Current Issue : April - June Volume : 2011 Issue Number : 2 Articles : 15 Articles
The study reports bilayered osmotic tablets for sustained co-delivery of isoniazid (INH) and rifampicin (RMP). Polyethylene oxide (PEO) as release retardant was incorporated with INH layer, whereas wicking agent (sodium lauryl sulphate) and buffer (citric acid) were used as solubility enhancer with RMP layer. Bilayered core tablets were coated with cellulose acetate and drilled with two orifices, one at each side. Release profiles of different batches were compared using model dependent and model independent approaches. A significant increase in the release rate of RMP was observed in the presence of buffer and wicking agents. PEO at a concentration of 20 %w/w of total INH core showed zero-order release pattern. Plasticizer concentrations of 1% w/w and membrane thickness of 100 µm were found to be optimum in maintaining the integrity of tablets. Optimized formulation delivered both drugs at approximately zero-order rate up to 24 hrs, independent of pH and agitation rate of the release media. SEM studies showed that coating membrane and orifice maintained their intactness throughout the study period. No interaction between drug and excipients was revealed by DSC study. Formulations, tested for stability at 40±2°C and 75±5% RH for 3 months, were found to be stable....
Lysosomes are membrane-delimited, hydrolase rich organelles responsible for the degradation of biological macromolecules. They also play an important part in processing essential metabolites. A genetic defect in a protein responsible for maintaining the lysosomal system results in the accumulation within lysosomes of partially degraded molecules, the initial step in the process leading to a lysosomal storage disease. The defective protein may be a luminal lysosomal enzyme or protein cofactor, a lysosomal membrane protein or a protein involved in the post-translational modification or transport of lysosomal proteins. Lysosomal storage diseases (LSD’s) comprise a diverse group of monogenetic disorders with complex clinical phenotypes that include both systemic and central nervous system pathologies. They encompass greater than 40 distinct inherited metabolic diseases and have a collective incidence of 1 in 7000–8000 live births. LSD’s are progressive and may present at any age affecting any number of tissues and organ systems. Most of the genes for the lysosomal proteins have been cloned, permitting mutation analysis in individual cases. This information can be used for genotype/phenotype correlation, genetic counseling and the selection of patients for novel forms of therapy, such as substrate deprivation or dispersal, enzyme replacement, bone-marrow transplantation and gene transfer. In this article, we will briefly review the cell biological and clinical features of these diseases and discuss the progress towards the development of effective treatments....
The objective of the present study is to develop colon targeted drug delivery system by using combination of Xanthan gum and Guar gum in different proportions by employing Theophylline as model drug. Matrix tablets containing various excipients and Xanthan gum were prepared by wet granulation technique using different concentrations. All the prepared tablets were evaluated for Hardness, Weight variation, Drug uniformity, Friability and In-vitro drug release study. The final product is expected to release its contents in colonic region. The results of in-vitro study indicated that matrix tablets containing combination of Xanthan gum and Guar gum (20:10) and PVP as binder are most suitable to deliver the drug specifically in colonic region. The final formulation F6 which contains Xanthan gum and Guar gum in the proportion of 20:10 was suitable for achieving colon specific drug delivery for the treatment of nocturnal symptoms of asthma....
An attempt has been made to develop buccal mucoadhesive bilayered tablet comprising of drug containing bioadhesive core layer and drug free backing layer to release the drug for sustained period of time. Buccal tablets of Atenolol were prepared by direct compression method. Mucoadhesive polymers Carbopol (CP934P), Hydroxylpropylmethyl cellulose (HPMC K4M), Polyvinylpyrolidone (PVP K32) in combination with backing layer of ethyl cellulose were used. The formulations were then evaluated with respect to physical characteristics, surface pH, swelling index, mucoadhesive strength, disintegration time, In vitro drug release and In vitro permeation. The tablets were evaluated for In vitro drug release in phosphate buffer pH 6.8 for 8 hr using USP Type 2 dissolution test apparatus. The physical characteristics, surface pH, swelling index, bioadhesive strength, disintegration time and In vitro drug release were shown to be dependent on characteristics and composition of bioadhesive material used. Formulation F2 showed maximum release of the drug (93.02 ± 0.4%) with non fickian release mechanism and permeated 54.21 ± 2.9% of the drug through sheep buccal membrane. The present study proves that mucoadhesive bilayered tablets of Atenolol with controlled drug release properties can be successfully prepared by direct compression method using HPMC K4M and Polyvinyl pyrollidone K32 as mucoadhesive polymers and ethyl cellulose as backing layer....
