Alginate microspheres obtained by the spray drying technique as mucoadhesive carriers of ranitidine

Contemporary Aspects of Designing Marine Polysaccharide Microparticles as Drug Carriers for Biomedical Application

The main goal of modern pharmaceutical technology is to create new drug formulations that are safer and more effective. These formulations should allow targeted drug delivery, improved drug stability and bioavailability, fewer side effects, and reduced drug toxicity. One successful approach for achieving these objectives is using polymer microcarriers for drug delivery. They are effective for treating various diseases through different administration routes. When creating pharmaceutical systems, choosing the right drug carrier is crucial. Biomaterials have become increasingly popular over the past few decades due to their lack of toxicity, renewable sources, and affordability. Marine polysaccharides, in particular, have been widely used as substitutes for synthetic polymers in drug carrier applications. Their inherent properties, such as biodegradability and biocompatibility, make marine polysaccharide-based microcarriers a prospective platform for developing drug delivery systems. This review paper explores the principles of microparticle design using marine polysaccharides as drug carriers. By reviewing the current literature, the paper highlights the challenges of formulating polymer microparticles, and proposes various technological solutions. It also outlines future perspectives for developing marine polysaccharides as drug microcarriers.

Chitosan-coated alginate (CCA) nanoparticles for augmentation of topical antihistaminic activity of diphenhydramine: in-vitro optimization, skin histopathology and pharmacodynamic studies with in vitro/in vivo correlation

OBJECTIVE

The aim of the present study was to formulate chitosan-coated alginate nanoparticles containing the drug diphenhydramine hydrochloride (DHH).

SIGNIFICANCE

Diphenhydramine hydrochloride (DHH) is the prototype of H₁-antihistaminic drugs. It is a lipophilic drug, that easily crosses the blood-brain barrier when taken orally causing decrements in alertness and performance. Multiple applications of topical drug product are required. Thus, drug incorporation in nanocarriers would increase the skin penetration powers increasing the drug efficacy.

METHODS

Chitosan coated alginate (CCA) nanoparticles were prepared via polyelectrolyte complex technique adopting 2³ full factorial design. Three factors, namely, alginate concentration, drug to alginate ratio and CaCl₂ volume, each in two levels were studied. The prepared formulae were evaluated utilizing entrapment efficiency (EE), particle size (PS), polydispersity index (PDI), zeta potential (ZP) and in vitro release. Characterization process was then followed by optimization.

RESULTS

At alginate conc. of 1%, drug to alginate ratio of 2:1 and CaCl₂ volume of 4 mL, NP8 was chosen as a candidate formula. Histopathological examination on shaved rat dorsal skin disclosed the safety of NP8 with no signs of necrosis or even inflammation. The enhanced topical delivery of diphenhydramine hydrochloride enclosed in the developed nanoparticles was further proved by induction of allergic reaction using intradermal histamine injection. The results revealed the superior ability of NP8 to decrease the diameter of the formed wheal in comparison to marketed DHH product.

CONCLUSION

Thus, CCA nanoparticles are considered as a candidate nanocarriers for fortifying the topical antihistaminic activity of DHH.

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

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

Alginates Combined with Natural Polymers as Valuable Drug Delivery Platforms

Alginates (ALG) have been used in biomedical and pharmaceutical technologies for decades. ALG are natural polymers occurring in brown algae and feature multiple advantages, including biocompatibility, low toxicity and mucoadhesiveness. Moreover, ALG demonstrate biological activities per se, including anti-hyperlipidemic, antimicrobial, anti-reflux, immunomodulatory or anti-inflammatory activities. ALG are characterized by gelling ability, one of the most frequently utilized properties in the drug form design. ALG have numerous applications in pharmaceutical technology that include micro- and nanoparticles, tablets, mucoadhesive dosage forms, wound dressings and films. However, there are some shortcomings, which impede the development of modified-release dosage forms or formulations with adequate mechanical strength based on pure ALG. Other natural polymers combined with ALG create great potential as drug carriers, improving limitations of ALG matrices. Therefore, in this paper, ALG blends with pectins, chitosan, gelatin, and carrageenans were critically reviewed.

