Micro-encapsulation is utilized in the pharmaceutical sector for the following purposes:
- Drugs that are released in a sustained or protracted manner, such as aspirin.
- Bitter medications can be masked by disguising their taste., e.g., acetyl-p-aminophenol and masking of unpleasant odors.
- Elimination of incompatibilities, e.g., eutectic substances stabilization of drugs sensitive to oxygen, light, moisture, e.g., vitamins A and K. ...
What is microencapsulation in pharmaceuticals?
Microencapsulation is a process where by small discrete solid particles or small liquid droplets are surrounded and enclosed by an intact shell. Microencapsulation is used to modify and delayed drug release form pharmaceutical dosage forms.
What are the advantages and disadvantages of microencapsulation?
Microencapsulation: Advantages and disadvantages 1 The core material is the specific material to be coated and can be liquid or solid. It can also be a mixture of active... 2 Coating material – These agents are capable of forming a film that is cohesive, chemically compatible, and non –... More ...
What are the materials used in microencapsulation?
The main important material used in microencapsulation is core material (which is specified material to be coated) and coating material (which is capable of forming film).since it is applicable in pharma industry, agriculture industry, food industry, construction industry.
How many times is the process of microencapsulation repeated during processing?
38. The cyclic process is repeated, perhaps several hundred times during processing, depending on: the purpose of microencapsulation the coating thickness desired Until the core material particles are thoroughly encapsulated.
What is meant by microencapsulation?
Microencapsulation is a process in which active substances are coated by extremely small capsules. It is a new technology that has been used in the cosmetics industry as well as in the pharmaceutical, agrochemical and food industries, being used in flavors, acids, oils, vitamins, microorganisms, among others.
How do microencapsulation particles release drugs?
Mechanism and kinetics of drug release Major mechanisms of drug release from microcapsules include diffusion, dissolution, osmosis and erosion.
What are the reasons for microencapsulation?
The reasons for microencapsulation are numerous. It is mainly used to increase the stability and life of the product being encapsulated, facilitate the manipulation of the product and provide for the controlled release of the contents.
What are the methods of microencapsulation?
Large number of techniques for microencapsulation include spray chilling, spray cooling, fluidized bed coating, liposome entrapment, extrusion, freeze drying, and coacervation.
Which of the following are components of microencapsulation?
Coat Rigidization.Coat Deposition.Evaporation of the solvent from the matrix material.Formation of three immiscible chemical phases.
What are the types of microcapsules?
Different types of microcapsules: (i) simple microcapsule, (ii) matrix (microsphere), (iii) irregular microcapsule, (iv) multicore microcapsule, (v) multiwall microcapsule, and (vi) assembly of microcapsule.
How do you prepare microencapsulation?
Microcapsules were prepared by dispersion in distilled water (solid content 10%, w/v) of the polymers pectin and casein under constant mechanical shaking. Sodium hydroxide (4.0 M) was used to adjust pH to 8.0 ± 0.1. After complete dispersion, acetaminophen (test drug) was added at the proportion of 1:1 (polymer/drug).
Do probiotics need to be microencapsulated?
Clearly, microencapsulation plays an important role in protecting probiotic bacteria from the degradation that our digestive system was designed to do. It ensures they can stay viable through to the colon and, most importantly, benefit our health the way they are intended.
What are the characteristics of diffusion controlled release systems?
What are the characteristics of Matrix diffusion-controlled release systems? Explanation: In this system, the drug is dispersed into an insoluble matrix of a rigid nonswellable hydrophobic material or swellable hydrophilic material. Materials such as insoluble plastic PVC and fatty acids are used as rigid matrix.
What is a microencapsulation system?
Microencapsulation is a process in which a very tiny droplet of particle such as solid, liquid or even gas can be entrapped, coated or surrounded with a polymeric particle.
When was the first microencapsulation?
The process had its origin in the late 1930s as a cleaner substitute for carbon paper and carbon ribbons as sought by the business machines industry. The ultimate development in the 1950s of reproduction paper and ribbons that contained dyes in tiny gelatin capsules released on impact by a typewriter key or the pressure of a pen or pencil was the stimulus for the development of a host of microencapsulated materials, including drugs.
What is the process of encapsulating a liquid?
Microencapsulation is a process by which very tiny droplets or particles of liquid, solid or even gas material are surrounded or coated with a continuous film of polymeric material.
