Current Issue : July-September Volume : 2013 Issue Number : 3 Articles : 18 Articles
Combinatorial chemistry and high-throughput screening used in drug discovery have resulted in an70% of new drug candidatesshown poor aqueous solubility in recent years which leads to low oral bioavailability. In clinical use, the poor bioavailability of a drug substancemight result in limited therapeutic potential, thereby leading toinsufficient clinical outcomes. Among the approaches of solubility and bioavailability enhancement, Self emulsifying formulations have great potential for hydrophobic drugs. Conventionally SEDDS were prepared in liquid forms which have various disadvantages of liquid dosage forms. Accordingly, solid SEDDS were prepared by various solidification techniques. This article reviews the recent advancement in solid SEDDS with emphasis on solidification technique, solid SEDDS dosage forms, their associated problems and future directions for the research....
The objective of the article is to review the microsphere based technologies and their recent advances in floating drug delivery systems. Floating drug delivery systems are designed for poorly soluble, unstable and locally acting drugs in the gastrointestinal tract. They bear lower bulk density than gastric content and thus float in the stomach for a prolonged period of time. Designing of floating microspheres is one of the approaches in delivering a drug in controlled release pattern, to achieve plasma concentration rendering better therapeutically efficacy via improved biopharmaceutical characteristics of the drug. This review provides advancements in microsphere based floating drug delivery systems (FDDS) with different categories of drugs addressing related critical issues....
The objective of this article is to review the systems based on site specific drug delivery to colon and its recent approaches. The eagerness to develop dosage form which is free from harmful side effects leads to development of site specific drug delivery system that should have additional advantages such as low dose thus reducing the cost of treatment with lower systemic side effects. The Colon targeted Drug Delivery System has recently gained importance in addressing specific needs in the therapy of colonic diseases and highly desirable for local treatment of a various bowel diseases (such as ulcerative colitis, crohn’s disease, amoebiosis, colonic cancer) and systemic delivery of protein and peptide drugs. Various oral approaches for colon targeted delivery of drugs may be categorized as ph dependent (delayed) release, time controlled, pressure controlled and microbial triggered system (i.e. prodrug and polysaccharides). Most recent approach in this field are ADEPT (antibody-directed enzyme prodrug therapy), GDEPT (gene-directed enzyme prodrug therapy) and hydrogels (enzymaticaly degradable gels)....
The aim of this review is to explore the advancement in the field of polymeric drug delivery carriers particularly bioadhesive microspheres. Microspheres as carriers of drug become an approach of controlled release dosage form in novel drug delivery system. Particularly bioadhesive microspheres posses prolonged residence time at the site of action and allowed to intimate contact with bioadhesive membrane and show therapeutic effect. Bioadhesive microspheres present an impact on drug candidate’s characteristics for improvement of drug absorption. The objective of review is to discuss the theories of bioadhesion, principle underlying the development and evaluation of bioadhesive microspheres and their applications. Various methods employed to prepare bioadhesive microspheres like spray drying, solvent evaporation, hot melt microencapsulation, polymerization emulsification phase separation which are use for low as well as high molecular drugs. Bioadhesive microspheres have been developed for oral, buccal, nasal, ocular, rectal and vaginal routes for either systemic or local effects. Bioadhesive microspheres provide a unique system for many pharmaceuticals and can be tailored to adhere to mucosal tissue and show effect....
The modified release matrix dosage form is preferred in order to avoid fluctuations in the blood levels, which was observed in the conventional dosage form of Nifedipine. The main objective of this study was to formulate sustain release pellet of Nifedipine and compress it into tablet as final dosage form. The drug has low half life of 2 hrs & it is rapidly eliminated. The Multiple Unit System retained in gastrointestinal tract (GIT) for more than 12 hrs and distributed throughout the GIT. Pellets were prepared by Extrusion and Spheronization technique using HPMC K4M as binder and evaluated for micromeritics property. Mixtures of Ethyl Cellulose & Eudragit RSPO were used as coating polymers in different concentrations. Polymer coated pellet were compacted into tablets with a blend of excipients comprising of Microcrystalline Cellulose. SEM photographs and in-vitro release profiles for compacted pellets showed no apparent damage to the coated pellets as a result of the compaction process. The physicochemical parameters of tablets were evaluated as per official methods. Formulated tablets show sustained in-vitro dissolution probably due to optimized concentrations of polymers....
