Chitosan

Blending is an important method for improving the properties of polymers. PLA has been blended with many other polymers to improve its biodegradation as well as its mechanical properties. In the presented study; poly L(+)lactic acid [PLLA] has been blended with chitosan [Cs] as a biodegradable polymers to improve the release profile. PLLA was prepared via direct polycondensation reaction as mentioned in our previous publications. Riboflavin [RF] was chosen as a model drug to evaluate the release behavior through PLLA.Cs polymeric device. Different ratios of blends (1:1, 2:1 PLLA:Cs) were prepared and compared with PLLA alone. The prepared PLLA and PLLA.Cs blends were characterized and evaluated via microencapsulation of RF. The prepared microcapsules were characterized in terms of morphology and encapsulation efficiency [E.E.]. In vitro release profiles and kinetics studies were performed. The release profiles were investigated by the measurement of the riboflavin concentration in the release medium at various time intervals. It has been Cs ratio) rather than 2:1 ratio and pure PLLA. The highest encapsulation efficiency E.E. found, that the matrix degradation and riboflavin release profiles were high in case of (1:1 PLLA: was obtained in case of 1:1 PLLA:Cs blend (99%).

Chitosan is a linear polysaccharide composed of randomly distributed β-(1-4)-linked D-Glucosamine (deacetylated unit) and N-acetyl D-Glucosamine (acetylated unit). It is made by treating shrimp and other crustacean shells with the alkali, sodium hydroxide. Chitosan has some therapeutic activities like lowering cholesterol, antiulcer, and wound healing and antimicrobial activity. Recently electrospinnanofibers based on chitosan have been widely researched. Chitosan have many physicochemical properties like colorless, white hard, inelastic, nitrogenous polysaccharide. It chelate with many transitional metal ion .The degree of substitution of hydroxyl and amino group also influence the mechanical and biological properties of chitosan samples. In recent year a lots of biological, medical and commercial applicability are being used. The amino group in chitosan has a pKavalue of ~6.5, leads to a protonation in acidic to neutral solution with a charge density dependent on pH. This makes chitosan water-soluble. Though the drug delivery by chitosan is not approved by FDA, purified form are available for biomedical application. This review gives clear information about introduction properties processing and applications of chitosan.

Present study aims to prepare and evaluate mucoadhesive microspheres by ionotropic gelation method. Among all the formulations M10 was selected as optimized formulation for mucoadhesive microspheres based on the evaluation parameters and drug release studies. In vitro release study of formulation M10 showed 97.11% 12 h in a controlled manner, which is essential for disease like peptic ulcer. The release order kinetics for M10 was best fit with the highest correlation coefficient was observed in Higuchi model, indicating diffusion controlled principle. The innovator Abygate conventional tablet shows the drug release of 97.23% within 1 h. FT-IR and DSC analyses confirmed the absence of drug-polymer interaction. The results obtained from evaluation and performance study of Gatifloxacin mucoadhesive microspheres that system may be useful to achieve a controlled drug release profile suitable for peroral administration and may help to reduce the dose of drug, dosing frequency and improve patient compliance when compared with marketed product.

Terbutaline sulphate loaded microspheres were prepared for Nasal administration with the aim of avoiding first pass effect. The microspheres were prepared by a water-in-oil (w/o) emulsification-cross-linking technique by using chitosan as a mucoadhesive polymer, liquid paraffin (heavy and light, ratio 1:1) as a external phase, dioctyl sodium sulfosuccinate (0.2% w/v) as a stabilizer, volume of cross-linking agent (Glutaraldehyde, 25% solution, 1 mL) and time of cross linking 2 hrs. A 23 full factorial design was constructed to study the effect of three independent variables i.e. drug: polymer ratio (X1), volume of cross linking agent (ml) (X2), cross linking time (Hrs)(X3) while Particle size of the microspheres (Y1) and In vitro mucoadhesion (Y2) were taken as response parameters as the dependent variables. Particle size was found to be 26.11 ± 1.98 mm, which is favorable for intranasal absorption. The shape and surface characteristics were determined by scanning electron microscopy (SEM) which depicted the spherical nature and nearly smooth surfaces of the microspheres. The percentage encapsulation efficiency was found to be 74.4 ± 0.604%. In vitro mucoadhesion was performed using sheep nasal mucosa and was observed 72.32 ± 0.25%. FTIR Spectroscopy indicates characteristic peaks of the functional groups present in the drug, Differential scanning calorimetry and X-ray diffraction results indicated a molecular level dispersion of Terbutaline sulphate in the microspheres. In vitro release studies in pH 6.2 phosphate buffer indicated the mechanism of drug release was of zero order.

