In vitroandin vivostudies of ibuprofen-loaded biodegradable alginate beads

pH-responsive IPN beads of carboxymethyl konjac glucomannan and sodium carboxymethyl cellulose as a controlled release carrier for ibuprofen

The convergence of polymer and pharmaceutical sciences has advanced drug delivery systems significantly. Carbohydrate polymers, especially carboxymethylated ones, offer versatile benefits for pharmaceuticals. Interpenetrating polymer networks (IPNs) combine synthetic and natural polymers to enhance drug delivery. The study aims to develop IPN beads using sodium carboxymethyl cellulose (SCMC) and carboxymethyl konjac glucomannan (CMKGM) for controlled release of ibuprofen (IB) after oral administration. Objectives include formulation optimization, characterization of physicochemical properties, evaluation of pH-dependent swelling and drug release behaviors to advance biocompatible and efficient oral drug delivery systems. The beads were analyzed using SEM, FTIR, DSC, and XRD techniques. Different ratio of polymers (CMKGM:SCMS) and crosslinker concentrations (2&4 %w/v) were used, significantly impacting bead size, swelling, drug encapsulation, and release characteristics. DSC results indicated higher thermal stability in IPN beads compared to native polymers. XRD revealed IB dispersion within the polymer matrix. IPN beads size ranged from 580 ± 0.56 to 324 ± 0.27 μm, with a nearly spherical shape. IPN beads exhibited continuous release in alkaline conditions (pH 7.4) and minimal release in acidic media (pH 1.2). These findings suggest that the formulated IPN beads can modulate drug release in both acidic and alkaline environments, potentially mitigating the gastric adverse effects often associated with oral administration of IB.

Newly developed nano-biocomposite embedded hydrogel to enhance drug loading and modulated release of anti-inflammatory drug

A newly developed iron-based nano-biocomposite (nano Fe-CNB) impregnated alginate formulation (CA) is proposed to improve drug loading and exhibit pH-responsive behavior of model anti-inflammatory drug-ibuprofen for controlled release applications. The proposed formulation is investigated with conventional β-CD addition in CA. The nano Fe-CNB-based formulations with and without β-CD, (Fe-CNB β-CD CA and Fe-CNB CA) are compared with only CA and β-CD incorporated CA formulations. The results indicate the incorporation of nano-biocomposite or β-CD into CA enhances the drug loading (>40%). However, pH-responsive controlled release behavior is observed for nano Fe-CNB based formulations only. The release studies from Fe-CNB β-CD CA indicate ∼ 45% release in stomach pH (1.2) within 2 h. In contrast, Fe-CNB CA shows ∼20% release only in stomach pH and improved release (∼49%) at colon pH (7.4). The rheology and swelling studies indicate Fe-CNB CA remains intact in stomach pH with a minimal drug release, but it disintegrates at colon pH due to charge reversal behavior of nano-biocomposite and ionization of polymeric chains. Thus, Fe-CNB CA formulation is found to be a potential candidate for targeting colon delivery, inflammatory bowel disease, and post-operative conditions.

Encapsulation in alginate-polymers improves stability and allows controlled release of the UFV-AREG1 bacteriophage

The bacteriophage UFV-AREG1 was used as a model organism to evaluate the encapsulation via extrusion using different hydrocolloids. Pure alginate [0.75%, 1.0%, 1.5% and 2.0% (m/v)] and mixtures of alginate [0.75% or 1.0% (m/v)] with carrageenan [1.25% (m/v)], chitosan [0.5% (m/v)], or whey protein [1.5% (m/v)] were used to produce bacteriophage-loaded beads. The encapsulating solutions presented flow behavior of non-Newtonian pseudoplastic fluids and the concentration of hydrocolloid did not influence (p > 0.05) the morphology of the beads, except for alginate-chitosan solutions, which presented the higher flow consistency index (K) and the lower flow behavior index (n). The encapsulation efficiency was about 99% and the confocal photomicrography of the encapsulated bacteriophages labeled with fluorescein isothiocyanate showed homogenous distribution of the viral particles within the beads. The phages remained viable in the beads of alginate-whey protein even when submitted to pH 2.5 for 2 h. Beads incubated directly in simulated intestinal fluid (pH 6.8) resulted in a minimal of 50% release of the UFV-AREG1 phages after 5 min, even when previously submitted to the simulated gastric fluid (pH 2.5). Encapsulation enabled phages to remain viable under refrigeration for five months. Encapsulated UFV-AREG1 phages were sensitive to dehydration, suggesting the need for protective agents. In this study, for the first-time bacteriophages were encapsulated in alginate-carrageenan beads, as well as alginate-chitosan as a bead-forming hydrocolloid. In addition, a novel procedure for encapsulating bacteriophages in alginate-whey protein was proposed. The assembled system showed efficiency in the encapsulation of UFV-AREG1 bacteriophages using different hydrocolloids and has potential to be used for the entrapment of a variety of bioactive compounds.