The studies described in this work were designed to evaluate a new sublingual tablet system using low doses of piroxicam. In this system, water-soluble carrier particles are covered with piroxicam and a bioadhesive material during dry mixing. The formulation was evaluated and compared to the influence of accelerated-aging conditions on the drug content and in-vitro dissolution stability of piroxicam fast disintegrating mucoadhesive tablet. Dissolution efficiency (DE) was calculated from dissolution profiles that were performed according to the United State Pharmacopoeia monograph. This determination was performed at time zero, one and three months of storage; (40°C/75% RH). Each formulation was compared with the reference at the specified times, in terms of DE and similarity factor f2. The in-vitro drug release was studied in pH 7.2 Phosphate buffer using Franz diffusion cell. The model independent methods were used to estimate the kinetics of drug release. The criteria for selecting the most appropriate model were based on the goodness-of-fit test. Furthermore, experimentally, we assessed the in-vitro transfer of the prepared piroxicam non aqueous emulsion for steady state flux and permeability coefficient through an artificial cellulose acetate membrane....
The objective of the current investigation is to reduce dosing frequency and improve patient compliance by designing and systematically evaluating mucoadhesive microspheres of Valsartan. Frequent administration and variable low bioavailability (20-25%) after oral administration are problems of conventional dosage forms of valsartan can be attenuated by designing it in the form of mucoadhesive microspheres which would prolong the residence time at the absorption site to facilitate intimate contact with the absorption surface and thereby improve and enhance the bioavailability. Valsartan microspheres were formulated by emulsification solvent-evaporation technique using HPMC K100, Ethyl cellulose as a mucoadhesive polymer with 80.60% entrapment efficiency. The scanning electron microscopic study indicated that the microspheres were spherical in shape and the drug remained dispersed in the polymer matrix at amorphous state, which was further confirmed by X-ray diffraction analysis. The in-vitro wash-off test indicated that the microspheres had good mucoadhesive properties. The wash-off was faster at simulated intestinal fluid (phosphate buffer, pH 7.4) than that at simulated gastric fluid (0.1 M HCl, pH 1.2). The in-vitro drug release mechanism was non-fickian type controlled by swelling and relaxation of polymer. There was no significant change in drug content and cumulative drug release of drug-loaded microspheres stored at different storage condition after 9 weeks of study....
The aim of this research was to prepare floating microspheres consisting of (i) calcium silicate as porous carrier (ii) famotidine, an anti-ulcer agent and (iii) ethylcellulose as rate controlling polymer, by modified emulsion solvent diffusion technique and to evaluate their gastro-retentive and controlled release properties. The effect of process variables on the micromeritics properties, % yield, in-vitro floating behavior, mean particle size, percentage drug entrapment, and in-vitro drug release was studied. A 32 full factorial design employed to study the effect of drug: calcium silicate ratio and amount of ethylcellulose on % encapsulation efficiency, mean particle size and % drug release rate. Better entrapment, floating ability and drug release were obtained for batch F5 and F6.The mean particle size and % drug entrapment were increased but the drug release rate from the microspheres was decreased as the drug: calcium silicate ratio and amount of ethylcellulose were increased. The microspheres were found to be spherical in shape and highly porous. Thus, incorporation of calcium silicate in the microspheres proved to be an effective method to achieve the desired release pattern and buoyancy....
Present work conceptualizes a specific technology intended for chronotherapy. A major objective of chronotherapy in the treatment of several diseases is to deliver the drug in higher concentrations during the time of greatest need according to the circadian onset of diseases or symptoms..The objective of present study was to formulate and characterize single unit pulsatile drug Delivery of captopril which was aimed to release the drug after a lag time of 6 hour. Pulsatile drug delivery system (PDDS) concept was applied to that dosage form which gives lag phase followed by a burst release. The prepared pulsatile delivery system consisted of two different parts: a core tablet, containing the active ingredient, an erodible outer shell. The core tablet (CT) was prepared by 2 3 facorial design using superdisintegrants along with captopril. Coating of optimized CT was done by using hydroxyl propyl methyl cellulose (HPMC) E5, E15, and E50 at different concentration. Developed formulations were evaluated for their physical characteristics; drug content. In vitro drug release and rupture test were performed using united state pharmacopoeia paddle method at 50 rpm in 0.1 N hcl and phosphate buffer 6.8. Results revealed that both, the coating composition and coating level, are significant factors affecting drug release profile. Lag time increases as HPMC concentration increase. HPMC E50 has sufficient lag time as compare to HPMC E5 and E15 which showed compliance with chronotherapeutic objective of hypertension. Achieve chronotherapeutic release of captopril for treatment of hypertension....
