PLGA-PEG-PLGA tri-block copolymers as an in-situ gel forming system for calcitonin delivery

Ghahremankhani, Ali Afshar; Dorkoosh, Farid Abedin; Dinarvand, Rassoul

doi:10.1007/s00289-007-0807-4

Cited by 41 publications

(26 citation statements)

References 16 publications

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“…No significant burst release effect was observed. Gelation time did not affect the drug release profile of the system and the diffusion was the main mechanism for Calcitonin release from these systems [86]. Besides, calcitonin release kinetics, from a PLGA-PEG-PLGA polymeric solutions (25% w/w), could be controlled by using different excipients such as, for example, sodium lauryl sulfate that showed to reduce drug release rate from the systems [87].…”

Section: Pharmaceutical Applicationmentioning

confidence: 96%

Thermosensitive Self-Assembling Block Copolymers as Drug Delivery Systems

et al. 2011

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Self-assembling block copolymers (poloxamers, PEG/PLA and PEG/PLGA diblock and triblock copolymers, PEG/polycaprolactone, polyether modified poly(Acrylic Acid)) with large solubility difference between hydrophilic and hydrophobic moieties have the property of forming temperature dependent micellar aggregates and, after a further temperature increase, of gellifying due to micelle aggregation or packing. This property enables drugs to be mixed in the sol state at room temperature then the solution can be injected into a target tissue, forming a gel depot in-situ at body temperature with the goal of providing drug release control. The presence of micellar structures that give rise to thermoreversible gels, characterized by low toxicity and mucomimetic properties, makes this delivery system capable of solubilizing water-insoluble or poorly soluble drugs and of protecting labile molecules such as proteins and peptide drugs.

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Section: Pharmaceutical Applicationmentioning

confidence: 96%

Thermosensitive Self-Assembling Block Copolymers as Drug Delivery Systems

et al. 2011

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“…Additionally, the copolymer erosion rate decreases because of a salting-out effect and a decrease in water activity because of the drugs. Also, by increasing the drug concentration, the copolymer hydrogel viscosity increases, and it can also cause a slower release by diffusion (34).…”

Section: In Vitro Release Studymentioning

confidence: 99%

“…Some advantages of this copolymer (PLGA-PEG-PLGA) are that it does not require any organic solvent for its synthesis and purification, it has no systemic toxicity, it can deliver both hydrophobic and hydrophilic drugs, it is biodegradable and biocompatible, and it can stabilize and solubilize peptide and protein drugs, such as insulin (30), porcine growth hormone (31), testosterone (32), 5-fluorouracil (33), calcitonin (34), granulocyte colony-stimulating factor, and recombinant hepatitis B surface antigen. Gel formulations of this copolymer have been shown to provide a unique controlled release of paclitaxel (Oncogel®) in tumors for approximately 50 days with a minimal distribution in other organs (35).…”

Section: Introductionmentioning

confidence: 99%

Preparation and Investigation of Sustained Drug Delivery Systems Using an Injectable, Thermosensitive, In Situ Forming Hydrogel Composed of PLGA–PEG–PLGA

et al. 2012

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Abstract. In situ gelling systems are very attractive for pharmaceutical applications due to their biodegradability and simple manufacturing processes. The synthesis and characterization of thermosensitive poly(D,L-lactic-co-glycolic acid) (PLGA)-polyethylene glycol (PEG)-PLGA triblock copolymers as in situ gelling matrices were investigated in this study as a drug delivery system. Ring-opening polymerization using microwave irradiation was utilized as a novel technique, and the results were compared with those using a conventional method of polymerization. The phase transition temperature and the critical micelle concentration (CMC) of the copolymer solutions were determined by differential scanning calorimetry and spectrophotometry, respectively. The size of the micelles was determined with a light scattering method. In vitro drug release studies were carried out using naltrexone hydrochloride and vitamin B12 as model drugs. The rate and yield of the copolymerization process via microwave irradiation were higher than those of the conventional method. The copolymer structure and concentration played critical roles in controlling the sol-gel transition temperature, the CMC, and the size of the nanomicelles in the copolymer solutions. The rate of drug release could be modulated by the molecular weight of the drugs, the concentration of the copolymers, and their structures in the formulations. The amount of release versus time followed zero-order release kinetics for vitamin B12 over 25 days, in contrast to the Higuchi modeling for naltrexone hydrochloride over a period of 17 days. In conclusion, PLGA-PEG1500-PLGA with a lactide-to-glycolide ratio of 5:1 is an ideal system for the long-acting, controlled release of naltrexone hydrochloride and vitamin B12.

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“…The doublets at 8.74 and 7.7 ppm were attributed to the pyridine ring of isoniazid. The branched peaks at 3.5 and 4.4 ppm were attributed to the ethylene glycol repeat units at the center of the polymeric chains (20). In the mass spectrum, a symmetrical Gaussian curve (peaks separated by m ⁄ z = 44, the mass of each repeat unit) centered at approximately 525, 825, and 979 m ⁄ z confirms the stoichiometry where two molecules of isoniazid have been conjugated with one molecule of the PEG polymer [calc.…”

Section: Synthesis and Characterization Of Peg-bis(inh) Conjugatesmentioning

confidence: 95%

Design, Synthesis, and Antimycobacterial Property of PEG–bis(INH) Conjugates

et al. 2012

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Poly(ethylene glycol) derivatives of isoniazid with varying molecular weight of poly(ethylene glycol) were designed as antimycobacterial agents. Poly(ethylene glycol)-diacrylate of three different molecular weights (MW 258, 575, and 700) was conjugated with isoniazid by the Michael addition approach. The poly(ethylene glycol)-bis(isoniazid) conjugates thus obtained were completely characterized by FT-IR, 1 H and 13 C NMR, and ESI-MS spectroscopic techniques. Comparative MTT assay of the poly(ethylene glycol)-bis(isoniazid) conjugates showed much lower cytotoxicity than the neat isoniazid. MIC studies on Mycobaterium tuberculosis H37Rv showed potential antimycobacterial activity than the free isoniazid on a molar basis. The poly(ethylene glycol)-bis(isoniazid) conjugates were successfully radiolabeled with 99m-Technetium with more than 97% efficiency and stability to assess their in vivo fate. The Tc labeled poly(ethylene glycol)-bis(isoniazid) conjugates showed higher blood retention time in New Zealand rabbits which increased with increasing molecular weight of poly(ethylene glycol). Biodistribution studies in infection-induced murine models (BALB ⁄ c mice) showed significant retention of these conjugates at the site of infection for 72 h. The results of this study illustrate the potential utility of the PEGylated isoniazid conjugates as long circulating carriers for improved antitubercular drug therapy.

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PLGA-PEG-PLGA tri-block copolymers as an in-situ gel forming system for calcitonin delivery

Cited by 41 publications

References 16 publications

Thermosensitive Self-Assembling Block Copolymers as Drug Delivery Systems

Thermosensitive Self-Assembling Block Copolymers as Drug Delivery Systems

Preparation and Investigation of Sustained Drug Delivery Systems Using an Injectable, Thermosensitive, In Situ Forming Hydrogel Composed of PLGA–PEG–PLGA

Design, Synthesis, and Antimycobacterial Property of PEG–bis(INH) Conjugates

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