Spray drying as an efficient route for synthesis of silica nanoparticles-sodium alginate biohybrid drug carrier of doxorubicin

Biohybrids (a combination of biological material and inorganic nanoparticles) offer a number of advantages like improved functionality over conventional materials.Thus, to understand the practical application of biohybrids as drug carriers, a biohybrid drug carrier of colloidal silica nanoparticles (NP)-sodium alginate loaded with doxorubicin (Dox-biohybrid) was synthesized by evaporation induced self-assembly (EISA) using spray drying technique. Further, the morphology, size and interactions between various components of the biohybrid were studied through SEM, DLS and FTIR techniques. The drug loading efficiency, release profile, cellular uptake and cytotoxicity of Dox-biohybrid was investigated and compared with free Dox. The drug loading efficiencies of Dox-biohybrid, Dox-silica NP and Dox-sodium alginate were 93.7 %, 96.4 % and 88.3 % respectively. In vitro release study showed a slow release of entrapped Dox from Dox-biohybrid as compared to other carriers. This release was also pH-responsive with significantly higher cumulative drug release at pH 5.5 (cancer microenvironment) in comparison to pH 7.4 (physiological conditions). The empty biohybrid carrier did not show cytotoxicity to normal mouse lymphocytes upto a concentration of 25 μg/mL which was used further. The uptake of Dox from Dox-biohybrid by A549 cells was more than 2fold as compared to uptake from free Dox. in vitro viability assay revealed that treatment of lung carcinoma A549 cells with Dox-biohybrid resulted in 50 % loss of cell viability at 500 nM, compared to only 12 % loss with free Dox. Thus, we report the synthesis of a novel biohybrid drug delivery system by means of spray drying process that has promising applications in cancer treatment.

In vivo anti-inflammatory and anti-allergic activities of cynaroside evaluated by using hydrogel formulations

OBJECTIVES

Cynaroside (CYN) is the predominant derivative of luteolin in aerial parts of Bidens tripartita which has been used in folk medicine as a diaphoretic, diuretic, antiseptic and anti-inflammatory agent. In our study, alginate (ALG), which is an anionic polymer with bioadhesive properties, was used as a CYN carrier, and multiple hydrogel formulations were created. Additionally, the present study evaluated the in vivo anti-inflammatory and anti-allergic activities of all preparations.

METHODS

Novel gel formulations as topical carriers for CYN obtained from B. tripartita were developed and characterized. The bioadhesive properties of the designed preparations were also evaluated in an ex vivo model using the skin of hairless mice. In vitro CYN release from all formulations was examined and analysed by HPLC. Histopathological evaluation of mouse skin sections stained with H&E after carrageenan and oxazolone administration was also carried out. In addition, the influence of CYN on cell proliferation was examined by the PCNA staining method.

RESULTS

The results showed that 10 % CYN inhibited the release of anti-inflammatory mediators, and both tested concentrations, which included 5 % and 10 % (2 mg and 20 mg CYN per site, respectively), reduced oxazolone-induced ear swelling. Histopathological examination of the samples revealed a marked reduction in paw skin and ear tissue inflammation and in inflammatory infiltrates. The influence of CYN on cell proliferation was examined by the PCNA staining method, and the staining and distribution of PCNA-immunoreactive (PCNA-IR) cells were observed. After the application of the 5 % and 10 % hydrogels, the investigated samples showed decreased nuclear immunoreactivity to PCNA, which was similar to that of the control. Moreover, after application of the placebo formulation, fewer PCNA-IR cells were also observed.

CONCLUSION

The obtained data suggest that the topical application of CYN significantly reduces the number of T cells, mast cells and histiocytes in mouse skin with inflammation or atopic dermatitis.

