Progesterone-loaded chitosan microspheres: a long acting biodegradable controlled delivery system

Chitosan microspheres-based controlled-release nitrogen fertilizers improve the biological characteristics of Brassica rapa ssp. pekinensis and the soil

Present study investigates the impact of chitosan microspheres-based controlled-release nitrogen fertilizer (Cm-CRNFs) on biological characteristics of Brassica rapa ssp. pekinensis (Chinese cabbage) and soil. The study was carried out under various four treatments, urea (0.8033 g), blank chitosan microspheres (without urea), Cm-CRNFs (0.8033 g), and a control group (CK). The results indicated that Cm-CRNFs significantly prolonged the nitrogen release and enhanced the plant shoot length, shoot diameter, number of branches, pods, total amino acids, and vitamin C of Brassica rapa ssp. pekinensis as well as increased the soil nutrient availability. Chao index of bacterial diversity analysis showed a significant reduction of 15.89 % in Cm-CRNFs, but the Shannon index value in Cm-CRNFs was increased by 23.55 % compared to CK. Furthermore, Cm-CRNFs treatment significantly influenced genus richness level of Arthrobacter, Archangium, Bacillus, and Flavihumibacter. Moreover, relative abundance of bacteria significantly enhanced Cm-CRNFs, including Acidobacteriota, Acitinobacteriota, Cloroflexi, Cyanobacteria, and Patescibacteria. Soil enzyme activity such as: urease, acid phosphatase, and catalase enzymes in Cm-CRNFs and urea treatment significantly increased. Besides, other enzymes such as: cellulase and β-glucosidase activity decreased in the Cm-CRNFs treatment. It was concluded that Cm-CRNFs potentially prolonged discharge of micro/macronutrients and improved soil bacterial diversity, which ultimately enhanced the soil fertility and improved the soil enzyme activity.

Fabrication and analysis of chitosan oligosaccharide based mucoadhesive patch for oromucosal drug delivery

OBJECTIVE

Fabrication and analyses of mucoadhesive patches made from chitosan oligosaccharide for the purpose of oromucosal drug delivery.

SIGNIFICANCE

The mucosal epithelium in the oral cavity, consisting of buccal and sublingual epithelium, has gained significant attention in the last decade as an alternative anatomical site for systemic drug delivery that could potentially minimize the challenges of solid oral dosage and parenteral delivery. In this study, we have fabricated and tested drug-loaded chitosan oligosaccharide-based patches for the oromucosal drug delivery.

METHODS

The chitosan oligosaccharide (with and without alginate) based patches were fabricated using the conventional solvent casting method and were analyzed for their swelling capacity, hydrophilicity, anti-cancer activity, in vitro drug release, and in vivo drug release activity. The in-house developed artificial saliva was used for the swelling study.

RESULTS

Alginate-containing patches showed lesser swelling ability compared to the bare chitosan oligosaccharide-based patches. The former was also found to be more hydrophobic compared to the latter one. Both the unloaded patches restricted the growth of epithelial cancer cells indicating their anti-cancer behavior. In vitro drug release indicated a super case II release pattern while in vivo study demonstrated the release of drug from the patch into the plasma indicating the purpose of the fabricated patch.

CONCLUSIONS

The chitosan oligosaccharide-based mucoadhesive hydrogel patch fabricated in this study can be highly suitable for possible translational purposes.

Composition of Piperine with Enteric-Coated Chitosan Microspheres Enhances the Transepithelial Permeation of Curcumin in Sheep Intestinal Mucosa and Caco-2 Cells

Objectives The purpose of this study was to investigate the efficacy of enteric-coated chitosan microspheres with herbal bioenhancer, piperine, as a suitable composition for improving the permeation of curcumin through biological membranes using suitable ex vivo models.

Material and Methods Chitosan microspheres of curcumin and piperine were prepared by an emulsion cross-linking method using glutaraldehydes the cross-linking agent and characterized for size, shape, entrapment efficiency, mucoadhesion, and in vitro release. The effect of piperine on the permeation of curcumin through excised sheep intestinal mucosa and Caco-2-cell monolayer was investigated.

Statistical Analysis The data from permeation studies were analyzed by Student's t-test using Statistical Package for the Social Sciences (SPSS) software (SPSS, Chicago, IL, United States) with p-values <0.05 indicating statistical significance.

