Evaluation of the super disintegrant functionnalities of alginic acid and calcium alginate for the design of orodispersible mini tablets

Algal Phycocolloids: Bioactivities and Pharmaceutical Applications

Seaweeds are abundant sources of diverse bioactive compounds with various properties and mechanisms of action. These compounds offer protective effects, high nutritional value, and numerous health benefits. Seaweeds are versatile natural sources of metabolites applicable in the production of healthy food, pharmaceuticals, cosmetics, and fertilizers. Their biological compounds make them promising sources for biotechnological applications. In nature, hydrocolloids are substances which form a gel in the presence of water. They are employed as gelling agents in food, coatings and dressings in pharmaceuticals, stabilizers in biotechnology, and ingredients in cosmetics. Seaweed hydrocolloids are identified in carrageenan, alginate, and agar. Carrageenan has gained significant attention in pharmaceutical formulations and exhibits diverse pharmaceutical properties. Incorporating carrageenan and natural polymers such as chitosan, starch, cellulose, chitin, and alginate. It holds promise for creating biodegradable materials with biomedical applications. Alginate, a natural polysaccharide, is highly valued for wound dressings due to its unique characteristics, including low toxicity, biodegradability, hydrogel formation, prevention of bacterial infections, and maintenance of a moist environment. Agar is widely used in the biomedical field. This review focuses on analysing the therapeutic applications of carrageenan, alginate, and agar based on research highlighting their potential in developing innovative drug delivery systems using seaweed phycocolloids.

Orally disintegrating drug carriers for paediatric pharmacotherapy

Non-compliance, dosing inaccuracy, choking risk, flavour, and instability, are some of the issues associated with paediatric, oral dosage forms - tablets, capsules, solutions, and suspensions. Orally disintegrating drug carriers, a dosage form with growing interest, are thought to overcome several of the challenges associated with these conventional formulations by rapidly disintegrating within the buccal cavity without the need for water. This review serves as an up-to-date report on the various types of orodispersible delivery systems, currently being developed or commercialized, by detailing their characteristics, manufacturing processes, and applications in the paediatric population. Mentioned are orodispersible tablets, films, wafers and lyophilisates, mini-tablets, capsules, granules, electrospun fibers and webs. Also highlighted are the choice of excipients, quality control requirements, and expected pharmacokinetics of orally disintegrating drug carriers concerning the paediatric population. Overall, orodispersible formulations, particularly tablets, films, and lyophilisates/wafers, have shown to be a valuable addition to medication administration in minors, thus the execution of more targeted research and development activities is expected to lead to enhanced paediatric care and outcomes.

Alginate-based matrix tablets for drug delivery

INTRODUCTION

As a nature-derived polymer with swelling and gelling properties, alginate has found wide biopharma-relevant applications. However, there is comparatively limited attention on alginate in tablet formulations. Therefore, this review aimed to provide an overview of the applications of alginate in solid dosage form formulations.

AREAS COVERED

This review outlines the role of alginate for oral sustained release formulations. For better insights into its application in drug delivery, the mechanisms of drug release from alginate matrices are discussed alongside the alginate inherent properties and drug properties. Specifically, the influence of alginate properties and formulation components on the resultant alginate gel and subsequent drug release is reviewed. Modifications of the alginate to improve its properties in modulating drug release are also discussed.

EXPERT OPINION

Alginate-based matrix tablets is useful for sustaining drug release. As a nature-derived polymer, batch consistency and stability raise some concerns about employing alginate in formulations. Furthermore, the alginate gel properties can be affected by formulation components, pH of the dissolution environment and the tablet matrix micro-environment pH. Conscientious efforts are pivotal to addressing these formulation challenges to increase the utilization of alginate in oral solid dosage forms.

Orally Dispersible Dosage Forms for Paediatric Use: Current Knowledge and Development of Nanostructure-Based Formulations

The paediatric population has always suffered from a lack of medicines tailored to their needs, especially in terms of accurate dosage, stability and acceptability. Orodispersible dosage forms have gone through a resurrection as an alternative to liquid formulations or fractioned solid formulations, although they are still subject to several inconveniences, among which the unpleasant taste and the low oral bioavailability of the API are the most significant hurdles in the way of achieving an optimal drug product. Nanostructures can address these inconveniences through their size and variety, owing to the plethora of materials that can be used in their manufacturing. Through the formation and functionalisation of nanostructures, followed by their inclusion in orodispersible dosage forms, safe, stable and acceptable medicines intended for paediatric use can be developed.

