Al-Shohani, A

Awwad, S

Brocchini, S

Khaw, PT

UCL Discovery

14th European Symposium on Controlled Drug DeliveryA SUSTAINED RELEASE PROTEIN FORMULATION FOR INTRAOCULAR USESahar Awwad1,2, Athmar Al-Shohani1,2, Peng T. Khaw2 and Steve Brocchini1,21UCL School of Pharmacy, London, United Kingdom. 2National Institute for Health Research(NIHR) Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCLInstitute of Ophthalmology, London, United Kingdom.E-mail: s.awwad@ucl.ac.ukIntroductionAn ageing population, together with a greater understanding of ocular disease, are driving thedevelopment of new generations of protein therapeutics for ocular use. Currently, antibodies totreat age related macular degeneration (AMD) are administered about every 4-6 weeks byintravitreal (IVT) injections. Although IVT injections are generally safe, they require a clinicalprocedure that can be uncomfortable for the patient. There is also an economic burden for treatingincreasingly large numbers of AMD patients, many of whom will be treated for decades.Much effort is now focused on the need to develop ocular dosage forms that can beadministered less frequently. We have recently developed an in vitro ocular outflow model (the PK-Eye) that can be used to estimate the human ocular half-life and stability of new proteintherapeutics and new dosage forms1 to be administered to the back of the eye. Our model is usedto aid the pre-clinical development of novel, long-acting therapies. As more stable proteintherapeutics are developed, doses with higher concentrations may be possible. This will allow theclinical exploitation of a therapeutic tail which is difficult to evaluate in animal models due to thegeneration of anti-drug antibodies (ADAs). To increase the half-life of bevacizumab, we now reportthe preparation of a N-Isopropylacrylamide (NIPAM) in situ forming gel in the presence ofbevicizumab (Avastin), which is used in IVT injections. The half-life and binding activity ofbevacizumab were determined in an effort to optimise the cross-link density of the NIPAM gel.Results and DiscussionBevacizumab (1.0 mL; 25.0 mg/mL, pharmaceutical preparation) was mixed with NIPAM (40.0mg) and ammonium per sulfate (APS, 4.0 mg). Different amounts (~4, 8 and 12 μL) of poly(eth-ylene glycol) diacrylate (PEG-DA) crosslinker were added to the polymerisation mixture, along withN,N,N,N-tetramethylethylenediamine (TEMED), and the mixture was incubated for ~24 hours at4°C. Both injection and gel formation of the bevacizumab loaded gels were separately evaluated inthe PK-Eye (flow rate: 2.0 μL/min, fixed temperature at 37°C). Samples were analysed by high performance liquid chromatography (HPLC) at 280 nm to calculate the release kinetics. Bindingproperties of released bevacizumab were evaluated against its ligand (vascular endothelial growthfactor, VEGF) using surface plasmon resonance (SPR).For efficiency, PBS, rather than simulated vitreous was used in the PK-Eye to determinerelease kinetics. Bevacizumab gels (2.5 mg, 100 μL) with different amounts of PEGDA (4 uL, 8 uL and 12 uL) displayed a t1/2 of approximately ~2.01 ± 0.01, 3.66 ± 1.21 and 2.55 ± 0.03 daysrespectively in a bimodal release profile. These studies showed continuous release ofbevacizumab after a month. In contrast, gel-free doses of bevacizumab (2.5 and 5.0 mg) displayeda t1/2 of 2.3 ± 0.8 and 3.4 ± 0.7 days respectively. Samples collected throughout the 4 week studywere evaluated by SPR, and they all displayed binding affinity to VEGF. These binding studiesindicated that bevacizumab maintained its binding properties in the gels and in the PK-Eye.ConclusionDifferent thermoresponsive NIPAM gels that were prepared in the presence of bevacizumab dis-played a prolonged release profile compared to bevacizumab injection alone. The gel formulationwas bimodal, with the release of bevacizumab being observed for a month. SPR results indicatedthat the bevacizumab released from the gels maintained its binding properites throughout the 4week study. These studies indicate that it is possible to extend the duration of protein release usinga thermoresponsive gel that is prepared in the presence of the protein.References1. Awwad S, Lockwood A, Brocchini S, Khaw PT. The PK-Eye: A Novel In Vitro Ocular Flow Model forUse in Preclinical Drug Development. J Pharm Sci. 2015;104(10):3330-3342. doi:10.1002/jps.24480.

A Sustained Release Protein Formulation For Intraocular Use

http://discovery.ucl.ac.uk/1528716/1/SaharAmsterdam%20conference%202016%20final%20abstract.pdf

A Sustained Release Protein Formulation For Intraocular Use

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