustained drug release, where 90% of THC was released over 4 days. Furthermore, THC-NC-S had a magnificent potential for maintaining high chemopreventive activity, as demonstrated by significant regression in the dysplasia degree and a decline in cyclin D1 (control: 40.4 ± 12.5, THC-NC-S: 12.07 ± 5.2), culminating in significant amelioration after 25 days of treatment. Conclusively, novel THC-NC-S represent a promising platform for local therapy of OPL, preventing their malignant transformation into cancer.

Evaluation of Oromucosal Natural Gum-Based Emulgels as Novel Strategy for Photodynamic Therapy of Oral Premalignant Lesions

Photodynamic therapy (PDT) recently has been shown as a promising option in the treatment of premalignant lesions of the soft oral tissues. Effective delivery of photosensitizer is challenging due to poor drug adherence to the oromucosal epithelium. In the present work, emulgels composed of natural polysaccharide gums (tragacanth, xanthan and gellan) were evaluated as novel oromucosal platforms of delta-aminolevulinic acid (ALA) for PDT. Apart from mucoadhesive and textural analysis, the specific steps involved studies on drug penetration behavior and safety profile using a three-dimensional human oral epithelium model (HOE). All designed emulgels presented greater mucoadhesiveness when compared to commercial oromucosal gel. Incorporation of ALA affected textural properties of emulgels, and tragacanth/xanthan formulation with greater hardness and cohesiveness exhibited a protective function against the mechanical tongue stress. Permeability studies revealed that ALA is capable of penetrating across oromucosal epithelium by passive transport and all formulations promoted its absorption rate when compared to a commercial topical product with ALA. Importantly, the combination of tragacanth and xanthan profoundly enhanced photosensitizer retention in the buccal epithelium. Tested samples performed negligible reduction in cell viability and moderately low IL-1β release, confirming their non-irritancy and compatibility with HOE. Overall, the presented findings indicate that tragacanth/xanthan emulgel holds promise as an oromucosal ALA-carrier for PDT strategy.

Sonophoresis-assisted transdermal delivery of antimigraine-loaded nanolipomers: Radio-tracking, histopathological assessment and in-vivo biodistribution study

Migraine is a disabling neurovascular polygenic disorder affecting life quality with escorted socioeconomic encumbrances. Herein, we investigated the consolidated amalgamation of passive lipomer approach alongside active sonophoresis assisted transdermal delivery of zolmitriptan (ZT) using high frequency ultrasound pre-treatment protocol to mitigate migraine attacks. A modified nanoprecipitation technique was utilized to prepare zolmitriptan loaded lipomers (ZTL) adopting 23 factorial design. Three factors were scrutinized namely lipid type, ZT: lipid ratio and ZT: Gantrez® ratio. The prepared systems were characterized regarding particle size, zeta potential, polydispersity index, entrapment efficiency and in-vitro release studies. The best achieved ZTL system was evaluated for ZT- Gantrez® intermolecular interactions, drug crystallinity, morphology, ex-vivo permeation and histopathological examination. Finally, a comparative in-vivo biodistribution study through radiotracking technique using Technetium-99 m was adopted. L2 was the best-achieved ZTL system with respect to spherical particle size (390.7 nm), zeta-potential (-30.8 mV), PDI (0.2), entrapment efficiency (86.2%), controlled release profile, flux (147.13 μg/cm2/hr) and enhancement ratio (5.67). Histopathological studies proved the safety of L2 system upon application on skin. L2 revealed higher brain Cmax (12.21 %ID/g), prolonged brain MRT (8.67 hr), prolonged brain 0.23 hr), significantly high relative bioavailability (2929.36%) and similar brain Tmax (0.5 hr) compared to I.V. route with higher brain/blood ratio. Thus, sonophoresis assisted transdermal delivery of ZTL offers a propitious alterative to alleviate migraine symptoms.

Chitosan-based buccal mucoadhesive patches to enhance the systemic bioavailability of tizanidine

Tizanidine hydrochloride (TZN) is a muscle relaxant used to treat a variety of disorders such as painful muscle spasms and chronic spasticity. TZN has low oral bioavailability due to extensive first-pass metabolism and is used orally at a dose of 6-24 mg per day. In the present study, buccal patches were prepared by solvent casting method using chitosan glutamate (Chi-Glu) and novel chitosan azelate (Chi-Aze) which was synthesised in-house for the first time, to enhance the bioavailability of TZN by bypassing first-pass metabolism. The characterisation, mucoadhesion and drug release studies were performed. Chi-Aze patches retained their integrity longer in the buccal medium and showed higher ex vivo drug permeability compared to that prepared with Chi-Glu. In vivo studies revealed that buccal formulation fabricated with Chi-Aze (3%) showed approx 3 times more bioavailability than the orally administered commercial product. Results of the studies indicate that Chi-Aze, prepared by conjugation of chitosan and a fatty acid, the patch formulation is a promising buccal mucoadhesive system due to the physical stability in buccal medium, the good mucoadhesiveness and the high TZN bioavailability. Moreover, Chi-Aze patch might be an alternative to oral formulations of TZN to reduce the dose and frequency of drug administration.