In a previous note, small unilamellar liposomes were prepared using an extrusion procedure (SUVETs) from a lipid mixture known for its fusogenic properties towards eukaryotic cell membranes (namely, dipalmitoylphosphatidylcholine, DPPC; dioleoylphosphatidylethanolamine, DOPE; and cholesterol hemisuccinate, CHEMS). The antibiotic vancomycin (VAN) was loaded with high efficiency in these vesicles that, in vitro, were able to inhibit the growth of wild and standard Gram-negative bacterial strains. Since neither the free antibiotic nor VAN-loaded ‘classical’ (non fusogenic) liposomes showed any activity against the same microorganisms, we have further developed the investigation by preparing a series of VAN-loaded fusogenic SUVETs, in which the molar ratios between the three ingredients was varied, or alternatively removing one of them.In this paper we present the technological details and the in vitro microbiological data of these new SUVETs. All the prepared samples showed a close profile of activity against the tested bacterial strains. This confirms that the activity of liposomal VAN against Gram-negative bacteria appears to be linked both to the presence of the fusogenic DOPE and the inclusion of CHEMS in the composition of the liposomes....
Background/Hypothesis: Curing of matrix tablet as a function of time may sustain the action of dosage form and reduce the usage of polymer concentration which ultimately leads to reduction in product cost. Method: Eudragit RLPO -based matrix tablets, were manufactured to investigate release rate and mechanism of drug release by fitting the dissolution data obtained to various kinetic models viz. Zero order, First order, Higuchi, Hixon-Crowell and Korsmeyer-Peppas. Scanning electron microscopy was used to assess changes in the microstructure of the tablets and mechanism of drug release. IR spectroscopy, XRD, and DSC studies were performed on cured and uncured matrix formulations for assessing the drug compatibility during curing treatment. Results revealed that Korsmeyer-Peppas model was best suited for all formulations indicating drug release by diffusion and erosion. Dissolution study of various compositions with and without curing, justifies that, timed curing reduces usage of polymer concentration and sustains the action of dosage form. It was also apparent that changes in the microstructure of matrix tablets after curing could be related to the alteration in drug release and was ultimately dependent on polymer concentration and the time of curing. IR spectroscopy, XRD, and DSC showed no change in the crystal form of Lornoxicam. Conclusion: With curing, lower concentration of polymer is sufficient to achieve desired drug release from matrix tablet which ultimately leads to reduction in product cost....
The present investigation was designed with the objective of role of electrolyte on the drug release from aceclofenac floating minimatrices. The formulations were fabricated by a simple extrusion technique. Minimatrices of size 1.14-1.5 mm were prepared by different drug: polymer ratio of 1:1, 1:2, 1:3 ratios. Calcium carbonate and calcium chloride were incorporated to produce effervescence and as an electrolyte respectively. Pale ash to white coloured minimatrics showed no interactions in DSC Thermograms. Although Aceclofenac because of its weakly acidic nature was poorly soluble in gastric pH, calcium chloride as an electrolyte does enhanced the solubility and henceforth the drug release as well as buoyancy, but seldom influenced other parameters....
In recent years scientific and technological advances have been made in development of controlled oral drug delivery system by overcoming physiological adversities, such as short residence time and unpredictable gastric emptying time (GET). Oral sustained release gastro-retentive dosage forms (GRDFs) offer many advantages for drugs with absorption from upper parts of gastrointestinal tract and for those acting locally in the stomach, improving the bioavailability of the medication. Floating Drug Delivery Systems (FDDS) is one amongst the GRDFs used to achieve prolonged gastric residence time. The gastroretention could help to provide greater availability of new products and improve therapeutic activity and substantial benefits to patients. Floating Drug delivery system are designed to prolong the gastric residence time after oral administration, at particular site and controlling the release of drug especially useful for achieving controlled plasma level a swell as improving bioavailability....