Development and optimization of Fe3+-crosslinked sodium alginate-methylcellulose semi-interpenetrating polymer network beads for controlled release of ibuprofen

In this study, ionically crosslinked beads of sodium alginate (NaAlg) and methylcellulose (MC) were prepared as semi-interpenetrating polymer networks (semi-IPN) in the size range of 1.97 ± 0.09-1.22 ± 0.13 mm by crosslinking with FeCl₃ and loaded with ibuprofen (IBU), which is a nonsteroidal anti-inflammatory drug. The highest 93.33% entrapment efficiency of IBU was achieved, and the drug release behaviors, mean particle size, and entrapment efficiency of beads were investigated in terms of the polymer composition, a ratio of ibuprofen to polymer, exposure time to crosslinker, and concentration of the crosslinking agent. Semi-IPN formulations prepared were also characterized using Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), X-ray Diffraction (X-RD), and scanning electron microscopy (SEM). It was observed that IBU-loaded beads displayed better release performance with an increase amount of NaAlg in the structure. Finally, the optimum IBU release was obtained as 93.9% for beads containing 66.7% (w/w) NaAlg, 33.3% (w/w) MC, IBU/polymer ratio of 1/4, FeCl₃ concentration of 0.1 M, and crosslinking time of 90 min. The in vitro release rate was fitted to five empirical equations, and the diffusion exponent n, which indicated that the release mechanism of IBU from beads followed the Anomalous and Case II transport mechanism.

An Observational Study Evaluating the Introduction of a Prolonged-Release Protein Substitute to the Dietary Management of Children with Phenylketonuria

Dietary restriction of phenylalanine combined with a protein substitute prevents intellectual disability in patients with phenylketonuria (PKU). However, current protein substitutes are associated with low adherence owing to unpalatability and burdensome administration regimens. This prospective, observational acceptability study in children with PKU assessed the use of a prolonged-release protein substitute designed with an ethyl cellulose and arginate coating masking the bitter taste, smell and reducing the osmolarity of free amino acids. The study product was mixed with the subject’s food or drink and replaced ≥1 dose per day of the subject’s usual protein substitute for 7 days. Seven of 13 subjects were able to take their prescribed dose over the 7 day period. Most subjects mixed the test protein substitute with food or fruit juice. Reduced blood phenylalanine levels (n = 5) and improved phenylalanine/tyrosine ratio (n = 4) were recorded from baseline to Day 7, respectively. Four subjects reported fewer gastrointestinal symptoms compared to baseline. There were no cases of diarrhoea, constipation, bloating, nausea or vomiting. No adverse reactions were reported. In conclusion, the novel prolonged-release protein substitute was taken in a different way to a typical protein substitute and enabled satisfactory blood phenylalanine control. The study product was well tolerated; subjects experienced fewer gastrointestinal symptoms than with their previous treatment. Although the results of this pilot study provide reassuring data, longer-term studies evaluating adherence and blood phenylalanine control are necessary.

Alginate gel particles-A review of production techniques and physical properties

The application of hydrocolloid gel particles is potentially useful in food, chemical, and pharmaceutical industries. Alginate gel particles are one of the more commonly used hydrocolloid gel particles due to them being biocompatible, nontoxic, biodegradable, cheap, and simple to produce. They are particularly valued for their application in encapsulation. Encapsulation in alginate gel particles confers protective benefits to cells, DNA, nutrients, and microbes. Slow release of flavors, minerals, and drugs can also be achieved by encapsulation in gel particles. The particle size and shape of the gel particles are crucial for specific applications. In this review, current methods of producing alginate gel particles will be discussed, taking into account their advantages, disadvantages, scalability, and impact on particle size. The physical properties of alginate gel particles will determine the effectiveness in different application conditions. This review will cover the current understanding of the alginate biopolymer, gelation mechanisms and factors affecting release properties, gel strength, and rheology of the alginate gel particle systems.