Triamcinolone acetonide release modelling from novel bilayer mucoadhesive films: an in vitro study

OBJECTIVES

Recurrent aphthous stomatitis (RAS) is a painful disorder that commonly appears as ulcers on the oral mucosa, lasting ∼two weeks (minor) to months (major and herpetiform). Current treatment often necessitates the use of topical steroids in the form of pastes, mouthwashes, or gels, but these forms are often ineffective due to inadequate drug contact time with the ulcers. In this study, the performance of novel bilayer mucoadhesive buccal films loaded with triamcinolone acetonide (TA) has been evaluated for targeted drug delivery.

METHODS

Experimental mucoadhesive films of hydroxypropyl methylcellulose (HPMC), polyvinyl alcohol (PVA), and polyvinyl pyrrolidone (PVP) were prepared by the solvent casting method, and ethyl cellulose (EC) was applied as the backing layer. The films were characterized for their physical properties, including swelling index (SI), folding endurance, adhesion force with porcine buccal mucosa, residence time and in-vitro drug release.

RESULTS

The data showed that the films were flexible with folding endurance> 300 times. With porcine buccal mucosa i) suitable adhesion forces were obtained (between 2.72 and 4.03 N), ii) residence times of> 24 h, and iii) surface pH between 6.8 and 7.1 indicating they would be non-irritant. All films released 100% TA over 6 h, but with varying profiles. The release of TA (over 6 h) from PVP-free films followed Fickian diffusion kinetics (diffusion-controlled release of drug), whereas the mechanism of release from PVP-containing films was found to be a superposition of diffusion-controlled and erosion-controlled release (anomalous).

SIGNIFICANCE

The developed films hold great promise for potentially treating RAS and other oral conditions.

Design and in vitro effectiveness evaluation of Echium amoenum extract loaded in bioadhesive phospholipid vesicles tailored for mucosal delivery

The Echium amoenum Fisch. and C.A. Mey. (E. amoenum) is an herb native from Iranian shrub, and its blue-violet flowers are traditionally used as medical plants. In the present study, an antioxidant phytocomplex was extracted from the flowers of E. amoenum by ultrasounds-assisted hydroalcoholic maceration. The main components, contained in the extract, have been detected using HPLC-DAD, and rosmarinic acid was found to be the most abundant. The antioxidant power of the extract along with the phenolic content were measured using colorimetric assays. The extract was loaded in liposomes, which were enriched adding different bioadhesive polymers (i.e., mucin, xanthan gum and carboxymethyl cellulose sodium salt) individually or in combination. The main physico-chemical properties (i.e. size, size distribution, surface charge) of the prepared vesicles were measured as well as their stability on storage. The viscosity of dispersion and the ability of vesicles to interact with mucus were evaluated measuring their stability in a mucin dispersion and mobility in a mucin film. The biocompatibility and the ability of the formulations to protect keratinocytes from damages caused by hydrogen peroxide and to promote the cell migration were measured in vitro.

Recent Advances and Prospects for Plant Gum-Based Drug Delivery Systems: A Comprehensive Review

This work is an effort to first introduce plant-based gums and discussing their drug delivery applications. The composition of these plant gums and their major characteristics, which make them suitable as pharmaceutical excipients are also described in detail. The various modifications methods such as physical and chemical modifications of gums and polysaccharides have been discussed along with their applications in different fields. Consequently, plant-based gums modification such as etherification and grafting is attracting much scientific attention to satisfy industrial demand. The evaluation tests to characterize gum-based drug delivery systems have been summarized. The release behavior of drug from plant-gum-based drug delivery is being discussed. Thus, this review is an attempt to critically summarize different aspect of plant-gum-based polysaccharides to be utilized in drug delivery systems having potential industrial applications.

