Formulation design of hydroxypropyl cellulose films for use as orally disintegrating dosage forms

Influence of Casting Variables on Release Kinetics of Orally Disintegrating Film

As a new form for supplying vitamin C, orally disintegrating films (ODFs) were developed C based on hyaluronic acid (HA) under varying casting conditions and the properties were analyzed. The films with different thicknesses (2, 3, and 8 mm, for CT2, CT4, and CT8, respectively) were produced by adjustments made to casting height. Two types of 8 mm thick ODFs produced by single or double casting (4 + 4 mm for CTD4+4) methods were also compared. As film thickness increased, water vapor permeability and tensile strength also increased. Even at equal thickness, manufacturing with double casting exhibited a stronger texture and reduced disintegration compared to single casting. All ODFs met the World Health Organization's recommended daily vitamin C intake (45 mg/day) with a single sheet. Films showed over 80% dissolution in various solvents, adhering to the Hixson-Crowell cube root law, indicating vitamin C release occurred via porous penetration of the eluate. For CT2, CT4, and CTD4+4, vitamin C release was primarily governed by diffusion within the gel matrix and HA erosion. However, for CT8, HA erosion-induced release somewhat dominated. Based on the sensory test, it seems desirable to adjust the thickness of the film to 2 or 4 mm, because a thickness greater than that increased the foreign body sensation due to prolonged residence in the oral cavity.

Preparation of Gel Forming Polymer-Based Sprays for First Aid Care of Skin Injuries

Currently, there are several types of materials for the treatment of wounds, burns, and other topical injuries available on the market. The most used are gauzes and compresses due to their fluid absorption capacity; however, these materials adhere to the surface of the lesions, which can lead to further bleeding and tissue damage upon removal. In the present study, the development of a polymer-based gel that can be applied as a spray provides a new vision in injury protection, respecting the requirements of safety, ease, and quickness of both applicability and removal. The following polymeric sprays were developed to further obtain gels based on different polymers: hydroxypropyl cellulose (HPC), polyvinyl pyrrolidone (PVP) and hydroxypropyl methylcellulose (HPMC) using polyethylene glycol (PEG) as a plasticizer. The developed sprays revealed suitable properties for use in topical injuries. A protective film was obtained when sprayed on a surface through a casting mechanism. The obtained films adhered to the surface of biological tissue (pig muscle), turning into a gel when the exudate was absorbed, and proved to be washable with saline solution and contribute to the clotting process. Moreover, biocompatibility results showed that all materials were biocompatible, as cell viability was over 90% for all the materials.

Influence of cellulose viscosity on the physical, mechanical, and barrier properties of the chitosan-based films

This research paper presents a comprehensive investigation into developing biodegradable films for food packaging applications using chitosan (CN) in conjunction with three distinct types of cellulose (CE), each characterized by varying viscosities. The primary objective was to assess the influence of cellulose viscosity on the physical, mechanical, and barrier properties of the resulting films. The medium-viscosity cellulose imparted numerous advantageous qualities to the biodegradable films. These films exhibited optimal thickness (31 μm), ensuring versatility in food packaging while maintaining favorable mechanical properties, blending strength, and flexibility. Also, medium-viscosity cellulose significantly improved the films' barrier performance, particularly regarding oxygen permeability [1.80 × 10-6 (g.mm.m-2. s-1)]. Furthermore, the medium-viscosity cellulose contributed to superior moisture-related properties, including reduced water vapor permeability [14.80 × 10-9 (g.mm.m-2. s-1. Pa-1)], moisture content (13.22 %), and water solubility (22.87 %), while maintaining an appropriate degree of swelling (41.88 %). Moreover, the study employed advanced analytical techniques, including FTIR, XRD, and TGA, to provide critical insights into the films' chemical, structural, and thermal aspects. This research underscored the importance of the viscosity of film formulation materials as a crucial element in designing and efficiently producing films for food packaging.

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.

