Formulation, optimization, and pharmacodynamic evaluation of chitosan/phospholipid/β-cyclodextrin microspheres

Effect of Microsphere Concentration on Catechin Release from Microneedle Arrays

In this work, microspheres were developed by cross-linking glutaraldehyde in an aqueous gelatin solution with a surfactant and solvent. A poly(vinyl alcohol) (PVA) solution was produced and combined with catechin-loaded microspheres. Different microsphere concentrations (0%, 5%, 10%, and 15%) were applied to the PVA microneedles. The moisture content, particle size, swelling, and drug release percentage of microneedles were studied using various microsphere concentrations. Fourier transform infrared and scanning electron microscopy (SEM) investigations validated the structure of gelatin microspheres as well as their decoration in microneedles. The SEM scans revealed that spherical microspheres with a wrinkled and folded morphology were created, with no physical holes visible on the surface. The gelatin microspheres generated had a mean particle size of 20-30 μm. Ex vivo release analysis indicated that microneedles containing 10% microspheres released the most catechin, with 42.9% at 12 h and 84.4% at 24 h.

Berberine hydrochloride-loaded dung beetle chitosan/sodium alginate microspheres ameliorate DSS-induced colitis and regulate gut microorganisms in mice

Berberine hydrochloride (BH) has long been known for its therapeutic efficacy. In the present study, we aimed to treat mice with colitis using dung beetle chitosan (DCS) -transported BH. To achieve this, BH-loaded DCS/sodium alginate microspheres (SA-DCS-BH) were prepared. The SA-DCS-BH was characterized using SEM, DLS, FT-IR, and XRD, then was used for administration and anti-inflammatory examination in mice. SEM and DLS confirmed the surface morphology of the microspheres, and the particle size was relatively uniform. FT-IR and XRD results confirmed that BH was successfully loaded. In vitro and in vivo studies showed that SA-DCS-BH had slow-release ability. After treatment with SA-DCS-BH, DAI was significantly reduced, colon weight and length increased, spleen length and weight reduced, concentrations of pro-inflammatory cytokines in colonic tissues were reduced, and gut microbiota species abundance was modulated. In addition, this study found a correlation between specific microbes and colitis indicators, Muribaculaceae showed sequential growth after receiving BH, SA-CS-BH, and SA-DCS-BH treatments, respectively. It was concluded that SA-DCS-BH effectively delivered the BH to the intestine with slow-release ability and exhibited anti-inflammatory effects by immune response. Compared to commercial chitosan, DCS has potential for modulating intestinal microorganisms and more suitable carrier for intestinal drug delivery systems.

A Novel Candidate for Guided Tissue Regeneration: Chitosan and Eggshell Membrane

Background The primary cause of adult tooth loss is commonly attributed to periodontal disease, a condition that weakens the supportive structures around the teeth. In addressing periodontal diseases, surgeons often employ the guided tissue regeneration (GTR) technique, which involves the use of a barrier membrane. Aim The aim of the present study is to assess the composition and mechanical strength of chitosan and eggshell membrane. This research was conducted to provide insights into their potential application in facilitating tissue regeneration. Materials and procedures Chitosan and eggshell membrane were combined to create the membrane. Scanning electron microscopy (SEM) using FEI Quanta FEG 650 SEM (JSM IT-800, JEOL Ltd., Akishima, Tokyo, Japan) was carried out, and mechanical properties were used to measure the parameters of membrane characterization.  Results In the dry condition, the membrane's tensile strength was 0.30 MPa and its elongation at break was 8.2%. In the wet condition, the membrane's tensile strength was 0.13 MPa and its elongation at break was 22.6%. The SEM results depicted membrane surface with pore sizes ranging from 16 to 100 meters, and the result obtained from membrane porosity test was 31.2%.  Conclusion The chitosan-eggshell membrane exhibited a fibrous surface with a desirable pore size for use as a GTR membrane, but it has low mechanical strength.

Aspirin effect on bone remodeling and skeletal regeneration: Review article

Bone tissues are one of the most complex tissues in the body that regenerate and repair themselves spontaneously under the right physiological conditions. Within the limitations of treating bone defects, mimicking tissue engineering through the recruitment of scaffolds, cell sources and growth factors, is strongly recommended. Aspirin is one of the non-steroidal anti-inflammatory drugs (NSAIDs) and has been used in clinical studies for many years due to its anti-coagulant effect. On the other hand, aspirin and other NSAIDs activate cytokines and some mediators in osteoclasts, osteoblasts and their progenitor cells in a defect area, thereby promoting bone regeneration. It also stimulates angiogenesis by increasing migration of endothelial cells and the newly developed vessels are of emergency in bone fracture repair. This review covers the role of aspirin in bone tissue engineering and also, highlights its chemical reactions, mechanisms, dosages, anti-microbial and angiogenesis activities.