Design and Characterization of Agarose/HPMC Buccal Films Bearing Ondansetron HCl In Vitro and In Vivo: Enhancement Using Iontophoretic and Chemical Approaches

The study was aimed at designing and characterizing the ondansetron hydrochloride (OND) bearing agarose (AG), and hydroxypropyl methyl cellulose (HPMC) mucoadhesive buccal films employing glycerol as a plasticizer. The buccal delivery of ondansetron hydrochloride was remarkably boosted by employing physical (iontophoresis) and chemical enhancement approaches (chemical penetration enhancers). To explore the influence of different formulation components, i.e., agarose, hydroxypropyl methyl cellulose (HPMC), and glycerol on various evaluating parameters, i.e., tensile strength, swelling index, ex vivo mucoadhesion time, and subsequently on in vitro drug release, a D-optimal design was opted. A buccal film bearing OND was mounted on bovine buccal mucosa for ex vivo permeation studies and impact of chemical and physical enhancement techniques on the permeation profile was also analysed. A linear release profile was revealed in in vitro drug release of OND over 60 minutes and outcomes ascertained the direct relationship between HPMC content and in vitro drug release and inverse relationship was depicted by AG content. The FTIR and DSC thermal analysis was executed to determine the physicochemical interactions and results exposed no chemical interactions between drug and polymers. The drug (OND) appeared as tiny crystals on smooth film surface during scanning electron microscopy (SEM) analysis. A notable enhancement in permeation flux, i.e., 761.02 μg/min of OND during ex vivo permeation studies was witnessed after the application of current (0.5-1 mA) without any time lag and with enhancement ratio of 3.107. A time lag of 15 minutes, 19 minutes, and 26 minutes with permeation flux of 475.34 μg/min, 399.35 μg/min, and 244.81 μg/min was observed after chemical enhancer pretreatment with propylene glycol, Tween 80, and passive, respectively. Rabbit was employed as the experimental animal for pharmacokinetic studies (in vivo) and cats for pharmacological activity (in vivo), and the results illustrated the enhanced bioavailablity (2.88 times) in the iontophoresis animal group when compared with the rabbits of control group. Likewise, a remarkable reduction in emesis events was recorded in cats of iontophoresis group. Conclusively, the histopathological examinations on excised buccal mucosa unveiled no severe necrotic or cytopathetic outcomes of current.

Development of biocompatible nanoparticles of tizanidine hydrochloride in orodispersible films: In vitro characterization, ex vivo permeation and cytotoxic study on carcinoma cells

BACKGROUND

The main limitations of the therapeutic effectiveness of tizanidine hydrochloride (TNZ) are its low bioavailability due to its tendency to undergo first-pass metabolism and short biological half-life. These factors make it an ideal candidate for formulating orally disintegrating films.

METHODS

The fast-dissolving film of TNZ HCl was prepared by the solvent-casting method and characterized using scanning electron microscopy, FTIR and XRD, and evaluated for critical quality attributes for this type of dosage forms such as disintegration time, tensile strength, drug content, dissolution, and ex-vivo permeability. In vitro cytotoxicity studies were also conducted on cancer cell lines to confirm cytotoxic effect.

OBJECTIVE

The present study was aimed to prepare nanoparticles of tizanidine hydrochloride using biodegradable polymers and loading them on orodispersible films to obtain a sustained release dissolution profile with improved permeability and further study the cytotoxicity on A549 lung carcinoma cells, MCF7 breast cancer cells and HOP 92 non-small lung adenocarcinoma cells.

RESULTS

The polymeric matrix containing the drug provided a rapid disintegration time varying between 7±2 and 30±2 seconds, adequate tensile strength between 1.4 and 11.25 N/mm2, and improved permeability through porcine buccal mucosa when compared to the reference product.

CONCLUSION

A study of cytotoxic effect on the MCF-7 breast cancer cells and A549 lung carcinoma cells revealed that tizanidine hydrochloride nanoparticles at 2.3 mg/film exhibited an IC50 value of 65.1 % cytotoxicity on MCF-7, approximately 100% on HOP92, and 83.5 % on A549 lung carcinoma cells, thus paving the way for a new paradigm of research for cytotoxic study on MCF-7, HOP92 and A549 cell lines using the subject drug model prepared as oral films or biodegradable nanoparticles in oral films for site-specific targeting.

3D Printed Buccal Films for Prolonged-Release of Propranolol Hydrochloride: Development, Characterization and Bioavailability Prediction

Gelatin-polyvinylpyrrolidone (PVP) and gelatin-poly(vinyl alcohol) (PVA) mucoadhesive buccal films loaded with propranolol hydrochloride (PRH) were prepared by semi-solid extrusion 3D printing. The aim of this study was to evaluate the effects of the synthetic polymers PVP and PVA on thermal and mechanical properties and drug release profiles of gelatin-based films. The Fourier-transform infrared spectroscopy showed that hydrogen bonding between gelatin and PVP formed during printing. In the other blend, neither the esterification of PVA nor gelatin occurred. Differential scanning calorimetry revealed the presence of partial helical structures. In line with these results, the mechanical properties and drug release profiles were different for each blend. Formulation with gelatin-PVP and PRH showed higher tensile strength, hardness, and adhesive strength but slower drug release than formulation with gelatin-PVA and PRH. The in silico population simulations indicated increased drug bioavailability and decreased inter-individual variations in the resulting pharmacokinetic profiles compared to immediate-release tablets. Moreover, the simulation results suggested that reduced PRH daily dosing can be achieved with prolonged-release buccal films, which improves patient compliance.