Results The formulations showed mucoadhesion for a period of more than 6 hours which was influenced by the chitosan content. The rate of drug release of uncoated formulation followed first-order kinetics, and the mechanism of release was non-Fickian transport. Optimized formulation was coated with a pH-sensitive polymer, Eudragit S-100, by a solvent evaporation technique in different concentrations and evaluated for ex vivo permeation through sheep intestinal mucosa and Caco-2-cell monolayer. Scanning electron microscopy images of the optimized coated formulation showed spherical particles with smooth surfaces. The calculated permeation flux and permeability coefficient of curcumin from microspheres were at least 20% greater in the presence of piperine through the intestinal mucosa and 30% through the Caco-2-cell monolayer model. The permeability coefficient of curcumin from microspheres with piperine was 1.93 × 10 to 5 cm/sec and significantly greater (p < 0.05) than that of microspheres devoid of piperine and from aqueous dispersion (p < 0.005).

Conclusion The study confirmed the contribution of piperine and mucoadhesive microspheres toward improved permeation of curcumin through biological membranes, thereby providing an approach that has the potential of increasing transport through intestinal epithelial cells and possibly enhancing the oral bioavailability of this drug.

Hydrogel Composites with Different Dimensional Nanoparticles for Bone Regeneration

The treatment of large segmental bone defects and complex types of fractures caused by trauma, inflammation, or tumor resection is still a challenge in the field of orthopedics. Various natural or synthetic biological materials used in clinical applications cannot fully replicate the structure and performance of raw bone. This highlights how to endow materials with multiple functions and biological properties, which is a problem that needs to be solved in practical applications. Hydrogels with outstanding biocompatibility, for their casting into any shape, size, or form, are suitable for different forms of bone defects. Therefore, they have been used in regenerative medicine more widely. In this review, versatile hydrogels are compounded with nanoparticles of different dimensions, and many desirable features of these materials in bone regeneration are introduced, including drug delivery, cell factor vehicle, cell scaffolds, which have potential in bone regeneration applications. The combination of hydrogels and nanoparticles of different dimensions encourages better filling of bone defect areas and has higher adaptability. This is due to the minimally invasive properties of the material and ability to match irregular defects. These biological characteristics make composite hydrogels with different dimensional nanoparticles become one of the most attractive options for bone regeneration materials.

Synthesis and Properties of New Multilayer Chitosan@layered Double Hydroxide/Drug Loaded Phospholipid Bilayer Nanocomposite Bio-Hybrids

A novel bio-hybrid drug delivery system was obtained involving a Mg/Al-NO₃ layered double hydroxide (LDH) intercalated either with ibuprofenate anions (IBU) or a phospholipid bilayer (BL) containing a neutral drug, i.e., 17β-estradiol, and then embedded in chitosan beads. The combination of these components in a hierarchical structure led to synergistic effects investigated through characterization of the intermediates and the final bio-composites by XRD, TG, SEM, and TEM. That allowed determining the presence and yield of IBU and of BL in the interlayer space of LDH, and of the encapsulated LDH in the beads, as well as the morphology of the latter. Peculiar attention has been paid to the intercalation process of the BL for which all available data substantiate the hypothesis of a first interaction at the defect of the LDH, as well as on the interaction mode of these components. ¹H, ³¹P and ²⁷Al MAS-NMR studies allowed establishing that the intercalated BL is not homogeneous and likely formed patches. Release kinetics were performed for sodium ibuprofenate as well as for the association of 17β-estradiol within the negatively charged BL, each encapsulated in the LDH/chitosan hybrid materials. Such new bio-hybrids offer an interesting outlook into the pharmaceutical domain with the ability to be used as sustained release systems for a wide variety of anionic and, importantly, neutral drugs.

Colon-targeting of progesterone using hybrid polymeric microspheres improves its bioavailability and in vivo biological efficacy

This study aims to enhance progesterone (PG) oral bioavailability via its incorporation into hybrid colon-targeted pectin/NaCMC microspheres (MS) cross-linked with Zn²⁺ and Al³⁺. The MS were characterized for particle morphology, encapsulation efficiency, swelling behavior, drug release, mucoadhesivity and colon-specific degradability. Response-surface methodology was adopted to optimize the fabrication conditions. Enhancement of in vivo drug performance was evaluated through pharmacokinetic and pharmacodynamic studies. The optimized formulation was typically spherical with a mean diameter of 1031 µm and drug entrapment efficiency of 88.8%. This formulation exhibited pH-dependent swelling, negligible drug release in simulated gastric fluid and sustained-release pattern in simulated small intestinal fluid with a mean t_50% of 26.5 h. It also showed prolonged and preferential adhesion to rat colonic mucosa, as well as expedited degradation in presence of rat caecal contents. The MS significantly increased the area under the curve and mean residence time by 1.8 and 2.3-fold, respectively compared to the free drug. Orally administered MS showed ~10 times increase in myometrial thickness compared with the drug suspension and elicited uterine responses very similar to that obtained parenterally. These results confirm the ability of this new carrier system to improve the oral bioavailability of PG and attain adequate clinical efficacy.

