Controlled Release Drug delivery system

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Optimization of the Gastroretentive Controlled Release Drug Delivery System of Clarithromycin

Optimization of the Gastroretentive Controlled Release Drug Delivery System of Clarithromycin

Accepted: 06 Oct 2014 The The present study investigates the development of an optimized Gastroretentive controlled release drug delivery system. Statistical experimental design and data analysis using response surface methodology is also illustrated. A Box Behnken Design (BBD) was selected and the three factors were evaluated at 3 levels respectively. the amount of HPMC K4M(X1), HPMC E15LV (X2) and sodium bicarbonate (X3) were selected as independent variables and the dependent variables were floating lag time (Y1),T50%(Y2) and T90%(Y3). Fifteen BBD formulations were formulated and dissolution studies and floating characteristics were performed on these formulations. The dissolution data obtained were then fitted to the PCP disso version 2.08 software. Linear regression analysis and model fitting depicted that the formulations followed zero order and Korsmeyer-Peppas kinetic models. The optimized formulation variable was found to be significant for the release properties (P < 0.05) and floating lag time.
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 ORAL CONTROLLED RELEASE DRUG DELIVERY SYSTEM: AN OVERVIEW

 ORAL CONTROLLED RELEASE DRUG DELIVERY SYSTEM: AN OVERVIEW

Oral drug delivery is the most preferred and convenient option as the oral route provides maximum active surface area among all drug delivery system for administration of various drugs. The attractiveness of these dosage forms is due to awareness to toxicity and ineffectiveness of drugs when administered by oral conventional method in the form of tablets and capsules. Usually conventional dosage form produces wide range of fluctuation in drug concentration in the bloodstream and tissues with consequent undesirable toxicity and poor efficiency. The maintenance of concentration of drug in plasma within therapeutic index is very critical for effective treatment. These factors as well as factors such as repetitive dosing and unpredictable absorption lead to the concept of oral controlled release drug delivery systems. Controlled release drug delivery system works on many different mechanisms to control the release rate of drugs. Various mechanisms like osmotic pressure, matrix system, reservoir system, altered density system etc. have been utilized as formulation approaches. The present article contains brief review on various formulation approaches for controlled release drug delivery system.
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Formulation and Evaluation of Lamivudine Sustained Release Matrix Tablets Using Synthetic Polymers

Formulation and Evaluation of Lamivudine Sustained Release Matrix Tablets Using Synthetic Polymers

Amelia Avachat, et al. (2007) was developed and characterized an oral controlled release drug delivery system for concomitant administration of diclofenac sodium (DS) and chondroitin sulfate (CS). A hydrophilic matrix-based tablet using different concentrations of hydroxypropyl methylcellulose (HPMC) was developed using wet granulation technique to contain 100 mg of DS and 400 mg of CS. Formulations prepared were evaluated for the release of DS and CS over a period of 9 hours in pH 6.8 phosphate buffer using United States Pharmacopoeia (USP) type II dissolution apparatus. Along with usual physical properties, the dynamics of water uptake and erosion degree of tablets were also investigated. The in vitro drug release study revealed that HPMC K100 CR at a concentration of 40% of the dosage form weight was able to control the simultaneous release of both DS and CS for 9 hours. The release of DS matched with the marketed CR tablet of DS with similarity factor (f2) above 50.
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CHRONOTHERAPY: A REVIEW

CHRONOTHERAPY: A REVIEW

Chronotherapy refers to the use of circadian, ultradian, infradian & seasonal or other rhythmic cycles in the application of therapy. There are number of conditions which show a circadian pattern and advantage could be taken by timing and adjusting the administration of drugs according to the circadian rhythm of the disease. Some of the conditions, which may be significantly benefited, are hypertension, myocardial infarction, bronchial asthma, peptic ulcer, arthritis, duodenal ulcer, diabetes, neurological disorder, cancer and hypercholesterolemia. Chronotherapy can be classified into time controlled systems wherein the drug release is controlled primarily by the delivery system, stimuli induced PDDS in which release is controlled by the stimuli, such as the pH or enzymes present in the intestinal tract or enzymes present in the drug delivery system and externally regulated system where release is programmed by external stimuli like magnetism, ultrasound, electrical effect and irradiation .
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Journal of Applied Pharmaceutical Science