Fucidin, a topical antibacterial agent indicated in the treatment of bacterial infections. It works by interfering with bacterial protein synthesis, specifically by preventing the translocation of the elongation factor G (EF-G) from the ribosome. The aim of the present study was to prepare topical gel by using gel forming polymers along with chitosan and to study the effect of the concentration of polymers, effect of alone Fucidin, combined effect of Aloe Vera with vitamin C on different gel parameters and wound healing activity. The gel formulations were prepared by soaking method using Carbopol 934p as gelling agent/gel base. IR spectroscopy studies suggested that the formulations prepared is a physical mixture and the drug is compatible with other excipients. The prepared gel formulations were evaluated for drug content, pH and rheological parameters like viscosity, spreadability and extrudability. The percentage release of Fucidin from plain gel was slow as compared to other drug loaded gel formulations. The formulation (F8) showed maximum percentage release (99.56%). All the gel formulations showed more than 80% reduction in wound contraction. The gel formulation containing Fucidin along with 1% chitosan and 1% sodium alginate showed 99.4% reduction in wound area after 12 days.

Hepatic targeting of Concanavalin A appended myristoyl chitosan nanoparticles containing Epirubicin. Myristoyl chitosan was synthesised by reacting native chitosan with myristoyl chloride and  degree of acylation was determined by Ninhydrin assay. Nanoparticles of chitosan and myristoyl chitosan were prepared by ionic gelation and the method was optimised for processing parameters based on particle size, zeta potential and entrapment efficiency (EE). The nanoparticles of chitosan and myristoyl chitosan were conjugated with concanavalin A by incubation and the conjugation was confirmed by zeta potential measurement. The surface morphology of the optimized formulation was checked with the help of SEM and was further studied for organ distribution studies in Wistar rat model. Myristoyl chitosan synthesised was confirmed by FT-IR studies. Degree of acylation was found out to be 42.2 ± 2.7%. The optimized Con A conjugated nanoparticles prepared by chitosan (Ch17) and myristoyl chitosan (MCh17) was found to be spherical in shape with particle size 244.4nm and 275.8nm, zeta potential of 0.307mV and 0.133mV, entrapment efficiency 45.01±1.32% and 40.10±1.23% respectively. In vitro drug release (PBS 7.4) from Ch17 was 93.02±1.66% and followed Higuchi model, while release from MCh17 was 68.53±2.27% and followed Peppas model. Both the formulation were stable for 1 month at the temperature of 2-8oC. In vivo liver uptake of MCh17 nanoparticles was 93.6±10.11% while it was  87.0±7.55% with Ch17. Epirubicin loaded MCH17 nanoparticle showed high uptake by liver with concomitant reduction in blood level of Epirubicin in comparison to  Ch17 nanoparticles.

The use of chitosan (CS) is use for the encapsulation of active components has gained interest in the last years due to its mucous adhesiveness, non-toxicity, biocompatibility and biodegradability. The benefits of encapsulating active agents in such polymer matrix include their protection from the surrounding medium or processing conditions and their controlled release. In this present study Chitosan was employed for the encapsulation of caffeoyl derivatives and medicinal plants (Artemisia pallens (Tulsi), Ocimum tenuiflorum or  Ocimum  sanctum (Marikolunthu ).Encapsulation has been done with the help of ionic gelation method.  Chitosan and TPP- (Tripolyphosphate pentasodium) were mainly involved. The active components were added to the TPP solution and this was added dropwise to the chitosan solution with continuous stirring and also in this case, to investigate the anti-oxidant activity of the methonolic extract of caffeoyl derivative and medicinal plants.Anti-oxidant activity of methonolic extract was determined by DPPH -(1, 1-diphenyl 1-2 picryl hydrazyl)  free radical scavenging activity. Then the effect of encapsulating systems on the active ompound stability and its release properties was analysed.