Gellan Gum-Based Bilayer Mucoadhesive Films Loaded with Moxifloxacin Hydrochloride and Clove Oil for Possible Treatment of Periodontitis

Background/Objective

Periodontitis is a widely spread oral infection and various antibiotics are utilized for its treatment, but high oral doses and development of antibiotic resistance limit their use. This study was aimed at development of natural polymer-based mucoadhesive bilayer films loaded with moxifloxacin hydrochloride (Mox) and clove essential oil (CEO) to potentially combat bacterial infection associated with periodontitis.

Methods

Films were synthesized by double solvent casting technique having an antibiotic in the gellan gum-based primary layer with clove oil in a hydroxyethyl cellulose-based secondary layer.

Results

Prepared films were transparent, flexible, and showed high antibacterial response against both gram-positive and gram-negative bacteria. The films showed excellent pharmaceutical attributes in terms of drug content, folding endurance, swelling index, and mucoadhesive strength. Solid state characterization of formulation showed successful incorporation of drug and oil in separate layers of hydrogel structure. An in-vitro release study showed an initial burst release of drug followed by sustained release for up to 48 hours.

Conclusion

The prepared mucoadhesive bilayer buccal films could be used as a potential therapeutic option for the management of periodontitis.

Role of mucoadhesive polymers in retention of toothpaste in the oral cavity

Retention of active ingredients of toothpastes in the mouth following brushing determines the efficiency of these oral care formulations. In this study, new in vitro methodologies for the observation and measurement of toothpaste retention in the oral cavity were developed and used to evaluate the efficiency of formulations containing different mucoadhesive hydrophilic polymers. The findings suggest that using Carbopol ETD 2020 and Carbopol Ultrez 10 as binders in toothpaste prolongs the retention time of these formulations in the oral cavity. The in vitro methodologies tested, coupled with texture analysis, were able to accurately characterise the behaviour of the toothpaste and produce detailed images showing how it is retained in the oral cavity. This study has not only produced a new method for studying the behaviour of toothpaste and other formulations in the oral cavity but is also the first to investigate how different types of mucoadhesive binders can be used to improve toothpaste retention.

An Updated Overview of the Emerging Role of Patch and Film-Based Buccal Delivery Systems

Buccal mucosal membrane offers an attractive drug-delivery route to enhance both systemic and local therapy. This review discusses the benefits and drawbacks of buccal drug delivery, anatomical and physiological aspects of oral mucosa, and various in vitro techniques frequently used for examining buccal drug-delivery systems. The role of mucoadhesive polymers, penetration enhancers, and enzyme inhibitors to circumvent the formulation challenges particularly due to salivary renovation cycle, masticatory effect, and limited absorption area are summarized. Biocompatible mucoadhesive films and patches are favored dosage forms for buccal administration because of flexibility, comfort, lightness, acceptability, capacity to withstand mechanical stress, and customized size. Preparation methods, scale-up process and manufacturing of buccal films are briefed. Ongoing and completed clinical trials of buccal film formulations designed for systemic delivery are tabulated. Polymeric or lipid nanocarriers incorporated in buccal film to resolve potential formulation and drug-delivery issues are reviewed. Vaccine-enabled buccal films have the potential ability to produce both antibodies mediated and cell mediated immunity. Advent of novel 3D printing technologies with built-in flexibility would allow multiple drug combinations as well as compartmentalization to separate incompatible drugs. Exploring new functional excipients with potential capacity for permeation enhancement of particularly large-molecular-weight hydrophilic drugs and unstable proteins, oligonucleotides are the need of the hour for rapid advancement in the exciting field of buccal drug delivery.