Comparison of Hydroxypropyl Methylcellulose and Alginate Gel Films with Meloxicam as Fast Orodispersible Drug Delivery

The aim of the study was the preparation and comparison of two types of orodispersible gel films (ODF) by the solvent casting method. Natural polymers: sodium alginate (ALG) or hydroxypropyl methylcellulose (HPMC) were used as the gel film formers, and Kollidon or microcrystalline cellulose was used as the disintegrant. Meloxicam (MLX), the drug used to treat rheumatic diseases for children and adults, was proposed as the active pharmaceutical ingredient (API). The influence of the polymer and disintegrant on the properties of ODF was investigated. The evaluation of prepared gel films was based on appearance description, mass uniformity measurement, disintegration time, API content, film wettability, and water content. Also, the dissolution test was prepared in a basket apparatus using artificial salvia (pH = 6.8) as the medium. The obtained API release profiles were analyzed for the similarity factors (f2) with the DDSolver software. The results showed that independently of the polymer or disintegrant, using the solvent casting method, gel films have a similar appearance and active substance content close to the theoretical value and water content of less than 10%. Only the type of polymer influences the release profiles of MLX. However, the disintegration time was longer than 30 s, which makes the films non-fast-dissolving drug delivery systems. This means that for the ODF system, further evaluation is required, and some changes in the composition of the film have to be done.

Recent advances in cellulose, pectin, carrageenan and alginate-based oral drug delivery systems

Polymers-based drug delivery systems constitute one of the highly explored thrust areas in the field of the medicinal and pharmaceutical industries. In the past years, the properties of polymers have been modified in context to their solubility, release kinetics, targeted action site, absorption, and therapeutic efficacy. Despite the availability of diverse synthetic polymers for the bioavailability enhancement of drugs, the use of natural polymers is still highly recommended due to their easy availability, accessibility, and non-toxicity. The aim of the review is to provide the available literature of the last five years on oral drug delivery systems based on four natural polymers i.e., cellulose, pectin, carrageenan, and alginate in a concise and tabulated manner. In this review, most of the information is in tabulated form to provide easy accessibility to the reader. The data related to active pharmaceutical ingredients and supported components in different formulations of the mentioned polymers have been made available.

Interfacial Structure and Electrostatics Related to Solute Activity in a Model Anionic-Surfactant/Polymer Self-Assembly

Polymer/surfactant composites are used in industry as an excipient for water-insoluble solutes. Such enhanced dissolution ability of composite media is related to the spontaneous formation of pre-micellar polymer surfactant aggregates (PS) at a magnitude of order lower than the surfactant critical micelle concentration in water. Combining electrochemical and spectroscopic studies, we investigate the microscopic interfacial structure (i.e., interface electrostatics and surface polarity) of PS formed in composite media. We establish that in a composite system, a mere change in the polymer concentration at a fixed surfactant concentration makes possible to regulate the counter-ion binding ability, surface potential, surface charge density, packing and surface polarity of the PS interface. Our study shows that the higher dissolution of water-insoluble nonionic solutes in composite media is driven by the depressing of surface charge density and polarity of the PS interface. A similar modulation of the PS interface acts as a barrier for the passive relocation of water-soluble charged solutes into the PS pseudo-phase. The time-resolved fluorescence anisotropy study allows us to underline the effect of surface charge modulation on the dynamical aspects of solutes at the PS interface.

Variability in the substitution pattern of hydroxypropyl cellulose affects its physico-chemical properties

Hydroxypropyl cellulose (HPC) is a water-soluble polymer with many applications in food, pharmaceutical, medical, or paints industries. Past studies have reported that differences in functionality can occur between products of similar pharmaceutical grades. Understanding the origin of these differences is a major challenge for the industry. In this work, the structure and physico-chemical properties of several HPC samples of the same commercial grade were studied. Structural analysis by NMR and enzymatic hydrolysis were performed to study molar substitution and distribution of substituents along the polymer chain respectively. Water-polymer interactions, surface properties as well as rheological and thermal behavior were characterized to tentatively correlate them with the structure, and gain new insights into the structure-function relationship of this polymer. The differences in structure revealed between the samples affect their properties. The unexpected behavior of one sample was attributed to a more heterogeneous substitution pattern, with the coexistence of highly and weakly substituted regions along the same polymer chain. The more block-like distribution of substituents has a great effect on the clouding behavior and surface tension reduction ability of the polymer.

