Water-swellable polymers

Abstract

A water-swellable linear polyurethane polymer is formed by reacting a polyethylene oxide (e.g. PEG 4000 to 35,000), a difunctional compound (e.g. a diamine or diol such as 1,10-decanediol) with a diisocyanate. The ratio of the three components is generally in the range 0.1-1.5 to 1 to 1.1-2.5. The polyurethane is water-swellable in the range 300 to 1700% and soluble in certain organic solvents such as dichloromethane. It can be loaded with pharmaceutically active agents, particularly of high molecular weight, to produce controlled release compositions, such as pessaries etc.

1 . A water-swellable linear polymer obtainable by reacting together 
 (a) a polyethylene oxide;    (b) a difunctional compound, and    (c) a difunctional isocyanate.    
   
   
       2 . A polymer according to  claim 1  wherein the polyethylene oxide has a number average molecular weight of 4000 to 35,000.  
   
   
       3 . A polymer according to  claim 1  wherein the polyethylene oxide has a number average molecular weight of 8000 to 12,000.  
   
   
       4 . A polymer according to  claim 1  wherein the difunctional compound is a diamine or diol.  
   
   
       5 . A polymer according to  claim 4  wherein the diol is a C 5  to C 20  diol.  
   
   
       6 . A polymer according to  claim 5  wherein the diol is a 1,10-decanediol.  
   
   
       7 . A polymer according to  claim 5  wherein the diol is 1,6-hexanediol, 1,12-dodecanediol or 1,16-hexadecanediol.  
   
   
       8 . A polymer according to  claim 1  wherein the ratio of components (a) to (b) to (c) in terms of equivalent weights is in the range 0.1-1.5 to 1 to 1.1-2.5.  
   
   
       9 . A polymer according to  claim 8  wherein the ratio is 0.2-0.9 to 1 to 1.2-1.9  
   
   
       10 . A polymer according to  claim 9  wherein the ratio is 0.5-0.9 to 1 to 1.5-1.9  
   
   
       11 . A polymer according to  claim 1  which is swellable in water up to 500%.  
   
   
       12 . A polymer according to  claim 1  which is swellable in water up to 1700%.  
   
   
       13 . A polymer according to  claim 1  which is soluble in dichloromethane.  
   
   
       14 . A method of making a polymer according to  claim 1  which comprises reacting together components (a), (b) and (c).  
   
   
       15 . A controlled release composition which comprises a polymer of  claim 1  together with an active agent.  
   
   
       16 . A composition according to  claim 15  wherein the molecular weight of the active agent is in the range 200 to 20,000.  
   
   
       17 . A composition according to  claim 15  wherein the active agent is a prostaglandin.  
   
   
       18 . A composition according to  claim 15  wherein the active agent is terbutaline sulphate, clindamycin sulphate, oxytocin, misoprostol or progesterone.  
   
   
       19 . A composition wherein the active agent is an H 2  receptor antagonist, antimuscaririe, prostaglandin analogue, proton pump inhibitor, aminosalycilate, corticosteroid, chelating agent, cardiac glycoside, phosphodiesterase inhibitor, thiazide, diuretic, carbonic anhydrase inhibitor, antihypertensive, anti-cancer, anti-depressant, calcium channel blocker, analgesic, opioid antagonist, antiplatel, anticoagulant, fibrinolytic, statin, adrenoceptor agonist, beta blocker, antihistamine, respiratory stimulant, micolytic, expectorant, benzodiazepine, barbiturate, anxiolytic, antipsychotic, tricyclic antidepressant, 5HT, antagonist, opiate, 5HT, agonist, antiemetic, antiepileptic, dopaminergic, antibiotic, antifungal, anthelmintic, antiviral, antiprotozoal, antidiabetic, insulin, thyrotoxin, female sex hormone, male sex hormone, antioestrogen, hypothalamic, pituitary hormone, posterior pituitary hormone antagonist, antidiuretic hormone antagonist, bisphosphonate, dopamine receptor stimulant, androgen, non-steroidal anti-inflammatory, immuno suppressant local anaesthetic, sedative, antipsioriatic, silver salt, topical antibacterial, vaccine.  
   
   
       20 . A composition according  claim 15  in the form of a suppository, pessary, buccal insert or film.