Ionically Crosslinked Chitosan Membranes Used as Drug Carriers for Cancer Therapy Application

The aim of this paper was to prepare, by the freeze-drying method, ionically crosslinked chitosan membranes with different contents of pentasodium tripolyphosphate (TPP) and loaded with 1,4-naphthoquinone (NQ14) drug, in order to evaluate how the physical crosslinking affects NQ14 release from chitosan membranes for cancer therapy application. The membranes were characterized by Fourier transform infrared spectroscopy (FTIR), wide-angle X-ray diffraction (WAXD), scanning electron microscopy (SEM), swelling degree, and through in vitro drug release and cytotoxicity studies. According to the results, the molecular structure, porosity and hydrophilicity of the chitosan membranes were affected by TPP concentration and, consequently, the NQ14 drug release behavior from the membranes was also affected. The release of NQ14 from crosslinked chitosan membranes decreased when the cross-linker TPP quantity increased. Thus, depending on the TPP amount, the crosslinked chitosan membranes would be a potential delivery system to control the release of NQ14 for cancer therapy application. Lastly, the inhibitory potential of chitosan membranes ionically crosslinked with TPP and loaded with NQ14 against the B16F10 melanoma cell line was confirmed through in vitro cytotoxicity studies assessed via MTT assay. The anti-proliferative effect of prepared membranes was directly related to the amount of cross-linker and among all membranes prepared, such that one crosslinked with 0.3% of TPP may become a potential delivery system for releasing NQ14 drug for cancer therapy.

Preparation of TPP-crosslinked chitosan microparticles by spray drying for the controlled delivery of progesterone intended for estrus synchronization in cattle

PURPOSE

Planned reproduction in cattle involves regulation of estrous cycle and the use of artificial insemination. Cycle control includes the administration of exogenous progesterone during 5-8 days in a controlled manner allowing females to synchronize their ovulation. Several progesterone delivery systems are commercially available but they have several drawbacks. The aim of the present contribution was to evaluate chitosan microparticles entrapping progesterone as an alternative system.

METHODS

Microparticles were prepared by spray drying. The effect of formulation parameters and experimental conditions on particle features and delivery was studied. A mathematical model to predict progesterone plasma concentration in animals was developed and validated with experimental data.

RESULTS

Microparticle size was not affected by formulation parameters but sphericity enhances as Tween 80 content increases and it impairs as TPP content rises. Z potential decreases as phosphate content rises. Particles remain stable in acidic solution but the addition of surfactant is required to stabilize dispersions in neutral medium. Encapsulation efficiencies was 69-75%. In vitro delivery studies showed burst and diffusion-controlled phases, being progesterone released faster at low pH. In addition, delivery extend in cows was affected mainly by particle size and hormone initial content, while the amount injected altered plasma concentration. Theoretical predictions with excellent accuracy were obtained.

CONCLUSION

The mathematical model developed can help to find proper particle features to reach specific delivery rates in the animals. This not only save time, money and effort but also minimized experimentation with animals which is desired from an ethical point of view.

Method Validation for Progesterone Determination in Poly(methyl methacrylate) Nanoparticles Synthesized via Miniemulsion Polymerization

Exogenous progesterone has several applications in human health and in veterinary medicine, especially in fixed-time artificial insemination protocol. Progesterone nanoencapsulation in biocompatible polymers, such as poly(methyl methacrylate) (PMMA), is an alternative to substitute silicone-based release device traditionally used for estrus control. Progesterone concentration inside the nanoparticles must be precisely known; for that reason, a validation methodology must be applied to ensure reliable results, suitable for nanoparticles application. In this work, an UV-Vis spectrophotometric method was validated for the determination of progesterone in PMMA nanoparticles synthesized by miniemulsion polymerization. Chloroform was used as solvent, showing selectivity to the encapsulated drug and the components of the polymeric matrix did not influence progesterone recovery. Detection and quantitation limits (DL and QL) obtained were 0.32 and 0.96 mg·L−1, respectively, and precision tests (between different analysts and equipment) indicated acceptable Relative Standard Deviations (RSD < 5%). Miniemulsion polymerization reactions were carried out producing two different morphologies: nanospheres (NS) and nanocapsules (NC), with average intensity diameters (Dz) of 150–200 nm and 240–300 nm, respectively. Polymerization gravimetric conversions obtained for both cases were higher than 95% and encapsulation efficiencies greater than 69% and 90% for the nanospheres and nanocapsules, respectively.