Targeted delivery of quercetin by nanoparticles based on chitosan sensitizing paclitaxel-resistant lung cancer cells to paclitaxel

Chemotherapy plays crucial roles in the clinical treatment of non-small cell lung cancer (NSCLC). Nevertheless, acquired chemoresistance is a common and critical problem that limits the clinical application of chemotherapy. Quercetin (QUE), a natural bioflavonoid, has significant antitumor potential, which has been verified in many drug-resistant cancer cell lines and animal models. Here, we explored whether QUE could reverse the resistance of NSCLC to paclitaxel (PTX)-based therapy. The results of cell viability revealed that QUE could synergistically enhance the cytotoxicity of PTX in A549 and A549/Taxol cells. Furthermore, Akt and ERK phosphorylation had no significant changes in A549/Taxol cells treated with PTX. However, it was significantly inhibited by the combination treatment of QUE and PTX. To improve the antitumor activity of PTX due to its hydrophobicity and eliminate its toxicity, we prepared targeted biodegradable cetuximab chitosan nanoparticles (Cet-CTS NPs) to deliver PTX and QUE using ionic cross-linking technique. The targeted NPs displayed a particle size of 290 nm and sustained release of PTX and QUE. In addition, the targeted Cet-CTS NPs loaded with PTX and QUE inhibited tumor growth in PTX-resistant A549/Taxol cells. Cet-QUE NPs decreased tumor growth in PTX-resistant xenografts. In conclusion, the administration of QUE by using Cet-CTS NPs could provide a prospective strategy for the treatment of PTX-resistant lung cancer.

Cyclodextrin complexes: Perspective from drug delivery and formulation

Cyclodextrins (CDs) have been widely investigated as a unique pharmaceutical excipient for past few decades and is still explored for new applications. They are highly versatile oligosaccharides which possess multifunctional characteristics, and are mainly used to improve the physicochemical stability, solubility, dissolution rate, and bioavailability of drugs. Stability constant, factors affecting complexation, techniques to enhance complexation efficiency, the preparation methods for molecular inclusion complexes and release of guest molecules are discussed in brief. In addition, different CD derivatives and their pharmacokinetics are elaborated. Further, the significance of CD complex in aqueous solubility, dissolution and bioavailability, stability, and taste masking is explained. The recent advancement of CDs in developing various drug delivery systems is enlightened. Indeed, the potential of CDs by means of inclusion complex formation have widen the applicability of these materials in various drug delivery systems including ocular, osmotic, mucoadhesive, transdermal, nasal, and targeted delivery systems. Feasibility studies have been performed on the benefit of these cyclic oligomers as nanocarriers, a strategy that can modify the drugs with improved physicochemical properties. Studies also demonstrated the feasibility of CDs to self-assemble in the form of stable nanoaggregates, which may extend the scope of CDs in drug delivery to the continually expanding list of new drug entities.

The Evaluation of Proanthocyanidins/Chitosan/Lecithin Microspheres as Sustained Drug Delivery System

Proanthocyanidin (PC) has attracted wide attention on cosmetics and pharmaceutical due to its antioxidant, anticancer, antimicrobial, antiangiogenic, and anti-inflammatory activities. However, PC applications are limited because of its sensitivity to thermal treatment, light, and oxidation and the poor absorption in the gastrointestinal tract. Thus, a novel dosage form of PC needs to be designed to improve its stability and bioavailability for drug delivery. The objective of this study is to fabricate proanthocyanidins/chitosan/lecithin (PC/CTS/LEC) microspheres and investigate various characteristics. In the current study, PC/CTS/LEC microspheres were prepared by spray-drying technology. The yield (61.68%), encapsulation efficiency (68.19%), and drug loading capacity (17.05%) were found in the results. The scanning electron microscope demonstrated that the microspheres were spherical in shape with wrinkled surfaces. DSC study displayed that the microspheres stability was greatly improved when comparing with bare PC. The in vitro release study showed that the 76.92% of PC was released from microspheres within 48 h. The moisture contents of microspheres ranged from 8% to 13%. The swelling rate and tapped density of microspheres were elevated with increasing the concentration of chitosan in the formulations. The moisture uptake of microspheres was saturated at 40°C/RH75% within 12 h. Our results indicated that the stability of PC/CTS/LEC microspheres was enhanced, and it is a promising carrier for sustained drug delivery system.

Guided bone regeneration with asymmetric collagen-chitosan membranes containing aspirin-loaded chitosan nanoparticles

Introduction

Membranes allowing the sustained release of drugs that can achieve cell adhesion are very promising for guided bone regeneration. Previous studies have suggested that aspirin has the potential to promote bone regeneration. The purpose of this study was to prepare a local drug delivery system with aspirin-loaded chitosan nanoparticles (ACS) contained in an asymmetric collagen-chitosan membrane (CCM).

Methods

In this study, the ACS were fabricated using different concentrations of aspirin (5 mg, 25 mg, 50 mg, and 75 mg). The drug release behavior of ACS was studied. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were used to examine the micromorphology of ACS and aspirin-loaded chitosan nanoparticles contained in chitosan-collagen membranes (ACS-CCM). In vitro bone mesenchymal stem cells (BMSCs) were cultured and critical-sized cranial defects on Sprague-Dawley rats were made to evaluate the effect of the ACS-CCM on bone regeneration.