What are the two methods of encapsulation?
There are different technique to encapsulate the material by chemical method which includes coacervation method, polymeric-polymeric incompatibility, and physical method which include air suspension method, pan coating, spray drying, and centrifugal extrusion.
How does a coating chamber recirculate particles?
The coating chamber is arranged such that the particles pass upwards through the coating zone, then disperse into slower moving air and sink back to the base of the coating chamber, making repeated passes through the coating zone until the desired thickness of coating is achieved.
What are the two basic groups of microencapsulation?
In general, microencapsulation techniques are divided into two basic groups, namely chemical and physical, with the latter being further subdivided into physico-chemical and physico-mechanical techniques. Some of the important processes used for microencapsulation are summarized in the table -2.
What is Lupin used for?
Based on this novel drug delivery technique, Lupin has already launched in the market world’s first Cephalexin (Ceff-ER) and Cefadroxil (Odoxil OD) antibiotic tablets for treatment of bacterial infections. Aspirin controlled release version ZORprin CR tablets are used for relieving arthritis symptoms. Quinidine gluconate CR tablets are used for treating and preventing abnormal heart rhythms. Niaspan CR tablet is used for improving cholesterol levels and thus reducing the risk for a heart attack. Glucotrol (Glipizide SR) is an anti diabetic medicine used to control high blood pressure.
What is the morphology of microcapsules?
22. Morphology of Microcapsules The morphology of microcapsules depends mainly on the core material and the deposition process of the shell. 1- Mononuclear (core-shell) microcapsules contain the shell around the core. 2- Polynuclear capsules have many cores enclosed within the shell. 3- Matrix encapsulation in which the core material is distributed homogeneously into the shell material. - In addition to these three basic morphologies, microcapsules can also be mononuclear with multiple shells, or they may form clusters of microcapsules.
How can the solubility of polymers be enhanced?
56. <ul><li>The solubility of polymers can be enhanced by using </li></ul><ul><li>co-solvents. </li></ul><ul><li>In some cases nonsolvents are used; this increases the solubility </li></ul><ul><li>in supercritical fluids, but the shell materials do not dissolve at </li></ul><ul><li>atmospheric pressure. </li></ul>. 57.
What is microencapsulation?
Microencapsulation is a process by which individual particles of an active agent can be stored within a shell, surrounded or coated with a continuous film of polymeric material to produce particles in the micrometre to millimetre range, for protection and/or later release.
What is microencapsulation technology?
Microencapsulation technology was developed for microbial cell immobilization starting in 1993 to overcome the drawbacks encountered with gel entrapment, such as limited cell loading due to the small void space of polymer matrix and cell leakage [73 ]. A microcapsule consists of a semi-permeable, spherical, thin, and strong polymer membrane surrounding a liquid core, with a diameter varying from a few microns to 1 mm [ 39]. Because of the absence of a solid or gelled core and small diameter, mass transfer limitation is reduced in microencapsulation.
Why is microencapsulation important?
Therefore, microencapsulation is very suitable for improving the stability of thermochromic mixtures. After being encapsulated, the thermal stability and the resistances to leaching, acid and solvent for thermochromic materials would be significantly enhanced, which obviously extends their application fields.
When was microcapsule made?
The production of microcapsules began in 1930s and boomed in 1970s. According to the forming mechanism and condition of shell, microencapsulation methods can be divided into three categories, namely physical, chemical and physicochemical methods ( Jyothi et al., 2010) ( Table 15.5). As for physical method, the microencapsulation is based on ...
When was microencapsulation first used?
Microencapsulation technology has been used commercially since the 1950s when it became established as the basis for carbonless copy paper and is now used widely within the food processing (Vilstrup, 2001 ), pharmaceutical ( Benita, 1996 ), agrochemical ( Knowles, 1998) and cosmetic industries ( Meyer, 2005 ). Similarly, the technology has played a significant role in new developments in the textile industry and has been used, for example, to impart a range of long-lasting finishes to textile materials, including fragrances, antimicrobials, insecticides, fire retardants and temperature-control phase-change materials ( Nelson, 1991, 2001; Marinkovic et al., 2006 ). Microencapsulation has also been the major force behind the rise of ‘cosmeto-textiles’ delivering moisturising agents, vitamins and anti-wrinkle/anti-ageing active ingredients onto the skin ( Cognis, 2007 ). A significant area for research and development within the textile sector has been the microencapsulation of dyes and pigments for a wide range of applications. Microencapsulated dyes and pigments are now well established, particularly within the textile printing sector and within the novelty apparel sector where a number of thermo-and photochromic finishes are available. More at the experimental stage is the development of micro-encapsulated dyes to improve traditional textile dyeing processes, much of the research being aimed at reducing the environmental impact of textile dyeing, particularly in reducing water usage and colour contamination of water courses.
