The Experts below are selected from a list of 46476 Experts worldwide ranked by ideXlab platform
Bing Zhang - One of the best experts on this subject based on the ideXlab platform.
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ultrafast photoinduced charge transfer character in ofloxacin singlet decay
Chemical Physics Letters, 2018Co-Authors: Miaomiao Zhou, Song Zhang, Lian Wang, Bing ZhangAbstract:Abstract The mechanism of intramolecular charge transfer (CT) and the following radiationless dynamics of ofloxacin Pharmaceutical Product were investigated using femtosecond absorption spectroscopy combined with quantum chemical calculations. The CT and the intersystem crossing (ISC) processes have been established to be the major relaxation pathways responsible for the ultrafast nonradiation of the excited S1 state. The CT occurs within a time constant of ∼1.4 ps. The following ISC is determined to be ∼158 ps and triplet yield can be measured to keep ∼0.33. Simultaneous, the quantum yields of CT and triplet-triplet state absorption are contributed to be 0.29 and 0.38, respectively.
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ultrafast investigation of photoinduced charge transfer in aminoanthraquinone Pharmaceutical Product
Scientific Reports, 2017Co-Authors: Song Zhang, Simei Sun, Miaomiao Zhou, Lian Wang, Bing ZhangAbstract:We investigated the mechanism of intramolecular charge transfer and the following radiationless dynamics of the excited states of 1-aminoanthraquinone using steady state and time-resolved absorption spectroscopy combined with quantum chemical calculations. Following photoexcitation with 460 nm, conformational relaxation via twisting of the amino group, charge transfer and the intersystem crossing (ISC) processes have been established to be the major relaxation pathways responsible for the ultrafast nonradiative of the excited S1 state. Intramolecular proton transfer, which could be induced by intramolecular hydrogen bonding is inspected and excluded. Time-dependent density functional theory (TDDFT) calculations reveal the change of the dipole moments of the S0 and S1 states along the twisted coordinate of the amino group, indicating the mechanism of twisted intra-molecular charge transfer (TICT). The timescale of TICT is measured to be 5 ps due to the conformational relaxation and a barrier on the S1 potential surface. The ISC from the S1 state to the triplet manifold is a main deactivation pathway with the decay time of 28 ps. Our results observed here have yield a physically intuitive and complete picture of the photoinduced charge transfer and radiationless dynamics in anthraquinone pharmaceutial Products.
Aparajita Goyal - One of the best experts on this subject based on the ideXlab platform.
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the market impacts of Pharmaceutical Product patents in developing countries evidence from india
The American Economic Review, 2016Co-Authors: Mark Duggan, Craig Garthwaite, Aparajita GoyalAbstract:In 2005, as the result of a World Trade Organization mandate, India began to implement Product patents for Pharmaceuticals that were compliant with the 1995 Trade-Related Aspects of Intellectual Property Rights (TRIPS). We combine Pharmaceutical Product sales data for India with a newly gathered dataset of molecule-linked patents issued by the Indian patent office. Exploiting variation in the timing of patent decisions, we estimate that a molecule receiving a patent experienced an average price increase of just 3-6 percent with larger increases for more recently developed molecules and for those produced by just one firm when the patent system began. Our results also show little impact on quantities sold or on the number of Pharmaceutical firms operating in the market.
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the market impacts of Pharmaceutical Product patents in developing countries evidence from india
The American Economic Review, 2016Co-Authors: Mark Duggan, Craig Garthwaite, Aparajita GoyalAbstract:In 2005, as the result of a World Trade Organization mandate, India implemented a patent reform for Pharmaceuticals that was intended to comply with the 1995 Trade-Related Aspects of Intellectual Property Rights (TRIPS). Exploiting variation in the timing of patent decisions,we estimate that a molecule receiving a patent experienced an average price increase of just 3–6 percent, with larger increases for more recently developed molecules and for those produced by justone firm when the patent system began. Our results also show little impact on quantities sold or on the number of Pharmaceutical firms operating in the market.