Results

Drug release behavior results of ACS showed that the nanoparticles fabricated in this study could successfully sustain the release of the drug. TEM showed the morphology of the nanoparticles. SEM images indicated that the asymmetric membrane comprised a loose collagen layer and a dense chitosan layer. In vitro studies showed that ACS-CCM could promote the proliferation of BMSCs, and that the degree of differentiated BMSCs seeded on CCMs containing 50 mg of ACS was higher than that of other membranes. Micro-computed tomography showed that 50 mg of ACS-CCM resulted in enhanced bone regeneration compared with the control group.

Conclusion

This study shows that the ACS-CCM would allow the sustained release of aspirin and have further osteogenic potential. This membrane is a promising therapeutic approach to guiding bone regeneration.

Thermosensitive Chitosan Hydrogels Containing Polymeric Microspheres for Vaginal Drug Delivery

Thermosensitive hydrogels have increasingly received considerable attention for local drug delivery based on many advantages. However, burst release of drugs is becoming a critical challenge when the hydrogels are employed. Microspheres- (MS-) loaded thermosensitive hydrogels were thus fabricated to address this limitation. Employing an orthogonal design, the spray-dried operations of tenofovir (TFV)/Bletilla striata polysaccharide (BSP)/chitosan (CTS) MS were optimized according to the drug loading (DL). The physicochemical properties of the optimal MS (MS F) were characterized. Depending on the gelation temperature and gelating time, the optimal CTS-sodium alginate- (SA-) α,β-glycerophosphate (GP) (CTS-SA-GP) hydrogel was obtained. Observed by scanning electron microscope (SEM), TFV/BSP/CTS MS were successfully encapsulated in CTS-SA-GP. In vitro releasing demonstrated that MS F-CTS-SA-GP retained desirable in vitro sustained-release characteristics as a vaginal delivery system. Bioadhesion measurement showed that MS-CTS-SA-GP exhibited the highest mucoadhesive strength. Collectively, MS-CTS-SA-GP holds great promise for topical applications as a sustained-release vaginal drug delivery system.

Cyclodextrins as Emerging Therapeutic Tools in the Treatment of Cholesterol-Associated Vascular and Neurodegenerative Diseases

Cardiovascular diseases, like atherosclerosis, and neurodegenerative diseases affecting the central nervous system (CNS) are closely linked to alterations of cholesterol metabolism. Therefore, innovative pharmacological approaches aiming at counteracting cholesterol imbalance display promising therapeutic potential. However, these approaches need to take into account the existence of biological barriers such as intestinal and blood-brain barriers which participate in the organ homeostasis and are major defense systems against xenobiotics. Interest in cyclodextrins (CDs) as medicinal agents has increased continuously based on their ability to actively extract lipids from cell membranes and to provide suitable carrier system for drug delivery. Many novel CD derivatives are constantly generated with the objective to improve CD bioavailability, biocompatibility and therapeutic outcomes. Newly designed drug formulation complexes incorporating CDs as drug carriers have demonstrated better efficiency in treating cardiovascular and neurodegenerative diseases. CD-based therapies as cholesterol-sequestrating agent have recently demonstrated promising advances with KLEPTOSE® CRYSMEB in atherosclerosis as well as with the 2-hydroxypropyl-β-cyclodextrin (HPβCD) in clinical trials for Niemann-Pick type C disease. Based on this success, many investigations evaluating the therapeutical beneficial of CDs in Alzheimer's, Parkinson's and Huntington's diseases are currently on-going.

Characterization, in Vivo Evaluation, and Molecular Modeling of Different Propofol-Cyclodextrin Complexes To Assess Their Drug Delivery Potential at the Blood-Brain Barrier Level

In this study, we investigated the ability of the general anesthetic propofol (PR) to form inclusion complexes with modified β-cyclodextrins, including sulfobutylether-β-cyclodextrin (SBEβCD) and hydroxypropyl-β-cyclodextrin (HPβCD). The PR/SBEβCD and PR/HPβCD complexes were prepared and characterized, and the blood-brain barrier (BBB) permeation potential of the formulated PR was examined in vivo for the purpose of controlled drug delivery. The PR/SBEβCD complex was found to be more stable in solution with a minimal degradation constant of 0.25 h^-1, a t_1/2 of 2.82 h, and a K_c of 5.19 × 10³ M^-1 and revealed higher BBB permeability rates compared with the reference substance (PR-LIPURO) considering the calculated brain-to-blood concentration ratio (logBB) values. Additionally, the diminished PR binding affinity to SBEβCD was confirmed in molecular dynamics simulations by a maximal Gibbs free energy of binding (ΔG_bind = -18.44 kcal·mol^-1), indicating the more rapid PR/SBEβCD dissociation. Overall, the results demonstrated that SBEβCD has the potential to be used as a prospective candidate for drug delivery vector development to improve the pharmacokinetic and pharmacodynamic properties of general anesthetic agents at the BBB level.