Drug-loaded Chitosan Microspheres Research Articles

Preparation of drug-loaded chitosan microspheres repair materials.

With the development of society and the progress of science and technology, microspheres, as a new polymer material, have been applied to all aspects of human beings. Microspheres can play a huge role in food safety, electronic technology, sewage treatment, biomedicine, etc., and are non-toxic or harmless. There are three main types of substrates for the preparation of microspheres: natural polymers, semi-synthetic polymer materials, and synthetic polymer materials. In this study, the inorganic material kaolin was modified by the emulsification-crosslinking method with chitosan and composite microspheres with large interlayer spacing were prepared, which were characterized by Fourier Transform Ioncyclotron Resonancel (FTIR) analysis and Scanning Electron Microscope (SEM). The prepared kaolin/chitosan microspheres were then placed in different amounts of aspirin and the optimal dose was investigated by encapsulation efficiency and drug loading rate. The drug release rate of 0.5 h, 1 h, 1.5 h, 2 h, 4 h, 6 h, and 12 h was then determined by simulating the human colon to determine the performance of the sustained-release drug. The experimental results showed that after the prepared composite microspheres were loaded with aspirin drug, we got the optimal dosage of 0.1 g by discussing the encapsulation efficiency and drug loading rate of the drug-loaded microspheres, and the encapsulation efficiency reached 80.80%, while the drug loading rate was 24.40%, the drug release capacity reached about 83% in about 12 hours. The research shows that the kaolin/chitosan drug-loaded microspheres prepared by the emulsification and cross-linking method are excellent drug-loading materials.

Mupirocin-Loaded Chitosan Microspheres Embedded in Piper betle Extract Containing Collagen Scaffold Accelerate Wound Healing Activity.

This study reports the formulation of mupirocin-loaded chitosan microspheres embedded in Piper betle extract containing collagen scaffold as combinational drug delivery for improved wound healing. Selection of chitosan type (molecular weight and degree of deacetylation) was carried out based on their antibacterial efficacy. The low molecular weight chitosan was selected owing to the highest antibacterial action against gram-positive as well as gram-negative bacteria. Low molecular weight chitosan-microspheres showed spherical shape with largely smooth surface morphology, 11.81% of mupirocin loading, and its controlled release profile. The XRD, DSC thermograms, and FT-IR spectral analysis revealed the mupirocin loaded in molecularly dispersed or in amorphous form, and having no chemical interactions with the chitosan matrix, respectively. The in vivo study indicates potential effect of the mupirocin, Piper betle, and chitosan in the collagen scaffold in the wound healing efficiency with approximately 90% wound healing observed at the end of 15 days of study for combinational drug-loaded chitosan microspheres-collagen scaffold-treated group. The histopathology examination further revealed tissue lined by stratified squamous epithelium, collagen deposition, fibroblastic proliferation, and absence of inflammation indicating relatively efficient wound healing once treated with combinational drug-loaded chitosan microspheres containing scaffold.

Formulation Development and Evaluation of Lansoprazole Mucoadhesive Microsphere

Lansoprazole belongs to a class of antisecretory compounds, the substituted benzimidazoles, that do not exhibit anticholinergic or histamine H2-receptor antagonist properties, but rather suppress gastric acid secretion by specific inhibition of the (H+,K+)-ATPase enzyme system at the secretary surface of the gastric parietal cell. Because this enzyme system is regarded as the acid (proton) pump within the parietal cell, lansoprazole has been characterized as a gastric acid-pump inhibitor, in that it blocks the final step of acid production. This effect is dose-related and leads to inhibition of both basal and stimulated gastric acid secretion irrespective of the stimulus. The aim of the present study was to develop lansoprazole loaded thiolated chitosan microspheres were prepared by emulsifying method using liquid paraffin light and heavy in ratio of 50:50 as a dispersing medium and glutaraldehyde used as a cross-linking agent. The prepared microspheres were evaluated for mean particle size and particle size distribution, drug content, mucoadhesion measurement and in-vitro drug release. FT-IR spectroscopic analysis was performed to ascertain drug polymer interaction. The release profiles showed first order release behavior up to 12 hours where the highest drug release was 88.89 % of the lansoprazole loaded in the thiolated chitosan microspheres, indicating a strong crosslinking between chitosan and glutaraldehyde. From the results of the present investigation it may be concluded that drug loaded chitosan microspheres can be prepared by a simple technique which avoids the use of complex apparatus and special precautions. Keywords: Lansoprazole, Thiolated chitosan, Microspheres, Glutaraldehyde, Mucoadhesion measurement