Biomedical Applications of Bacteria-Derived Polymers

Plastics have found widespread use in the fields of cosmetic, engineering, and medical sciences due to their wide-ranging mechanical and physical properties, as well as suitability in biomedical applications. However, in the light of the environmental cost of further upscaling current methods of synthesizing many plastics, work has recently focused on the manufacture of these polymers using biological methods (often bacterial fermentation), which brings with them the advantages of both low temperature synthesis and a reduced reliance on potentially toxic and non-eco-friendly compounds. This can be seen as a boon in the biomaterials industry, where there is a need for highly bespoke, biocompatible, processable polymers with unique biological properties, for the regeneration and replacement of a large number of tissue types, following disease. However, barriers still remain to the mass-production of some of these polymers, necessitating new research. This review attempts a critical analysis of the contemporary literature concerning the use of a number of bacteria-derived polymers in the context of biomedical applications, including the biosynthetic pathways and organisms involved, as well as the challenges surrounding their mass production. This review will also consider the unique properties of these bacteria-derived polymers, contributing to bioactivity, including antibacterial properties, oxygen permittivity, and properties pertaining to cell adhesion, proliferation, and differentiation. Finally, the review will select notable examples in literature to indicate future directions, should the aforementioned barriers be addressed, as well as improvements to current bacterial fermentation methods that could help to address these barriers.

Optimization of taste-masked dapoxetine oral thin films using factorial design: in vitro and in vivo evaluation

Dapoxetine HCl is used for the treatment of premature ejaculation. Dapoxetine is primarily metabolized in the liver and kidney and its metabolites are inactive; resulting in reduced bioavailability. Also, one of the commonly encountered issues in the oral dapoxetine formulae is its bitter taste. Thus, the objective of this study was to develop and to optimize novel dapoxetine taste-masked oral thin films (OTFs), to offer a faster dissolution rate, rapid release pattern, lower liver metabolism, and better patient compliance. To achieve our goal, the applicability of either pullulan or maltodextrin as strip forming polymers were investigated in the preparation of (OTFs), while glycerol was used as a plasticizer. Also, the physicochemical characteristics of dapoxetine in a resinate complex with AmberLite^TM -IRP69 as taste masking were evaluated. Furthermore, a 2³ factorial design was used to study and to optimize the effect of the independent variables (strip forming polymer (X₁), glycerol (X₂) and AmberLite^TM (X₃) amounts) on the disintegration time (Y₁), degree of elongation (Y₂), and degree of in vitro drug release in phosphate buffer pH 6.8 at 5 minutes (Q5min, Y₃) as responses. P2 batch (OTF) (pullulan 96 mg, glycerol 12 mg, AmberLite^TM 32 mg, and dapoxetine 30 mg) was identified as an optimized formulation showing an in vitro disintegration time 9.33 s, 35.56% elongation, and 91.43% Q5min; excellent in vivo disintegration time; good overall taste acceptability and stable resinate complex.

Dual Drug Loaded Bilayer Hydrogel Coated with Citric Acid for the Treatment of Dry Mouth Syndrome

The objective of the present study is to formulate the bilayer hydrogel of Aceclofenac and Itraconazole followed by surface spray coating with citric acid to treat inflammation, oral candidiasis, and xerostomia conditions in HIV patients. The hydrogel was prepared by the chemical cross-linking method using polyvinyl alcohol as polymer at the concentrations of 3%, 5%, 7%, and 9% w/v, for both the individual drugs and the combination bilayer. The amount of cross-linking agent (glutaraldehyde 1% v/v) and the catalyst (concentrated hydrochloric acid [HCl], dilute HCl, and acetic acid) was optimized at the level of 0.1 mL each in every hydrogel system, based on the required physical properties. The hydrogels were subjected for various evaluation parameters like weight variation (0.054-0.300 g), diameter (9.5-12.5 mm), thickness (2.5-4.0 mm), drug content (2.5-2.8 mg/mL), and swelling study. The increase in the polymer composition had led to a significant increase in the thickness and weight of the hydrogel and a corresponding decrease in the swelling index. Other characterization techniques like Fourier Transform Infra-Red Spectroscopy, X-Ray Diffraction, ThermoGravimetry-Differential Scanning Calorimetry, and optical microscopy analysis were carried out to study physicochemical interactions, crystallinity, thermal, and surface properties of the optimized hydrogel, respectively. The in vitro drug release studies by United States Pharmacopeia dissolution basket model and ex vivo permeation studies using Franz diffusion cell with goat buccal skin were carried out for 6 h, in different media such as distilled water, phosphate buffer pH 6.8, and simulated salivary fluid.

