Microspheres is a novel drug delivery system which involves entrapment of a drug moiety in a polymeric membrane to alter the release profile of the drug. The present book provides a guide on development and evaluation methodology for microspheres for anticancer drug. Ethyl cellulose microsphere for anticancer drug 5-Flurouracil is selected as a model example. 5-FU is an antimetabolite and immunosuppressive agent. It is used in the treatment of breast, colon, stomach, pancreas, ovary, urinary bladder and lung cancers. But it has a rapid plasma clearance and a short half-life. The drug can be encapsulated in microspheres to prolong its residence time and thereby its action. The ethyl cellulose microspheres containing 5-FU were prepared by a w/o/w emulsification solvent evaporation technique. The process variables in the preparation of 5- FU loaded ethyl-cellulose microspheres were optimized.A factorial design was employed to evaluate the effect of the selected independent variables on some in-vitro attributes of microspheres. Accelerated stability studies of 5- FU loaded ethyl cellulose microspheres was performed.
Polymers are defined by patterns of repeating chemical structures called monomers. They are among the common constituents of both living and non-living matters on the planet. Perhaps, polymers are major inputs in pharmaceutical formulations and also in the new frontiers of nano-based drug/vaccine delivery systems. Most natural polymers, as such, are not however suitable for a number of applications unless their properties are tailored and tamed via certain modifications. Such modifications of polymers as part of developing robust pharmaceutical excipients have also traditionally targeted to reduce their noxious properties and annihilate in vivo toxicities. The book explored the fundamental aspects of starch-based polymeric cross-linking using food grade cross-linking agent. The cross-linked starch microparticles which were physico-chemically characterized and loaded with model drug demonstrated impressive drug-release-sustaining capability. Readers in the Pharmaceutical industry and researchers in the academia and specialized laboratories working on design and development of drug delivery systems are the main beneficieries of the this book.
Microparticles are one of the key novel drug delivery systems has been widely used to precisely modulate release rate. Microparticles based polymeric systems fabricated using suitable carrier has been extensively explored as an effective matrix for controlled and sustained release delivery of many drugs. With the controlled release systems, the rate of drug release matches the rate of drug elimination, and therefore the drug concentration is within the therapeutic window for the majority of the 24-hr period.The aim of this study was to prepare Eudragit microspheres containing Tramadol HCl by solvent evaporation method to achieve a controlled drug release profile. Investigation of the effect of various processing and formulation factors such as polymer type, drug: polymer ratio, stirring speed to obtain spherical particles. Then yield of production, shape, and mean particle size, particle size distribution, encapsulation efficiency, surface properties and release rate of drug from the microspheres were performed.
The text book entitled “MATRIX TABLETS: AN APPROACH TOWARDS SUSTAINED RELEASE DRUG DELIVERY” emphasizes on the general introduction, approaches to sustained release drug delivery system, matrix tablets, method of preparation, drug release mechanism, evaluation of SRDDS and packaging of matrix tablets. An attempt has been made to cover various marketed preparation and patents related to of sustained release matrix tablets. The book may be beneficial for the pharmacy professional, students and research scholars for thorough knowledge, basics and updatation in the area till date.
The present study deals with the design, development and evaluation of microspheres of an antidiabetic drug by using different polymers for entrapping the drug to give controlled release, minimize frequent dosing thus improving patient compliance. Two different methods were used for preparing the different formulation of microspheres viz. ionotropic gelation method and non-aqueous solvent evaporation method.
Microsphere carrier systems made from the biodegradable polymers have attracted considerable attention for several years in sustained drug delivery. However, the short residence time at the site of absorption could be overcome by coupling bioadhesion characteristics to microspheres and developing bioadhesive microspheres with the help of bioadhesive polymers. Neostigmine Bromide – a cholinesterase inhibitor is widely used for the treatment of Myasthenia Gravis. It is presently marketed in conventional dosage form as a tablet in usual strength of 15-30 mg for peroral route. Extent of absorption of drug through oral route is only 1-2% of 30 mg of administered dose. Hence there is need of novel nasal drug delivery system for the treatment of Myasthenia Gravis. To overcome inherent drawbacks associated with conventional dosage forms of Neostigmine Bromide, an attempt is being made in the present research work to develop an alternative drug delivery system in the form of Nasal mucoadhesive microspheres to increase the rate and extent of absorption and to reduce the dosing frequency of the formulation.
Microspheres constitute an important part of particulate drug delivery systems by virtue of their small size and efficient carrier capacity. Microspheres are the carrier linked drug delivery system in which particle size is ranges from 1-1000 µm range in diameter having a core of drug and entirely outer layers of polymer as coating material. Microsphere drug administration offers a number of advantages in therapeutics ,where the controlled release of drug delivery as well as the predictable and reproducible drug release kinetics are important feature of them.The main aim and objective of the present study was to investigate the possibility of obtaining a prolonged relatively constant effective level of Rabeprazole sodium using sodium CMC as polymer.