Preparation of Drug-loaded Chitosan Microspheres and Its Application in Paper-based PVC Wallpaper

By screening through test, it was found that the drug-loaded chitosan microspheres with the average particle size of 615 nm may be prepared with NaF as the mold-proof drug, chitosan as the drug carrier and sodium tripolyphosphate as the cross-linking agent; and they can improve the aspergillus niger-proof effect if loaded onto the base paper surface of the paper-based PVC wallpaper. The results show that NaF and chitosan have mold-proof synergistic effects; the mold-proof effect of the wallpaper may be improved by increasing the dose of chitosan; when the mass ratio of NaF, sodium tripolyphosphate and chitosan was 2:7:28, the paper-based PVC wallpaper with good mold-proof property can be prepared.

Recoverability of freeze-dried doxorubicin-releasing chitosan embolic microspheres

The purpose of this study is to investigate the recoverability of freeze-dried chitosan microspheres (MS). The factors influencing the integrity of chitosan MS during freeze-drying and rehydration procedures were determined, with focusing on choosing a suitable rehydration method and a freeze-drying excipient. Mean MS size, size distribution and sphericity of recovered chitosan MS were evaluated. Furthermore, the impacts of freeze-drying and rehydration procedure on the elasticity of chitosan MS were explored and the release profiles were evaluated. The recoverability of lyophilized chitosan MS was largely dependent on rehydration method and freeze-drying excipients. When using the optimized recovery processes, deformable drug-loaded chitosan MS can be rapidly recovered to exhibit the initial physico-mechanical properties such as elasticity. Release profiles also were not significantly changed after rehydration procedure. It is therefore expected drug-loaded chitosan MS can be stably freeze-dried with the prevention of drug release during storage and rapidly recovered to be used as deformable embolic materials possibly applicable for anti-cancer embolotherapy.

Evaluation of the factors influencing stomach-specific delivery of antibacterial agents for Helicobacter pylori infection.

Because Helicobacter pylori infection is localized in the gastric mucus layer and at the mucus layer-epithelial cell interface, we have developed amoxycillin- and metronidazole-containing chitosan microspheres for stomach-specific drug delivery. Drug-loaded porous chitosan microspheres were prepared by simultaneous crosslinking and precipitation with sodium tripolyphosphate. The release of antibacterial agents into simulated gastric fluid (SGF, pH 1.2), and the stability and permeability through gastric mucin, were examined at 37 degrees C. Because of the high porosity of drug-loaded chitosan microspheres, all the amoxycillin and metronidazole were released in 2 h. High-performance liquid chromatography assays of the antibacterial agents in SGF at 37 degrees C indicated 40% degradation of amoxycillin after 10 h. Metronidazole was completely stable for up to 24 h in SGF. Amoxycillin and metronidazole were highly permeable through the gastric mucin gel layer. The results of this study show that acid-stable antibacterial agents, such as metronidazole, that rapidly permeate the gastric mucus layer would be very effective for the complete eradication of H. pylori infection when delivered specifically at the site of infection in the stomach.

Manufacturing Drug Loaded Chitosan Microspheres by Spray Drying: Development, Characterization, and Potential Use in Dentistry

The aim of this work was to determine specifications for spray-drying manufacturing of sustained-release drug-loaded microparticles with potential application in dentistry. Chitosan was used as the microencapsulation polymer and ketoprofen as the model drug. A 1:1 chitosan/ketoprofen suspension was spray-dried under different operating conditions. The size distribution, morphology, total drug load, and release profile of the powders were characterized. In vitro release studies were performed with the powder samples entrapped in cellulose dialysis tubes. The microparticles produced had a narrow size distribution (mean diameter ranging from 2.11 to 3.27 µm), good sphericity, and a smooth surface. In vitro release studies showed a linear drug dissolution behavior.