Orodispersible Films-Current State of the Art, Limitations, Advances and Future Perspectives

Orodispersible Films (ODFs) are drug delivery systems manufactured with a wide range of methods on a big scale or for customized medicines and small-scale pharmacy. Both ODFs and their fabrication methods have certain limitations. Many pharmaceutical companies and academic research centers across the world cooperate in order to cope with these issues and also to find new formulations for a wide array of APIs what could make their work profitable for them and beneficial for patients as well. The number of pending patent applications and granted patents with their innovative approaches makes the progress in the manufacturing of ODFs unquestionable. The number of commercially available ODFs is still growing. However, some of them were discontinued and are no longer available on the markets. This review aims to summarize currently marketed ODFs and those withdrawn from sale and also provides an insight into recently published studies concerning orodispersible films, emphasizing of utilized APIs. The work also highlights the attempts of scientific communities to overcome ODF's manufacturing methods limitations.

A Sustainable Hydroxypropyl Cellulose-Nanodiamond Composite for Flexible Electronic Applications

Designing fully green materials for flexible electronics is an urgent need due to the growing awareness of an environmental crisis. With the aim of developing a sustainable, printable, and biocompatible material to be exploited in flexible electronics, the rheological, structural and charge transport properties of water-based hydroxypropyl cellulose (HPC)-detonation nanodiamond (DND) viscous dispersions are investigated. A rheological investigation disclosed that the presence of the DND affects the orientation and entanglement of cellulose chains in the aqueous medium. In line with rheological analyses, the NMR diffusion experiments pointed out that the presence of DND modifies the hydrodynamic behavior of the cellulose molecules. Despite the increased rigidity of the system, the presence of DND slightly enhances the ionic conductivity of the dispersion, suggesting a modification in the charge transport properties of the material. The electrochemical analyses, performed through Cyclic Voltammetry (CV) and Electrochemical Impedance Spectroscopy (EIS), revealed that the HPC-DND system is remarkably stable in the explored voltage range (-0.1 to +0.4 V) and characterized by a lowered bulk resistance with respect to HPC. Such features, coupled with the printability and filmability of the material, represent good requirements for the exploitation of such systems in flexible electronic applications.

Novel Features of Cellulose-Based Films as Sustainable Alternatives for Food Packaging

Packaging plays an important role in food quality and safety, especially regarding waste and spoilage reduction. The main drawback is that the packaging industry is among the ones that is highly dependent on plastic usage. New alternatives to conventional plastic packaging such as biopolymers-based type are mandatory. Examples are cellulose films and its derivatives. These are among the most used options in the food packaging due to their unique characteristics, such as biocompatibility, environmental sustainability, low price, mechanical properties, and biodegradability. Emerging concepts such as active and intelligent packaging provides new solutions for an extending shelf-life, and it fights some limitations of cellulose films and improves the properties of the packaging. This article reviews the available cellulose polymers and derivatives that are used as sustainable alternatives for food packaging regarding their properties, characteristics, and functionalization towards active properties enhancement. In this way, several types of films that are prepared with cellulose and their derivatives, incorporating antimicrobial and antioxidant compounds, are herein described, and discussed.