Mucoadhesive improvement of alginate microspheres as potential gastroretentive delivery carrier by blending with Bletilla striata polysaccharide

As polysaccharide from Bletilla striata (BSP) was anticipated with mucoadhesive improvement in sodium alginate (SA) microspheres, BSP was mixed with SA to construct a composite microsphere to retain in the gastrointestinal tract for a long time. The morphological properties, particle size and thermodynamic properties of the microspheres in combination with comprehensive evaluations in the swelling properties, mucin adsorption, ex vivo and in vivo gastric retention were determined to characterize the mucoadhesion of SA-BSP blend microspheres. Results showed that the prepared microspheres were discrete and spherical. The addition of BSP increased flexibility and reduced rigidity of SA microsphere. Furthermore, the swelling property, mucin adsorption ability and the retention rate on the gastric mucosa of SA matrix were increased after blending with BSP. Mucoadhesion tests showed the SA-BSP microspheres stayed much longer in rats' stomach than the SA microsphere did. Above all, the SA-BSP microspheres with the enhanced mucoadhesion suggested being a potential drug carrier in developing the gastroretentive drug delivery system.

Applications of alginate microspheres in therapeutics delivery and cell culture: Past, present and future

Polymers are the backbone of pharmaceutical drug delivery. There are several polymers with varying properties available today for use in different pharmaceutical applications. Alginate is widely used in biomedical research due to its attractive features such as biocompatibility, biodegradability, inertness, low cost, and ease of production and formulation. Encapsulation of therapeutic agents in alginate/alginate complex microspheres protects them from environmental stresses, including the acidic environment in the gastro-intestinal tract (GIT) and enzymatic degradation, and allows targeted and sustained delivery of the agents. Microencapsulation is playing an increasingly important role in drug delivery as evidenced by the recent surge in research articles on the use of alginate in the delivery of small molecules, cells, bacteria, proteins, vaccines, and for tissue engineering applications. Formulation of these alginate microspheres (AMS) are commonly achieved by conventional external gelation method using various instrumental manipulation such as vortexing, homogenization, ultrasonication or spray drying, and each method affects the overall particle characteristics. In this review, an inclusive summary of the currently available methods for the formulation of AMS, its recent use in the encapsulation and delivery of therapeutics, and future outlook will be discussed.

Microencapsulation of Rhizobium leguminosarum bv. trifolii with guar gum: Preliminary approach using spray drying

Rhizobium leguminosarum bv trifolii strains TA1 and CC275e have been widely used as effective nitrogen fixing strains for white clover in New Zealand, but rhizobia survival on seeds is usually poor due to different stress conditions. The aim of this study was to select one of those commercial strains grown in a solid carrier (core) and study the influence of the core:polymer ratio in a microencapsulation process by spray drying using guar gum as coating material. First, strains TA1 and CC275e grown on peat and diatomaceous earth were exposed to temperature and desiccation stress. Both strains were stable at 40 °C and completely died after five minutes at 80 °C, while CC275e was more stable than TA1 at 60 °C. TA1 and CC275e slightly decreased viability after six hours drying with either carriers, with no differences between strains. A central composite design was used to develop the microencapsulation process. Independent variables were: inlet temperature (130 °C) and feed flow rate (5 mL/min). Microparticles presented rhizobia loading in 10⁷ CFU/g and mean particle size between 10 and 30 μm. Optimized process reached 50% yield and 10⁷ CFU/g loading. Rhizobia viability dropped two logarithmic units during the microencapsulation/drying process, possibly due to the negative effects of dehydration and high outlet temperature (≈70 °C), suggesting the need to continue optimizing the process by improving the thermal profile in the drying chamber.

Production, deformation and mechanical investigation of magnetic alginate capsules

