IMPROVING EFFECTIVENESS OF DRUGS

Abstract: There is disclosed a method for improving the effectiveness of a drug comprising the steps of encapsulating the drug in liposome membranes and loading the thus encapsulated drug into cells extracted from the intended patient.

Description: IMPROVING EFFECTIVENESS OF DRUGS This invention relates to improving the effectiveness of drugs. Certain drugs are known to be effective against cancerous tissue, but have severe side effects on healthy tissue. The concept of targeting has been discussed for some time, in which a drug is delivered, usually in minute but effective doses, directly to disease tissue but without also dosing surrounding healthy cells. Some approaches depend upon the synthesis of new chemicals which, for example, mainly affect cells with a high nucleic acid turnover, due to their fast reproduction. This "magic bullet" or pharmacological approach, however, is difficult where a tumour cell is only quantitatively different from normal cells and has a tendency to produce toxicity. Another approach is pharmaceutical targeting, in which specially designed delivery devices direct the activity of a non-selective drug. In a "magic gun" system, guidance is imposed on the device such that it permeates only relevant areas, instead cf inertly diffusing throughout the tissues until a recognition event occurs . A targetted drug can reach widely disseminated cells. Most primary tumours produce secondary or metastatic growths which often prove fatally resistant. A device that killed these growths would be a significant step forward. An obvious possibility is to harness the cognitive powers of the natural immune system. Tumour cells are known to exhibit surface antigens, which are capable of provoking immunity despite the host's failure to counter a thriving tumour. In this approach, drugs have been attached, by various means, to a specific monoclonal antibody. When in contact with tumour cells in vitro, this worked well, but it failed in vivo. The present invention provids an effective drug delivery technique which does not have rhe problems of prior suggestions. The invention comprises a method for improving the effectiveness of a drug comprising the steps of encapsulating the drug in liposome membranes and loading the thus encapsulated drug into cells extracted from the intended patient. The cells may be macrophages or related onocytes, and may be taken from the peritoneum of the patient or from blood. The extracted cell fraction may be added to a culture medium combined with an agent preventing cell adhesion. Without such an agent, the cells may adhere to the walls of a culture flask, for example, which can make harvesting difficult. Such an agent may comprise PVP coated colloidal silica, which is sold under the name Percoll by Pharmacia Inc. A suitable culture medium is RPMI 40, and a suitable composition is one part ten-fold strength RPMI 40 culture medium and nine parts Percoll. A cell activator may be added, such as adjuvent peptide or MDP, with or without the addition of liposomes at this stage. This, especially with liposomes, rapidly activates macrophages to a tumouricidal state. In any event, the cells are cultured in the composition until activated, as may be determined microscopically by inspection from time to time. This may take several hours at body temperature. The liposome encapsulated drug nay then be added and the composition further incubated until phagocytosis occurs, i.e. the cells imbibe the liposome encapsulated drug. After this, the drug loaded cells may be separated centrifugally and re-suspended into a drug-free saline solution for re-introduction into the patient. The invention also comprises a kit for carrying out the method above described comprising a culture flask containing a composition of culture medium and cell adhesion preventive agent. The invention also comprises a composition for carrying out the method above described or for use in a kit as described containing a culture medium and a cell adhesion preventive agent. Such composition can include also the optional elements referred to above. Obviously, made-up preparations and culture flasks must all be aseptic, and likewise techniques for introducing the cell fraction and additives.

Claims: CLAIMS 1. A method for improving the effectiveness of a drug comprising the steps of encapsulating the drug in liposome membranes and loading the thus encapsulated drug into cells extracted from the intended patient. 2. A method according to claim 1, wherein the cells are macrophages or related monocytes. 3. A method according to claim 1 or claim 2, wherein the cells are taken from the peritoneum of the patient or from blood. 4. A method according to any one of the preceding claims, wherein the extracted cell fraction is added to a composition comprising a culture medium combined with an agent preventing cell adhesion. 5. A method according to claim 4, wherein the agent comprises PVP coated coloidal silica. 6. A method according to claim 4, wherein the culture medium is RPMI 40. 7. A method according to any one of claims 4 to 6, wherein the composition comprises one part ten-fold strength RPMI 40 culture medium and nine parts PVP coated coloidal silica. 8. A method according to any one of claims 4 to 7, wherein the composition further comprises a cell activator such as adjuvent peptide or MDP, with or without the addition of liposomes at this stage. 9. A method according to any one of claims 4 to 8, wherein the cells are cultured in the composition until activated. 10. A method according to claim 9, wherein cell activation is determined by microscopial inspection. 11. A method according to any one of claims 4 to 10, wherein the liposome encapsulated drug is incubated in the composition until phagocytosis occurs, i.e. the cells imbibe the liposome encapsulated drug. 12. A method according to claim 11, wherein the drug loaded cells are separated centrifugally and re-suspended into a drug-free saline solution for re-introduction into the patient. 13. A kit for carrying out the method disclosed in claims 1 to 12, comprising a culture flask containing a composition of culture medium and cell adhesion preventive agent. 14. A composition for carrying out the method disclosed in claims 1 to 12 or for use in a kit as described in claim 13 containing a culture medium and a cell adhesion preventive agent. 15. A composition according to claim 14 also comprising a cell activator such as adjuvent peptide or MDP.

Inventors: TAYLOR MARGARET JOAN, TAYLOR, MARGARET, JOAN
Applicants: ALPHA HEALTHCARE LTD, TAYLOR MARGARET JOAN, ALPHA HEALTHCARE LIMITED, TAYLOR, MARGARET, JOAN
Application year: 1993
Main classification: A61K9
IPC codes: A61K9, A61K35, C12N5