Design and Concept of Polyzwitterionic Copolymer Microgel Drug Delivery Systems In Situ Loaded with Non-steroidal Anti-inflammatory Ibuprofen

Nowadays, the modern pharmaceutical investigations are directed toward obtaining of new polymer micro- and nano-sized drug delivery carriers. In this respect, the use of hydrogel carriers based on polyzwitterions (PZIs) is an opportunity in the preparation of polymer drug delivery systems with desired characteristics. This paper describes the synthesis and characterization of micro-structured p(VA-co-DMAPS) systems with different compositions in situ loaded with Ibuprofen by emulsifier-free emulsion copolymerization (EEC) in water. The mean size of the prepared microparticles was measured by SEM and particles have been visualized by AFM. The inclusion of Ibuprofen in the polyzwitterionic copolymer microgel systems was established by using DSC. In vitro drug release experiments were carried out in order to estimate the ability of the obtained microgels to modify the release of water-insoluble Ibuprofen.

In vitro and in vivo assessment of novel pH-sensitive interpenetrating polymer networks of a graft copolymer for gastro-protective delivery of ketoprofen

Novel pH-sensitive IPN microbeads exhibited drug release in response to changing pH and reduced side effects of ketoprofenin vivo.

Enzymatic Polymerization of an Ibuprofen-Containing Monomer and Subsequent Drug Release

Novel ibuprofen-containing monomers comprising naturally occurring and biocompatible compounds were synthesized and subsequently polymerized via enzymatic methods. Through the use of a malic acid sugar backbone, ibuprofen was attached as a pendant group, and then subsequently polymerized with a linear aliphatic diol (1,3-propanediol, 1,5-pentanediol, or 1,8-octanediol) as comonomer using lipase B from Candida antarctica, a greener alternative to traditional metal catalysts. Polymer structures were elucidated by nuclear magnetic resonance and infrared spectroscopies, and thermal properties and molecular weights were determined. All polymers exhibited sustained ibuprofen release, with the longer chain, more hydrophobic diols exhibiting the slowest release over the 30 d study. Polymers were deemed cytocompatible using mouse fibroblasts, when evaluated at relevant therapeutic concentrations. Additionally, ibuprofen retained its chemical integrity throughout the polymerization and in vitro hydrolytic degradation processes. This methodology of enzymatic polymerization of a drug presents a more environmentally friendly synthesis and a novel approach to bioactive polymer conjugates.

Ibuprofen microencapsulation within acrylamide-grafted chitosan and methylcellulose interpenetrating polymer network microspheres: Synthesis, characterization, and release studies

This study deals with the development of interpenetrating polymer network (IPN) microspheres of acrylamide (AAm) grafted onto a chitosan (CS) backbone and methylcellulose (MC). Chitosan-graft-polyacrylamide (CS-g-PAAm) was synthesized by cerium (IV) ammonium nitrate-induced free radical graft polymerization. The grafting percentage was found to be 50.58%. The synthesized graft copolymer and MC were used to prepare microspheres by the water-in-oil (w/o) emulsion-crosslinking method, and crosslinked with glutaraldehyde (GA) as drug delivery matrices of ibuprofen (IBU). The release of IBU from microspheres decreased when the amount of CS-g-PAAm in the polymer matrix and amount of crosslinker added were increased, while it increased with the increase of the IBU/polymer ratio.