Modeling of Progesterone Release from Poly(3-Hydroxybutyrate) (PHB) Membranes

Poly(3-hydroxybutyrate) (PHB) biodegradable polymeric membranes were evaluated as platform for progesterone (Prg)-controlled release. In the design of new drug delivery systems, it is important to understand the mass transport mechanism involved, as well as predict the process kinetics. Drug release experiments were conducted and the experimental results were evaluated using engineering approaches that were extrapolated to the pharmaceutical field by our research group. Membranes were loaded with different Prg concentrations and characterized by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and Fourier transform infrared spectroscopy (FTIR). SEM images showed that membranes have a dense structure before and after the progesterone addition. DSC and FTIR allowed determining the influence of the therapeutic agent in the membrane properties. The in vitro experiments were performed using two different techniques: (A) returning the sample to the receptor solution (constant volume of the delivery medium) and (B) extracting total volume of the receptor solution. In this work, we present a simple and accurate "lumped" second-order kinetic model. This lumped model considers the different mass transport steps involved in drug release systems. The model fits very well the experimental data using any of the two experimental procedures, in the range 0 ≤ t ≤ ∞ or 0 ≤ M t  ≤ M ∞. The drug release analysis using our proposed approaches is relevant for establishing in vitro-in vivo correlations in future tests in animals.

Tartrate/tripolyphosphate as co-crosslinker for water soluble chitosan used in protein antigens encapsulation

In drug delivery research, several toxic chemical crosslinkers and non-toxic ionic crosslinkers have been exploited for the synthesis of microparticles from acetic acid soluble chitosan. This paper hypothesized the implementation of sodium potassium tartrate (SPT) as an alternative crosslinker for sodium tripolyphosphate (TPP) and SPT/TPP co-crosslinkers for synthesis of the microparticles using water soluble chitosan (WSC) for encapsulation of Bovine serum albumin (BSA) as a model protein, and Tetanus toxoid (TT) as a model vaccine. The crosslinking was confirmed by FT-IR, SEM with EDS. The XRD entailed molecular dispersion of proteins and thermal analysis confirmed the higher stability of STP/TPP co-crosslinked formulations. The resultant microparticles were exhibiting crosslinking degree (52-67%), entrapment efficiency (72-80%), particle size (0.3-1.7μm), zeta potential (+24 to 46mV) and mucoadhesion (41-68%). The superiority of SPT over TPP was confirmed by higher crosslinking degree and entrapment efficiency. However, co-crosslinking were advantageous in higher regression values for Langmuir adsorption isotherm, slower swelling tendency and extended 30days controlled in-vitro release study. TT release obeyed the Quasi-Fickian diffusion mechanism for single and cocrosslinked formulations. Overall, in crosslinking of chitosan as biological macromolecules, STP/TPP may be alternative for single ionic crosslinked formulations for protein antigen delivery.

Review on the delivery of steroids by carrier proteins

Due to the poor solubility of steroids in aqueous solution, delivery of these biomaterials is of major biomedical importance. We have reviewed the conjugation of testosterone and it aliphatic dimer and aromatic dimer with several carrier proteins, human serum albumin (HSA), bovine serum albumin (BSA) and milk beta-lactoglobulin (b-LG) in aqueous solution at physiological pH. The results of multiple spectroscopic methods, transmission electron microscopy (TEM) and molecular modeling were compared here. Steroid-protein bindings are via hydrophilic and H-bonding contacts. HSA forms more stable conjugate than BSA and b-LG. The stability of steroid-protein conjugates is testosterone>dimer-aromatic>dimer-aliphatic. Encapsulation of steroids by protein is shown by TEM images. Modeling showed the presence of H-bonding, which stabilized testosterone-protein complexes with the free binding energy of -12.95 for HSA and -11.55 for BSA and -8.92kcal/mol for b-LG conjugates. Steroid conjugation induced major perturbations of serum protein conformations. Serum proteins can transport steroids to the target molecules.

The Immunogenicity of CRISP1 Plasmid-Based Contraceptive Vaccine can be Improved When Using Chitosan Nanoparticles as the Carrier

PROBLEM

To evaluate the effectiveness and security of a contraceptive vaccine using plasmid DNA encoding mouse CRISP1 as antigen and chitosan nanoparticles as the carrier.

METHOD OF STUDY

Chitosan-pcDNA3.1-mCRISP1 Nanoparticles (CS-DNA NPs) were prepared and characterized in terms of morphology, zeta potential, polydispersity index, and binding capacity of pDNA. The cytotoxicity and gene transfer capability of CS-DNA NPs were assessed in COS-7 cells compared to Lipofectamine 2000(™) . Four groups of mice received three injections of 0.9% normal saline, pcDNA3.1 vector, pcDNA3.1-CRISP1, or CS-DNA NPs, respectively. ELISA was used to examine the immune responses. Fertility and mean litter size were analyzed by natural mating.