The main objective of the present research was to formulate and evaluate extended release matrix tablets of antihypertensive drug Felodipine (FEL). The various batches of extended release tablets were prepared using different concentrations of Kollidon SR and HPMC K 15 and in-vitro release was compared with innovator tablet. Coating of the optimized batch was done using Opadry seal coat and sunset yellow because FEL has problem of light as well as moisture sensitivity. The extended release tablets were prepared by direct compression method and formulated using different polymer ratios. Hydrophilic polymer likeHydroxypropyl methylcellulose K15M (15-35%) and hydrophobic polymer like Kollidon SR (10-305%) were used. Compatibility of the drug with various excipients was studied. The compressed tablets were evaluated for hardness, friability,weight variation, drug content, swelling index and in vitro release study. The optimized formulations were selected on the basis of acceptable tablet properties and in vitro drug release compared with innovator tablet. Optimized betch tablet were coated using Opadry seal coat and sunset yellow by Pan coating method to give protection against light and moisture. Accelerated stability study was performed on optimized batch. The resulting formulation produced robust tablets with optimum hardness, consistent weight uniformity and friability. Tablets containing only Kollidon SR was not give similar release profile with innovator tablet. Addition of hydrophilic polymer and optimization of their concentration gave similar release profile with innovator tablet. The optimized tablets exhibited gradual and extended release of drug up to 12 hr. The results of dissolution studies indicated that formulation F2 (KSR-40mg and HPMC-50mg) and F7 (KSR-60mg and HPMC-30mg), exhibited drug release pattern very close to innovator release profile. So. From that F10(KSR-50mg and HPMC-50mg) was prepared, exhibited same release profile to that of innovator product.The optimized formulation F10 showed diffusion-dominated drug release coupled with erosion. From the obtained results it was concluded that the release of Felodipine from matrix tablets depends on the percent of polymers in the tablet. From the experimental data, an optimal formulationwas developed which has proved to be similar with the dissolution profile of the chosen innovator product and which was protected against light and moisture by opadry seal coat and sunset yellow....
Hydrogels are swellable polymeric materials and due to properties like three dimensional network, swelling characterisitics, biocompatibility and similarity to natural tissues are of primary interest of the researchers. Glucose sensitive hydrogels include pH sensitivity based, lectin based and viscosity based phenylboronic acid containing approaches. The main concept is to achieve glucose sensitivity which can be achieved by modification of the polymers. This article overview the basic concepts which can be included for tighter control over the glucose level just similar to that of the endogenous released insulin which can be helpful to avoid diabetic complications and to provide better patient compliance....
Magnetic drug delivery is a novel approach to delivery drug using engineered ’smart’ micro carriers which appears to overcome a number of limitations facing current methods of delivering medicines. These microcarriers include magnetic microspheres, magnetic liposomes, magnetic nanoparticles, magnetic resealed erythrocytes, magnetic emulsion etc. This review paper will summarize about mechanism of magnetic targeted drug delivery, magnetic carriers, benefits and drawbacks of magnetic targeting, characterization and application of magnetism in targeted drug delivery and some other field. They offer high potential for numerous biomedical applications, such as cell separation, automated DNA extraction, gene targeting, drug delivery, MRI and hyperthermia....
Fast dissolving systems becoming more and more acceptable in the population having difficulty in swallowing the conventional oral solid dosage form. To overcome this trouble different fast dissolving/dispersible system arrived in market, of which orodispersible tablets and mouth dissolving tablets (MDT) cover maximum area. Now research is going on for formulation and development of mouth dissolving films, since it is more advantageous over MDT. Now a day’s researchers are giving more emphasis on developing convenient method for preparation of film so as to increase its industrial applicability. USFDA has approved this dosage form and hence many researchers opt. for patenting their technique. Mouth dissolving films has given a new platform for the researchers in the sector of formulation. This film technology is still at beginning stage and has bright future since it fulfils all patient needs. Here in this review recent work which has been done in the development of mouth dissolving film is taken in to account....
Nanoemulsions are submicron sized emulsions which are clear, transparent and thermodyanmically stable with a droplet size ranging from 5-200nm. acts as drug carriers for improving the delivery of therapeutic agents. Nanoemulsion are isotropic liquid mixtures of oil, water, surfactant and co-surfactant. Nanoemulsions have widespread applications in different fields such as pharmaceutics and food technology. Nanoemulsion offers a promising vehicle for increasing the aqueous solubility of poorly water-soluble drugs. The development of nanoemulsions aimed at improving the required bioavailability levels of therapeutic agents. This review mainly discusses about the preparation methods, characterization and applications of nanoemulsions....
