The Experts below are selected from a list of 285 Experts worldwide ranked by ideXlab platform
Yousef Javadzadeh - One of the best experts on this subject based on the ideXlab platform.
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Nanosizing of drugs: Effect on Dissolution Rate.
Research in pharmaceutical sciences, 2015Co-Authors: S Maleki Dizaj, Zhila Vazifehasl, Sara Salatin, Khosro Adibkia, Yousef JavadzadehAbstract:The solubility, bioavailability and Dissolution Rate of drugs are important parameters for achieving in vivo efficiency. The bioavailability of orally administered drugs depends on their ability to be absorbed via gastrointestinal tract. For drugs belonging to Class II of pharmaceutical classification, the absorption process is limited by drug Dissolution Rate in gastrointestinal media. Therefore, enhancement of the Dissolution Rate of these drugs will present improved bioavailability. So far several techniques such as physical and chemical modifications, changing in crystal habits, solid dispersion, complexation, solubilization and liquisolid method have been used to enhance the Dissolution Rate of poorly water soluble drugs. It seems that improvement of the solubility properties ofpoorly water soluble drugscan translate to an increase in their bioavailability. Nowadays nanotechnology offers various approaches in the area of Dissolution enhancement of low aqueous soluble drugs. Nanosizing of drugs in the form of nanoparticles, nanocrystals or nanosuspensions not requiring expensive facilities and equipment or complicated processes may be applied as simple methods to increase the Dissolution Rate of poorly water soluble drugs. In this article, we attempted to review the effects of nanosizing on improving the Dissolution Rate of poorly aqueous soluble drugs. According to the reviewed literature, by reduction of drug particle size into nanometer size the total effective surface area is increased and thereby Dissolution Rate would be enhanced. Additionally, reduction of particle size leads to reduction of the diffusion layer thickness surrounding the drug particles resulting in the increment of the concentration gradient. Each of these process leads to improved bioavailability.
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liquisolid technique for Dissolution Rate enhancement of a high dose water insoluble drug carbamazepine
International Journal of Pharmaceutics, 2007Co-Authors: Yousef Javadzadeh, Baharak Jafarinavimipour, Ali NokhodchiAbstract:Different liquisolid formulations of carbamazepine were accomplished by dissolving the drug in the non-toxic hydrophilic liquids, and adsorbing the solution onto the surface of silica. In order to reduce the amounts of carrier and aerosil in liquisolid formulations, some additives namely polyvinylpyrrolidone (PVP), hydroxypropyle methylcellulose (HPMC) and polyethylene glycol (PEG 35000) were added to liquid medication to increase loading factor. The effects of various ratios of carrier to coating material, PVP concentration, effect of aging and type of the carrier on Dissolution Rate of liquisolid compacts were studied. X-ray crystallography and differential scanning calorimetery (DSC) were used for evaluation of physicochemical properties of carbamazepine in liquisolid formulations. The results showed that the drug loading factor was increased significantly in the presence of additives. Liquisolid formulations containing PVP as additive, exhibited significantly higher drug Dissolution Rates compared to the compacts prepared by the direct compression technique. It was shown that microcrystalline cellulose had more liquid retention potential in comparison with lactose, and the formulations containing microcrystalline cellulose as carrier, showed higher Dissolution Rate. By decreasing the ratio of microcrystalline cellulose to silica from 20 to 10, an improvement in Dissolution Rate was observed. Further decrease in the ratio of microcrystalline cellulose:silica from 10 to 5 resulted in a significant reduction in Dissolution Rate. Increasing of PVP concentration in liquid medication caused a dramatic increase in Dissolution Rate at first 30 min. The results showed that the Dissolution Rate of liquisolid tablets was not significantly affected by storing the tablets at 25 °C/75% relative humidity for a period of 6 months. The results of DSC and X-ray crystallography did not show any changes in crystallinity of the drug and interaction between carbamazepine and exipients during the process.
