Effect of cross-linking on physicochemical properties of tapioca starch and its application in soup product (original) (raw)
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The role of chitosan as a mucoadhesive agent in mucosal drug delivery
Journal of Drug Delivery Science and Technology, 2012
Mucoadhesive properties of chitosan are supported by an exceedingly high number of papers and have been studied using a number of different methods. Also, the myriad of chitosan derivatives that have been synthesized and proposed for pharmaceutical use have been studied for mucoadhesion, looking at the changes in mucoadhesivity induced by structure modifications. The review will briefly recall the possible mechanisms involved in chitosan mucoadhesivity, among which ionic interactions with mucin chains and hydration state are the prevailing ones. Furthermore, adhesion mechanism inevitably depends on the environmental conditions as well as on the type of physical and pharmaceutical form considered. Therefore, the testing methods used for mucoadhesivity should be carefully chosen. The present review will report on the experience acquired by the authors in the field. The focus will be on some examples of liquid, semisolid, solid and nanoparticulate formulations based on either chitosan or chitosan derivatives and on how it is possible to choose the most suitable testing method depending on the envisaged mucoadhesion mechanism and on the physical/pharmaceutical form under examination.
Influence of glutaraldehyde on drug release and mucoadhesive properties of chitosan microspheres
Carbohydrate Polymers, 1998
Among bioadhesive drug delivery systems, chitosan microspheres can be considered useful formulations for mucosal administration of drugs. The feasibility of modulating drug release from chitosan microparticles is due to polymer cross-linking, i.e. by glutaraldehyde. The aim of this work was to develop a new simple 'in vitro' technique based on electron microscopy in order to study the effect of polymer crosslinking density on mucoadhesive properties of the chitosan microspheres. This technique consists of scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observations on morphological changes of chitosan microspheres with various cross-linking densities in contact with mucin solution. The results of SEM and TEM analyses have permitted to confirm the high affinity for mucin of uncross-linked chitosan microspheres and thus their bioadhesive properties. Moreover, bioadhesive characteristics of the microparticulate drug delivery systems were depressed for glutaraldehyde cross-linked chitosan microspheres. 0
International Journal of Pharmaceutical Investigation, 2020
Objectives: This research was aimed to evaluate a novel approach for preparation of mucoadhesive microspheres which can reside in the gastrointestinal tract for an extended time period. The microspheres contained amoxicillin, an anti-bacterial agent useful for the eradication of Helicobacter pylori. Methods: Ten different formulations were prepared by chemical cross-linking technique using gluteraldehyde as a cross linking agent and chitosan as mucoadhesive polymer. Natural release retardant polymers like guar gum, gum ghatti and xanthan gum were employed. All the microspheres were characterized for morphology, particle size, drug entrapment efficiency, swelling index, bioadhesion to mucosal tissue and in vitro drug dissolution and anti-bacterial activity against E. coli. Results: The FTIR and DSC data indicated that there were no interactions between the drug and polymers used. All the microspheres exhibited good flow properties. The microspheres had a spherical shape with rough surface. The microspheres showed a good mucoadhesivity and also anti-bacterial activity. The release of the drug was prolonged to 12h when incorporated into mucoadhesive microspheres. Conclusion: Data obtained in this study concluded that mucoadhesive microspheres of amoxicillin can be used to effectively clear H. pylori from the gastrointestinal tract due to prolonged residence time resulting from mucoadhesion. In this study drug release was diffusion controlled and followed zero order kinetics.
