Protective Nutraceutical Delivery Systems for Optimal Eye Health--Part 3 of 4

This is the third of four parts. Read parts 1 and 2 here and here.

Phospholipid Suspensions

The ability to deliver supplements for eye health through solubilized formulations in vivo is another essential factor for optimal bioavailability. There are many instances when an excess amount of surfactants and/or emulsifiers are used to solubilize a drug or supplement, and this alone can pose a health issue, due solely on the inherent nature of the surfactant itself. This is important when it involves the eye, which is so delicate.

Lutein is a vital and well-established supplement for overall eye health. It is a xanthrophyll carotenoid , which when it is supplemented, acts as a powerful antioxidant to protect the underlying structures of the retina against oxidative damage.   

Korean investigators^{1have shown that a self-emulsifying (solubilizing), phospholipid suspension (SEPS) consisting of a high concentration of phospholipids (which is safe and compatible for the eye), combined with a relatively low concentration of surfactant, works well to enhance the bioavailability of lutein. This was shown using animal study data, (Sprague Dawley rats and beagle dogs), where accumulation studies demonstrated the excellent ability of SEPS to enhance the bioavailability of lutein. From this study it was concluded that SEPS containing lutein could be very promising as a lipid-based delivery system for the prevention of ocular diseases1. This study is another example how an alternative delivery system (circumventing traditional oral-delivery), improves the potential (via a direct application of a stabilized suspension), and improves the bioavailability of a well-established supplement (lutein) for the eye.}

There are many other alternative delivery systems that have amazing potential for the advancement of eye health that utilize supplements as either integral parts of their delivery system, as transport vehicles themselves, or as the actual protected therapeutic ingredients.

A major health issue for a great number of people of all ages is dry eye. Many people supplement with the Omega-3 fats, DHA, EPA, and GLA (gamma-Linolenic acid), in order to alleviate this condition, and for many, high doses of these are obtained by utilizing the omega-3 fish oils as well. Epidemiological studies do suggest that the dietary omega-3 PUFAs may protect against dry eye². It has also been noted that dietary DHA, EPA, and GLA may reduce the increases in specific prostaglandins (PGE 1 and PGE 2), which are associated with dry eye, although supporting research on this was performed on Female Lewis rats, where dry eye was induced by the use of the ant-emetic, scopolamine³. In this study, PGE1 and PGE2  levels were inhibited in the exorbital lachrymal glands of the scopolamine-induced dry eye rodents supplemented with PUFA³.  

Although the omega-3 fish oils and PUFAs are usually added to the diet or taken orally in pill, capsule, powder, or gel form, investigators have shown that the topical administration of PUFAs has also been deemed effective for dry eye on the basis of preliminary human studies as well as on animal data results⁴.  DHA and its derivatives appear to be safe and effective when the topical route has been utilized for dry eye patients. Investigators hypothesize that these positive results in humans may be the result of inflammatory subsidence as well as from regeneration of damaged corneal nerves⁴. A topical route for a formulated PUFA/fish oil mixture may be quite effective. It appears to be safe and circumvents the likely breakdown and oxidation of these supplements that may readily occur during the processes of digestion, absorption, and transport in the body. 

References

1.). Shanmugam, S. and Park, J.M., et al. (2011) Enhanced bioavailability and retinal accumulation of Lutein from self-emulsifying phospholipid suspension (SEPS). Int. J. Pharm., 412, 99.

2.)  Viau, S. and Pasquis, B., et al. (2011) No consequences of dietary n-3 polyunsaturated fatty acid deficiency on the severity of scopolamine-induced dry eye. Graefes  Arch. Clin. Exp. Opthalmol., 249, 547.

3.) Viau, S. and Maire, M.A., et. al. (2009) Efficacy of a 2-month dietary supplementation with polyunsaturated fatty acids in dry eye induced by scopolamine in a rat model. Graefes Arch. Clin. Exp. Opthalmol., 247, 1039.

4.) Cortina, M.S. and Bazan, H.E. (2011) Docosahexaenoic acid, Protectins, and Dry Eye. Curr. Opin. Clin. Nutr. Metab. Care. 14, 132.