ACCENT JOURNAL OF ECONOMICS ECOLOGY & ENGINEERING Peer Reviewed and Refereed Journal, ISSN NO. 2456-1037
Available Online: www.ajeee.co.in/index.php/AJEEE
Vol. 07, Issue 02,February 2022 IMPACT FACTOR: 7.98 (INTERNATIONAL JOURNAL) 117 MUCOADHESIVE MICROSPHERES: A PROMISING APPROACH FOR TARGETED DRUG
DELIVERY – A COMPREHENSIVE REVIEW
Usha Kondla
Assoc. Professor, Department of Pharmaceutical Analysis, Princeton College of Pharmacy, Hyderabad, Telangana, India
Dayyala Lavanya
Asst. Professor, Department of Pharmaceutical Analysis, Princeton College of Pharmacy, Hyderabad, Telangana, India
Abstract - This article's goal is to go over the fundamentals of making and evaluating mucoadhesive microspheres, as well as the research done on these systems. The design of drug delivery systems is currently focused on the issue of mucoadhesion. The adhesion of two materials, at least one of which is a mucosal surface, is commonly referred to as mucoadhesion. Mucoadhesive microspheres can be made to have a longer residence time at the site of application or absorption, make it easier to get close to the underlying absorption surface, and help drugs work better or better as a treatment. For either systemic or local effects, these mucoadhesive microspheres have recently been developed for oral, buccal, nasal, ocular, rectal, and vaginal routes. The purpose of this review article is to provide an overview of the various aspects of mucoadhesion, including mucoadhesive materials, factors that affect mucoadhesion, methods for evaluating them, and a variety of mucoadhesive drug delivery systems.
Keywords: Microspheres, site-specific, mucoadhesion, and the mechanism of mucoadhesion
1 INTRODUCTION 1.1 Microspheres
Microspheres are solid, roughly spherical particles with sizes ranging from 1 to 1000 m. During the manufacturing process or afterward through absorption, substances can be incorporated into microspheres in either a liquid or a solid state. Microparticles or microspheres are general wordings that include both microcapsule and micromatrix.
Microcapsules, where the ensnared substance is totally encircled by an unmistakable container wall, and micromatrices, where the entangled substance is scattered all through the microsphere matrix.1
1.2 Mucoadhesive Microspheres
By developing novel delivery systems known as "mucoadhesive microspheres"
and coupling microspheres with mucoadhesion characteristics, mucoadhesive microspheres can be made.
“6 In general, microspheres have the
potential to be utilized for controlled and targeted drug delivery; However, there are additional advantages to coupling mucoadhesive properties to microspheres, such as efficient absorption and improved bioavailability of drugs due to a high surface-to-volume ratio, a much closer contact with the mucus layer, and specific drug targeting to the absorption site achieved by anchoring plant lectins, bacterial adhesions, and antibodies,etc.
on the microspheres' surface.
Over the past few years, there has been a lot of interest in the potential use of microspheres in pharmaceuticals. One method called microencapsulation is used to control and delay drug release, which prolongs therapeutic activity. Compared to conventional formulations, it offers greater effectiveness, lower toxicity, lower dosing, and longer-lasting stability.
Mucoadhesive microspheres can be customized to stick to any mucosal tissue
ACCENT JOURNAL OF ECONOMICS ECOLOGY & ENGINEERING Peer Reviewed and Refereed Journal, ISSN NO. 2456-1037
Available Online: www.ajeee.co.in/index.php/AJEEE
Vol. 07, Issue 02,February 2022 IMPACT FACTOR: 7.98 (INTERNATIONAL JOURNAL) 118 remembering those found for eye, nasal
depression, urinary and gastrointestinal lot, in this manner offering the potential outcomes of restricted as well as fundamental controlled arrival of medications.
1.3 Advantages of Mucoadhesive Microspheres
The formulation stays longer at the delivery site due to adhesion and intimate contact 8, which increases API bioavailability. It may be permitted to treat the disease with lower API concentrations for. It is a great way to deliver drugs to the whole body that have a high first-pass metabolism, increasing their bioavailability. By utilizing specific bioadhesive molecules, drug molecules can be targeted at specific sites or tissues, such as the gastrointestinal (GI) tract. It reduces administration frequency by increasing formulation residence time at the target site and controlling API release.
Due to API localization at the disease site, significant cost reductions and dose- related side effects may also be achieved.
As a result, patient compliance will rise and medication administration will become more convenient. It improves drug absorption by causing uniform and extensive drug distribution throughout the gastrointestinal tract. The drug is released over an extended period of time.
It keeps the amount of drug in the therapeutic plasma constant. The disease condition is better controlled and the intensity of local or systemic side effects is reduced when steady state levels fluctuate less. The processability (more soluble, dispersible, and flowable) is improved.
Because plasma levels are better controlled, high-potency drugs have a wider margin of safety. Drugs that break down in the acidic or alkaline environment of the intestine, such as buccal, sublingual, or vaginal, can be given through this route.