RESULTS

CS-DNA NPs have a spherical or elliptical shape with a mean diameter of 189.3 nm, positive zeta potential, and good DNA condensation. It also showed high DNAse resistance and good transfection efficiency without cell toxicity. The titers of anti-mCRISP1 antibodies from CS-DNA NP-immunized mice were significantly higher than that of pcDNA3.1-CRISP1 group. Male and female CS-DNA NP-immunized animals were recognized with a statistically significant reduction in their fertility compared with pcDNA3.1-CRISP1-immunized mice.

CONCLUSION

This study demonstrated that using chitosan-DNA nanoparticles as the carrier can improve the immunogenicity of mCRISP1 DNA contraceptive vaccine with good security.

Preparation, characterization, and potential application of chitosan, chitosan derivatives, and chitosan metal nanoparticles in pharmaceutical drug delivery

Naturally occurring polymers, particularly of the polysaccharide type, have been used pharmaceutically for the delivery of a wide variety of therapeutic agents. Chitosan, the second abundant naturally occurring polysaccharide next to cellulose, is a biocompatible and biodegradable mucoadhesive polymer that has been extensively used in the preparation of micro-as well as nanoparticles. The prepared particles have been exploited as a potential carrier for different therapeutic agents such as peptides, proteins, vaccines, DNA, and drugs for parenteral and nonparenteral administration. Therapeutic agent-loaded chitosan micro- or nanoparticles were found to be more stable, permeable, and bioactive. In this review, we are highlighting the different methods of preparation and characterization of chitosan micro- and nanoparticles, while reviewing the pharmaceutical applications of these particles in drug delivery. Moreover, the roles of chitosan derivatives and chitosan metal nanoparticles in drug delivery have been illustrated.

The mechanism of action of acid-soluble chitosan as an adjuvant in the formulation of nasally administered vaccine against HBV

Recently, numerous attempts have been made to evaluate the potential of chitosan as an adjuvant; however, few have explored the mechanism underlying the adjuvant activity of chitosan.

In vitro evaluation of suspoemulsions for in situ-forming polymeric microspheres and controlled release of progesterone

One possibility to obtain a higher dose of drug in a lower formulation volume can be by using of saturated quantity of drug in one of the phases of an emulsion. These formulations are called suspoemulsions (S/O/W). When a hydrophobic polymer is added to the organic phase of suspoemulsions, these formulations can be used to entrap the drug inside microspheres after in situ precipitation of the polymer-drug-excipients mix. In this work, performance and stability of progesterone suspensions in triacetin as organic phase of suspoemulsions were evaluated. These formulations were compared with O/W emulsions. Mathematical models were used to study in vitro release profiles. The results confirmed that S/O/W systems could be an attractive alternative to O/W formulations for the entrapment of progesterone inside poly(d,l-lactide-co-glycolide) microspheres. Diffusive-based models fit the in vitro release of progesterone from in situ-formed microspheres. For longer release periods, a time-dependent diffusion coefficient was successfully estimated.

Preparation and Characterization of Genipin-Crosslinked Chitosan Microspheres for the Sustained Release of Salidroside

Chitosan microspheres (CsMs) that encapsulate salidroside (Sal) were prepared by the emulsion crosslinking method with naturally occurring genipin (Gp) and then examined for their in vitro release. Sal-loaded CsMs (Sal-CsMs) showed nearly spherical and smooth surfaces with internal voids. The particle size of Sal-CsMs ranged within 0.56–5.01 μm, and their encapsulation efficiency and loading capacity were beyond 77.58% and 23.29%, respectively. The stability of Sal improved after entrapment into the CsMs. The release rate of Sal from CsMs was initially rapid, followed by sustained release. The release behavior depended on the pH of the release medium. The main release mechanisms underlying the release procedure were anomalous behavior and Fickian diffusion. These results indicated that CsMs with a novel crosslinker of Gp was a potential carrier system for producing functional foods containing Sal.

Long-acting injectable hormonal dosage forms for contraception

Although great efforts have been made to develop long-acting injectable hormonal contraceptives for more than four decades, few long-acting injectable contraceptives have reached the pharmaceutical market or even entered clinical trials. On the other hand, in clinical practice there is an urgent need for injectable long-acting reversible contraceptives which can provide contraceptive protection for more than 3 months after one single injection. Availability of such products will offer great flexibility to women and resolve certain continuation issues currently occurring in clinics. Herein, we reviewed the strategies exploited in the past to develop injectable hormonal contraceptive dosages including drug microcrystal suspensions, drug-loaded microsphere suspensions and in situ forming depot systems for long-term contraception and discussed the potential solutions for remaining issues met in the previous development.

