In vitro characterization of a controlled-release ocular insert for delivery of brimonidine tartrate

Mealy, Joshua E.; Fedorchak, Morgan V.; Little, Steven R.

doi:10.1016/j.actbio.2013.09.024

Cited by 28 publications

(16 citation statements)

References 24 publications

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“…Therefore, the histological evaluation of the retina and cornea was performed on the thermogel-treated eyes. Both soluble PEG and biodegradable PLGA blocks have low cytotoxicity, and have been approved by FDA to use in clinic [60][61][62]. Moreover, some marketed intravitreal implants are also constructed based on PLGA [11].…”

Section: Discussionmentioning

confidence: 99%

Sustained intravitreal delivery of dexamethasone using an injectable and biodegradable thermogel

et al. 2015

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Section: Discussionmentioning

confidence: 99%

Sustained intravitreal delivery of dexamethasone using an injectable and biodegradable thermogel

et al. 2015

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“…We have modified the conventional oil‐in‐water emulsion technique to synthesize core‐shell microspheres that encapsulated high loadings of BT, and enabled sustained in vitro release of BT over 1 month with minimal initial burst release. Our mild synthesis process also managed to encapsulate the BT without affecting its efficacy, as the in vivo release of microspheres‐encapsulated BT successfully reduced IOP for over 50 d. While others have attempted to deliver BT to treat glaucoma using subconjunctival implants, results have been limited to 4 weeks even in cases where microsphere systems were used …”

Section: Discussionmentioning

confidence: 99%

“…In this approach, the BT‐loaded M/CS may be implanted in the subconjunctiva, and may be periodically replaced when the BT release is complete (Figure S1, Supporting Information). Subconjunctival implants have been previously used to deliver drugs for conditions such as uveitis and glaucoma for extended periods of up to 1 month without damage to surrounding tissue . Biodegradable polymer films have also been implanted in the subconjunctiva for up to 6 months without surrounding tissue damage or inflammation, confirming the safety of the subconjunctival location for long‐term implantation.…”

Section: Introductionmentioning

confidence: 90%

Long‐Term Subconjunctival Delivery of Brimonidine Tartrate for Glaucoma Treatment Using a Microspheres/Carrier System

Pek

Mohamed

et al. 2016

Adv Healthcare Materials

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Core-shell polymer microspheres with poly(d,l-lactic-co-glycolic acid) core and poly(l-lactic acid) (PLLA) shell are developed for the long-term subconjunctival release of brimonidine tartrate (BT) in order to reduce intraocular pressure (IOP) in the treatment of glaucoma. The PLLA-rich shell acts as a diffusion barrier, enabling linear release of BT over an extended period of 40 d. The microspheres are encased in a porous non-degradable methacrylate-based carrier for ease of subconjunctival implantation in a glaucoma-induced rabbit model. In vivo release of BT from the microspheres/carrier system has enabled a significant, immediate IOP reduction of 20 mmHg, which is sustained for 55 d. Long-term IOP reduction may be maintained by periodic replacement of the microspheres/carrier system.

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“…So many attempts were performed in the history to fix this problem in ophthalmic drug delivery. The literature survey reveals that the intraocular bioavailability of topically applied drugs is ranging from 5-10% of total administered, which is extremely poor 4,5 . Therefore, there is a need for controlled or sustained ocular drug delivery system.…”

Section: Introductionmentioning

confidence: 99%

Chitosan Loaded Microspheres of Tropicamide as Controlled Release of Drug for Ocular Drug Delivery System

Saini¹,

Kumar²,

Choudhary³

et al. 2017

Int. Res. J. Pharm.

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Ocular drug delivery via conventional eye drop is a convenient route of administration but it has serious limitations due to rapid clearance of the formulation from the eye. This study aimed to prepare and evaluate the sustained/controlled release of tropicamide microspheres with chitosan to increase ocular residence time of drug and also improve the bioavailability. The tropicamide loaded chitosan microspheres were prepared by ionic gelation technique using different ratios of polymer i.e. chitosan and cross-linking polymer i.e. sodium TPP. Microspheres were optimized by employing (2 2 ) factorial design and evaluated for particle size, entrapment efficiency, surface morphology and drug release profile. The entrapment efficiency was found to be higher with increase in the chitosan concentration. The increasing concentration of chitosan also showed the sustained release effect on the drug release. The optimized formulation showed the smooth morphology and average particle size was found to be about 15µm.The in-vitro release profile of tropicamide loaded microspheres showed a sustained release pattern as compared to pure drug. The results revealed that microspheres would be the promising candidates for enhancing the residence time by mucoadhesion which leads to enhancement of bioavailability of the tropicamide drug.

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In vitro characterization of a controlled-release ocular insert for delivery of brimonidine tartrate

Cited by 28 publications

References 24 publications

Sustained intravitreal delivery of dexamethasone using an injectable and biodegradable thermogel

Sustained intravitreal delivery of dexamethasone using an injectable and biodegradable thermogel

Long‐Term Subconjunctival Delivery of Brimonidine Tartrate for Glaucoma Treatment Using a Microspheres/Carrier System

Chitosan Loaded Microspheres of Tropicamide as Controlled Release of Drug for Ocular Drug Delivery System

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