What is the morphology of microcapsules?
The ultimate morphology of microcapsules mainly depends on the morphology of core materials. Generally, solid core remains its morphologies during microencapsulation, while microcapsules with liquid core are usually spherical resulting from the process of mechanical dispersion or emulsion. Table 15.5.
Is microencapsulation a delivery system?
Microencapsulation as a delivery system has proved itself useful in a variety of commercial applications in many areas of industry. The techniques used to produce these capsules range from simple blend operations to complex polymeric coating systems. The systems discussed in this chapter provide only a brief introduction to the world of microencapsulation and its potential applications. It would be extremely difficult to list all the potential applications for encapsulation systems as the list would be vast, but it can be summarized by the following statement.
Why are microspheres important?
Microspheres received much attention not only for prolonged release, but also for targeting of anticancer drugs to the tumor. The intent of the paper is to highlight the potential of microencapsulation technique as a vital technique in novel drug delivery. Microencapsulation is a rapidly expanding technology.
What are the kinetics of drug release?
KINETICS OF DRUG RELEASE:#N#Release of the active constituent is an important consideration in case of microcapsules.Many therotically possible mechanisms may be considered for the release of the drug from the microparticulates.#N#1. Liberation due to polymer erosion or degradation#N#2. Self diffusion through the pore#N#3. Release from the surface of the polymer.#N#4. Pulsed delivery initiated by the application of an oscillating or sonic field.
Why is microencapsulation used in pharmaceuticals?
Within the pharmaceutical industry, the technique is used to prevent enzymatic degradation of active agents when entered in the body. It is also one of the major benchmarks for controlled release dosage forms. Microencapsulation has evolved as a replacement for sustain release patches owing to dosage convenience possessed by microencapsulation products.
Why is microencapsulation important?
Microencapsulation not only prevents early degradation but also increases the bioavailability of the molecules when required under certain biological conditions. To end with, microencapsulation is a vital process when it comes in handling sensitive molecules in pharmaceuticals, food & beverages, Fragrances, textiles, agrochemicals, and various other industries.
What is silk polypeptide?
Silk polypeptides are likely to form highly stable films on the skin surface, lipophilic liquids and hydrophilic liquids.
Is spray coating a commercial process?
On a commercial scale, spray coating and gel particles are most widely used processes as of now, but in coming years various lab scale processes are expected to enter commercial business opening new opportunities for manufacturers to offer enhanced products.
Advantages of Microencapsulating Drugs
It Masks the taste of bitter drugs to make them more palatable and improving patient compliance. Eudragit E100 is the most commonly used coating material for this purpose. The microencapsulated drugs do not interact with the taste receptors as it insoluble in the mouth. E.g., Ofloxacin.
Disadvantages of Microencapsulation
The cost of the materials used and the formulation process might be higher than standard formulations.
Why is microencapsulation used?
Microencapsulation is used for masking the undesirable flavor and aroma of certain compounds before incorporating them into any food. For instance, fish oil and certain bitter tasting compounds can all be used in foods without rendering the food with unpleasant taste and smell, all thanks to microencapsulation.
How do microcapsules vary in particle size?
The particle size of the microcapsules depends on the different techniques which are used to produce the microcapsules. Table 3 shows the variation in the particle sizes due to different techniques used. Morphology of the microcapsules refers to the internal as well as the external structure of the capsules which largely depend on the operating conditions that are used to produce the microcapsules as well as the wall materials used. Different types of capsules can be obtained—simple sphere surrounded by the wall material, capsules with irregular core, multiple distinct cores within a continuous coating of wall material, multiwalled microcapsules and core particles embedded within the matrix of wall material, as shown in Figure 2 .
What is the role of porosity in microcapsules?