Emulsion cross-linked chitosan/nanohydroxyapatite microspheres for controlled release of alendronate

Sustained delivery of growth factors has emerged as an essential requirement for bone tissue engineering applications for the treatment of various kinds of bone defects. Chitosan (CH) has attracted particular attention for drug delivery and bone tissue engineering because of its favorable biocompatibility and biodegradability. In this study, a composite microsphere system containing CH and nanohydroxyapatite (nHA)-alendronate (AL) particles was fabricated by employing both emulsification and cross-linking strategies. The microspheres were characterized for their surface morphology, composition, size distribution, drug loading efficiency and release properties. The results showed that loading efficiency and sustained release of hydrophilic AL were significantly improved, which is ideal for locally sustained release in the bone microenvironment. In vitro osteogenic studies showed that the microspheres could enhance the osteogenic activity of rabbit adipose-derived stem cells. In conclusion, the CH/nHA-AL composite microspheres exhibit promising properties as a candidate for local treatment for bone defects.

Docetaxel-loaded chitosan microspheres as a lung targeted drug delivery system: in vitro and in vivo evaluation

The aim of this study was to prepare docetaxel-loaded chitosan microspheres and to evaluate their in vitro and in vivo characteristics. Glutaraldehyde crosslinked microspheres were prepared using a water-in-oil emulsification method, and characterized in terms of the morphological examination, particle size distribution, encapsulation ratio, drug-loading coefficient and in vitro release. Pharmacokinetics and biodistribution studies were used to evaluate that microspheres have more advantage than the conventional formulations. The emulsion crosslinking method was simple to prepare microspheres and easy to scale up. The formed microspheres were spherical in shape, with a smooth surface and the size was uniform (9.6 ± 0.8 μm); the encapsulation efficiency and drug loading of prepared microspheres were 88.1% ± 3.5% and 18.7% ± 1.2%, respectively. In vitro release indicated that the DTX microspheres had a well-sustained release efficacy and in vivo studies showed that the microspheres were found to release the drug to a maximum extent in the target tissue (lung). The prepared microspheres were found to possess suitable physico-chemical properties and the particle size range. The sustained release of DTX from microspheres revealed its applicability as drug delivery system to minimize the exposure of healthy tissues while increasing the accumulation of therapeutic drug in target sites.

Controlled release matrices and micro/nanoparticles of chitosan with antimicrobial potential: development of new strategies for microbial control in agriculture

The control of micro-organisms responsible for pre- and postharvest diseases of agricultural products, mainly viruses and fungi, is a problem that remains unresolved, together with the environmental impact of the excessive use of chemicals to tackle this problem. Current efforts are focused on the search for efficient alternatives for microbial control that will not result in damage to the environment or an imbalance in the existing biota. One alternative is the use of natural antimicrobial compounds such as chitosan, a linear cationic biopolymer, which is biodegradable, biocompatible and non-toxic, has filmogenic properties and is capable of forming matrices for the transport of active substances. The study of chitosan has attracted great interest owing to its ability to form complexes or matrices for the controlled release of active compounds such as micro- and nanoparticles, which, together with the biological properties of chitosan, has allowed a major breakthrough in the pharmaceutical and biomedical industries. Another important field of study is the development of chitosan-based matrices for the controlled release of active compounds in areas such as agriculture and food for the control of viruses, bacteria and fungi, which is one of the least exploited areas and holds much promise for future research.

Design and application of chitosan microspheres as oral and nasal vaccine carriers: an updated review

Chitosan, a natural biodegradable polymer, is of great interest in biomedical research due to its excellent properties including bioavailability, nontoxicity, high charge density, and mucoadhesivity, which creates immense potential for various pharmaceutical applications. It has gelling properties when it interacts with counterions such as sulfates or polyphosphates and when it crosslinks with glutaraldehyde. This characteristic facilitates its usefulness in the coating or entrapment of biochemicals, drugs, antigenic molecules as a vaccine candidate, and microorganisms. Therefore, chitosan together with the advance of nanotechnology can be effectively applied as a carrier system for vaccine delivery. In fact, chitosan microspheres have been studied as a promising carrier system for mucosal vaccination, especially via the oral and nasal route to induce enhanced immune responses. Moreover, the thiolated form of chitosan is of considerable interest due to its improved mucoadhesivity, permeability, stability, and controlled/extended release profile. This review describes the various methods used to design and synthesize chitosan microspheres and recent updates on their potential applications for oral and nasal delivery of vaccines. The potential use of thiolated chitosan microspheres as next-generation mucosal vaccine carriers is also discussed.

