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

Insights from Syzygium aromaticum Essential Oil: Encapsulation, Characterization, and Antioxidant Activity

Alginate encapsulates loaded with clove essential oil (CEO) were prepared by ionic gelation, with subsequent freeze-drying. The objective of the present work was to develop a product with the ability to protect CEO against its easy volatility and oxidation. The following techniques were used to characterize the formulations: eugenol release, degree of swelling, GC/MS, TGA/DSC, and SEM. The alginate solution (1.0%) containing different concentrations of CEO (LF1: 1.0%; LF2: 0.5%; LF3: 0.1%) was dropped into a 3.0% CaCl2 solution. After lyophilization, the encapsulated samples were wrinkled and rigid, with high encapsulation power (LF3: 76.9% ± 0.5). Three chemical components were identified: eugenol (the major one), caryophyllene, and humulene. The antioxidant power (LF1: DPPH IC50 18.1 µg mL-1) was consistent with the phenol content (LF1: 172.2 mg GAE g-1). The encapsulated ones were thermally stable, as shown by analysis of FTIR peaks, eugenol molecular structure was kept unaltered. The degree of swelling was 19.2% (PBS). The release of eugenol (92.5%) in the PBS solution was faster than in the acidic medium. It was concluded that the low-cost technology used allows the maintenance of the content and characteristics of CEO in the three concentrations tested, offering a basis for further research with essential oil encapsulates.

Preparation and Investigation of a Nanosized Piroxicam Containing Orodispersible Lyophilizate

Non-steroidal anti-inflammatory piroxicam (PRX) is a poorly water-soluble drug that provides relief in different arthritides. Reducing the particle size of PRX increases its bioavailability. For pediatric, geriatric, and dysphagic patients, oral dispersible systems ease administration. Moreover, fast disintegration followed by drug release and absorption through the oral mucosa can induce rapid systemic effects. We aimed to produce an orodispersible lyophilizate (OL) consisting of nanosized PRX. PRX was solved in ethyl acetate and then sonicated into a poloxamer-188 solution to perform spray-ultrasound-assisted solvent diffusion-based nanoprecipitation. The solid form was formulated via freeze drying in blister sockets. Mannitol and sodium alginate were applied as excipients. Dynamic light scattering (DLS) and nanoparticle tracking analysis (NTA) were used to determine the particle size. The morphology was characterized by scanning electron microscopy (SEM). To establish the crystallinity, X-ray powder diffraction (XRPD) and differential scanning calorimetry (DSC) were used. A disintegration and in vitro dissolution test were performed. DLS and NTA presented a nanosized PRX diameter. The SEM pictures showed a porous structure. PRX became amorphous according to the XRPD and DSC curves. The disintegration time was less than 1 min and the dissolution profile improved. The final product was an innovative anti-inflammatory drug delivery system.

Captopril Polyvinyl Alcohol/Sodium Alginate/Gelatin-Based Oral Dispersible Films (ODFs) with Modified Release and Advanced Oral Bioavailability for the Treatment of Pediatric Hypertension

Hypertension can begin in childhood; elevated blood pressure in children is known as pediatric hypertension. Contrary to adult hypertension, there is a scarcity of commercial medications suitable for the treatment of pediatric hypertension. The aim of this study was to develop orally dispersible films (ODFs) loaded with captopril for the treatment of hypertension in children. Captopril-loaded ODFs were composed of different blends of synthetic polymers, such as polyvinyl alcohol (PVA) and polyvinyl pyrrolidone, and natural polymers, such as sodium alginate (SA) and gelatin. The ODFs were characterized based on their mechanical and thermal properties, drug content, surface morphology, in vitro disintegration, in vitro release, and bioavailability. A novel HPLC method with precolumn derivatization was developed to precisely and selectively determine captopril levels in plasma. A low concentration of PVA and a high concentration of SA generated ODFs with faster hydration and disintegration rates. SA-based films exhibited fast disintegration properties (1-2 min). The optimized modified-release film (F2) showed significant (p < 0.05) enhancement in bioavailability (AUC = 1000 ng min/mL), with a value 1.43 times that of Capoten® tablets (701 ng min/mL). While the plasma concentration peaking was in favor of the immediate-release tablet, Tmax was significantly prolonged by 5.4 times for the optimized ODF (3.59 h) compared with that of the tablets (0.66 h). These findings indicate uniform and sustained plasma concentrations, as opposed to the pulsatile and rapid plasma peaking of captopril from the immediate-release tablets. These findings suggest that the modified release of oral films could offer more favorable plasma profiles and better control of hypertension than the conventional release tablets.