The objective of present investigation was to develop sustained release matrix tablet of ambroxol hydrochloride and salbutamol sulphate combination for the treatment of nocturnal asthma. In the present study the effect of various formulation factors such as polymer proportion, polymer viscosity and compression force on the in vitro release of drugs was studied. To analyze the concentration value of ambroxol hydrochloride and salbutamol sulphate simultaneous equations were formed. Infrared spectroscopy study confirms that drugs and other excipients are compatible with each other. The powder mixtures were evaluated for there micromeritic properties showed satisfactory compressibility and flow properties. Formulations were developed by using polymer HPMC (K4M, K15M, and K100M) in varying concentrations by direct compression method. The developed drug delivery system were evaluated for there pharmacotechnical properties which comply with official specifications. Invitro dissolution study were carried out in 0.1 N HCL for first 2 hrs and in phosphate buffer pH 6.8 up to 12 hrs using USP Type II dissolution apparatus revealed that the release rate decreases with increase in polymer concentration, viscosity grade and compression force. In vitro dissolution study also revealed that HPMC K100M at a concentration of 20% of the dosage form weight was found to be significant to control simultaneous releases of both drugs for 12 hrs, exhibit non-Fickian diffusion with heguchi release kinetics. Swelling and erosion study of formulation indicates that swelling followed by erosion could be the mechanism of drugs release. The batch reproducibility study and accelerated stability study was also performed for optimized formulation (FH-15) indicated that formulation was reproducible and stable. It may conclude that developed sustained release matrix tablet of ambroxol hydrochloride and salbutamol sulphate combination could perform therapeutically better than conventional dosage forms, leading to improve efficacy, feasibility and better patient compliance....
A multiple-unit floating drug delivery system based on gas formation technique was developed, in order to prolong the gastric residence time and to increase the overall bioavailability of the dosage form. The floating bead formulations were prepared by dispersing nimodipine together with calcium carbonate in a mixture of sodium alginate and hydroxypropyl methylcellulose solution and then dripping the dispersion into an acidified solution of calcium chloride. Calcium alginate beads were formed, as the alginate underwent ionotropic gelation by calcium ions, and carbon dioxide developed from the reaction of carbonate salts with acid. The obtained beads were able to float due to CO2 gas formation and the gas entrapment by the polymeric membrane. The prepared beads were evaluated for percent drug loading, drug entrapment efficiency, morphology, surface topography, buoyancy, in-vitro release, and release kinetics. The formulations were optimized for different weight ratios of the gas-forming agent and sodium alginate. The beads containing higher amounts of calcium carbonate demonstrated an instantaneous, complete, and excellent floating ability over a period of 24 hours. The increased amount of the gas forming agent did not affect the time to float, but increased the drug release from the floating beads, while increasing the coating level of the gas-entrapped membrane, increased the time to float, and slightly retarded the drug release. Good floating properties and sustained drug release were achieved. Finally, these floating beads seemed to be a promising gastroretentive drug delivery system....
The aim of the investigation was to develop and evaluate matrix type transdermal drug delivery systems (TDDS) of Dexamethasone. Dexamethasone is a steroid and used in a treatment of rheumatoid arthritis. The matrix type TDDS of Dexamethasone were prepared by solvent evaporation technique. Four formulations (composed of hydroxyl propylmethyl cellulose and poly vinyl pyrrolidone in the ratios of 9:1, 8:2, 7:3, 6:4 in formulations F1, F2, F3 and F4,) were prepared. 15 % w/v of propylene glycol as plasticizer in methanol and water as solvent system. The prepared transdermal patches were evaluated for in-vitro release, moisture absorption, tensile strength, drug content uniformity and mechanical properties. Preparation of standard curve for Dexamethasone in solution of 5 % methanolic phosphate buffer pH 6.8. In vitro drug release profile was performed by diffusion cell using above solution. Take absorbance at same time interval by UV spectrophotometer and calculate % drug release at particular time interval. The maximum drug release in 6 hrs for formulations was in the range of 85.75 % to 99.56 %. The mechanical properties, tensile strength, elastic modulus (0.204 kg/cm2 and 18.33 % for batch code F4) reveal that the formulations were found to be strong but not brittle. Average thickness (0.26 mm for F4), folding endurance 72 for F4 and % moisture uptake (4.78% for F4) also found in prepared patches. Drug content was 94.79 for F4 and swellability was 23.43 % for F4. Dexamethasone matrix type transdermal therapeutic systems could be prepared having suitable mechanical properties & sustained release dosage form. The permeation profile was matrix diffusion type....