Mucoadhesive Gelatin Buccal Films with Propranolol Hydrochloride: Evaluation of Mechanical, Mucoadhesive, and Biopharmaceutical Properties

This study processes and characterizes propranolol hydrochloride/gelatin mucoadhesive buccal films. Two types of gelatin are used: Gelatin from porcine skin, type A (GA), and gelatin from bovine skin (GB). The influence of gelatin type on mechanical, mucoadhesive, and biopharmaceutical characteristics of buccal films is evaluated. Fourier-Transfer infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) analysis show that GA with propranolol hydrochloride (PRH) in the film (GAP) formed a physical mixture, whereas GB with PRH (GBP) form a compound-complex. Results of mechanical testing (tensile test, hardness) revealed that GAP films exhibit higher elastic modulus, tensile strength, and hardness. A mucoahesion test shows that GBP has higher adhesion strength, while GAP shows higher work of adhesion. Both in vitro release study and in silico simulation indicated that processed films can provide effective drug transport through the buccal mucosa. In silico simulation shows improved bioavailability from buccal films, in comparison to the immediate-release tablets-indicating that the therapeutic drug dose can be markedly reduced.

Oral care product formulations, properties and challenges

This review explores the physical, chemical and structural properties of key components of oral care products, whilst looking at the challenges which need to be overcome to continue to improve the efficacy of oral care, and improve dental health. Oral care has been an essential part of all populations and cultures around the world for thousands of years. To maintain good oral health, dental plaque causing bacteria and malodour must be controlled whilst also strengthening and protecting the teeth to prevent dental caries. Advanced modern formulations need to provide controlled and extended release of ingredients vital for dental health. With modern day products such as toothpastes and mouthwashes, it has never been easier to maintain good oral hygiene and health, yet the incidence of dental caries is still on the rise. The complex formulations of modern toothpastes and mouthwashes makes them one of the most sophisticated pharmaceutical products on the market today. The demands of the consumer coupled with the complexity of the oral cavity make it one of the most challenging development processes.

Effects of Sucrose Palmitate on the Physico-Chemical and Mucoadhesive Properties of Buccal Films

In our current research, sucrose palmitate (SP) was applied as a possible permeation enhancer for buccal use. This route of administration is a novelty as there is no literature on the use of SP in buccal mucoadhesive films. Films containing SP were prepared at different temperatures, with different concentrations of SP and different lengths of hydroxypropyl methylcellulose (HPMC) chains. The mechanical, structural, and in vitro mucoadhesive properties of films containing SP were investigated. Tensile strength and mucoadhesive force were measured with a device and software developed in our Institute. Positron annihilation lifetime spectroscopy (PALS) and X-ray powder diffractometry (XRPD) were applied for the structure analysis of the films. Mucoadhesive work was calculated in two ways: from the measured contact angle and compared with direct mucoadhesive work, which measured mucoadhesive force, which is direct mucoadhesion work. These results correlate linearly with a correlation coefficient of 0.98. It is also novel because it is a new method for the determination of mucoadhesive work.

Development and In Vitro/Ex Vivo Characterization of Vaginal Mucoadhesive Bilayer Films Based on Ethylcellulose and Biopolymers for Vaginal Sustained Release of Tenofovir

Young women in sub-Saharan Africa have the highest risk of human immunodeficiency virus (HIV) acquisition through sexual contact of all groups. Vaginal controlled release of antiretrovirals is a priority option for the prevention of sexual transmission of the virus in women. In this manuscript, bilayer films were prepared based on ethylcellulose and a natural polymer (xanthan or tragacanth gum) plasticized with glycerol and tributylcitrate for tenofovir-controlled release. The mechanical properties and microstructure of the blank films were characterized by texture analysis, Fourier transform infrared spectroscopy, and scanning electron microscopy. The loaded films were evaluated in simulated vaginal fluid through release and swelling studies and ex vivo mucoadhesion assessments. The results show that the preparation method produced bilayer films with adequate mechanical properties. The contribution of both layers allowed the sustained release of tenofovir and a mucoadhesion time of up to 360 h. The toxicity of the materials was evaluated in three cell lines of vaginal origin. The films constituted by ethylcellulose and xanthan gum in a 2:1 proportion (EX2-D) showed the longest mucoadhesion time, with 15 days of tenofovir-controlled release, zero toxicity, and optimal mechanical properties. These films are therefore a promising option for offering women a means of self-protection against the sexual transmission of HIV.

Xanthan gum derivatives: review of synthesis, properties and diverse applications

Natural polysaccharides are well known for their biocompatibility, non-toxicity and biodegradability. These properties are also inherent to xanthan gum (XG), a microbial polysaccharide. This biomaterial has been extensively investigated as matrices for tablets, nanoparticles, microparticles, hydrogels, buccal/transdermal patches, tissue engineering scaffolds with different degrees of success. However, the native XG has its own limitations with regards to its susceptibility to microbial contamination, unusable viscosity, poor thermal and mechanical stability, and inadequate water solubility. Chemical modification can circumvent these limitations and tailor the properties of virgin XG to fulfill the unmet needs of drug delivery, tissue engineering, oil drilling and other applications. This review illustrates the process of chemical modification and/crosslinking of XG via etherification, esterification, acetalation, amidation, and oxidation. This review further describes the tailor-made properties of novel XG derivatives and their potential application in diverse fields. The physicomechanical modification and its impact on the properties of XG are also discussed. Overall, the recent developments on XG derivatives are very promising to progress further with polysaccharide research.