Colon-specific drug delivery has gained increased importance in the delivery of drugs for the treatment of local diseases associated with the colon, such as Crohn's disease, ulcerative colitis, colorectal cancer and amoebiasis. Metronidazole, an antiprotozoal drug is clinically effective in colonic diseases, both locally and systemically. The aim of this work was to prepare and evaluate Eudragit coated chitosan microspheres of metronidazole for colon targeting. Chitosan microspheres were prepared by emulsion dehydration method using different ratios of drug and polymer. Eudragit coated chitosan microspheres were performed by solvent evaporation method and were evaluated for percentage yield, flow property, particle size analysis, surface morphology, determination of drug content, drug entrapment efficiency, degree of swelling, in vitro drug release and its kinetic profile. The percentage yield of all formulations was more than 80%. The microspheres showed a spherical structure with a smooth surface morphology. The drug entrapment efficiency was found to be in between 68.8%-81.6%. The in vitro release was found to be in following order F3>F1>F2>F4>F5>F6. In the case of F3 only 13.03% of the drug was released in 5 hrs, but it showed high and fast increase in drug release from 6th hr in pH 6.8 phosphate buffer. It shows 90.52% drug release after 12hrs.The formulations gave good fit to the Zero order and the mechanism of drug release was diffusion. The results clearly demonstrated that the Eudragit S100 coated metronidazole chitosan microspheres is a potential system for colon-specific drug delivery.

For the evaluation of the wound healing activity polymer composite films were prepared by using Chitosan and in combination with Sodium CMC with and without glutaraldehyde were prepared by solvent casting method. Mupirocin was incorporated into selected polymeric films. All the polymeric composite films were characterized by IR study suggested that there was no chemical reaction has taken place, only ionic complexes were formed. All the films were evaluated for thickness, folding endurance and tensile strength. The thickness of all the films was uniform,The folding endurance suggested good flexibility of the films as propylene glycol was used as a plasticizer, Films shown good tensile strength  necessary for better handling . The water vapour penetration suggested that films without cross linker absorbs more moisture compared to films containing cross linking agent. The presence of cross linking agent shown optimum bio-adhesion. All the polymer composite films were evaluated for in vitro swelling study. The films showed good swelling in water more than 6 hrs retaining the shape of the films. The addition of cross linking agent decreased the swelling. Selected polymer composite films were evaluated for in vivo wound healing activity. All the polymeric films showed more than 80% reduction in wound contraction. The mupirocin loaded polymeric composite containing Sodium CMC, shown more than 95% of reduction in wound area after 12 day. Hence it can be concluded that polymer composite films of chitosan-alginate containing mupirocin along with Sodium CMC showed good wound healing and could be used in effective management of wound.

Chitosan is a natural, biologically safe polymer synthesized from chitin by deacetylation reaction. It is a tough, biodegradable, biocompatible, non-toxic linear polysaccharide suitable for various applications in pharmaceutical drug delivery technology. Chitosan has unique physicochemical and biological characteristics demanded for the development of safe and effective drug delivery systems.  One of the most properties of chitosan is for chelation. It can selectively bind to desired materials such as cholesterol, fats, metal ions, and protein and tumor cells. It also does not cause allergic reactions and rejection and is biodegradable in nature. It is metabolized into harmless products (amino sugars), which are completely absorbed by the human body. Chitosan being a good cationic polymer for membrane formation; have also been useful as artificial kidney membranes. Along with these properties it also possesses certain medicinal applications such as analgesic, hypocholesterolemic, hemostatic  antitumor, anti-oxidant spermicidal, CNS depressant, immunoadjuvant properties, antacid, antiulcer activities, wound and burn healing action and has been found to be suitable for immobilization of enzymes and living cells in ophthalmology Important applications of chitosan in the pharmaceutical industry are in the development of nasal, vaginal, ophthalmic, transdermal & topical, buccal, parenteral, colon-specific and in implantable drug delivery systems. This paper discusses the potential of chitosan in the development of drug delivery systems.