Preparation and Evaluation of Mucoadhesive Beads/Discs of Alginate and Algino-Pectinate of Piroxicam for Colon-Specific Drug Delivery Via Oral Route

Background:

Objective:

Materials and Methods:

Results:

Conclusions:

Biodegradable polyesters containing ibuprofen and naproxen as pendant groups

Controlled release of nonsteroidal anti-inflammatory drugs such as ibuprofen and naproxen could be beneficial for the treatment of inflammatory diseases while reducing the side effects resulting from their continuous use. Novel biodegradable polyesters solely comprised of biocompatible components (e.g., tartaric acid, 1,8-octanediol, and ibuprofen or naproxen as pendant groups) have been synthesized using tin(II) 2-ethylhexanoate as catalyst at 130 °C and subsequently characterized to determine their structures and physicochemical properties. The polymers release the free drug (ibuprofen or naproxen) in vitro in a controlled manner without burst release, unlike the release rates achieved when the drugs are encapsulated in other polymers. These new biomaterials are not cytotoxic toward mouse fibroblasts up to 0.10 mg/mL. The drugs retain their chemical structure following hydrolytic degradation of the polymer, suggesting that bioactivity is preserved.

A novel impinging aerosols method for production of propranolol hydrochloride-loaded alginate gel microspheres for oral delivery

Propranolol hydrochloride was directly encapsulated in alginate gel microspheres (40-50 µm in diameter) using a novel method involving impinging aerosols of CaCl(2) cross-linking solution and sodium alginate solution containing the drug. Microspheres formulated using 0.1 M CaCl(2) exhibited the highest drug loading (14%, w/w of dry microspheres) with 66.5% encapsulation efficiency. Less than 4% and 35% propranolol release occurred from hydrated and dried microspheres, respectively, in 2 h in simulated gastric fluid (SGF). The majority of the drug load (90%) was released in 5 and 7 h from hydrated and dried microspheres, respectively, in simulated intestinal fluid (SIF). Prior incubation of hydrated microspheres (cross-linked using 0.5 M CaCl(2)) in SGF prolonged the time of release in SIF to 10 h, which has implications for the design of protocols and correlation with in vivo release behaviour. Restricted propranolol release in SGF and complete extraction in SIF demonstrate the potential of alginate gel microspheres for oral delivery of pharmaceuticals.

pH-responsive interpenetrating network hydrogel beads of poly(acrylamide)-g-carrageenan and sodium alginate for intestinal targeted drug delivery: synthesis, in vitro and in vivo evaluation

In the present work, we synthesized pH-responsive interpenetrating network (IPN) hydrogel beads of polyacrylamide grafted κ-carrageenan (PAAm-g-CG) and sodium alginate (SA) for targeting ketoprofen to the intestine. The PAAm-g-CG was synthesized by free radical polymerization followed by alkaline hydrolysis under nitrogen gas. The PAAm-g-CG was characterized by elemental analysis, FTIR spectroscopy and thermogravimetric analysis (TGA). The drug-loaded IPN hydrogel beads were prepared by simple ionotropic gelation/covalent crosslinking method. The amorphous nature of drug in the beads was confirmed by differential scanning calorimetry and X-ray diffraction studies. The spherical shape of the beads was confirmed by scanning electron microscopic analysis. The beads exhibited ample pH-responsive behavior in the pulsatile swelling study. The ketoprofen release was significantly increased when pH of the medium was changed from acidic to alkaline. The beads showed maximum of 10% drug release in acidic medium of pH 1.2, and about 90% drug release was recorded in alkaline medium of pH 7.4. Stomach histopathology of albino rats indicated that the prepared beads were able to retard the drug release in stomach leading to the reduced ulceration, hemorrhage and erosion of gastric mucosa.

Design and characterization of sustained release ketoprofen entrapped carnauba wax microparticles

CONTEXT

Ketoprofen is a non-steroid anti-inflammatory drug (NSAID) used in the treatment of rheumatic diseases and in mild to moderate pain. Ketoprofen has a short biological half-life and the commercially available conventional release formulations require dosages to be administered at least 2-3 times a day. Due to these characteristics, ketoprofen is a good candidate for the preparation of controlled release formulations.

OBJECTIVES

In this work, a multiparticulate-sustained release dosage form containing ketoprofen in a carnauba wax matrix was developed.

METHODS

Particles were prepared by an emulsion congealing technique. System variables were optimized using fractional factorial and response surface experimental design. Characterization of the particles included size and morphology, flow rate, drug loading and in vitro drug release.

RESULTS

Spherical particles were obtained with high drug load and sustained drug release profile. The optimized particles had an average diameter of approximately 200 µm, 50% (w/w) drug load, good flow properties and prolonged ketoprofen release for more than 24 h.

