Ophthalmic formulations comprising cooperative complexes of low- and high-molecular-weight hyaluronic acid

Abstract

Disclosed are ophthalmic formulations which use complexes called L/H-HA, obtainable by subjecting at least two fractions of hyaluronic acids and/or other glycosaminoglycans with different molecular weights to an appropriate heat cycle.

1 . Ophthalmic formulations comprising as active ingredients cooperative hybrid complexes named L/H-HA, obtainable by heating at 100-130° C. for 10-30 min a mixture of an aqueous solution of at least one fraction (L-HA) of hyaluronic acid or of chondroitin sulphate, keratan sulphate or chondroitin (CS, KS, C), said fraction having an average molecular weight ranging from 1·104 to 5·105 Da, and of an aqueous solution of at least one fraction (H-HA) of hyaluronic acid having an average molecular weight at least 5 times higher than that of L-HA and in any event ranging from 5·104 Da to 5·106 Da, the weight ratio of L-HA to H-HA in the L/H-HA complex ranging from 0.5 to 2. 
     
     
         2 . Ophthalmic formulations according to  claim 1  wherein the H-HA fraction has a molecular weight ranging from 5·105 Da to 3·106 Da and the L-HA fraction has a molecular weight ranging from 3·104 Da to 1·105 Da. 
     
     
         3 . Ophthalmic formulations according to  claim 1  wherein the low molecular weight fraction consists of glycosaminoglycans other than hyaluronic acid with an average molecular weight ranging from 1·104 to 1·105 Da. 
     
     
         4 . Ophthalmic formulations according to  claim 3  wherein the glycosaminoglycans are chondroitin sulphate, keratan sulphate and chondroitin. 
     
     
         5 . Ophthalmic formulations according to  claim 1  comprising water as solvent and characterized by a viscosity lower than 100 mPa s. 
     
     
         6 . Ophthalmic formulations according to  claim 1  in the form of eye drops, ointments or ophthalmic sprays. 
     
     
         7 . Ophthalmic formulations according to  claim 6 , characterised by a viscosity lower than 30 mPa·S. 
     
     
         8 . Ophthalmic formulations according to  claim 1  comprising other active ingredients for ophthalmic use, buffering agents, salts, osmolarity adjusting agents, preservatives, lenitives and rheological agents. 
     
     
         9 . Method of treating dry eye syndrome with tear substitutes comprising the ophthalmic formulations according to  claim 1 .