Journal of Applied Pharmaceutical Science

Among all the hydrogels, chitosan is found to be highly significant in the pharmaceutical field because of its favorable biological properties such as biodegradability (Struszczyk et al., 1991) and biocompatibility (Chandy et al., 1990; Hiran et al., 1990) Chitosan, a deacetylated derivative of chitin, is a naturally occurring polysaccharide found abundantly in marine crustaceans, insects and fungi. The drug release studies show that chitosan has been proved to be a very good agent for controlled drug release. There are many processes that can be used to encapsulate drugs within chitosan matrixes such as ionotropic gelation, Prilling Method, Extrusion Method, spray drying, emulsification- solvent evaporation and coacervation. Combinations of these processes are also used in order to obtain microparticles with specific properties and performances (Singh et al., 2011). Biodegradable polymers are recently used for research as they have got superior functional qualities such as their ability to be safely administered within the body, negating the need for surgery, triggers drug release at local sites preventing systemic toxicity, and degrade in a controlled manner for effective, long-term drug release. Therefore, as a growing need of environmental simulation there are various researches done on biodegradable polymers (Xi Zhu et al., 2012). Chitosan being a biodegradable polymer has been a part of smart delivery systems as they possess characteristics like biocompatibility, biodegradability, mucoadhesive, antimicrobial, biocompatibility and bioadhesion (Sharma et al., 2012). Chitosan beads have high potential for developing a successful gastroretentive drug delivery system since they combine both bioadhesion and floating capabilities, especially for drugs that are poorly soluble in intestinal medium and readily soluble acidic medium. The chitosan beads will serve as depot reservoir that will allow the continuous gradual release of small amounts of drug in solution form to the upper part of the small intestine (the main site of absorption) leading to higher and more uniform blood levels of the drug. Thus, reduced adverse effects are highly expected. The qualities of using chitosan as a drug delivery system involves controlled release, decreased particle size leads to increases surface area and hence increased therapeutic action, increased efficacy, decreased toxicity and Increased patient compliance and convenience (Mirkka et al., 2012).In our study, Levocetirizine dihydrochloride was incorporated in a system consisting of hydrogel beads formed by chitosan and were investigated for their in vitro drug release and interactive effects of polymer and drug.
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DEVELOPMENT AND CHARACTERIZATION OF CONTROLLED RELEASE DRUG DELIVERY SYSTEMS OF VALSARTAN MATRIX TABLETS

DEVELOPMENT AND CHARACTERIZATION OF CONTROLLED RELEASE DRUG DELIVERY SYSTEMS OF VALSARTAN MATRIX TABLETS

possessing the two main properties that are single dose or less frequent dosing for the whole duration of treatment and the dosage form must release active drug directly at the site of action Thus the objective of the pharmacist is to develop systems that can be as ideal system as possible. Attempts to develop a single- dose therapy for the whole duration of treatment have focused attention on controlled or delayed release drug delivery systems. The therapy of many chronic diseases requires a repeated dosing of a drug .drugs having a short half-life have to administered up to several times daily within short intervals. To reduce the application frequently delayed formulations have been developed. The therapy of many chronic diseases requires a repeated dosing of a drug .drugs having a short half-life have to administered up to several times daily within short intervals. To reduce the application frequently delayed formulation have been developed.
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 CHITOSAN LOADED MICROSPHERES OF TROPICAMIDE AS CONTROLLED RELEASE OF DRUG FOR OCULAR DRUG DELIVERY SYSTEM

 CHITOSAN LOADED MICROSPHERES OF TROPICAMIDE AS CONTROLLED RELEASE OF DRUG FOR OCULAR DRUG DELIVERY SYSTEM

The amount of polymers i.e. chitosan and sodium tripolyphosphate was taken each at two levels i.e. maximum (3% w/v for chitosan and 2% w/v for sodium tripolyphosphate) and minimum (1.5% w/v for chitosan and 1% w/v for sodium tripolyphosphate) for fixed amount of tropicamide drug to obtain four formulations as shown in Table-1. The amounts of chitosan and sodium tripolyphosphate used in factorial design were determined from literature and maximum and minimum amount were fixed by preparing the trial formulations. Trial formulation showed that when the concentration of chitosan was below minimum value (1.5% w/v), the yield of the microspheres was very low and a polymer film was formed when concentration of chitosan above from maximum level (3.0% w/v). Four formulations were prepared according to the factorial design (2 2 ) by taking maximum and minimum concentrations of
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Development and In Vitro/In Vivo Evaluation of Floating In Situ Gelling Oral Liquid Extended Release Formulation of Furosemide