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the market impacts of Pharmaceutical Product patents in developing countries evidence from india
Social Science Research Network, 2014Co-Authors: Mark Duggan, Craig Garthwaite, Aparajita GoyalAbstract:In 2005, as the result of a World Trade Organization mandate, India began to implement Product patents for Pharmaceuticals that were compliant with the 1995 Trade-Related Aspects of Intellectual Property Rights (TRIPS). We combine Pharmaceutical Product sales data for India with a newly gathered dataset of molecule-linked patents issued by the Indian patent office. Exploiting variation in the timing of patent decisions, we estimate that a molecule receiving a patent experienced an average price increase of just 3-6 percent with larger increases for more recently developed molecules and for those produced by just one firm when the patent system began. Our results also show little impact on quantities sold or on the number of Pharmaceutical firms operating in the market.Institutional subscribers to the NBER working paper series, and residents of developing countries may download this paper without additional charge at www.nber.org.
Hans Lennernas - One of the best experts on this subject based on the ideXlab platform.
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in silico predictions of gastrointestinal drug absorption in Pharmaceutical Product development application of the mechanistic absorption model gi sim
European Journal of Pharmaceutical Sciences, 2013Co-Authors: Erik Sjogren, Hans Lennernas, Bertil Abrahamsson, Jan Westergren, Iain Grant, Gunilla Hanisch, Lennart Lindfors, Christer TannergrenAbstract:Oral drug delivery is the predominant administration route for a major part of the Pharmaceutical Products used worldwide. Further understanding and improvement of gastrointestinal drug absorption predictions is currently a highly prioritized area of research within the Pharmaceutical industry. The fraction absorbed (fabs) of an oral dose after administration of a solid dosage form is a key parameter in the estimation of the in vivo performance of an orally administrated drug formulation. This study discloses an evaluation of the predictive performance of the mechanistic physiologically based absorption model GI-Sim. GI-Sim deploys a compartmental gastrointestinal absorption and transit model as well as algorithms describing permeability, dissolution rate, salt effects, partitioning into micelles, particle and micelle drifting in the aqueous boundary layer, particle growth and amorphous or crystalline precipitation. Twelve APIs with reported or expected absorption limitations in humans, due to permeability, dissolution and/or solubility, were investigated. Predictions of the intestinal absorption for different doses and formulations were performed based on physicochemical and bioPharmaceutical properties, such as solubility in buffer and simulated intestinal fluid, molecular weight, pKa, diffusivity and molecule density, measured or estimated human effective permeability and particle size distribution. The performance of GI-Sim was evaluated by comparing predicted plasma concentration–time profiles along with oral pharmacokinetic parameters originating from clinical studies in healthy individuals. The capability of GI-Sim to correctly predict impact of dose and particle size as well as the in vivo performance of nanoformulations was also investigated. The overall predictive performance of GI-Sim was good as >95% of the predicted pharmacokinetic parameters (Cmax and AUC) were within a 2-fold deviation from the clinical observations and the predicted plasma AUC was within one standard deviation of the observed mean plasma AUC in 74% of the simulations. GI-Sim was also able to correctly capture the trends in dose- and particle size dependent absorption for the study drugs with solubility and dissolution limited absorption, respectively. In addition, GI-Sim was also shown to be able to predict the increase in absorption and plasma exposure achieved with nanoformulations. Based on the results, the performance of GI-Sim was shown to be suitable for early risk assessment as well as to guide decision making in Pharmaceutical formulation development.
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bioequivalence of oral Products and the biopharmaceutics classification system science regulation and public policy
Clinical Pharmacology & Therapeutics, 2011Co-Authors: Kevin S Amidon, Peter Langguth, Hans Lennernas, Gordon L AmidonAbstract:The demonstration of bioequivalence (BE) is an essential requirement for ensuring that patients receive a Product that performs as indicated by the label. The BE standard for a particular Product is set by its innovator, and this standard must subsequently be matched by generic drug Products. The Biopharmaceutics Classification System (BCS) sets a scientific basis for an improved BE standard for immediate-release solid oral dosage forms. In this paper, we discuss BE and the BCS, as well as the issues that are currently relevant to BE as a Pharmaceutical Product standard.