CONCLUSIONS

Carnauba wax microspheres prepared in this work represent a new multiparticulate-sustained release system for the NSAID ketoprofen, exhibiting good potential for application in further pharmaceutical processes.

Gastroretentive drug delivery system of acyclovir-loaded alginate mucoadhesive microspheres: formulation and evaluation

In the present study, mucoadhesive alginate microspheres of acyclovir were prepared to prolong the gastric residence time using a simple emulsification phase separation technique. The particle size of drug-loaded formulations was measured by SEM and the particle size distribution was determined using an optical microscope and mastersizer. The release profile of acyclovir from microspheres was examined in simulated gastric fluid (SGF pH 1.2). The particles were found to be discreet and spherical with the maximum particles of an average size (70.60 ± 2.44 µm). The results indicated that the mean particle size of the microspheres increased with an increase in the concentration of polymer and decreased with increase in stirring speed. The entrapment efficiency was found to be in the range of 51.42-80.46%. The concentration of the calcium chloride (% w/v) of 10% and drug-polymer ratio of 1:4 resulted in an increase in the entrapment efficiency and the extent of drug release. The optimized alginate microspheres were found to possess good mucoadhesion (66.42 ± 1.01%). The best fit model with the highest regression coefficient values (R²) was predicted by Peppas model (0.9813). In Gamma scintigraphy analysis, the section of GIT was critically analyzed and much differentiation was present at each time point after oral administration, which revealed that the optimized formulation demonstrated gastroretention in vivo for more than 4 h, which revealed that optimized formulation could be a good choice for gastroretentive systems.

Adipic acid dihydrazide treated partially oxidized alginate beads for sustained oral delivery of flurbiprofen

In this study, periodate oxidation of sodium alginate was controlled such that the oxidized alginate could form isolatable beads with Ca(+2) ions. The beads of oxidized alginate having a degree of oxidation 1 mol%, entrapped 89% flurbiprofen and released almost all of its content within 1.5 h in pH 7.2 phosphate buffer solution. The beads were covalently crosslinked with adipic dihydrazide (ADH) in addition to ionic crosslinks and were characterized. Scanning electron microscopy revealed that the beads were spherical having smooth surfaces. The drug entrapment efficiency decreased (90-86%) with increasing concentration of ADH (2-6% w/v) in the gelation medium. However, the beads prolonged the drug release in alkaline dissolution medium up to 8 h depending upon the concentration of ADH. The beads prepared with 2% ADH swelled more rapidly and led to faster drug release in either pH 1.2 HCl solution or pH 7.2 phosphate buffer solution. The swelling tendencies were reduced and the drug release became slower with higher concentrations in either fluid. The drug diffusion from the beads followed super case II transport mechanism. FTIR spectroscopy indicated stable nature of flurbiprofen in the beads and therefore had potential as sustained oral delivery system for the drug.

Studies on mefenamic acid microparticles: formulation, in vitro release, and in situ studies in rats

In this study, we investigated the in vitro characteristics of mefenamic acid (MA) microparticles as well as their effects on DNA damage. MA-loaded chitosan and alginate beads were prepared by the ionotropic gelation process. Microsponges containing MA and Eudragit RS 100 were prepared by quasi-emulsion solvent diffusion method. The microparticles were characterized in terms of particle size, surface morphology, encapsulation efficiency, and in vitro release profiles. Most of the formulation variables manifested an influence on the physical characteristics of the microparticles at varying degrees. We also studied the effects of MA, MA-loaded microparticles, and three different polymers on rat brain cortex DNA damage. Our results showed that DNA damage was higher in MA-loaded Eudragit microsponges than MA-loaded biodegradable chitosan or alginate microparticles.

Hydrogels of Dextran Containing Nonsteroidal Anti-Inflammatory Drugs as Pendant Agents

The oral administration of nonsteroidal anti-inflammatory drugs (NSAIDs) is often associated with upper gastrointestinal tract side effects. To reduce these effects and improve the therapeutic efficacy, NSAIDs are often formulated as controlled release systems. We have prepared a new formulation consisting of dextran hydrogels containing NSAIDs as pendant agents, through ultraviolet irradiation of solutions of dextran functionalized with methacrylic groups in the presence of the drug derivatized in the same way. Release studies of different drugs from this system, carried out in media simulating the gastrointestinal tract, have demonstrated that the amount of released drug is strictly related to the concentration of the polymer in the solution submitted to irradiation as well as to its derivatization degree. Our obtained data confirm that the system is able to realize a colon-specific drug delivery.