Anti-Adhesive Properties of Calcium Alginate from Sargassum fusiforme against Particulate Matter-Induced Inflammation

Fine dust generated by particulate matter (PM) pollution is a serious ecological issue in industrialized countries and causes disorders of the respiratory system and skin in humans. In the previous study, Sargassum fusiforme was treated with citric acid to remove heavy metals. In this study, the transfer of PM-mediated inflammatory responses through the skin to macrophages was evaluated. Moreover, the anti-adhesive effects of calcium alginate isolated from S. fusiforme (SFCA) against PM-induced inflammation were investigated. The structures of processing and unprocessing SFCA were then analyzed by Fourier-transform infrared spectroscopy (FT-IR), revealing minimal change after acid-processing. SFCA had protective effects both in PM-stimulated HaCaT keratinocytes and RAW 264.7 macrophages. In cellular environments, it was found that SFCA attenuated signal protein expressions such as inducible nitric oxide synthase (iNOS), cyclooxygenase (COX)-2, prostaglandin E₂ (PGE₂), and pro-inflammatory cytokines. Furthermore, macrophages were added to the culture medium of PM-stimulated keratinocytes to induce inflammation. SFCA was observed to significantly inhibit inflammatory responses; additionally, SFCA showed an in vivo anti-adhesive effect in zebrafish embryos.

Development of Immediate Release Tablets Containing Calcium Lactate Synthetized from Black Sea Mussel Shells

Nowadays, the use of marine by-products as precursor materials has gained great interest in the extraction and production of chemical compounds with suitable properties and possible pharmaceutical applications. The present paper presents the development of a new immediate release tablet containing calcium lactate obtained from Black Sea mussel shells. Compared with other calcium salts, calcium lactate has good solubility and bioavailability. In the pharmaceutical preparations, calcium lactate was extensively utilized as a calcium source for preventing and treating calcium deficiencies. The physical and chemical characteristics of synthesized calcium lactate were evaluated using Fourier Transform Infrared Spectroscopy, X-ray diffraction analysis and thermal analysis. Further, the various pharmacotechnical properties of the calcium lactate obtained from mussel shells were determined in comparison with an industrial used direct compressible Calcium lactate DC (PURACAL^®). The obtained results suggest that mussel shell by-products are suitable for the development of chemical compounds with potential applications in the pharmaceutical domain.

Orodispersible tablets for pediatric drug delivery: current challenges and recent advances

INTRODUCTION

Child appropriate dosage forms are indispensable in modern medicine and are a prerequisite for successful pediatric drug therapy. For years, experts have called for a paradigm shift, from liquid dosage forms to novel oral solid dosage forms. This review aims to shed light on recent developments in Orodispersible tablets (ODTs) and mini-tablets (ODMTs).

AREAS COVERED

This review focuses on the presentation and critical discussion of current challenges as well as recent advances in ODTs for pediatric drug delivery. Highlighted aspects are the evidence for acceptability by children, e.g. in comparison to other dosage forms, and limitations given by tablet size at different ages, as well as advances in special ODT formulations (taste masking, modified release, enabling formulations).

EXPERT OPINION

It is the authors' belief that OD(M)Ts have significant potential as dosage forms in pediatric therapy that has not yet been fully exploited. The reasons for this are, first, that the number of direct acceptance studies is extremely low and the resulting knowledge is therefore rather anecdotal. Despite the high relevance, there seems to be reluctance both in the therapeutic use and conduction of respective studies in children. However, if one combines the knowledge from the few existing studies, surveys, and from approved products, it becomes apparent that so far there is no evidence on limitations of the use of ODTs in pediatric patients.

Sodium alginate and alginic acid as pharmaceutical excipients for tablet formulation: Structure-function relationship

Alginic acid and its sodium salt are well-accepted pharmaceutical excipients fulfilling several roles in the development of solid oral dosage forms. Although they have attractive advantages as safety, abundance, relatively low cost and biodegradability, these natural polysaccharides possess a high variability that may limit their use as excipients for tablet formulation. Thus, to obtain robust formulations and high-quality drug products with consistent performance a complete understanding of the structure-property relationship becomes necessary as the structure of alginates affects both, technological and biopharmaceutical properties. This review compiles the compaction studies carried out that relate the structure of alginates to their mechanical and dissolution performances. The different analytical methods used to determine the chemical composition, primary structure and molecular weight distribution, major factors affecting the behavior of alginates in direct compression, are also exposed. Finally, different strategies reported to improve the properties of alginic acid as direct compression excipient are discussed.