Microspheres made from lipids and polymers provide an interesting opportunity for use as drug delivery vehicles for numerous therapeutics that can range in size from small molecules to macromolecules like peptide/protein. In addition, cationization on the lipid-based microsphere systems has tremendous application for drug absorption enhancement and for ‘ferrying’ compounds across cell membranes. Surely excipients play an important role not only to make an acceptable microsphere product but also to minimize/prevent the degradation of the incorporated drug molecules. Special emphasis is being given particularly on various instability problems and investigated mechanistic ways to obviate the possible instability problems of peptide/protein drug during microsphere preparation as well as its release from the microspheres. This book surveys a comprehensive list of published examples of excipients relevant to currently or previously marketed drugs. With this coverage, this book enlists a myriad of excipients available for the formulation scientist to design the lipidic and polymeric microspheres.
Magnetic drug targeting is a young field. Magnetic microspheres (MMS), since introduced in the1970s, have been benefiting a broad variety of applications in bio-science and biotechnology. Magnetic microspheres have potential use as magnetic seeds for drug delivery. The results concerning the effect of prepared magnetic microspheres on the viscosity, osmotic fragility and aggregation of RBCs under the influence of magnetic field.
In the recent years considerable attention has been focused on the development of new drug delivery systems. Recently, several new techniques for drug delivery are made which are capable of controlling the rate of drug delivery, sustaining the duration of therapeutic activity or targeting the delivery of the drug to a tissue. A basic concept in ophthalmic research and development is that the therapeutic efficacy of an ophthalmic drug can be greatly improved by prolonging its contact with the corneal surface. Ocular drugs and delivery systems are currently undergoing a process of design optimization due to inherent physiological and anatomical constraint of the eye leading to limited absorption of topically applied drugs. Eye being a most delicate organ, ocular drug delivery is a challenge for the formulator. Novel trend in ocular research is to formulate a dosage form which not only prolongs the residence of system in eye but also helps to reduce the elimination of the drug and side effects. This book describes design, development and evaluation of such novel vesicular system for sustained ocular delivery of antiglaucoma drug.
Gastric Emptying is a complex process,which is highly variable and makes in-vivo performance of the drug delivery systems uncertain. In order to avoid this variability,efforts have been made to increase the retention time of the drug delivery systems for more than 12 hours. The floating or gastroretentive controlled drug delivery systems are useful in such applications. The present work adresses the physiology of the gastric emptying process with respect to gastroretentive drug delivery systems.
The present work relates to bring out the importance of microencapsulation technology and development of microspheres for the antidiabetic drugs which will reduce dosing, patient non compliance and will produce better therapeutic results as compared to conventional drug delivery systems. Novel drug delivery systems as microspheres not only reduce the repeated administration to overcome non-compliance, but also help to increase the therapeutic value by reducing toxicity and increasing the bioavailability. Development of microspheric drug delivery system will enhance the bioavailability of drugs that need continuous administration especially when given by oral route.
Co-delivery of embedded growth factor-loaded microspheres and adult stem cells in a hydrogel matrix was studied for its potential as a cell-based therapeutic strategy for cartilage regeneration in partial thickness chondral defects. A photopolymerizable N-methacrylate glycol chitosan (MGC) was employed to form an in situ gel that was embedded with two formulations of growth factor-loaded microspheres and human adipose-derived stem cells (ASC). The polymeric microspheres were used as a delivery vehicle for the controlled release of growth factors to stimulate differentiation of the ASC towards the chondrocyte lineage. Bone morphogenetic protein-6 (BMP-6) and transforming growth factor-b3 (TGF-b3) were delivered at 5 ng/day at highly bioactive states. The ratio of collagen type II to I per cell was significantly higher for ASC chondrogenesis induced by the sustained release of BMP-6 and TGF-b3 in MGC gels than that of non-induced ASC or with soluble growth factor administration in the culture media. Thus, the co-delivery of growth factor-loaded microspheres and ASC in MGC gels successfully induced ASC chondrogenesis and is a promising strategy for cartilage repair.
The novel carriers have been exploited through almost all the routes of administration. Many newer carriers are evolving with the advent of technology and the demand of targeted delivery like microemulsions. Microemulsions are clear, stable, isotropic mixtures of oil, water and surfactant. These systems are currently of interest because of their considerable potential to act as drug delivery vehicles by incorporating a wide range of drug molecules. In addition to oral and intravenous delivery, they are amenable for sustained and targeted delivery through nasal, pulmonary, vaginal and topical routes. Intranasal drug delivery system is a promising alternative route of administration for poor bioavailability drugs and it has advantages in term of increase patient acceptibility and compliance.The intent of the paper focuses on use of microemulsion technology in intranasal drug delivery along with mechanism.
A Microsponge delivery system (MDS) is “Patented, highly cross-linked, porous, polymeric microspheres polymeric system consisting of porous microspheres that can entrap wide range of actives. It is a unique technology for the controlled release consists of micro porous beads, typically 10-25 microns in diameter, loaded with active agent. Aceclofenac belongs to a group of medicines called non-steroidal anti-inflammatory drugs (NSAIDs). It works by blocking the action of cyclooxygenase. The pharmacokinetic profile and intracellular metabolism of Aceclofenac provide a strong rationale for the development of a sustained release formulation. A Microsponge based drug delivery system of Aceclofenac was planned for development and characterization for in vitro performances. The effect of Eudragit RS100 and PVA on formulation of microsponges was determined by using 32 factorial design. Aceclofenac Microsponge were prepared using an Quasi emulsion solvent diffusion method by adding an organic internal phase containing Aceclofenac, Eudragit RS100, Tri ethyl citrate and solvent into a stirred aqueous phase containing polyvinyl alcohol.