The design of oral controlled drug delivery systems should be primarily aimed to achieve the more predictability and reproducibility to control the drug release, drug concentration in the target tissue and optimization of the therapeutic effect of a drug by controlling its release in the body with lower and less frequent dose. Several controlled release drug delivery strategies have been proposed to overcome these limitations. Although all these approaches improve the oral bio availability of large molecules, none of them offers a complete solution for adequate and safe oral administration. To resolve such kind of problems there are lots of researches are going on. Recently for especially gastrointestinal drug delivery system many changes are come to occur. The recent advance in GIT drug delivery system is gastrointestinal (GIT) patch system for oral drug delivery system. Gastrointestinal patch systems with integrated multifunction could overcome the challenges related to conventional drug delivery. Several gastrointestinal patch systems provide bio-adhesion, drug protection and unidirectional drug release....
The biggest problem in oral drug delivery is low and erratic bioavailability, which mainly results from one or more factors. This, in turn, may lead to irreproducible clinical response or a therapeutic failure in some cases due to sub therapeutic plasma drug levels. From an economic point of view, low oral bioavailability results in the wasting of a large portion of an oral dose and adds to the cost of drug therapy, especially when the drug is an expensive one. Several pharmaceutical companies over the last few years much research efforts have been made in this area to adverse various biological and technological issues. Now a day the liquisolid system comes in a picture as an innovative approach for improving the low bioavailability of poorly soluble drugs by increasing their solubility. The term \"liquisolid systems\" refers to powdered forms of liquid medications formulated by converting liquid lipophilic drugs, or drug suspensions or solutions of water-insoluble solid drugs in suitable non-volatile solvent systems, into \"dry\" (i.e., dry-looking), nonadherent, free-flowing and readily compressible powder admixtures by blending with selected carrier and coating materials....
ABSTRACT \r\nTransdermal drug delivery system is emerging system as compaired to oral and parenteral. In TDDS, patch system was developed to control the release of drug .Conventional transdermal drug delivery system achieved advantages over the oral and parenteral. Consequently a number of vesicular drug delivery systems such as liposomes, niosomes were been developed as novel transdermal drug delivery system. Firstly, it delivers the drug at a rate directed by the needs of the body, over the period of treatment. Secondly, it channels the active entity to the site of action. Liposomal as well as niosomal systems, are not suitable for transdermal delivery, because of their poor skin permeability, breaking of vesicles, leakage of drug, aggregation, and fusion of vesicles. To overcome these problems, a new type of carrier system called \"transfersome\", has recently been introduced, which is capable of transdermal delivery of low as well as high molecular weight drugs.Transferosomes is a supramolecular entity that can pass through a permeability barrier and there by transport material from the application to the destination site. These are more elastic than standard liposomes. Transferosomes have been widely used as a novel carrier for effective transdermal drug delivery. Transferosomes enhances the penetration of most of the low as well as high molecular weight drugs, while in case of lipophilic drugs the entrapment efficiency can reach upto 90%.It is now widely used as a novel carrier for both systemic as well as topical delivery of drugs....
In present scenario, all the world wide researcher of Pharmaceutical field is well versed with the fact that the overall action of a drug molecule is not only dependent on its inherent therapeutic activity, rather on the efficiency of its delivery at the site of action. Many drug delivery systems (DDS) are aimed to sustain drug blood concentration and controlling the rate of drug delivery to the target tissue, but mucoadhesion is one of the most prominent and latest systems in the design of gastro retentive drug delivery systems. It prolongs the residence time of the dosage form at the site of application or absorption and facilitates an intimate contact of the dosage form with the underline absorption surface and thus contributes to improved and / or better therapeutic performance of the drug. In recent years many such mucoadhesive drug delivery systems have been developed for oral, buccal, nasal, gastrointestinal, rectal and vaginal routes for both systemic and local effects. The present review compile the recent literature with special focus on various gastroretentive approaches that have recently become leading methodologies in the field of site-specific orally administered controlled release drug delivery. In order to understand various physiological difficulties to achieve gastric retention, Finally, advantages of gastroretentive drug delivery systems were covered in detail....
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