Evaluation of mucoadhesive properties of chitosan microspheres prepared by different methods
AAPS PharmSciTech, 2004
The mucoadhesive properties of chitosan microspheres prepared by different methods were evaluated by studying the interaction between mucin and microspheres in aqueous solution. The interaction was determined by the measurement of mucin adsorbed on the microspheres. A strong interaction between chitosan microspheres and mucin was detected. The intensity of the interaction was dependent upon the method of preparation of chitosan microspheres and the amount of mucin added. The extent of mucus adsorption was proportional to the absolute values of the positive zeta potential of chitosan microspheres. The zeta potential in turn was found to be dependent upon the method of preparation of microspheres. The adsorption of type III mucin (1% sialic acid content) was interpreted using Freundlich or Langmuir adsorption isotherms. The values of r 2 were greater for Langmuir isotherm as compared with Freundlich isotherm. The adsorption of a suspension of chitosan microspheres in the rat small intestine indicated that chitosan microspheres prepared by tripolyphosphate cross-linking and emulsification ionotropic gelation can be used as an excellent mucoadhesive delivery system. The microspheres prepared by glutaraldehyde and thermal cross-linking showed good stability in HCl as compared with microspheres prepared by tripolyphosphate and emulsification ionotropic gelation.
Chitosan as floating-mucoadhesive polymers in gastroretentive drug delivery
2023
Oral drug delivery is limited by incomplete absorption in the digestive tract. The absorption of oral drugs in the stomach is affected by several factors, including gastric residence time, which causes the drug to be unable to be retained in the stomach for a long time, causing suboptimal drug absorption. One of the drug delivery systems that can prolong contact duration within the stomach is gastroretentive drug delivery system (GRDDS). GRDDS has various advantages, notably in improving the bioavailability of drugs. Several systems are involved in the GRDDS, including the floating and mucoadhesive systems. The floating system makes the drug float so it can be retained longer in the stomach. There are two mechanisms in the floating system: the effervescent and non-effervescent mechanisms. The mucoadhesive system works by adhering to the mucus or epithelial cells of the stomach. The mechanisms of mucoadhesive systems involves two stages: the contact and consolidation stages. The combination of the floating and mucoadhesive systems is aimed to improve the efficiency and effectiveness of a preparation for prolonged retention in the stomach. The choice of polymer is one of the crucial factors affecting this system. Chitosan is a natural polymer that has been evaluated for its potential in a gastroretentive floating beads delivery system. It has various advantageous properties, such as nontoxicity, biocompatibility, and biodegradability.
Factors Affecting Preparations of Chitosan Microcapsules for Colonic Drug Delivery
This work aimed at studying factors affecting preparations of chitosan microcapsules for colonic drug delivery. Chitosan microcores (CS, 45kDa, 87% degree of deacetylation) containing diclofenac sodium (DS) coated with Eudragit®S100 (ED) were prepared by a desolvation technique. Sodium sulfate was used as a desolvating agent and the drying process was freeze-drying. Factors affecting morphology, particle size and zeta potential of microcapsules were evaluated, i.e. weight ratio of DS:CS:ED, surfactant (polysorbate 80), anti-adherent (silicon dioxide), and the use of sonication or homogenization in preparation processes. The weight ratio of DS:CS:ED at 1:2:6 provided the smallest microcapsules of about 82.37±1.61 micrometer in diameter and they were in aggregated forms. Zeta potential of the microcapsules was around -25.74 +4.78 mV which indicated that the core particles of CS and DS with zeta potential of 42.14±1.74 mV were encapsulated by ED. Increasing the amount of CS and ED, the...
Self-stabilized chitosan and its complexes with carboxymethyl starch as excipients in drug delivery
Bioactive Materials, 2018
This study focuses on the behavior of chitosan (CHI) and its polyelectrolyte complexes with carboxymethyl starch (CMS) used as monolithic matrices with acetaminophen as drug tracer. Two different chitosan grades were tested alone or associated in various ratios with CMS as excipients for tablets obtained by direct compression. The degree of deacetylation (DDA) of CHI, estimated from 1 H NMR and FTIR data, was correlated with X-ray diffraction and scanning electron microscopy (SEM) to evaluate structural organization of the monolithic matrices. In vitro drug dissolution assays showed major differences in CHI kinetic profiles between tablets exposed to acidic medium for 2h (to mimick gastric passage) prior to dissolution in simulated intestinal fluid (SIF), and those administered directly to SIF. Prior exposure to acidic SGF conducted to longer dissolution profiles (release completed after 16 h) and preservation of tablet shape, whereas tablets directly incubated in SIF were rapidly disintegrated. The improved properties of chitosan matrices exposed to SGF may be related to an outer compact coating layer (visible in SEM). The effect of self-stabilization of chitosan in acidic medium was compared to that due to formation of polyelectrolyte complexes (PEC) in co-processed polymeric systems (CHI:CMS). The self-formed membrane following exposure to gastric acidity appears to help maintaining tablet integrity and allows higher drug loading, recommending CHI and its complexes with CMS as excipients for drug delivery.