Development and In Vitro/In Vivo Evaluation of Floating In Situ Gelling Oral Liquid Extended Release Formulation of Furosemide

Floating in situ gel as gastroretentive drug delivery system represents a revolution in oral controlled release dosage forms in comparison with conventional oral liquids, as it prolongs the residence time of the drugs that have narrow absorption windows in the absorptive sites like stomach or upper gastrointestinal tract by having a bulk density lower than gastric fluids and thus remains buoyant in the stomach without affecting the gastric emptying rate until the drug released slowly, continuously and completely. This study was undertaken to formulate furosemide oral solution, which undergoes gelation when it is in direct contact with gastric fluid by using primary polymer (sodium alginate) in addition to the secondary polymer (iota-carrageenan) at different concentrations. Different variables that affect drug release profile like cross linking agent, combination of polymer, gas generating agent and drug concentrations were studied to optimize the best formulation through measuring their effects on viscosity, gel strength, floating lag time and floating duration. The best formulation exhibited 94.9% release of the drug after 5 h with effective floating property. In vivo test was applied and demonstrated good indication to the gastroretentive property of the optimum formulation through its relation to the diuretic property of the drug, and it agreed with in vitro release and the proposed kinetic mathematical modeling. Keywords:
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Controlled quercetin release from high-capacity-loading hyperbranched polyglycerol-functionalized graphene oxide

Controlled quercetin release from high-capacity-loading hyperbranched polyglycerol-functionalized graphene oxide

compared to the acidic solution and rapid-burst effect is not proper for anticancer drug delivery and cancer therapy, as the drug would immediately be removed from blood circulation (pH 7.4) by reticuloendothelial system macrophages before reaching cancer tissue. Due to the acidic tumor environment, pH-dependent drug release from HPG-GO nanocarriers could be exploited for controlled drug-delivery applications, subsequently reducing premature drug release and its related side effects. HPG seems to play two key roles in HPG-GO nanocarriers: stabilizing GO sheets in electrolyte solutions and preventing fast drug release in neutral media. It could be a good candidate for smart drug release.
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NAIL AS A PROMISING DRUG DELIVERY SYSTEM FOR CONTROLLED RELEASE

NAIL AS A PROMISING DRUG DELIVERY SYSTEM FOR CONTROLLED RELEASE

The nail plate is the most visible part of the nail apparatus, consists of tightly packed dead cells and is highly keratinized. It is also very variable among individuals. The plates can be small, large, wide, narrow, hard, smooth, ridged, thin, etc. Disorders of the nail unit range from relatively innocuous conditions such as pigmentation in heavy smokers, to painful and debilitating states where the nail unit can be dystrophied, hypertrophied, inflamed, infected etc,. Oral therapy has the inherent disadvantages of systemic adverse effects and drug interactions while topical therapy is limited by the low permeability of the nail plats 1-3 .
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Preparation and in vitro and in vivo Evaluation of Chitosan-Gliclazide Mucoadhesive Microparticles by an Emulsification- Desolvation- Crosslinking Technique

Preparation and in vitro and in vivo Evaluation of Chitosan-Gliclazide Mucoadhesive Microparticles by an Emulsification- Desolvation- Crosslinking Technique

Introduction: Recently much emphasis is being laid on the development of microparticles because of their potential benefits such as increased bioavailability, reduced risk of systemic toxicity, reduced risk of local irritation and predictable gastric emptying. Objective: The objective of the present study is to prepare and evaluate mucoadhesive microparticles of chitosan-gliclazide for oral controlled release. Methods: A new method namely emulsification-desolvation-crosslinking was used for the preparation of chitosan- gliclazide microparticles and the microparticles were evaluated by in vitro and in vivo methods. Results: Spherical chitosan-gliclazide microparticles could be prepared by the emulsification-desolvation-crosslinking method. The method was reproducible with regard to size and size distribution of the microparticles. The chitosan-gliclazide microparticles exhibited good muoadhesive property. Gliclazide release from the chitosan microparticles was slow and extended over longer periods of time and depended on the proportion of core: coat. Gliclazide release from the chitosan microparticles was by diffusion mechanism. Microparticles (F3) prepared using a core: coat ratio of 8:2 gave slow and controlled release of gliclazide over 12 hr similar to that of commercial gliclazide SR tablets. In the in vivo evaluation, the gliclazide microparticles (F3) gave a slower reduction in serum glucose levels and the reduced glucose levels were sustained over longer periods of time. Conclusion: Microparticles (F3) are considered as a promising microparticulate drug delivery system for oral controlled release of gliclazide over 12 hr for b.i.d administration.
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Mesoporous silica nanoparticles as delivery system against diseases

