The modulation of granulomatous tissue and tumour angiogenesis by diclofenac in combination with hyaluronan (HYAL EX-0001).

In a novel application, hyaluronan has been utilized as a delivery system for topical and i.v. therapeutics. Clinical trials and case reports show that topical diclofenac delivered in hyaluronan (HYAL CT-1101) is effective against basal-cell carcinoma and actinic keratosis. The effect of this drug formulation on tumour growth and angiogenesis, as well as granulomatous tissue angiogenesis, has been investigated experimentally. The evidence that hyaluronan has a permissive effect on the inhibition of granulomatous tissue angiogenesis by diclofenac (as assessed by the carminel/gelatin vascular casting method) when injected into the lesion or applied topically is reviewed. Topical diclofenac in hyaluronan also induces a regression of the existing neo-vasculature of granulomatous tissue when applied therapeutically. The diclofenac formulated in hyaluronan was also found to be profoundly effective against the development of subcutaneous Colon-26 tumours in syngeneic balb/c mice (T/C ratio after 12 days topical application of 0.174, p < 0.0001). Analysis of the tumour vasculature showed that vascular development was retarded by 12 days. This was shown by the reduction in the tumour density of carmine in the vascular casts, as well as reduced blood-vessel density visualized by rat anti-mouse CD31 immunohistology. Hyaluronan alone had a significant effect on tumour development with a 50% inhibition of tumour growth and only a transient reduction in vascularity. The effects noted when diclofenac is formulated in hyaluronan, and applied topically, could be related to trans-dermal delivery and deposition properties of hyaluronan, and to the binding properties of hyaluronan to areas of pathology with high expression of hyaluronan receptors such as RHAMM, ICAM-1, and CD44.