Wall matrix, which holds the core is designed in such a way so as to direct the mass transfer between the environment and core (Rosenberg et al., 1985; Jackson & Lee, 1991; Shahidi & Han, 1993 ). The porosity of the wall material plays a great role in controlling the permeation of volatiles within the capsule (Arshady, 1993; Dziezak, 1988 ). It also determines the oxidative stability of the core of the microcapsule by controlling the permeation of oxygen through it. In case of volatile cores, wall permeability is a major factor for increasing the chances of core loss during storage (Rosenberg et al., 1985 ). Moreau and Rosenberg ( 1999) examined the porosity of the spray-dried microcapsules, encapsulating anhydrous milk fat within the mixture of lactose and whey protein as wall system by using gas displacement pycnometry. In this study, helium and nitrogen were used as the permeating gases. Results showed the differences in the way of penetration of helium and nitrogen through the microcapsules. It was seen that helium could fill all the accessible volume very fast, while penetration of nitrogen was comparatively slower. Overall, the results of gas-displacement pycnometry indicated the presence of pores characterizing both, anhydrous milk fat containing and core-free microcapsules (Rosenberg et al., 1985 ). The microcapsules containing milk fat were found to be more porous than the ones, which were free from the core material. Similar characteristics were obtained for the microcapsules encapsulating fish oil with dextrin and sodium caseinate wall materials. Those microcapsules also exhibited molecular-sieve kind of porosity, that is, with pores, which are minute enough to prevent the entry of molecules. Likewise, Allan-Wojtas et al. ( 2008) also reported the study of calcium alginate microcapsules, encapsulating probiotic bacteria. For studying the microstructure of the capsules, cryo-Scanning Electron Microscopy (cryo-SEM) and Transmission Electron Microscopy (TEM) were used. SEM results revealed the differences between the structure of bacteria containing and the core-free capsules. The bacteria containing capsules were found to be more porous as compared to the core free capsules, hence attributing to the fact that the bacteria interfered with the formation of cross linking of the alginate with calcium chloride, as described by Truelstrup Hansen et al. ( 2002) and Sultana et al. ( 2000 ). TEM analysis also showed the similar results. Hence, for determining the porosity of microcapsules, gas displacement pycnometry and electron microscopy, both can prove to be very important tools for analyzing the microstructure of the capsules, useful for designing the carrier substances for a particular core material.
What is fluidized bed coating?
Fluidized bed coating is an encapsulation method in which coating material is sprayed onto the fluidized core material. Here, the core material is fluidized by application of air, onto which a coating material is sprayed. Different fluidized bed coating methods are: (a) Top spray (b) bottom spray, and (c) tangential spray. In this method of encapsulation, coating efficiency of the wall material is dependent on various parameters like feed rate of the wall material, atomization pressure of the nozzle, inlet air temperature, and velocity, etc. Coronel-Aguilera & San Martín-González ( 2015) encapsulated spray dried beta carotene with hydroxypropyl cellulose using fluidized bed coating. Here, temperature and feed rate of hydroxypropyl cellulose was varied to determine how these factors effected the film forming ability of the coating material and, hence, the stability of beta carotene during storage.
How is encapsulation done?
Encapsulation using emulsification technique is done by dispersing the core in an organic solvent, containing the wall material. The dispersion is then emulsified in the oil or water, to which emulsion stabilizer is added. Encapsulation of the core occurs by formation of a compact polymer layer around it, by evaporation of the organic solvent. This is one of the frequently used techniques of encapsulation as the procedures involved are very simple. This technique is widely used for encapsulating enzymes and microorganisms. Song et al. ( 2013) reported encapsulation of probiotics in alginate-chitosan using emulsification and demonstrated better resistance of the probiotics under stimulated gastrointestinal conditions.
What is the compound called that is encapsulated?
The compound or active material which is encapsulated is called the core and the material which is used for encapsulating is called the encapsulant. Encapsulants can be either polymeric or nonpolymeric materials like cellulose, ethylene glycol, and gelatin. There are several techniques used for microencapsulation.
Is spray drying good for microencapsulation?
Although spray drying is one of the most extensively used methods for microencapsulation and has many stated advantages also, some studies have portrayed certain drawbacks of the technique. Fang et al. ( 2006) reported that when hot air is used as a drying medium for encapsulation of omega-3 fatty acids, dried powder has particles with highly porous structure, making the powder more prone to oxidation, thus, reducing the shelf life. Similar results were reported by Kolanowski ( 2005 ), while developing spray dried fish oil powder. Thus, it can be said that the same method can be effective for encapsulating one kind of material, while having drawbacks for some other kind of materials.