Natural Gums in Drug-Loaded Micro- and Nanogels

Gums are polysaccharide compounds obtained from natural sources, such as plants, algae and bacteria. Because of their excellent biocompatibility and biodegradability, as well as their ability to swell and their sensitivity to degradation by the colon microbiome, they are regarded as interesting potential drug carriers. In order to obtain properties differing from the original compounds, blends with other polymers and chemical modifications are usually applied. Gums and gum-derived compounds can be applied in the form of macroscopic hydrogels or can be formulated into particulate systems that can deliver the drugs via different administration routes. In this review, we present and summarize the most recent studies regarding micro- and nanoparticles obtained with the use of gums extensively investigated in pharmaceutical technology, their derivatives and blends with other polymers. This review focuses on the most important aspects of micro- and nanoparticulate systems formulation and their application as drug carriers, as well as the challenges related to these formulations.

Poly(lactic acid) based Pearl Layer Moistureproof Membrane for Flexible Laminated Packaging

The development of bio-based polymer materials, such as polylactic acid (PLA) -based polymers, is an effective strategy to reduce dependence on petrochemical-based polymers. However, the preparation of bio-based polymers with high barrier properties is a major challenge. To overcome this challenge, a nacreous layer structure with a ' brick and mud ' pattern is mimicked to improve the overall performance of the material. In this paper, Poly (_L -lactic acid) (PLLA) and Polypropylene Glycol (PPG) was combined to prepare bio-based polyurethane (PU-PLLA), which is used as the slurry structure of nacreous layer. The bio-based biomimetic composite membrane (PU-PLLA/BN) is then obtained by adding boron nitride (BN, brick structure of pearl layer) to it. The water vapor permeability test results show that the permeability of PU-PLLA material can be reduced by more than 50% by 5 wt.% BN, which is because the addition of BN can increase the length and tortuosity of the gas molecular diffusion path in the composite. Therefore, this pearl-inspired PU-PLLA/BN film has excellent moisture resistance, which opens up a broad road for the practical application of PLLA in flexible laminated packaging.

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.

Sodium alginate and Naloxone loaded macrophage-derived nanovesicles for the treatment of spinal cord injury

Spinal cord injury (SCI) causes Ca²⁺ overload, which can lead to inflammation and neuronal apoptosis. In this study, we prepared a nanovesicle derived from macrophage membrane (MVs), which encapsulated sodium alginate (SA) and naloxone (NAL) to inhibit inflammation and protect neurons by reducing the free Ca²⁺concentration at the SCI site. Based on the transmission electron microscopy (TEM) image, the encapsulated sample (NAL–SA–MVs) had a particle size of approximately 134 ± 11 nm and exhibited a sustained release effect. The encapsulation rate of NAL and SA was 82.07% ± 3.27% and 72.13% ± 2.61% in NAL–SA–MVs, respectively. Targeting tests showed that the NAL–SA–MVs could accumulate in large quantities and enhance the concentration of SA and NAL at the lesion sites. In vivo and in vitro studies indicated that the NAL–SA–MVs could decrease the concentration of free Ca²⁺, which should further alleviate the inflammatory response and neuronal apoptosis. Anti-inflammation results demonstrated that the NAL–SA–MVs could reduce the pro-inflammation factors (iNOS, TNF-α, IL-1β, IL-6) and increase the expression of anti-inflammation factors (IL-10) at the cell and animal level. Concurrently, fluorescence, flow cytometry and western blot characterization showed that the apoptotic condition of the neurons was significantly inhibited. In addition, the motor function of C57 mice were significantly improved after NAL–SA–MVs treatment. In conclusion, it is suggested that the NAL–SA–MVs has tremendous potential in the treatment of SCI.

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.