In this article we investigated the deformation of alginate capsules in magnetic fields. The sensitivity to magnetic forces was realised by encapsulating an oil in water emulsion, where the oil droplets contained dispersed magnetic nanoparticles. We solved calcium ions in the aqueous emulsion phase, which act as crosslinking compounds for forming thin layers of alginate membranes. This encapsulating technique allows the production of flexible capsules with an emulsion as the capsule core. It is important to mention that the magnetic nanoparticles were stable and dispersed throughout the complete process, which is an important difference to most magnetic alginate-based materials. In a series of experiments, we used spinning drop techniques, capsule squeezing experiments and interfacial shear rheology in order to determine the surface Young moduli, the surface Poisson ratios and the surface shear moduli of the magnetically sensitive alginate capsules. In additional experiments, we analysed the capsule deformation in magnetic fields. In spinning drop and capsule squeezing experiments, water droplets were pressed out of the capsules at elevated values of the mechanical load. This phenomenon might be used for the mechanically triggered release of water-soluble ingredients. After drying the emulsion-filled capsules, we produced capsules, which only contained a homogeneous oil phase with stable suspended magnetic nanoparticles (organic ferrofluid). In the dried state, the thin alginate membranes of these particles were rather rigid. These dehydrated capsules could be stored at ambient conditions for several months without changing their properties. After exposure to water, the alginate membranes rehydrated and became flexible and deformable again. During this swelling process, water diffused back in the capsule. This long-term stability and rehydration offers a great spectrum of different applications as sensors, soft actuators, artificial muscles or drug delivery systems.

Original research paper. Characterization and taste masking evaluation of microparticles with cetirizine dihydrochloride and methacrylate-based copolymer obtained by spray drying

Taste of a pharmaceutical formulation is an important parameter for the effectiveness of pharmacotherapy. Cetirizine dihydrochloride (CET) is a second-generation antihistamine that is commonly administered in allergy treatment. CET is characterized by extremely bitter taste and it is a great challenge to successfully mask its taste; therefore the goal of this work was to formulate and characterize the microparticles obtained by the spray drying method with CET and poly(butyl methacrylate-co-(2-dimethylaminoethyl) methacrylate-co-methyl methacrylate 1:2:1 copolymer (Eudragit E PO) as a barrier coating. Assessment of taste masking by the electronic tongue has revealed that designed formulations created an effective taste masking barrier. Taste masking effect was also confirmed by the in vivo model and the in vitro release profile of CET. Obtained data have shown that microparticles with a drug/polymer ratio (0.5:1) are promising CET carriers with efficient taste masking potential and might be further used in designing orodispersible dosage forms with CET.

Novel Spray Dried Glycerol 2-Phosphate Cross-Linked Chitosan Microparticulate Vaginal Delivery System-Development, Characterization and Cytotoxicity Studies

Chitosan microparticulate delivery systems containing clotrimazole were prepared by a spray drying technique using glycerol 2-phosphate as an ion cross-linker. The impact of a cross-linking ratio on microparticle characteristics was evaluated. Drug-free and drug-loaded unmodified or ion cross-linked chitosan microparticles were examined for the in vitro cytotoxicity in VK2/E6E7 human vaginal epithelial cells. The presence of glycerol 2-phosphate influenced drug loading and encapsulation efficacy in chitosan microparticles. By increasing the cross-linking ratio, the microparticles with lower diameter, moisture content and smoother surface were observed. Mucoadhesive studies displayed that all formulations possessed mucoadhesive properties. The in vitro release profile of clotrimazole was found to alter considerably by changing the glycerol 2-phosphate/chitosan ratio. Results from cytotoxicity studies showed occurrence of apoptotic cells in the presence of chitosan and ion cross-linked chitosan microparticles, followed by a loss of membrane potential suggesting that cell death might go through the mitochondrial apoptotic pathway.

Alginate: Current Use and Future Perspectives in Pharmaceutical and Biomedical Applications

Over the last decades, alginates, natural multifunctional polymers, have increasingly drawn attention as attractive compounds in the biomedical and pharmaceutical fields due to their unique physicochemical properties and versatile biological activities. The focus of the paper is to describe biological and pharmacological activity of alginates and to discuss the present use and future possibilities of alginates as a tool in drug formulation. The recent technological advancements with using alginates, issues related to alginates suitability as matrix for three-dimensional tissue cultures, adjuvants of antibiotics, and antiviral agents in cell transplantation in diabetes or neurodegenerative diseases treatment, and an update on the antimicrobial and antiviral therapy of the alginate based drugs are also highlighted.