Micellar buccal film for safe and effective control of seizures: Preparation, in vitro characterization, ex vivo permeation studies and in vivo assessment

The current research article focused on formulating an easily applied, water-based buccal film loaded with the antiepileptic drug, lamotrigine (LTG). The designed film can be comfortably administered by epileptic patients to ensure a controllable therapeutic efficacy against seizures. The solubility of LTG in water was significantly improved by micellar solubilization. Upon testing several surfactants, three of them (Synperonic PE/P84, Brij L23, and Brij 78) achieved maximum possible solubility for LTG and were characterized for their micellar size, cloud point, and % transmittance. Selected micellar systems were incorporated within a buccal film prepared using solvent casting method based on either gelatin or polyvinylpyrrolidone (3%w/v) with 1.5%w/v propylene glycol as a plasticizer. Different micellar films were characterized for their physicochemical characteristics, swelling index, folding endurance, drug content uniformity, and in vitro LTG release. From the tested formulations, one formulation; LTG-BF1 (in which Brij 78 was used for the micellar solubilization and gelatin as the matrix former), was selected as the optimum and extensively studied for mucoadhesion, ex vivo permeation studies by Franz diffusion cells and confocal laser scanning microscopy. Results showed superior enhanced permeation of micellar film. LTG-BF1 was evaluated for the in vivo performance using rats. Status epilepticus was induced in rats by injecting Pentylenetetrazol (PTZ) i.p. at an initial dose of 30 mg/kg, followed by 10 mg/kg every10 min till 60 min. A group of rats receiving the designed buccal formulation (20 mg/kg) was compared with a group receiving the same dose of the oral market product and the normal control and PTZ groups. Rats receiving LTG-BF1 recorded reduced seizure scores at all stages, longer latency time, and higher threshold PTZ dose compared to PTZ and market product groups. In addition, LTG-BF1 reduced brain concentrations of TNF-α and TGF-β with an elevation of EAAT2 and GABA brain contents compared to PTZ and market product groups and ameliorated neuronal damage. In conclusion, LTG-loaded buccal micellar film proved a superior antiepileptic effect in PTZ induced acute epileptic model.

Recent advances of oral film as platform for drug delivery

Orally drug delivery film has received extensive interest duo to a distinct set of its advantageous properties compared to the traditional orally administered dosages, including faster rate of drug absorption, higher bioavailability and better patient compliance for children and elders with swallowing deficiencies. In particular, its potential capacity of delivering proteins and peptides has further attracted great attention. Lately, tremendous advances have been made in designing and developing both novel mucoadhesive films and orodispersible films to fulfill specific accomplishments of drug delivery. This review aims to summarize those newly developed oral films, discussing their formulation strategies, manufacturing methods as well as advantages and limitations thereof. Conclusions and future perspectives are also provided in brief.

Effect of Surfactant Tail Length on the Hydroxypropyl Cellulose-Mediated Premicellar Aggregation of Sodium n-Alkyl Sulfate Surfactants

Polymer/surfactant composites have emerged as a subject of interest for their diverse applications. The improved solution properties in polymer/surfactant composites have been correlated to the formation of premicellar surfactant aggregate-polymer complexes (PS) at a surfactant concentration well below their critical micelle concentrations. Using different physicochemical and spectroscopic techniques here we have studied PS formed by hydroxypropyl cellulose, a nonionic-biocompatible polymer, and alkyl sulfate surfactants of different tail lengths. Our study shows that an increase in surfactant tail length eases PS formation and enhances PS-induced polymer cross-linking and, correspondingly, solution viscosity. PS consisting of shorter tail surfactants and those with longer tail surfactants differ microscopically as the former offers more polar interior than the later as evidenced from fluorescence measurements. Our study establishes that shorter tail surfactants intend to stay loosely packed inside PS and allow larger water penetration, which creates a relatively polar hydrophobic core compared to the PS with longer tail surfactants. The stronger packing of PS with longer tail surfactants is an outcome of favorable interaction between polymer polar groups and surfactant headgroups, which further creates strongly hydrogen-bonded water in their hydration shell.

