Process for activation of drugs in a vibrational mill
A process is described for the activation (increase in solubility and bioavailability) of drugs. The process, carried out in a vibrational mill, is characterised by the use of given proportions between the physical mixture made up of drug and pharmaceutical carrier and the empty volume among the grinding means contained inside the mill. The process leads to obtaining powders for pharmaceutical use in which the drug has a high and constant degree of activation; this result is obtainable irrespective of the nature of the drug and carrier used, and of their weight ratio.
1. A process for the preparation of drug-carrier composites, comprising co-grinding a drug-carrier mixture in a vibrational mill, wherein:
the vibrational mill contains grinding means of a cylindrical shape, with flat or convex bases, said grinding means having: diameter and height, independently of one another, of between 0.4 cm and 3 cm, a dimensional ratio (rd) of between 0.5 and 2 , and a curvature ratio (rc) of between 0 and 0.5; and
the vibrational mill is charged with a volume of drug-carrier mixture of between 35% and 100% of the interstitial volume V i , wherein interstitial volume V i is the volume of empty spaces between the grinding means in the mill.
2. The process according to claim 1 , where the grinding means have a diameter and height, independently of one another, of between 0.6 cm and 1.3 cm, a dimensional ratio (rd) of between 0.65 and 1.5, and a curvature ratio (rc) of between 0 and 0.4.
3. The process according to claim 1 , wherein the grinding means occupy from 20% to 90% of the total internal volume of the grinding chamber.
4. The process according to claim 1 , where the grinding means comprise aluminum oxide, zirconium oxide or steel.
5. The process according to claim 1 , where the carrier is a solid substance for pharmaceutical use selected from the group consisting of cross-linked polymers, linear polymers, and non-polymeric carriers.
6. The process according to claim 1 , where the carrier and the drug are used in a weight ratio of between 12:1 and 0.5:1.
7. The process according to claim 1 , where the composite obtained by co-grinding is further transformed, with the optional addition of pharmaceutically acceptable excipients, into pharmaceutical formulations suitable for human or animal administration.
8. The process according to claim 7 , where said pharmaceutical formulations are selected from the group consisting of tablets, minitablets, capsules, microcapsules, granulates, pellets, suspensions, solutions, ointments, creams, implants and programmed-release devices.
9. A process for the preparation of a given number (n) of drug-carrier batches with a constant degree of activation, comprising n cycles of co-grinding drug-carrier mixtures, each having the same composition, in the same vibrational mill containing the same grinding means, wherein:
the vibrational mill contains grinding means of a cylindrical shape, with flat or convex bases, having: diameter and height, independently of one another, of between 0.4 cm and 3 cm, a dimensional ratio (rd) of between 0.5 and 2, and a curvature ratio (rc) of between 0 and 0.5; and
the vibrational mill is charged with a volume of drug-carrier mixture of between 35% and 100% of the interstitial volume V i , wherein the interstitial volume V i is the volume of empty spaces between the grinding means in the mill and in which the interstitial volume V i is determined only once and is used as a reference for all the n grinding cycles,
wherein the n cycles of co-grinding with the vibrational mill so charged produce n drug-carrier batches with a constant degree of activation.
10. A process for the preparation of drug-carrier composites, performed by co-grinding a drug-carrier mixture in a vibrational mill, wherein:
the vibrational mill contains grinding means of a cylindrical shape, with flat or convex bases; and
the vibrational mill is charged with a volume of drug-carrier mixture of between 35% and 100% of the interstitial volume V i , wherein the interstitial volume V i is the between the grinding means in the mill.
11. The process of claim 10 , wherein the grinding means have: diameter and height, independently of one another, of between 0.4 cm and 3 cm, a dimensional ratio (rd) of between 0.5 and 2.
12. The process of claim 11 , wherein the grinding means have a curvature ratio (rc) of between 0.1 and 0.5.
13. The process according to claim 10 , where the grinding means have a diameter and height, independently of one another, of between 0.6 cm and 1.3 cm, a dimensional ratio (rd) of between 0.65 and 1.5, and a curvature ratio (rc) of between 0.1and 0.4.