Performance Evaluation of a Novel Biosourced Co-Processed Excipient in Direct Compression and Drug Release

This study exposes the potential usefulness of a new co-processed excipient, composed of alginic acid and microcrystalline cellulose (Cop AA-MCC), for the preparation of immediate drug release tablets by direct compression. Evaluation of the physical and mechanical properties as well as the disintegration behavior of Cop AA-MCC in comparison to commercial co-processed excipients (Cellactose^®, Ludipress^®, Prosolv^® SMCC HD90 and Prosolv^® ODT) and to the physical mixture of the native excipients (MCC and AA), was carried out. The obtained results illustrate the good performance of Cop AA-MCC in terms of powder flowability, tablet tensile strength, compressibility, and disintegration time. Although, this new co-processed excipient showed a slightly high lubricant sensitivity, which was explained by its more plastic than fragmentary deformation behavior, it presented a low lubricant requirement due to the remarkably low ejection force observed during compression. Compression speed and dwell time seemed not to affect significantly the tabletability of Cop AA-MCC. The study exposed evenly the performance of Cop AA-MCC compared to Prosolv^® ODT, in terms of tabletability and dissolution rate of Melatonin. Cop AA-MCC presented comparable hardness, lower dilution potential, higher lubricant sensitivity, lower ejection force, and faster Melatonin's release time than Prosolv^® ODT. In summary, Cop AA-MCC exhibited interesting physical, mechanical, and biopharmaceutical properties, which demonstrate its concurrence to commercially available co-processed excipients. Furthermore, the simplicity of its composition and the scalability of its elaboration makes this multifunctional excipient highly recommended for direct compression.

Alginates as tablet disintegrants: Understanding disintegration mechanisms and defining ranges of applications

Alginates are biopolymers that have been investigated for their use in food and medical fields. Minimal information is available regarding their potential application as tablet superdisintegrants. Here we studied the disintegration action of sodium alginate (SA), calcium alginate (CA) and alginic acid (AA). Initially, we characterised the swelling and wicking abilities and the disintegration mechanism of pure disintegrants. We found that the liquid uptake of both CA and AA is more swelling-driven in phosphate buffer and more wicking-driven in hydrochloric acid and water. CA acts by shape-recovery, AA by a combination of swelling and shape-recovery mechanisms. SA cannot be used as disintegrant due to gelling. In the second part of the paper, the disintegration time of formulations with different physico-chemical properties and different alginate concentrations (i.e. 4% and 10%) was measured, thus delivering a direct readout for the ranges of application of alginates as tablets disintegrants. The main observations are: i) CA and AA often provide very rapid disintegration, similarly to the superdisintegrants used as controls; ii) the action of CA is more susceptible to the medium conditions than AA; iii) CA underperforms in hard tablets containing a binder; iv) both CA and AA have slightly slower disintegration than other superdisintegrants in tablets containing a hydrophobic component. While the suitability of CA as a disintegrant is formulation- and medium- dependent, AA appears as a promising tablet superdisintegrant, particularly for the development of uncomplicated hydrophilic formulations for the nutraceutical and supplement industry, where natural ingredients are favoured.

Advancing the understanding of the tablet disintegration phenomenon - An update on recent studies

Disintegration is the de-aggregation of particles within tablets upon exposure to aqueous fluids. Being an essential step in the bioavailability cascade, disintegration is a fundamental quality attribute of immediate release tablets. Although the disintegration phenomenon has been studied for over six decades, some gaps of knowledge and research questions still exist. Three reviews, published in 2015, 2016 and 2017, have discussed the literature relative to tablet disintegration and summarised the understanding of this topic. Yet, since then more studies have been published, adding to the established body of knowledge. This article guides a step forward towards the comprehension of disintegration by reviewing, concisely, the most recent scientific updates on this topic. Initially, we revisit the mechanisms of disintegration with relation to the three most used superdisintegrants, namely sodium starch glycolate, croscarmellose sodium and crospovidone. Then, the influence of formulation, storage, manufacturing and media conditions on disintegration is analysed. This is followed by an excursus on novel disintegrants. Finally, we highlight unanswered research questions and envision future research venues in the field.

