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Replacing the Animal Source of Viscous Fluids Used in Cataract Surgery with the Okra Plant Source

Periodic Report Summary 1 - OKRAVISION (Replacing the Animal Source of Viscous Fluids Used in Cataract Surgery with the Okra Plant Source)

Project Context and Objectives:
Eye cataract, leading to the loss of vision, is a serious problem for the aging population. This is currently cured by surgical procedure which requires a viscoelastic High Molecular Weight (HMW) product of Ophthalmic Viscosurgical Device (OVD) to fill the space in the eye created during the surgery and to protect the healthy endothelial cells. Due to the growing elderly population, this market segment is expected to grow at least 7% per year and will reach €80 Mn in the EU and €240 Mn worldwide by 2014. The market need for HMW products is currently served by Hyaluronic acid (HA) and cheaper alternatives derived from cellulose with properties inferior to HA.
HA is produced from rooster combs. The animal nature of the raw materials makes the SMEs particularly vulnerable in light of a bird flu outbreak, creating the threat of losing up to an entire year supply of the raw material with a single outbreak in the region. The manufacturers have currently to rely on few suppliers of the high-quality raw materials i.e. roosters bred on a special diet. In addition, using raw materials of animal origin in humans requires compliance with existing EU regulations (EC 1774/2002, Directives 90/426/EEC and 86/609/EEC, 3 R’s Declaration, as well as REACH). Hence is clearly advantageous to switch to a non-animal source of HMW substance instead of HA originating from rooster combs.
The main objective of the OkraVision project is to substitute animal based production of HMW HA with a cheaper and non-animal HMW substance: Rhamnopyranose–Galactopyranose–Galactopyranosyluronic Acid (RGGA) from the okra plant (fruit) with the targeted chain length of 800-1000 units, molecular weight (MW) of 5-6 MDa, and the targeted zero shear viscosity of 1-3 Million mPas for 1-2.5 % aqueous solution. This will be done by developing a continuous and automised extraction and purification process of HMW RGGA from the okra fruit with a production efficiency of 3 g of RGGA from 1 kg (0.3% weight-to-weight) of sliced okra fruit.

Project Results:
During the first reporting period the work was mainly focussed on research of different okra raw material and on finding optimal processing conditions in order to achieve RGGA with desired optical and viscoelastic properties. Purity of achieved HMW was also important. Okra from two different geographical origins – West Africa and Southeast Asia – was tested as a raw material. Experiments showed that the RGGA extracted from West African okra demonstrated better chemical and physical properties and the yield of RGGA from raw material was also higher. The extraction and purification method developed in OkraVision project gives 0.5% (weight-to-weight) yield of RGGA from raw okra, which is over 1.5 times higher than expected.
Purification of RGGA from okra is a complex process consisting over ten steps. These include pretreatment before extraction which must guarantee that high quality raw material is used, that it is cut into pieces of required size to achieve as high yield as possible. On the other hand viscoelastic properties of the RGGA are crucial from end-users point of view. Experimental work carried out in OkraVision project showed that processing conditions have to be carefully chosen to obtain a material with desired properties. It was observed that the viscosity of the extract considerably diminished during the downstream processing. Therefore additional crosslinking of RGGA is needed for increasing viscosity to the desired level.

Potential Impact:
The final result of the Okravision project is the prototype of a production line with a capacity to produce 3 kg of pure RGGA per year. OkraVision consortium aims to achieve RGGA with viscoelastic and optical properties similar to HA. This would enable to replace HA with RGGA in the use of OVDs, but also in other sectors where HA is used i.e. aesthetic surgery, joint lubrication application, and cosmetic industry.
In case the OkraVision project is fully successful, it has a clear socio-economic impact on the European society. RGGA can help the continuously ageing population of Europe in several ways. First, it can be used in ophthalmic applications, where due to the increase in average age, the number of elderly people who will develop cataracts requiring treatment will increase accordingly. The same the situation exists for RGGA used as a joint lubricant since the aging European population will develop more cases of osteoarthritis in the future that will need to be treated. On the other hand, the use of RGGA in aesthetic surgery will improve the quality of life of accident and burn victims, who need reconstructive surgery, offering them the product below the current market price for the existing alternative, HA. It will also be of value to breast cancer victims as it is seen as a safer alternative to the existing silicone implant alternative.
The use of HMW RGGA in cataract surgery (compared to LMW HA obtained by bacterial fermentation or HPMC) is a driver to reduce surgery time (by up to a factor of 2, from 10 minutes to 5-7 minutes) and thus enabling more surgeries per hour, reducing the waiting lists and therefore morbidity and saving on qualified surgeon’s time.
On the ethical side, okra based RGGA will reduce the need for or completely replace the rooster combs as the source of HMW HA. This enables to reduce the dependency on animal-derived materials in the EU with the associated need to dispose safely of the rooster remains as well as the threat of keeping rooster stock at times when a bird flu outbreak is likely to take place. On the other hand, the waste of RGGA production can be used in several environmentally friendly and useful ways. Possible applications include the application as animal food, biomass for biogas production, or fertilizer, for example.

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