Evaluation of cross-linked chitosan microparticles containing metronidazole for periodontitis treatment

The aims of this study were to find the optimal formulation for the preparation of metronidazole-loaded chitosan microparticles (MTZ-MPs) via an emulsion cross-linking process, and to compare the in vitro release of MTZ from hydrogels and films containing the drug in forms of MTZ-MPs and raw powders. The effects of emulsifier type and concentration, amount of cross-linking agent, cross-linking time, drug:chitosan ratio, form of drug adding and washing method on the properties of the MTZ-MPs were investigated. The results indicated that the optimal conditions for round and free-flowing MTZ-MPs with a high percentage of entrapped drug and preferable release profile were 1% of Span80 in soybean oil, 5% of glutaraldehyde based on chitosan solution, 30 min of cross-linking time, 1:1 drug:chitosan ratio, drug adding in form of ethanol solution and washing with hexane only. MTZ-MPs prepared from the optimal formulation were incorporated in mucoadhesive hydrogel and film. The release profiles of the drug from hydrogel and film containing MTZ-MPs were in prolong pattern compared with those containing drug powders. However, the hydrogels exhibited higher preferable pattern of release profile than the films. Therefore, the hydrogel containing MTZ-MPs was possible to be further clinically investigated for peridontitis treatment.

Drug delivery systems: An updated review

Drug delivery is the method or process of administering a pharmaceutical compound to achieve a therapeutic effect in humans or animals. For the treatment of human diseases, nasal and pulmonary routes of drug delivery are gaining increasing importance. These routes provide promising alternatives to parenteral drug delivery particularly for peptide and protein therapeutics. For this purpose, several drug delivery systems have been formulated and are being investigated for nasal and pulmonary delivery. These include liposomes, proliposomes, microspheres, gels, prodrugs, cyclodextrins, among others. Nanoparticles composed of biodegradable polymers show assurance in fulfilling the stringent requirements placed on these delivery systems, such as ability to be transferred into an aerosol, stability against forces generated during aerosolization, biocompatibility, targeting of specific sites or cell populations in the lung, release of the drug in a predetermined manner, and degradation within an acceptable period of time.

Evaluation of daidzein-loaded chitosan microspheres in vivo after intramuscular injection in rats

Daidzein-loaded chitosan microspheres were prepared by emulsification/chemical-crosslinking technique. The dialysis bag method determined the release of daidzein from the microspheres. It demonstrated that the accumulative release curve in vitro was fit for the zero-order release equation and had good correlation with the absorptive fraction in vivo, suggesting the dialysis bag method evaluated the release of the microspheres well. The release of chitosan determined by the ninhydrin assay in vitro was very slow, less than 3 percent at 35 day. The pathological section by hematoxylin-eosin staining found the good biocompatibility of the prepared microspheres in the injective site. Combining the degradation photos by scanning electron microscopy with the plasma concentration-time data, it was speculated that the drug on the surface of the microspheres firstly released, then the major of drug near the surface and the inner of the microspheres released by diffusion through the shallow cavities and crack, lastly the drug released rapidly and completely being companied with the beginning of polymer degradation.

Curcumin-containing chitosan nanoparticles as a potential mucoadhesive delivery system to the colon

In the present study, we investigate the mucoadhesive characteristics and release of the anticancer agent curcumin, contained in chitosan nanoparticles (CS-NPs). Such a system has potential therapeutic benefits in the treatment of colon cancer through prolonged retention and delivery. The CS-NPs were ionically gelled with tripolyphosphate (TPP) and registered an isoelectric pH of 6.2 (z-average diameter of 214 nm ± 1.0 nm). pH variations around the isoelectric point caused a reduction in CS-NPs electrical charge which correspondingly increased the z-average due to agglomeration. Curcumin release from CS-NPs was slowest at chitosan to TPP weight ratio of 3:1, with a significant retention (36%) at the end of 6 h. Adsorption isotherms of mucin on CS-NPs fitted both the Freundlich and Langmuir models, suggesting a monolayer-limited adsorption on heterogeneous sites with varied affinities. Encapsulated curcumin exerted an influence on the adsorption of mucin due to H-bonding as well as π-π interactions between the phenolic moieties of curcumin and mucin.