Due to presence of hydroxy and carboxy functional groups, xanthan gum is amenable to various chemical modification for producing derivatives such as carboxymethyl xanthan and carboxymethyl hydroxypropyl xanthan with desirable properties for end use.

Formulating injectable pastes of porous calcium phosphate glass microspheres for bone regeneration applications

Current trends in regenerative medicine treatments for bone repair applications focus on cell-based therapies. These aim to deliver the treatment via a minimally invasive injection to reduce patient trauma and to improve efficacy. This paper describes the injectability of porous calcium phosphate glass microspheres to be used for bone repair based on their formulation, rheology and flow behavior. The use of excipients (xanthan gum, methyl cellulose and carboxyl methyl cellulose) were investigated to improve flow performance. Based on our results, the flow characteristics of the glass microsphere pastes vary according to particle size, surface area, and solid to liquid ratio, as well as the concentration of viscosity modifiers used. The optimal flow characteristics of calcium phosphate glass microsphere pastes was found to contain 40 mg/mL of xanthan gum which increased viscosity whilst providing elastic properties (∼29,000 Pa) at shear rates that mirror the injection process and the resting period post injection, preventing the glass microspheres from both damage and dispersion. It was established that a base formulation must contain 1 g of glass microspheres (60-125 μm in size) per 1 mL of cell culture media, or 0.48 g of glass microspheres of sizes between 125 and 200 μm. Furthermore, the glass microsphere formulations with xanthan gum were readily injectable via a syringe-needle system (3-20 mL, 18G and 14G needles), and have the potential to be utilized as a cell (or other biologics) delivery vehicle for bone regeneration applications.

Formulation of sustained release bioadhesive minitablets containing solid dispersion of levofloxacin for once daily ocular use

This study aimed to increase ocular residence time of levofloxacin by formulation into zero-order sustained release mucoadhesive minitablets for once daily administration using a hydrophobic-hydrophilic polymeric matrix. Levofloxacin was first formulated into solid dispersion with different ratios of Eudragit^® RS then the resulting solid dispersion was mixed with different concentrations of Carbopol^® and other excipients to be finally compressed into minitablets. A 2⁴ full factorial design was employed to estimate the effects and interactions of two formulation factors, and to establish their relationships with selected responses in the developed minitablets. The studied factors were: drug to Eudragit^® RS ratio, and percent of Carbopol^® in the minitablets. Sixteen ocular minitablets formulations were prepared and evaluated for the cumulative percentages drug release at 6, 12, and 24 h, as well as mucoadhesion time, mucoadhesive strength, and swelling index as response variables. After optimizing the responses, the optimized formulation was found to be stable on sterilization using gamma-irradiation and storage at 40 °C/75% RH for six months. In vivo testing of the optimized formulation showed that the minitablets extended levofloxacin release up to 24 h without causing any ocular irritation. The optimized formulation exhibited superior microbiological activity compared to the commercial product.

A novel lidocaine hydrochloride mucoadhesive films for periodontal diseases

Periodontal diseases are inflammatory disorders caused primarily by dental plaque microorganisms that even may need surgery to remove damaged tissue. Adhesive biocompatible films may be an adequate form in order to improve drug retention or prevent microbial infections by covering the surgical site. In recent years, much attention has been focused on biocompatible inexpensive polymers, for biomedical and pharmaceutical potential applications. The objective of this research is the development of a film for mucosal application containing lidocaine hydrochloride (5%, w/w) as anesthetic drug. Lidocaine films were prepared with three biopolymers: hydroxypropylmethylcellulose (HPMC), chitosan (CH), or xanthan gum (XG). Their thickness and uniformity content were characterized. Rheological behavior of the hydrated films was studied using flow curves, creep and recovery tests and dynamic oscillatory measurements with a rheometer. The mucoadhesive assays were carried out with cheeks of Wistar rat using a universal tensile tester to know their adhesiveness. Finally, lidocaine delivery through the films was investigated in Franz cells. All films (n = 3 for each polymer) showed flexibility, a drug content of 0.015 ± 0.001 g/cm² and a thickness of 0.25 ± 0.01 mm. The results of the maximum detachment force in tensile tests and work adhesion indicated that XG is the polymer that showed greater power of mucoadhesion (p < 0.05). These properties show a good correlation with the rheological characteristics. In all cases, the lidocaine amount released at 30 min is around 4 mg/cm². This amount could be considered sufficient to guarantee the anesthetic effect.