Mesoporous silica nanoparticles as delivery system against diseases

Despite insolubility, non-specificity and high toxicity of therapeutics associated with biological obstacles such as drug resistance, blood-brain barrier and systemic enzymatic degradation, patients have to take their high dosages to attain the expected therapeutic efficacy for the disease-treatment. To overcome these complications, various drug carriers are being investigated in the pharmaceuticals to supply their therapeutics to the specific sites in the body. Nowadays, mesoporous silica nanoparticles (MSNPs) have emerged as promising candidate because they can overcome all the barriers maximally by producing their biological effectiveness in a controlled and sustained manner to the diseased site. As the mesoporous silica materials have the excellent favorable physicochemical features, the multi-functionalized MSNPs are capable to target and release their cargos into the diseased cells according to the requirement upon exposition to external or internal stimuli. This review demonstrates the state of knowledge for the consideration MSNPs as delivery system against various diseases.
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FORMULATION AND EVALUATION OF SUSTAINED RELEASE MATRIX TABLET OF A MODEL DRUG

FORMULATION AND EVALUATION OF SUSTAINED RELEASE MATRIX TABLET OF A MODEL DRUG

The basic rationale for controlled drug delivery is to alter the pharmacokinetics and pharmacodynamics of pharmacologically active moieties by using novel drug delivery system or by modifying the molecular structure and/or physiological parameters inherent in a selected route of administration.

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FORMULATION AND EVALUATION OF CLOPIDOGREL BISULPHATE FLOATING TABLETS

FORMULATION AND EVALUATION OF CLOPIDOGREL BISULPHATE FLOATING TABLETS

The present study was aimed to develop a novel drug delivery system of Clopidogrel bisulphite matrix floating tablets for controlled release. The mechanism involved was explained in four steps 1) Delivery of tablets to stomach through oral cavity 2) Floating of matrix tablet on stomach fluid due to effervescence 3) Diffusion of drug from the matrix 4) Prolonged release of Clopidogrel bisulphate from the matrix. The main aim and objective of present work was to develop an optimized floating tablets with prolonged drug delivery by comparing four polymers at two differentpolymeric concentrations.
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EVALUATION OF TAZAROTENE LOADED TOPICAL LIPOSOMAL GEL FOR MANAGEMENT OF ACNE

EVALUATION OF TAZAROTENE LOADED TOPICAL LIPOSOMAL GEL FOR MANAGEMENT OF ACNE

The aim of this work was to incorporate tazarotene in suitable liposomal formulation may modify its diffusion parameters in the skin and hence reduce its systemic absorption and consequently its adverse effects. The study was aimed to design a liposomal delivery system for topical administration of tazarotene capable of providing controlled and localized release of the encapsulated drug in order to minimize adverse effects associated with its topical use.

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Microspheres: a Novel Drug Delivery System an Overview

Microspheres: a Novel Drug Delivery System an Overview

Microspheress are characteristically free flowing powders consisting of proteins or synthetic polymers which are biodegradable in nature. Microspheress are particles between 0.1 and 200µm in size. A well designed controlled drug delivery system can overcome some of the problems of conventional therapy and enhance the therapeutic efficacy of a given drug. There are various approaches in delivering a therapeutic substance to the target site in a sustained controlled release fashion. A Microspheress has its drug dispersed throughout the particle i.e. the internal structure is a matrix of drug and polymeric excipients It is the reliable means to deliver the drug to the target site with specificity, if modified, and to maintain the desired concentration at the site of interest without untoward effects. Microspheress received much attention not only for prolonged release, but also for targeting of anticancer drugs to the tumour. Microsphere are spherical microparticles, and are used where consistent and predictable particle surface area is important. . A microspheres has a drug located centrally within the particle, where it is encased within a unique polymeric membrane In future by combining various other strategies, microspheres will find the central place in novel drug delivery, particularly in diseased cell sorting, diagnostics, gene & genetic materials, safe, targeted and effective in vivo delivery and supplements as miniature versions of diseased organ and tissues in the body.
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MODELING THE ORAL CAVITY WITH MUCOADHESIVE DRUG DELIVERY SYSTEMS - A POTENTIAL ALTERNATIVE TO CONVENTIONAL THERAPY