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enhancement of Dissolution Rate of piroxicam using liquisolid compacts
Farmaco, 2005Co-Authors: Yousef Javadzadeh, Ali Nokhodchi, Mohammadreza Siahishadbad, Mohammad BarzegarjalaliAbstract:Piroxicam is a poorly soluble, highly permeable drug and the Rate of its oral absorption is often controlled by the Dissolution Rate in the gastrointestinal. The poor Dissolution Rate of water-insoluble drugs is still a major problem confronting the pharmaceutical industry. There are several techniques to enhance the Dissolution of poorly soluble drugs. Among them, the technique of liquisolid compacts is a promising technique towards such a novel aim. In this study, the Dissolution behaviour of piroxicam from liquisolid compacts was investigated in simulated gastric fluid (SGF, pH 1.2) and simulated intestinal fluid (SIF, pH 7.2). To this end, several liquisolid tablets formulations containing various ratios of drug:Tween 80 (ranging from 10% to 50% w/w) were prepared. The ratio of microcrystalline cellulose (carrier) to silica (coating powder material) was kept constant in all formulations. The results showed that liquisolid compacts demonstRated significantly higher drug release Rates than those of conventionally made (capsules and directly compressed tablets containing micronized piroxicam). This was due to an increase in wetting properties and surface of drug available for Dissolution.
Diana Chow - One of the best experts on this subject based on the ideXlab platform.
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Metastable Polymorph of Etoposide with Higher Dissolution Rate
Drug development and industrial pharmacy, 1999Co-Authors: Jaymin C. Shah, Jivn R. Chen, Diana ChowAbstract:Etoposide, an anticancer drug, has low oral bioavailability because of low aqueous solubility, slow Dissolution Rate, and instability in acidic pH. Our objective was to enhance the aqueous solubility and Dissolution Rate of etoposide by polymorph formation. Preparation of various polymorphs of etoposide was attempted by crystallizing etoposide from organic solvents. Physicochemical properties of the crystals, namely, crystal habit, thermal behavior with hot-stage microscopy, thermal analysis by differential scanning calorimetry, IR spectrum, and solubility and Dissolution Rates, were examined. Based on the physicochemical characteristics, a metastable polymorph of etoposide was identified when it was crystallized from isopropanol. The metastable polymorph had an equilibrium solubility and intrinsic Dissolution Rate of 221 μg/ml and 16.3 μg/min/cm 2 , respectively; 1.9 and 1.7 times that of etoposide powder at 25°C, respectively.
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preformulation study of etoposide ii increased solubility and Dissolution Rate by solid solid dispersions
International Journal of Pharmaceutics, 1995Co-Authors: Jaymin C. Shah, Jivn R. Chen, Diana ChowAbstract:Abstract Etoposide, an anticancer drug, has low and erratic oral bioavailability which is due to low aqueous solubility, slow Dissolution Rate and instability in acidic pH. The study objective was to enhance the aqueous solubility and Dissolution Rate of etoposide by solid-state modifications, which was attempted by preparation of solid-solid dispersions by coprecipitating the drug with polyethylene glycols (PEG) of different molecular weights in various ratios. The solubility and Dissolution Rate of etoposide from the coprecipitates were evaluated. The coprecipitate of etoposide with PEG 8000 (1:10, PEG weight fraction of 0.91) increased its solubility 2-fold and Dissolution Rate 42-fold (190.7/zg/ml and 0.42 mg/min per cm2 vs 93.8/xg/ml and 0.01 mg/min per cm2 of etoposide pure powder, respectively). The coprecipitates with other PEGs (PEG 1500, PEG 3400, PEG 6000) and PVP 40000 also increased etoposide Dissolution Rate to a great extent.
Eugene L. Parrott - One of the best experts on this subject based on the ideXlab platform.
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Relationship of Dissolution Rate in anionic polymeric solutions to viscosity
Drug Development and Industrial Pharmacy, 1991Co-Authors: Shu-hwa Chang, Eugene L. ParrottAbstract:AbstractThe influence of viscosity on the Dissolution Rate of m-acetotoluidide in aqueous solutions of acacia, gelatin type B, sodium carboxymethylcellulose, sodium alginate and xanthan gum was investigated. The viscosity was measured by a rotational viscometer. The Dissolution Rates decreased as the viscosities of solutions of anionic polymers increased. The curves representing the relationship of Dissolution Rate and viscosity varied for each polymeric solution depending on the structural characteristics of the polymer.