Poor aqueous solubility of drugs is often a challenging task for formulators in the industry as the solubility is an essential factor for drug effectiveness, independent of the route of administration.. Conventional approaches for enhancement of solubility have limited applicability, especially when the drugs are poorly soluble simultaneously in aqueous and in non-aqueous media. Nanosuspension formulation can be used to enhance the solubility as well as the bioavailability of poorly soluble drugs. Nanosuspension is a biphasic system consisting of pure drug particle dispersed in an aqueous vehicle in which diameter of the suspended particle is less than 1000nm in size, with an average particle size ranging between 200 and 600 nm. These are simple to prepare and are more advantageous than other approaches. Techniques such as wet milling, high-pressure homogenization, emulsification-solvent evaporation and super critical fluid have been used in the preparation of nanosuspensions. It has the advantage of delivery by various routes, including oral, parenteral, pulmonary and ocular routes. The present review consist of the current methods used to prepare nanosuspensions, their application, advantages and their application in drug delivery....
The poor bioavailability and therapeutic response exhibited by conventional ophthalmic solutions due to rapid precorneal elimination of the drug may be overcome by the use of in situ gel-forming systems that are instilled as drops into the eye and undergo a sol–gel transition in the cul-de-sac. The present work describes the formulation and evaluation of an ophthalmic delivery system of an antiviral agent, Acyclovir sodium, based on the concept of pH-triggered in situ gelation. Polyacrylic acid (Carbopol® 940) was used as the gelling agent in combination with hydroxypropyl methylcellulose (HPMC) which acts as a viscosity enhancing agent. The developed formulation was therapeutically efficacious, stable and non-irritant and provided controlled release of the drug over an 8 hr period. The developed system is thus a viable alternative to conventional eye drops....
Furosemide is a weakly acidic diuretic indicated for treatment of edema and hypertension. It has very poor solubility but high permeability through stomach and upper gastrointestinal tract (GIT). It has very poor permeability in the intestinal region resulting in very limited absorption in the intestinal region. Hence stomach remains the preferential site for oral absorption of furosemide but due to its poor solubility in this region it has poor and variable oral bioavailibility of 10-90%. The aim of this study was to enhance the oral bioavailibilty of furosemide by preparation of nanosuspensions. The nanosuspensions were prepared by nanoprecipitation with ultrasonnication using DMSO (Dimethylsulfoxide) as solvent and water as antisolvent (NA). The prepared nanosuspensions were stabilized with Poly vinyl acetate (PVA).These were characterized for particle size, zeta potential, polydispersity index, Scanning electron microscopy (SEM), Differential scanning calorimetry (DSC), X-ray diffraction (XRD) and release. Nanosuspension of furosemide with average particle size in the range of 150 -300 nm were obtained. The preparation were homogenous as indicated by polydispersity index in the range of 0.3+ 0.1 and stable. The particle size and dispersity was found to be dependent on concentration of drug and stabiliser. DSC and XRD studies indicated that the crystalline furosemide drug was converted to amourphous form. Significant enhancement in saturation solubility of furosemide in simulated gastric fluid showing 36 fold increase was observed. It may be concluded that preparation of nanosuspension of furosemide may be useful in enhancement of saturation solubility of furosemide in gastric condition. This enhanced saturation solubility in simulated gastric fluid may lead to enhanced absorption of furosemide from stomach region where it has better permeability. The nanosuspension can be prepared by antisolvent precipitation with ultrasonnication using Poly vinyl acetate as a suitable steric stabilizer to prepare stable furosemide nanosuspensions....
The aim of this study was to prepare an inclusion complex of Olmesartan Medoxomil, a novel angiotensin II Type 1 (AT1) receptor antagonist with B-cyclodextrin (B-CD) to improve its apparent solubility, dissolution rate and stability. Olmesartan Medoxomil, a selective and competitive angiotensin II Type 1 (AT1) receptor antagonist, is a highly crystlline powder which is practically insoluble in water. Because of its limited aqueous solubility it exhibits poor dissolution characteristics and its oral absorption is dissolution rate limited. In this study the effect of β- cyclodextrin (βCD) on the aqueous solubility and dissolution rate of Olmesartan Medoxomil was investigated. Phase solubility profiles indicated that the solubility of Olmesartan Medoxomil was significantly increased in the presence of β-cyclodextrin and was classified as AL-type, indicating the formation of 1:1 stoichiometric inclusion complexes with a stability constant of 86.38. Solid complexes prepared by Neutralization method were investigated in solid state By UV Spectrophotometry and characterized by Fourier transform infrared spectroscopy, X-ray Diffraction & Scanning Electron Microscopy. Olmesartan Medoxomil Solubility significantly improved by complexation with β-cyclodextrin with respect to the drug alone....
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