Chitosan microspheres in novel drug delivery systems

The main aim in the drug therapy of any disease is to attain the desired therapeutic concentration of the drug in plasma or at the site of action and maintain it for the entire duration of treatment. A drug on being used in conventional dosage forms leads to unavoidable fluctuations in the drug concentration leading to under medication or overmedication and increased frequency of dose administration as well as poor patient compliance. To minimize drug degradation and loss, to prevent harmful side effects and to increase drug bioavailability various drug delivery and drug targeting systems are currently under development. Handling the treatment of severe disease conditions has necessitated the development of innovative ideas to modify drug delivery techniques. Drug targeting means delivery of the drug-loaded system to the site of interest. Drug carrier systems include polymers, micelles, microcapsules, liposomes and lipoproteins to name some. Different polymer carriers exert different effects on drug delivery. Synthetic polymers are usually non-biocompatible, non-biodegradable and expensive. Natural polymers such as chitin and chitosan are devoid of such problems. Chitosan comes from the deacetylation of chitin, a natural biopolymer originating from crustacean shells. Chitosan is a biocompatible, biodegradable, and nontoxic natural polymer with excellent film-forming ability. Being of cationic character, chitosan is able to react with polyanions giving rise to polyelectrolyte complexes. Hence chitosan has become a promising natural polymer for the preparation of microspheres/nanospheres and microcapsules. The techniques employed to microencapsulate with chitosan include ionotropic gelation, spray drying, emulsion phase separation, simple and complex coacervation. This review focuses on the preparation, characterization of chitosan microspheres and their role in novel drug delivery systems.

Pharmacokinetics study of bio-adhesive tablet of Panax notoginseng saponins

Panax notoginseng saponin (PNS) is the main active gradient of Chinese traditional medicine Panax notoginseng. Although its prominent therapeutic efficacy has been demonstrated by various researchers, the broader application is restricted by the low bioavailability of PNS. This article aims to discuss PNS's plasma pharmacokinetics after oral administration of bio-adhesive tablet of PNS to beagle dogs and improve its bioavailability in comparison with normal tablet. The bio-adhesive tablet was prepared according to our previous patent, using chitosan as main excipient. A simple and sensitive LC-MS/MS combined with solid-phase extraction (SPE) method for the analysis of PNS in dog's plasma was developed in our previous study, and was validated to apply in the pharmacokinetics study in this work. Three ingredients: Notoginsenoside R1 (R1), Ginsenoside Rg1 (Rg1) and Ginsenoside Rb1 (Rb1) (Figure 1), were chosen as indicators of PNS to analyze it in vivo. Statistically significant increase (P < 0.05) in pharmacokinetic parameters of PNS including AUC and Tmax for R1, Rg1 and Rb1, Cmax for R1 and Rb1, MRT for Rg1 were obtained after oral administration of bio-adhesive tablet of PNS comparing with its normal tablet. The formulation modification of using chitosan to prepare bio-adhesive tablet for oral administration is effective in improving the bioavailability of PNS, thereby enhancing its potential therapeutic effect and broadening its clinical application.

Sustained release optimized formulation of anastrozole-loaded chitosan microspheres: in vitro and in vivo evaluation

The purpose of this study was to develop sustained release formulation of anastrozole-loaded chitosan microspheres for treatment of breast cancer. Chitosan microspheres cross-linked with two different cross-linking agents viz, tripolyphosphate (TPP) and glutaraldehyde (GA) were prepared using single emulsion (w/o) method. A reverse phase HPLC method was developed and used for quantification of drug in microspheres and rat plasma. Influence of cross-linking agents on the properties of chitosan microspheres was extensively investigated. Formulations were characterized for encapsulation efficiency (EE), compatibility of drug with excipients, particle size, surface morphology, swelling capacity, erosion and drug release profile in phosphate buffer pH 7.4. EE varied from 30.4 ± 1.2 to 69.2 ± 3.2% and mean particle size distribution ranged from 72.5 ± 0.5 to 157.9 ± 1.5 μm. SEM analysis revealed smooth and spherical nature of microspheres. TPP microspheres exhibited higher swelling capacity, percentage erosion and drug release compared to GA microspheres. Release of anastrozole (ANS) was rapid up to 4 h followed by slow release status. FTIR analysis revealed no chemical interaction between drug and polymer. DSC analysis indicated ANS trapped in the microspheres existed in amorphous form in polymer matrix. The highest correlation coefficients (R (2)) were obtained for Higuchi model, suggesting a diffusion controlled mechanism. There was significant difference in the pharmacokinetic parameters (AUC(0-∞), Kel and t(1/2)) when ANS was formulated in the form of microspheres compared to pure drug. This may be attributed to slow release rate of ANS from chitosan microspheres and was detectable in rat plasma up to 48 h which correlates well with the in vitro release data.