Rutesh H Dave - One of the best experts on this subject based on the ideXlab platform.
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impact of nanosizing on solubility and Dissolution Rate of poorly soluble pharmaceuticals
Journal of Pharmaceutical Sciences, 2015Co-Authors: Sharad B Murdande, Dhaval A Shah, Rutesh H DaveAbstract:The quantitative determination of solubility and the initial Dissolution Rate enhancement of crystalline nanoparticles were critically investigated using a separation-based approach (ultracentrifugation and filtration). Four poorly soluble model compounds (griseofulvin, celecoxib, compound-X, and fenofibRate) were used in this investigation. The effect of the stabilizer concentration on the solubility of the unmilled compound was determined first to quantify its impact on the solubility and used for comparing solubility enhancement upon nanosizing. Methodologies were established for ultracentrifugation, ensuring satisfactory separation of crystalline nanoparticles. The data obtained using separation-based methodologies proved to be accuRate, reproducible, and were in fair agreement with what would be predicted from the Ostwald-Freundlich equation. The Dissolution studies under sink conditions were proved to be less efficient in quantifying the initial Dissolution Rate of crystalline nanoparticles. Nonsink Dissolution experiments were able to reduce the high-Dissolution velocity of nanoparticles and geneRated the best discriminative Dissolution profile. The enhancement in initial Dissolution Rate was significantly less than that expected from the Noyes-Whitney equation based on surface area change. This discriminatory Dissolution method can potentially be used further in the modeling of crystalline nanoparticles during drug development.
Jaymin C. Shah - One of the best experts on this subject based on the ideXlab platform.
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Metastable Polymorph of Etoposide with Higher Dissolution Rate
Drug development and industrial pharmacy, 1999Co-Authors: Jaymin C. Shah, Jivn R. Chen, Diana ChowAbstract:Etoposide, an anticancer drug, has low oral bioavailability because of low aqueous solubility, slow Dissolution Rate, and instability in acidic pH. Our objective was to enhance the aqueous solubility and Dissolution Rate of etoposide by polymorph formation. Preparation of various polymorphs of etoposide was attempted by crystallizing etoposide from organic solvents. Physicochemical properties of the crystals, namely, crystal habit, thermal behavior with hot-stage microscopy, thermal analysis by differential scanning calorimetry, IR spectrum, and solubility and Dissolution Rates, were examined. Based on the physicochemical characteristics, a metastable polymorph of etoposide was identified when it was crystallized from isopropanol. The metastable polymorph had an equilibrium solubility and intrinsic Dissolution Rate of 221 μg/ml and 16.3 μg/min/cm 2 , respectively; 1.9 and 1.7 times that of etoposide powder at 25°C, respectively.
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preformulation study of etoposide ii increased solubility and Dissolution Rate by solid solid dispersions
International Journal of Pharmaceutics, 1995Co-Authors: Jaymin C. Shah, Jivn R. Chen, Diana ChowAbstract:Abstract Etoposide, an anticancer drug, has low and erratic oral bioavailability which is due to low aqueous solubility, slow Dissolution Rate and instability in acidic pH. The study objective was to enhance the aqueous solubility and Dissolution Rate of etoposide by solid-state modifications, which was attempted by preparation of solid-solid dispersions by coprecipitating the drug with polyethylene glycols (PEG) of different molecular weights in various ratios. The solubility and Dissolution Rate of etoposide from the coprecipitates were evaluated. The coprecipitate of etoposide with PEG 8000 (1:10, PEG weight fraction of 0.91) increased its solubility 2-fold and Dissolution Rate 42-fold (190.7/zg/ml and 0.42 mg/min per cm2 vs 93.8/xg/ml and 0.01 mg/min per cm2 of etoposide pure powder, respectively). The coprecipitates with other PEGs (PEG 1500, PEG 3400, PEG 6000) and PVP 40000 also increased etoposide Dissolution Rate to a great extent.