The Structural Characteristics of Seaweed Polysaccharides and Their Application in Gel Drug Delivery Systems

In recent years, researchers across various fields have shown a keen interest in the exploitation of biocompatible natural polymer materials, especially the development and application of seaweed polysaccharides. Seaweed polysaccharides are a multi-component mixture composed of one or more monosaccharides, which have the functions of being anti-virus, anti-tumor, anti-mutation, anti-radiation and enhancing immunity. These biological activities allow them to be applied in various controllable and sustained anti-inflammatory and anticancer drug delivery systems, such as seaweed polysaccharide-based nanoparticles, microspheres and gels, etc. This review summarizes the advantages of alginic acid, carrageenan and other seaweed polysaccharides, and focuses on their application in gel drug delivery systems (such as nanogels, microgels and hydrogels). In addition, recent literature reports and applications of seaweed polysaccharides are also discussed.

Development of alginate esters as novel multifunctional excipients for direct compression

Methyl ester derivatives of alginic acid have been evaluated as potential multifunctional excipients for pharmaceutical direct compression. The use of alginic acid as an excipient in tablet formulation is limited because of certain drawbacks such as low tablet hardness and poor compressibility. The objective of this work is to improve these properties through esterification of alginic acid, chemical modification commonly used for enhancing the functionality of tableting excipients. It has been observed that the degree of methylation (DM) has a profitable impact in the physico-chemical and mechanical properties of the obtained materials. In general, an increase in the degree of methylation yielded tablets with higher tensile strength and better compressibility. Furthermore, modified alginates exhibited extended disintegration times compared to native alginic acid due to the introduced hydrophobicity. Finally, the functional versatility of the modified alginates as disintegrating and filling/binding agents was tested by formulating them with microcrystalline cellulose and lactose.

Alginate-poloxamer beads for clotrimazole delivery: Molecular interactions, mechanical properties, and anticandidal activity

Calcium alginate (CA) beads loaded with clotrimazole (CZ) were modified by adding poloxamer (PLX) in this study. Blends of PLX188 or PLX407 into sodium alginate (SA) dispersions caused a decrease in the SA zeta potential and led to viscosity synergism. SA with carboxyl and hydroxyl groups can interact with the hydroxyl groups of PLX via hydrogen bonding. A stronger interaction of SA with PLX407 was found when compared to the interaction between SA and PLX188. The PLX-CA beads gave a higher CZ entrapment efficiency than the CA beads. The highest PLX content used created an amorphous form of CZ in the beads because of the CZ solubilization by the PLX micelles. The addition of 0.5 or 1% w/v PLX can strengthen the CZ-loaded CA beads. Furthermore, the PLX-CA beads display a lower water uptake than the CA beads. PLX micellization can enhance CZ release and enhance the efficacy of CZ against Candida albicans. This study indicates that the molecular interaction of SA with PLX and the PLX micellization of CZ can improve the characteristics of CZ-loaded CA beads, which offer good potential for use as drug delivery systems or drug reservoirs in tablets for oral candidiasis.

Structure-Properties Relationship in the Evaluation of Alginic Acid Functionality for Tableting

The aim of this study is to investigate the relationship between the structural, molecular, and particulate properties of alginic acid and its functional characteristics in direct compression (tabletability, compressibility, elasticity, deformation mechanism, and disintegration ability). Therefore, accurate characterization of two different batches of alginic acid was executed (X-ray powder diffraction, Fourier-transform infrared spectroscopy, thermogravimetric analysis, scanning electronic microscopy, ¹H nuclear magnetic resonance, size exclusion chromatography - multi angle light scattering, viscosimetry, carboxylic acid titration, powder flowability, true density, laser granulometry). Results showed that molecular weight seems to affect tablet properties and that the alginic acid with the lowest molecular weight provides the hardest tablets with the lowest elastic recovery. Furthermore, these results show the potential interest of exploiting alginic acid as filler excipient in tablet formulation. Finally, disintegration properties of tested materials were found to be close to that of commercial superdisintegrants (Glycolys® and Kollidon Cl®) but not correlated to their swelling force. It can be concluded, for the first time, that the determination of alginic acid molecular weight seems key for applications in direct compression and in particular for obtaining tablets with reproducible strength.