Enhancing drug incorporation into tetracycline-loaded chitosan microspheres for periodontal therapy

PURPOSE

To identify optimal formulation parameters for enhancing the incorporation of tetracycline hydrochloride into chitosan microspheres for periodontal therapy.

METHODS

Tetracycline-loaded chitosan microspheres were prepared by ionotropic gelation. Various formulation parameters (salt form of drug, aqueous phase pH, anion structure, inorganic salts and electrolytes, preparation method) were investigated for their influence on drug incorporation efficiency. Microspheres were assessed in terms of drug entrapment and content, microsphere recovery, particle size and morphology.

RESULTS

Although drug incorporation efficiency was increased marginally, the use of a dihydrate form of the drug was not considered feasible due to the lowered microsphere recovery and higher costs. A decrease in the aqueous pH from 9 to 6 enhanced drug incorporation efficiency without an adverse effect on microsphere morphology. The use of inorganic salts/electrolytes and other approaches of microsphere preparation did not significantly enhance drug incorporation efficiency and these approaches also adversely affected microsphere morphology. The ionotropic preparation method in terms of the drug loading technique significantly affected drug incorporation efficiencies.

CONCLUSIONS

This study has shown that formulation variables can be exploited in order to enhance the incorporation of a water soluble drug into chitosan microspheres using the ionotropic gelation technique. Based on a comparison of all results obtained with the different approaches, the modification of the aqueous phase to pH 6 was identified as the most feasible approach.

Sulindac loaded alginate beads for a mucoprotective and controlled drug release

Ionotropic gelation was used to entrap sulindac into calcium alginate beads as a potential drug carrier for the oral delivery of this anti-inflammatory drug. Beads were investigated in vitro for a possible sustained drug release and their use in vivo as a gastroprotective system for sulindac. Process parameters such as the polymer concentration, polymer/drug ratio, and different needle diameter were analysed for their influences on the bead properties. Size augmented with increasing needle diameter (0.9 mm needle: 1.28 to 1.44 mm; 0.45 mm needle: 1.04 to 1.07 mm) due to changes in droplet size as well as droplet viscosity. Yields varied between 87% and 98% while sulindac encapsulation efficiencies of about 88% and 94% were slightly increasing with higher alginate concentrations. Drug release profiles exhibited a complete release for all formulations within 4 hours with a faster release for smaller beads. Sulindac loaded alginate beads led to a significant reduction of macroscopic histological damage in the stomach and duodenum in mice. Similarly, microscopic analyses of the mucosal damage demonstrated a significant mucoprotective effect of all bead formulation compared to the free drug. The present alginate formulations exhibit promising properties of a controlled release form for sulindac; meanwhile they provide a distinct tissue protection in the stomach and duodenum.

Theoretical and experimental investigations on the size of alginate microspheres prepared by dropping and spraying

In order to produce functional microspheres with different ranges of sizes for various applications, the size of alginate droplets prepared by dropping and spraying was studied. It was shown that the mean diameter could be controlled by liquid flow velocity and applied voltage as operating parameters using a conventional dropping and an electrostatic dropping method, separately. The formation mechanism of alginate droplets could be categorized into two different modes: Dripping mode and jetting mode. By employing an effective force analysis, the diameters in each modes showed to be well agreed with the numerical simulation within 7% deviations. It was testified that the initial amount of surface charges had a high impact on droplet diameter and the liquid flow velocity played a more important role on mean diameter of alginate droplets by electrostatic dropping method in dripping mode than in jetting mode. Then, an empirical equation and a semi-empirical model were used to simulate the diameter of droplets obtained by spraying and spraying with electrostatic field (SEF) method, respectively. The decrease in diameter was more sensitive to the increase of gas flow rate than to the decrease of liquid flow rate, and the results of two models fitted well with experimental values. The simulations showed that SEF yielded a 20% lower on droplet diameter than simple spraying method.