Why Chitosan? From properties to perspective of mucosal drug delivery
Non-parenteral drug delivery routes primarily remove the local pain at the injection site. The drugs administered through the oral route encounter the process of hepatic first pass metabolism. Among the alternative delivery routes, mucosal route is being investigated as the most preferred route. Different mucosal routes include the gastrointestinal tract (oral), vagina, buccal cavity and nasal cavity. Novel formulations are being developed using natural and synthetic polymers that could increase the residence time of the drug at mucosal surface in order to facilitate permeation and reduce (or bypass) the first pass metabolism. For recombinant drugs, the formulations are accompanied by enzyme inhibitors and penetration enhancers. Buccal cavity (buccal and sublingual mucosa) has smaller surface area than the gastrointestinal tract but the drugs can easily escape the first pass metabolism. Chitosan is the most applied natural polymer while synthetic polymers include Carbopol and Eudragit. Chitosan has inherent properties of mucoadhesion and penetration enhancement apart from biodegradability and efflux pump inhibition. This review hoards the important research purview of chitosan as a compatible drug carrier macromolecule for mucosal delivery on single platform.
Over the years, science has improved healthcare diagnosis and treatment of patients. Biochemical engineers have enhanced considerably our understanding of the physiological obstacles to maintain efficient drug delivery systems. Drug delivery is the process of administration of bioactive compounds to reach therapeutic targets. Microencapsulation can be defined as the technique of enveloping of the continuous phase of polymeric compound loaded liquid or solid tiny particle. Microencapsulation techniques are widely used to load active agents using biodegradable polymer like chitosan. This natural polysaccharide has many therapeutic uses, such as oral and parenteral delivery of drugs as well as multifaceted applications in cancer therapy. Chitosan is essential for a wide range of chemotherapy drugs delivery. Due to its biocompatible, mucoadhesive properties and absorption enhancing, chitosan has been used widely to microencapsulate therapeutic molecules as a coating agent to maintain the gastric mucosa without allergic or irritant reactions. The present review highlights the recent application of microencapsulation techniques using chitosan as coating polymer. Hence, the ionic cross-linking technique is the most common technique used by researchers despite its mild condition that increases the efficiency of therapeutics loading and reduces side effects.
A proposed new method for the crosslinking of chitosan microspheres
Drug Delivery, 1998
This work concerns microparticulate drug delivery systems based on the natural polymer, chitosan. A new method for the chemical crosslinking of spray-dried chitosan microspheres containing cetylpyridinium chloride (CPC), as a model of an amphiphilic drug, is here proposed and evaluated. The method consists of the exposure of spray-dried microspheres to the vapor of crosslinking agents that act in gaseous phase and under mild conditions. The novelty and the major advantage of the proposed method is that it does not involve liquid phases coming in contact with the microspheres and in which the drug could dissolve. Three different chemical crosslinking agents, glutaraldehyde, epichlorohydrin, and glyceraldehyde, have been used to evaluate the feasibility of the method. The microparticulate drug delivery systems prepared could find useful pharmaceutical applications as disinfectants and healing powders. The results obtained show that the crosslinking process is effective in promoting modulation of drug release rate from the microspheres. Glyceraldehyde appears to be a good crosslinking agent with the advantage of being nontoxic.