Buccal Bullfrog (Rana catesbeiana Shaw) Oil Emulsion: A Mucoadhesive System Intended for Treatment of Oral Candidiasis

Oral candidiasis (OC) is an infectious disease caused by microorganisms of the genus Candida, leading to lesions in the buccal cavity. Its treatment consists of the administration of topical or systemic antifungal agents, which may compromise the patient compliance due to its side effects, highlighting the need for alternative treatments. In this scenario, bullfrog oil, an animal oil composed of a pool of saturated and unsaturated fatty acids, is introduced as a potential antifungal raw material. Thus, the aim of this work was to produce a mucoadhesive emulsified system able to deliver the bullfrog oil in the buccal cavity to treat the OC. The emulsion was produced and characterized by visual inspection, droplet size, polydispersity index (PdI), and zeta potential over the course of 60 days. In addition, its mucoadhesive ability was evaluated using an in vitro mucin model. The antifungal activity, evaluated by the broth microdilution assay and the biocompatibility, performed against human erythrocytes, were also carried out. The emulsion showed a droplet size of 320.79 ± 35.60 nm, a PdI of 0.49 ± 0.08, and a zeta potential of -38.53 ± 6.23 mV, with no significant changes over 60 days. The mucoadhesive properties of the system was improved by the use of pharmaceutical excipients. The antifungal activity showed that the bullfrog oil and the emulsion were able to inhibit the growth of different Candida species. Furthermore, the emulsion showed no significant hemolytic effect. Overall, the system showed suitable physicochemical characteristics and biocompatibility, with substantial in vitro antifungal activity, suggesting that this system can be further investigated for OC treatment.

In situ gelling and mucoadhesive polymers: why do they need each other?

INTRODUCTION

Mucosal drug delivery is an attractive route of administration, particularly in overcoming deficits of conventional dosage forms including high first-pass metabolism and poor bioavailability. Fast drainage from the target mucosa, however, represents a major limitation as it prevents sufficient drug absorption. In order to address these problems, mucoadhesive in situ gelling drug delivery systems have been investigated as they facilitate easy application in combination with a longer residence time at the administration site resulting in more desirable therapeutic effects.

AREAS COVERED

The present review evaluates the importance of the combination of mucoadhesive and in situ gelling polymers along with mechanisms of in situ gelation and mucoadhesion. In addition, an overview about recent applications in mucosal drug delivery is provided.

EXPERT OPINION

In situ gelling and mucoadhesive polymers proved to be essential excipients in order to prolong the mucosal residence time of drug delivery systems. Due to this prolonged residence time both local and systemic therapeutic efficacy of numerous drugs can be substantially improved. Depending on the site of administration and the incorporated drug, combinations of different polymers with in situ gelling and mucoadhesive properties are needed to keep the delivery system as long as feasible at the target site.

Formulation and ex vivo-in vivo evaluation of pH-triggered brimonidine tartrate in situ gel for the glaucoma treatment using application of 32 factorial design

CONTEXT

Short residence time, poor bioavailability and poor permeability are the major problems for conventional eye drops treatment.

OBJECTIVE

The aim of this article is to develop, optimize and ex vivo-in vivo investigation of brimonidine tartrate in situ gel as compared to marketed eye drops for the treatment of glaucoma.

MATERIALS AND METHODS

The effect of independent variables, namely concentrations of polymers, on various dependent variables like viscosity at physiological pH and in vitro drug release were studied by using 3² factorial design. Further the optimized formulation was characterized for ex vivo and in vivo study.

RESULTS AND DISCUSSION

Experimental data demonstrated that optimized in situ gel formulation (F8) showed in vitro-ex vivo sustained release profile with polymer composites carbopol 974P and HPMC K4M. After 5 h of ex vivo transcorneal permeation study, the amount recovered from the corneal surface on the donor chamber 12.40% (124 ug) and the amount collected from the receptor chamber 76.8% (760 ug) of the initial dose 1 mg. The total amount recovered from the permeation experiment was 89.2%. Bioadhesive carbopol 974P and viscosity HPMC K4M composites optimized formulation (F 8) produce greater influence on the duration of drug action and improved intraocular pressure reduction activity as compared to marketed eye drop solution in in vivo study.

CONCLUSION

The developed in situ gelling system as a promising ophthalmic formulation to prolong the drug lowering effect on the intraocular pressure.