PLGA–PEG–PLGA hydrogel for ocular drug delivery of dexamethasone acetate

Gao, Yuan; Sun, Yan; Ren, Fuzheng; Gao, Shen

doi:10.3109/03639041003680826

Cited by 113 publications

(69 citation statements)

References 18 publications

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“…In particular the 20% (w/w) had a low critical solution temperature of 32 °C, which is close to the surface temperature of the eye and demonstrated potential thermosensitive gel-forming properties. This formulation may improve the bioavailability of some eye drugs [90].…”

Section: Pharmaceutical Applicationmentioning

confidence: 99%

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: 99%

Thermosensitive Self-Assembling Block Copolymers as Drug Delivery Systems

et al. 2011

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“…These results are concordant with previous reports. 17,[20][21][22] Effects of Drug and Polymer Concentration on Gelation Temperature of an RP-Loaded PLGA-PEG-PLGA Solution The gelation temperature of the RP-loaded 20% w/w PLGA-PEG-PLGA solution increased as the RP concentration increased (Table 1). When the RP concentration was 15 mg/mL, the gelation temperature was 35.8°C, which is slightly lower than body temperature.…”

Section: Resultsmentioning

confidence: 99%

“…The PLGA blocks can easily transit among located into different micelles, leading to bridging connections among individual micelles. 20) Such connectivity reduced the mobility of the solution and resulted in a sol-gel phase transition. As the temperature continues to rise, the hydrophobic interactions among the micelles are strengthened, and the aggregation of micelles increases to form a denser gel.…”

Section: Resultsmentioning

confidence: 99%

A PLGA–PEG–PLGA Thermosensitive Gel Enabling Sustained Delivery of Ropivacaine Hydrochloride for Postoperative Pain Relief

Huilin

Guo

et al. 2017

CHEMICAL & PHARMACEUTICAL BULLETIN

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Postoperative pain is a complex physiological response to disease and tissue injury. Moderate-to-severe pain typically occurs within 48 h after surgery. Amino amide local anesthetics are widely applied to manage postoperative pain, and they have high efficacy, a low risk for addiction and limited side effects. However, these anesthetics also have short half-lives, often necessitating continuous injection to obtain satisfactory pain relief. In the current work, we used a poly(lactic-co-glycolic acid) (PLGA)-polyethylene glycol (PEG)-PLGA (PLGA-PEG-PLGA) temperature-sensitive gel to deliver a local anesthetic, ropivacaine hydrochloride (RP), to prolong its analgesic effect. We investigated the influence of polymer and drug concentration on gelation temperature and the in vitro drug release rate from the temperature-sensitive gel. RP-loaded PLGA-PEG-PLGA solution is a liquid at room temperature and forms a gel at temperatures slightly lower than body temperature. With regard to the gel's drug release rate, 37.5, 51.3 and 72.6% of RP was released at 12, 24 and 48 h, respectively. This in vitro drug release profile conformed to the Higuchi equation. To assess pain control efficacy when using the gel, we evaluated the mechanical paw withdrawal reflex threshold, thermal pain threshold and incision cumulative pain scores in a rat incisional model. The results showed that the anti-pain effect of a single injection of RP-loaded gel at the incision site lasted for 48 h, which is significantly longer than the effect produced by injection of RP solution alone. The use of RP-loaded thermosensitive gels could provide a promising method for managing postoperative pain.Key words ropivacaine hydrochloride; thermogel; long acting; in vitro release; postoperative pain Postoperative pain is a complex physiological response to disease and tissue injury. Such pain can induce various pathophysiological changes, which can affect the functions of the respiratory, circulatory, digestive and endocrine systems. If not well controlled, postoperative pain can also lead to severe immune and metabolic disorders. The most severe pain often occurs immediately after the operation, with pain intensity decreasing with time. It has been reported that moderate-tosevere pain most often occurs in the 48 h after surgery.1,2) Opioids are the most common treatment for such pain; however, they have numerous side effects, including nausea, vomiting, respiratory depression, prolonged ileus, itching, tolerance, and development of hyperalgesia.3,4) Topical application of local anesthetics is being increasingly used to relieve postoperative pain to reduce opioid requirements and improve analgesic effects.Ropivacaine hydrochloride (RP) is a new amino amide local anesthetic with lower cardio-and neuro-toxicity than bupivacaine, making it particularly suitable for cardiac surgery and postoperative analgesia.5,6) Additionally, RP possesses lower lipid solubility and causes more vasoconstriction than bupivacaine, allowing better retention in the local environment. 5,...

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“…Injectable biodegradable copolymer hydrogels, which exhibit a sol-gel phase transition in response to external stimuli, such as temperature changes, have found several biomedical and pharmaceutical applications, such as drug delivery, cell growth, and tissue engineering (Gao et al, 2010;Kan et al, 2005;Kim et al, 2001;Nguyen & Lee, 2010;Qiao et al, 2006;Zentner et al, 2001). Such polymers are also biocompatible and biodegradable, and they represent an ideal system for treatment, being able to overcome the problem of carrier removal after injection (implantation).…”

Section: Temperature-induced Sol-gel Phase Transition Of Plga-peg-plgmentioning

confidence: 99%