Liposomes are microscopic or submicroscopic particles and are concentric bilayered vesicles in which an aqueous volume is entirely enclosed by a m
Advanced Drug Delivery Systems
Microspheres are colloidal particles whose size ranges from 1 to 1000 nm.The drug will be either dispersed or dissolved in the empty particles. The micro particulate drug delivery systems are considered and accepted as a reliable means to deliver the drug to the target site.The major applications include Controlled release peptide formulations, Intracellular Delivery, Drug delivery to tissue, treatment of macrophage associated diseases.
The present presentation is elaborating all necessary data like
Rationale for drug encapsulation into micro particles.
Loading of drug
Mechanism of Drug release.
Methods of preparation of microspheres.
Characterization of Microspheres.
Key words: Microspheres, Methods of preparation, Characterization, Applications
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Designing And Evaluation Of Mucoadhesive Microspheres Of Metronidazole For Oral Controlled Drug Delivery
Mucoadhesion has been a topic of interest in the design of drug delivery system to prolong the residence time of the dosage form with the under lying absorption surface to improve and enhance the bioavailability of drugs. The objective of this study is to develop, characterize, and evaluate mucoadhesive microspheres of Metronidazole employing various mucoadhesive polymers for prolonged gastrointestinal absorption. Metronidazole, an effective antiprotozoal drug that requires controlled release was used as the core in microencapsulation.
Microsphere containing Metronidazole were prepared employing sodium alginate in combination with four mucoadhesive polymers – sodium CMC, Methylcellulose, Carbopol and HPMC-K4M as coat materials with different polymers ratios. Further Chitosan coating was employed for better mucoadhesive property. The microspheres were filled in capsules for in-vivo evaluation. The microspheres were found to discrete, spherical, free flowing, and of the monolithic matrix type. The mucoadhesive property of the microcapsules was evaluated by an in nitro adhesion testing method known as wash-off method. Scanning Electron Microscopy indicated coarser surface texture which improves the adhesion through stronger mechanical interaction of the microspheres. The mucoadhesive microspheres were evaluated by in vitro and in vivo methods using Gamma Scintigraphy for controlled release.
Microspheres coated with HPMC-K4M and Carbopol polymer upon Chitosan coating retained spherical shapes which produced best drug release. The microspheres having good in vitro properties were used for in vivo evaluation. These mucoadhesive microspheres are, thus, suitable for oral controlled release of Metronidazole.
Systemic delivery of drugs via nasal route has many advantages for protein and peptide drug molecules as well as conventional molecules
The term microsphere is widely used in various areas, such as, materials and pharmaceutical sciences, for spherical particles composed of various natural and synthetic materials with diameters in the micrometer range (1μm to 1000μm (1mm)). Microspheres are manufactured in both solid and hollow form. Hollow microspheres are typically used as additives to lower the density of a material. Solid microspheres have numerous applications depending on what material they are constructed of, and what size they are. Microspheres are a subset of microparticles.
Microspheres also exert a direct effect on the mucosa, resulting in the opening of tight junctions between the epithelial cells. Starch and dextran microspheres have been administered repeatedly and can be classified as safe dosage forms.
The effects of mucoadhesive microspheres on the integrity or the opening of tight junction, and the viability and the recovery of nasal cell monolayer were also evaluated.
‘SMART’ drug delivery system (SDDS) is the multi targeted, pH responsive, Stimuli sensitive delivery systems.
Recent advances in the use of nano particles, liposomes, colloidal drug carriers and micelles in brain targeted drug delivery system
Target delivery of drug molecules to brain is one of the most challenging research areas in pharmaceutical sciences. The blood-brain barrier (BBB) represents an insurmountable obstacle for a large number of drugs, including antibiotics, antineoplastic agents, and a variety of central nervous system (CNS)-active drugs, especiallyneuropeptides. Therefore, various strategies have been proposed to improve the delivery of different drugs to this tissue which includesliposomes, colloidal drug carriers, micelles, chimeric peptide technology, intranasal and olfactory route of administration andnano technology.
The BBB is located at the level of brain capillaries, where there is a convergence of different cell types. The brain micro vessel endothelial cell (BMEC) that form the BBB, display important morphological characteristics such as the presence of tight junctions between the cells, the absence of fenestrations and a diminished pinocytics activity, that together help to restrict the passage of compounds from the blood into the extra cellular environment of the brain
The present topic deals in brief about the status of the BBB. The first part of this topic aims to review the strategies developed to circumvent the BBB and deliver drugs into the brain. The use of nano technology and liposomes are discussed which are crucial parts of this power point presentation as mainly used to target various CNS disorders. The later part contains future aspects of brain drug targeting...
Our power point presentation deals with Brain targeting technology, Colloidal drug carriers, Micelles, Liposomes, nano Technology
The scope of a drug delivery system is to introduce drugs within the body and facilitate their passage from the site of administration to the target site. Colloidal drug delivery systems (CDDS) consist of therapeutic compounds present in the colloidal state. Many types of CDDS are available such as: micelles, liposomes, nanoparticles, dendrimers, liquid crystals and hydrogels. Mechanisms of uptake of nanostructures from the gastrointestinal tract include persorption, endocytosis by enterocytes, paracellular transport, uptake by intestinal macrophages and passage through the gut associated lymphoid tissue. The major advantages of colloidal drug delivery systems are better drug targeting, delivery and release, with their additional potential to combine diagnosis, on account of their small size, with therapy. Some of the colloidal drug delivery systems involve the encapsulation of a drug moiety within a core surrounded by a layer of molecules that prevent the hydrolysis and enzymatic degradation of the drug moiety within thus improving the therapeutic efficacy.
The cytotoxicity of these drug delivery systems or their degradation products poses a major problem. Also there is a need to better understand the behaviour of these systems in vivo before their true value as delivery vectors can be assessed. This Online PowerPoint presentation deals with the advantages, demerits, mechanisms, associated problems and advances in Colloidal Drug Delivery Systems and emphasizes on their increasing use in newer drug delivery devices.
occular drug delivery systems help to improve drug absorption and effective therapy for diseases or disorders of eye.
Preparation and Characterization of Poly(D,L-lactide-co-glycolide) Microspheres for Controlled Relea
purpose of this research was to assess the physicochemical properties