Preparation and improvement of release behavior of chitosan microspheres containing insulin

Chitosan microsphere has potential applications in orally and other mucosally administration of protein and peptide drug, because it shows excellent mucoadhesive and permeation enhancing effect across the biological surfaces. The control of the size and size distribution of chitosan microsphere is necessary in order to improve its reproducibility, bioavailability and repeatable release behavior. Furthermore, it is a big challenge how to maintain the chemical stability of protein drug and improve its release behavior in the preparation of chitosan microspheres, because conventional crosslinking method by glutaraldehyde cannot be used in encapsulation of protein drug containing amino group. In this study, we established a method to prepare uniform-sized microsphere, and solve above problems by combining a special membrane emulsification technique and a step-wise crosslinking method. The preparative condition was optimized, and the chemical stability of protein, encapsulation efficiency, and release behavior were compared with conventional preparative method of drug-loaded chitosan microspheres. As a result, fairly uniform chitosan microspheres were obtained with a coefficient of variation (C.V.) value less than 11%, and the step-wise crosslinking method developed specially for membrane emulsification method provided the microspheres with higher encapsulation efficiency (80%), higher chemical stability of insulin (>95%), lower burst release and steady release behavior.

Mucoadhesive vaginal tablets as veterinary delivery system for the controlled release of an antimicrobial drug, acriflavine.

The aim of the study was the development of mucoadhesive vaginal tablets designed for the local controlled release of acriflavine, an antimicrobial drug used as a model. The tablets were prepared using drug-loaded chitosan microspheres and additional excipients (methylcellulose, sodium alginate, sodium carboxymethylcellulose, or Carbopol 974). The microspheres were prepared by a spray-drying method, using the drug to polymer weight ratios 1:1 and 1:2 and were characterized in terms of morphology, encapsulation efficiency, and in vitro release behavior, as MIC (Minimum Inhibitory Concentration), MBC (Minimum Bacterial Concentration), and killing time (KT). The tablets were prepared by direct compression, characterized by in vitro drug release and in vitro mucoadhesive tests. The microparticles have sizes of 4 to 12 microm; the mean encapsulation yields are about 90%. Acriflavine, encapsulated into the polymer, maintains its antibacterial activity; killing time of the encapsulated drug is similar to that of the free drug. In vitro release profiles of tablets show differences depending on the excipient used. In particular Carbopol 974, which is highly cross-linked, is able to determine a drug-controlled release from the matrix tablets for more than 8 hours. The in vitro adhesion tests, carried out on the same formulation, show a good adhesive behavior. The formulation containing microspheres with drug to polymer weight ratios of 1:1 and Carbopol 974 is characterized by the best release behavior and shows good mucoadhesive properties. These preliminary data indicate that this formulation can be proposed as a mucoadhesive vaginal delivery system for the controlled release of acriflavine.

Mucoadhesive vaginal tablets as veterinary delivery system for the controlled release of an antimicrobial drug, acriflavine