2 METHODS OF PREPARATION OF MUCOADHESIVE MICROSPHERES Mucoadhesive microspheres can be prepared by using different techniques like:
2.1 Complex Coacervation
The coating material phase and the core material are continuously stirred into a coating polymer solution after being prepared by dissolving immiscible polymer in a suitable vehicle. One of the techniques for phase separation, namely altering the temperature of the polymer solution, was used to achieve microencapsulation; by altering the medium's pH, by adding a salt, an incompatible polymer, or a non-solvent to the polymer solution, or by changing the medium's pH. by creating an interaction between polymers. The principle of this method is that when solutions of two hydrophilic colloids are mixed under suitable conditions, it results in a separation of liquid precipitate. Typically, coatings are hardened by thermal cross linking or desolvation techniques to form a self-sustaining microsphere.
2.2 Hot Melt Microencapsulation
After melting the polymer, the solid drug particles are continuously mixed into it.
After that, the prepared mixture is continuously stirred into a non-miscible solvent like silicone oil before being heated to a temperature above the polymer's melting point and stabilized as an emulsion. After cooling the emulsion to solidify the polymer particles, the microspheres are filtered and washed with petroleum ether.
2.3 Emulsion Solvent Evaporation Method
Polymer is dissolved in an organic solvent in this method, typically methylene chloride. The drug is then dispersed or dissolved within it. Droplets can be formed by dispersing the polymer and drug solution in an aqueous phase. The
ACCENT JOURNAL OF ECONOMICS ECOLOGY & ENGINEERING Peer Reviewed and Refereed Journal, ISSN NO. 2456-1037
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Vol. 07, Issue 02,February 2022 IMPACT FACTOR: 7.98 (INTERNATIONAL JOURNAL) 119 more volatile organic solvent can be
evaporated using constant mixing and high temperatures, leaving the solid polymer–drug particles suspended in an aqueous medium. The suspension is then filtered out of the particles. If the drug is water-soluble, an organic solvent immiscible solvent is used instead of an aqueous phase as the external phase
2.4 Solvent Removal
The method involves dissolving the drug and the polymer in a volatile organic solvent. This solution is then suspended in silicone oil containing span and methylene chloride and stirred until the solvent is extracted from the oil solution.
Petroleum ether is then added and stirred until the solvent is removed. After that, the microspheres were dried in a vacuum, a non-aqueous microencapsulation technique that works best with water- labile polymers like polyanhydrides.
3 MATERIALS USED IN THE FORMULATION OF MUCOADHESIVE MICROSPHERES
Mucoadhesive microspheres are made up by using mucoadhesive polymers.
Mucoadhesive delivery systems are being explored for the localization of the active agents to a particular site. Polymers have played a significant role in designing such systems so as to enhance the residence time of the active agent at the desired location. Polymers used in mucosal delivery system may be of natural or synthetic origin.
Mucoadhesive polymers that adhere to the mucin-epithelial surface can be conveniently divided into three broad classes:
Polymers that become sticky on placing them in water and achieve their mucoadhesion due to stickiness.
Polymers that adhere through nonspecific, noncovalent interactions that is primarily electrostatic in nature.
Polymers that bind to specific receptor site on tile self surface.
3.1 Characteristics of an Ideal Mucoadhesive Polymer
It should be nonirritant to the mucus membrane.
The chain length of polymers must be long enough to promote the interpenetration and it should not be too long that diffusion becomes a problem, but as the cross linking increases, the chain mobility decreases which reduces the mucoadhesive strength.
It should adhere quickly to most tissue and should possess some site specificity.
The polymer and its degradation products should be nontoxic and should be no absorbable from the GI tract.
It should preferably form a strong no covalent bond with the mucin epithelial cell surfaces.
It should allow easy incorporation of the drug and should offer no hindrance to its release.
It should posses sufficient high viscosity.
The polymers must not decompose on storage or during the shelf life of the dosage form.
The cost of polymer should not be high so that the prepared dosage form remains competitive.
4 CONCLUSION
In recent years, there has been a lot of interest in novel drug delivery systems in the field of modern pharmaceutical formulations. Due to their advantages of controlled and sustained release action as well as their versatility as a drug carrier, mucoadhesive microspheres have been attracting a lot of interest from various researchers and scholars. Mucoadhesive microspheres provide a novel pharmaceutical carrier system. With
ACCENT JOURNAL OF ECONOMICS ECOLOGY & ENGINEERING Peer Reviewed and Refereed Journal, ISSN NO. 2456-1037
Available Online: www.ajeee.co.in/index.php/AJEEE
Vol. 07, Issue 02,February 2022 IMPACT FACTOR: 7.98 (INTERNATIONAL JOURNAL) 120 these new specific targeting compounds
(lectins, thiomers, etc.), mucoadhesion has undoubtedly entered a new domain.
with scientists and medication organizations looking further into expected contribution of additional more modest complex particles, proteins and peptides, and DNA for future mechanical progression in the everevolving drug conveyance field. Mucoadhesive microspheres have been shown to be a promising method for delivering drugs to a specific site in a controlled or sustained manner. Because they deliver the drug to a specific site for a longer period of time, the drug's absorption increases, increasing its bioavailability. As a result, it can be said that mucoadhesive microspheres will also play a significant role in the future development of new pharmaceuticals made with more cutting- edge materials and methods.
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