| abstract |
Prepn. of colloidally dispersed system of a pharmaceutical (I) sparingly soluble in water comprises (a) selecting a gelatin (deriv.) or collagen hydrolysate having an isoelectric point (IEP) such that at a particular pH it will neutralise the charge on particles of (I), (b) converting the selected cpd. to aq. soln. form, (c) adjusting the pH (in accordance with (IEP) such that nanoparticles of (I) formed will be stabilised by (almost) complete charge neutralisation, and (d) before or after step (c), (I) is dissolved in the aq sol or a soln. of (I) is combined with the aq. sol. (I) can be replaced by other sparingly soluble organic and/or inorganic cpds. (Ia). Also new are the nanosols themselves. They consist of (a) an inner phase of (I) or (Ia) of particle size 10-800 nm., having a negative or positive surface charge, (b) an external phase of gelatin (deriv.) or collagen hydrolysate with opposite charge and the charge balance between the 2 phases is almost isoionic. USE/ADVANTAGE - The systems are useful in tablets (with rapid or slow release), capsules, parenteral or bioadhesive formulations. The bioavailability of almost any (I) can be improved (by increasing the dissolution rate/without use of harmful additives, and the total (I) dose may be reduced. The process is simple, can use many different sorts of gelatin and by balancing the charges, Ostwald ripening (growth of the larger colloidal particles) is prevented, resulting in a stable, monodisperse system |