The aim of the study was the development of mucoadhesive vaginal tablets designed for the local controlled release of acriflavine, an antimicrobial drug used as a model. The tablets were prepared using drug-loaded chitosan microspheres and additional excipients (methylcellulose, sodium alginate, sodium carboxymethylcellulose, or. Carbopol 974). The microspheres were prepared by a spray-drying method, using the drug to polymer weight ratios 1∶1 and 1∶2 and were characterized in terms of morphology, encapsulation efficiency, and in vitro release behavior, as MIC (Minimum Inhibitory Concentration), MBC (Minimum Bacterial Concentration), and killing time (KT). The tablets were prepared by direct compression, characterized by in vitro drug release and in vitro mucoadhesive tests. The microparticles have sizes of 4 to 12 μm; the mean encapsulation yields are about 90%. Acriflavine, encapsulated into the polymer, maintains its antibacterial activity; killing time of the encapsulated drug is similar to that of the free drug. In vitro release profiles of tablets show differences depending on the excipient used. In particular Carbopol 974, which is highly cross-linked, is able to determine a drug-controlled release from the matrix tablets for more than 8 hours. The in vitro adhesion tests, carried out on the same formulation, show a good adhesive behavior. The formulation containing microspheres with drug to polymer weight ratios of 1∶1 and Carbopol 974 is characterized by the best release behavior and shows good mucoadhesive properties. These preliminary data indicate that this formulation can be proposed as a mucoadhesive vaginal delivery system for the controlled release of acriflavine.

Formulation and in vivo evaluation of chlorhexidine buccal tablets prepared using drug-loaded chitosan microspheres

This investigation deals with the development of buccal formulations (tablets) based on chitosan microspheres containing chlorhexidine diacetate. The microparticles were prepared by a spray-drying technique, their morphological characteristics were studied by scanning electron microscopy and the in vitro release behaviour was investigated in pH 7.0 USP buffer. Chlorhexidine in the chitosan microspheres dissolves more quickly in vitro than does chlorhexidine powder. The anti-microbial activity of the microparticles was investigated as minimum inhibitory concentration, minimum bacterial concentration and killing time. The loading of chlorhexidine into chitosan is able to maintain or improve the anti-microbial activity of the drug. The improvement is particularly high against Candida albicans. This is important for a formulation whose potential use is against buccal infections. Drug-empty microparticles have an anti-microbial activity due to the polymer itself. Buccal tablets were prepared by direct compression of the microparticles with mannitol alone or with sodium alginate. After their in vivo administration the determination of chlorhexidine in saliva showed the capacity of these formulations to give a prolonged release of the drug in the buccal cavity.

Preparation and characterization of ampicillin loaded methylpyrrolidinone chitosan and chitosan microspheres

Ampicillin was embedded in microparticles made of a new derivative of chitosan: methylpyrrolidinone chitosan. They were prepared using different drug-to-polymer weight ratios and by a spray-drying technique. Spray-dried drug-loaded chitosan microspheres were prepared for comparison. The microparticles were characterized by scanning electron microscopy (SEM), particle size analysis, differential scanning calorimetry (DSC) and in vitro drug release. Microbiological assay was performed using different bacterial strains. Spray-dried microspheres of almost spherical shape, smooth surface and narrow size distribution were always obtained. Ampicillin loaded into both polymer matrices showed amorphous behaviour as determined by DSC. Drug-loaded microspheres resulted to control the drug release in a 30–120 min range, depending on chitosan type. Thermal denaturation of the microspheres does not modify drug release rate. The results of the microbiological assay show that the loading of ampicillin into chitosans is able to maintain or improve the anti-bacterial activity of the drug.

Different Molecular Weight Chitosan Microspheres: Influence on Drug Loading and Drug Release

Influence of chitosan molecular weight on drug loading and drug release of drug-loaded chitosan microspheres was studied. Chitosans of 70, 000 (LC), 750, 000 (MC), and 2, 000, 000 (HC) molecular weight were employed alone or as mixtures (HC/LC 1:1-1:2 w/w). Ketoprofen (ket) was chosen as the model drug to be encapsulated. Microspheres characterized by different theoretical polymer/drug ratios were prepared (2:1, 1:1, 1:2 w/w). Satisfactory ket contents were obtained for all batches of chitosan microspheres with the theoretical polymer/drug ratio 1:2 w/ w; microspheres made of HC/LC (1:2 w/w) were characterized by good drug content and encapsulation efficiency independent by polymer/drug ratio. Prepared chitosan microparticulate delivery systems can modulate ket release within 48 hr. Microspheres consisting of HC/LC (1:2 w/w) were the most suitable formulation in controlling drug release.