Author
G. Couarraze
Other affiliations: University of Paris
Bio: G. Couarraze is an academic researcher from Centre national de la recherche scientifique. The author has contributed to research in topics: Drug carrier & Controlled release. The author has an hindex of 6, co-authored 7 publications receiving 610 citations. Previous affiliations of G. Couarraze include University of Paris.
Topics: Drug carrier, Controlled release, Calcium, Solubility, Paracrystalline
Papers
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TL;DR: Alginate nanoparticles are interesting carriers because the drug-loading capacity could be > 50 mg of doxorubicin per 100 mg of alginate, and the data indicate that the formation of the particles probably occurs during the addition of the first component to the sodium alginates solution.
384 citations
TL;DR: The dispersion of liposomes within a 27% poloxamer gel presented an interesting system to control the release of a model oligonucleotide compare to a simple gel.
Abstract: Purpose. The main goal of this study was to develop an ocular controlled release formulation of a model oligonucleotide (pdT16), contained within liposomes dispersed within a thermosensitive gel composed by poloxamer 407.
124 citations
TL;DR: In this article, a new approach for the preparation of nanoparticles is presented, based on control of the gelification phenomenon of alginate by calcium ions, and it leads to small particles of a wide range of very well-defined sizes (250-850 nm).
Abstract: A new approach for the preparation of nanoparticles is presented. The method is based on control of the gelification phenomenon of alginate by calcium ions, and it leads to small particles of a wide range of very well-defined sizes (250–850 nm) depending on the alginate concentration. The particles are formed in a sodium alginate solution by addition of calcium chloride and then poly-L-lysine. The concentrations of sodium alginate and of calcium chloride were lower than those required for gel formation and corresponded to the formation of a pregel state. The size of the particles formed is greatly dependent on the order of addition of calcium and poly-L-lysine to the sodium alginate solution. This phenomenon can be attributed to the difference in the nature of the interactions between calcium and alginate and between poly-L-lysine and alginate. Furthermore, the data indicate that the formation of the particles probably occurs during the addition of the first component to the sodium alginate solution. Evaluation of the drug-loading capacity was done with doxorubicin as a drug model. The results indicate that alginate nanoparticles are interesting carriers because the drug-loading capacity could be >50 mg of doxorubicin per 100 mg of alginate.
75 citations
TL;DR: How the spherical crystallization process by QESD method can be applied to a water-soluble drug, salbutamol sulfate, and the influence of emulsifier concentration and of maturation time on the size of spherical particles is studied.
60 citations
TL;DR: These new systems of Spherulites known as complex dispersions show great potential for pharmaceutical applications such as controlled release and protection of encapsulated substances.
15 citations
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TL;DR: Alginate, being an anionic polymer with carboxyl end groups, is a good mucoadhesive agent and cross-linked alginate has more capacity to retain the entrapped drugs and mixing of alginates with other polymers such as neutral gums, chitosan, and eudragit have been found to solve the problem of drug leaching.
1,724 citations
TL;DR: Hydrogel nanoparticles have gained considerable attention in recent years as one of the most promising nanoparticulate drug delivery systems owing to their unique potentials via combining the characteristics of a hydrogel system with a nanoparticle, each with its own advantages and drawbacks.
1,704 citations
TL;DR: New findings have demonstrated immuno-modulation and cytotoxicity-promoting properties of Poloxamer 407 revealing significant pharmacological interest and, hence, human trials are in progress to specify these potential applications.
Abstract: Poloxamer 407 copolymer (ethylene oxide and propylene oxide blocks) shows thermoreversible properties, which is of the utmost interest in optimising drug formulation (fluid state at room temperature facilitating administration and gel state above sol-gel transition temperature at body temperature promoting prolonged release of pharmacological agents). Pharmaceutical evaluation consists in determining the rheological behaviour (flow curve or oscillatory studies), sol-gel transition temperature, in vitro drug release using either synthetic or physiological membrane and (bio)adhesion characteristics. Poloxamer 407 formulations led to enhanced solubilisation of poorly water-soluble drugs and prolonged release profile for many galenic applications (e.g., oral, rectal, topical, ophthalmic, nasal and injectable preparations) but did not clearly show any relevant advantages when used alone. Combination with other excipients like Poloxamer 188 or mucoadhesive polymers promotes Poloxamer 407 action by optimising sol-gel transition temperature or increasing bioadhesive properties. Inclusion of liposomes or micro(nano)particles in Poloxamer 407 formulations offers interesting prospects, as well. Besides these promising data, Poloxamer 407 has been held responsible for lipidic profile alteration and possible renal toxicity, which compromises its development for parenteral applications. In addition, new findings have demonstrated immuno-modulation and cytotoxicity-promoting properties of Poloxamer 407 revealing significant pharmacological interest and, hence, human trials are in progress to specify these potential applications.
1,036 citations
TL;DR: In the present update on mucoadhesive ocular dosage forms, the tremendous advances in the biochemistry of mucins, the development of new polymers, the use of drug complexes and other technological advances are discussed.
844 citations
TL;DR: This review summarizes the different methods of preparation of polymer nanoparticles including nanospheres and nanocapsules and presents the most recent innovations and progresses obtained over the last decade.
Abstract: This review summarizes the different methods of preparation of polymer nanoparticles including nanospheres and nanocapsules. The first part summarizes the basic principle of each method of nanoparticle preparation. It presents the most recent innovations and progresses obtained over the last decade and which were not included in previous reviews on the subject. Strategies for the obtaining of nanoparticles with controlled in vivo fate are described in the second part of the review. A paragraph summarizing scaling up of nanoparticle production and presenting corresponding pilot set-up is considered in the third part of the review. Treatments of nanoparticles, applied after the synthesis, are described in the next part including purification, sterilization, lyophilization and concentration. Finally, methods to obtain labelled nanoparticles for in vitro and in vivo investigations are described in the last part of this review.
793 citations