MODELING THE ORAL CAVITY WITH MUCOADHESIVE DRUG DELIVERY SYSTEMS - A POTENTIAL ALTERNATIVE TO CONVENTIONAL THERAPY

Oral mucosal drug delivery system is widely applicable as novel site for administration of drug and controlled release action by preventing first pass metabolism and enzymatic degradation due to GI microbial flora. The oral cavity represents a challenging area to develop an effective drug delivery modelling. This arises due to the various inherent functions of the oral cavity (eating, swallowing, speaking, chewing), as well as the presence of the fluid that is involved in all these activities, saliva. This fluid is continually secreted into and then removed from the mouth. Oral Mucosa drug delivery system provides local and systemic action. The delivery of drugs through the buccal mucosa has attracted much research interest over the past two decades and numerous approaches, both conventional and complex, have been developed in an attempt to deliver a variety of pharmaceutical compounds via the buccal route. To outline the progress in the in vitro and in vivo modeling of Mucosal drug delivery and provide a critical review of currently used methods. The purpose of this review is to represent the modeling of oral cavity with Mucoadhesive drug delivery systems and clarify the potential alternative to conventional therapy.
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FORMULATION AND EVALUATION OF MICROSPHERES CONTATING LAMAVUDINE

FORMULATION AND EVALUATION OF MICROSPHERES CONTATING LAMAVUDINE

A well designed controlled drug delivery system can overcome some of the problems of conventional therapy and enhance of a given drug. To obtain maximum therapeutic efficacy, it becomes necessary to deliver the agent to target tissue in the optimal amount in the right period of time there by causing little toxicity and minimal side effects. These are various approaches in delivering a therapeutic substance to the target site in a sustained controlled release fashion. The approach facilities the accurate delivery of small quantity of the potent drugs, reduced drugs concentration at the site other than the target site and the protection of the liable compound before and after the administration and prior to appearance at the site of action. One such approach is using microspheres as carries of drugs. [17] Microspheres are characteristically free flowing powders consisting of proteins or synthetic polymers having a particle size ranging from 1-1000 μm.
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Formulation Design Development and Evaluation of Extended Release Matrix Tablets of Trimetazidine Hydrochloride.

Formulation Design Development and Evaluation of Extended Release Matrix Tablets of Trimetazidine Hydrochloride.

The rate, extent and uniformity of absorption of a drug are important factors when considering it's formulation into a controlled - release system. Since the rate limiting step in drug delivery from a controlled-release system is its release from a dosage form, rather than absorption, a rapid rate of absorption of drug relative to its release is essential if the 'system is to be successful. In case of controlled release dosage form Kr<<< Ka this becomes most critical in the case of oral administration. Assuming that the transit time of a drug through the absorption half-life should be to 4 hrs. This corresponds to a minimum absorption rate constant Ka of 0.17 to 0.23 hr necessary for about 80 to 95 % absorption over a 9 to 12 hr transit time. For a drug with a very rapid rate of absorption, (i.e. Ka >>0.23 hr-1), the above discussion implies that a first order release rate constant Kr < 0.17 hr-1 is likely to result in unacceptable poor bioavailability in many patients. Therefore, slowly absorbed drugs will be difficult to formulate into controlled release systems where the criteria that Kr <<< Ka must be met.
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FORMULATION OF GASTRORETENTIVE DRUG DELIVERY SYSTEM (FLOATING TABLETS) OF NIFEDIPINE

FORMULATION OF GASTRORETENTIVE DRUG DELIVERY SYSTEM (FLOATING TABLETS) OF NIFEDIPINE

INTRODUCTION: CDDS are those convenient means of drug delivery systems which are meant to obtain a reduction of daily administration of drugs with fast absorption and elimination. Many controlled release systems have been developed for maintaining a therapeutically effective concentration of drug in systemic circulation for longer period of time as well as to reduce side effects 1 .

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