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the use of biopharmaceutic classification of drugs in drug discovery and development current status and future extension
Journal of Pharmacy and Pharmacology, 2005Co-Authors: Hans Lennernas, Bertil AbrahamssonAbstract:Bioavailability (BA) and bioequivalence (BE) play a central role in Pharmaceutical Product development and BE studies are presently being conducted for New Drug Applications (NDAs) of new compounds, in supplementary NDAs for new medical indications and Product line extensions, in Abbreviated New Drug Applications (ANDAs) of generic Products and in applications for scale-up and post-approval changes. The Biopharmaceutics Classification System (BCS) has been developed to provide a scientific approach for classifying drug compounds based on solubility as related to dose and intestinal permeability in combination with the dissolution properties of the oral immediate-release (IR) dosage form. The aim of the BCS is to provide a regulatory tool for replacing certain BE studies by accurate in-vitro dissolution tests. The aim of this review is to present the status of the BCS and discuss its future application in Pharmaceutical Product development. The future application of the BCS is most likely increasingly important when the present framework gains increased recognition, which will probably be the case if the BCS borders for certain class II and III drugs are extended. The future revision of the BCS guidelines by the regulatory agencies in communication with academic and industrial scientists is exciting and will hopefully result in an increased applicability in drug development. Finally, we emphasize the great use of the BCS as a simple tool in early drug development to determine the rate-limiting step in the oral absorption process, which has facilitated the information between different experts involved in the overall drug development process. This increased awareness of a proper bioPharmaceutical characterization of new drugs may in the future result in drug molecules with a sufficiently high permeability, solubility and dissolution rate, and that will automatically increase the importance of the BCS as a regulatory tool over time.
Eelco De Jong - One of the best experts on this subject based on the ideXlab platform.
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a group risk assessment approach for the selection of Pharmaceutical Product shipping lanes
International Journal of Production Economics, 2020Co-Authors: Shahrzad Faghihroohi, Alp Akcay, Yingqian Zhang, Ehsan Shekarian, Eelco De JongAbstract:Abstract This paper provides a risk assessment framework to select shipping lanes for Pharmaceutical Products. The main categories of risks are determined through an algorithm based on yes/no decisions. Then, according to the risk categories, a Failure Mode and Effects Analysis (FMEA) table is proposed for risk assessment of Pharmaceutical Product shipments and logistics. The evaluations are based on Intuitionistic Fuzzy Numbers (IFNs) to be able to account for the uncertainty in the experts’ judgments. By using an intuitionistic fuzzy hybrid TOPSIS (Technique for Order Preference by Similarity to Ideal Solution) approach, the evaluated risks of each shipment lane can be scored and prioritized. The proposed TOPSIS-based FMEA approach in the intuitionistic fuzzy environment provides an opportunity to aggregate the risk assessments of different experts in a practically efficient way. Different from the earlier literature, we address risk identification and risk assessment under uncertainty as the two key challenges in group decision making. Our method further provides a framework that integrates the categorization and evaluation of risks with subsequent decision making. A case study of shipping lane selection in the context of air cargo distribution of Pharmaceutical Products demonstrates a potential implementation of the proposed approach.
Fred D Ledley - One of the best experts on this subject based on the ideXlab platform.
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Development in Somatic Gene Therapy
Expert Opinion on Investigational Drugs, 1994Co-Authors: Fred D LedleyAbstract:Clinical trials of gene transfer have begun to validate the clinical potential of gene therapy. With this progress, attention has turned increasingly to analysing the ability of various methods of gene therapy to satisfy clinical and commercial needs. There are fundamental differences between cell-based therapies, which employ genetically modified cells as a therapeutic Product, virus-based therapies, which employ recombinant viral vectors as a therapeutic Product and gene-based therapies in which DNA itself is formulated as a Pharmaceutical Product, in terms of the technologies required to develop and produce the Product, the mode of clinical application, the clinical risks and the economics of commercialisation. This report reviews the potential indications for gene therapy and the status of various approaches to gene therapy in development in the context of a field which is moving rapidly from basic research to Product development.