Mechanical characteristics of orally disintegrating films: Comparison of folding endurance and tensile properties

The tensile test is the most widely used method for testing the mechanical characteristics of orally disintegrating films (ODFs). The other available test is the folding endurance (FE) test, which is more suitable for clarifying the actual strength during the manufacturing and dosing. However, the FE test is performed manually, and the FE number it generates has not been adequately analyzed as an index. The aim of this studies were to establish an automatic method for determining the FE number, and to compare the resulting FE numbers with the tensile properties. For this purpose, a desktop-model endurance test machine was used. First, the operating conditions-i.e., the folding angle, the folding speed and the weight requirement were optimized using ODF models. Secondly, the FE of ODFs prepared from three film formers (HPMC, HPC, and PVA) and with insoluble particles (calcium carbonate), plasticizers (glycerin) and APIs (acetaminophen), was evaluated and compared with the tensile properties. Lastly, the commercial ODFs were investigated. The results showed that our automatic system could be successfully used to determine the FE characteristics of ODFs. FE was suggested to relate to not only the strength but also the elongation during the tensile test.

[Particle Design Strategies for Developing Patient Centric Dosage Form Preparations]

Novel dosage form designs aiming at patient centric drug therapy are summarized here based on my carrier research in this field. The common key word for this research is particle design. The topics will be divided into two parts, based on the type of particle: coarse particles (powder) and colloidal particles. The former includes the preparation and characterization of functional particles prepared using a spray dryer. Solid dispersions, solvent deposition particles and dry emulsion systems are described. Polymer coated liposomes are described as a useful drug delivery carrier in several administration routes. As chitosan, a mucoadhesive polymer, was used as a coating polymer, the resultant chitosan-coated liposome was found to work as a good carrier for peptide drugs such as insulin and calcitonin in the gastrointestinal tract after oral administration. In another administration route (inhalation), polymer-coated liposomes enhanced the absorption of the drugs. Liposomal carriers applied to the surface of the eye as eye drops are able to deliver drugs to the posterior part of the eye, such as the retina. As a typical example of patient centric dosage form design, particle designs for the preparation of orally disintegrating tablets and films were introduced in one of our recent studies on oral dosage form design.

In Vitro Oral Cavity Model for Screening the Disintegration Behavior of Orodispersible Films: A Bespoke Design

The availability of biorelevant methods for the disintegration study of pharmaceutical orodispersible dosage forms is required. The disintegration of orodispersibles should be assessed using in vitro methods that can combine biorelevant volumes of disintegration medium and mechanical stresses mimicking in vivo conditions. This study proposes an adaptation of a mechanical oral cavity model for the disintegration study of orodispersible films. A periodic compression is applied to the sample in the presence of a biorelevant volume of artificial salivary fluid. Four orodispersible film samples (P1, C1, P2, and C2), differing in polymer type and molecular weight, and Listerine^® were tested and filmed during disintegration. An image analysis program was developed for the determination of the volume reduction of the film matrix over time, as a descriptor of film disintegration behavior. Samples P1 and Listerine^® showed a volume reduction at 180 s of >90%, C1, P2, and C2 were 85%, 48%, and 37%, respectively. The model was able to detect differences in the disintegration behavior of the 4 samples, and results were comparable with the benchmark product. The concept of disintegration behavior of orodispersible films was introduced for the first time as an informative method for the study of orodispersible dosage form.

Design of a new disintegration test system for the evaluation of orally disintegrating films

In the design of the orally disintegrating films (ODFs), it is important to determine the disintegration time (DT) precisely and properly. These films' DTs are usually assessed by a disintegration test defined in the pharmacopoeias, but under the conditions of such tests, a much larger volume of water is used and a stronger up-down movement is applied compared to the conditions of the human oral cavity. Here we developed and tested our new disintegration test system for ODFs. We chose a disintegration test device (the Tricorptester®, Okada Seiko, Tokyo) for orally disintegrating tablets. This device enabled the mechanical dropping of the test medium. We designed an exclusive fixture for ODFs, made an opening in the center of the fixture, and optimized the size of the opening (i.e., the cell). We also investigated that test conditions including the types of test media, the dropping height, flow rate, dropping methods, and medium holding methods. With a passage sensor attached to the Tricorptester, the device was able to automatically detect the DTs of ODFs. We thus successfully developed a new disintegration test system and optimized the operating conditions. Using this system, model ODFs and the commercial ODFs can be properly evaluated.