Method for preparing solid lipid nanoparticles containing antibodies in ion pair form using the fatty acid coacervation technique

A method for preparing solid lipid nanoparticles containing antibodies, comprising the steps of: (a) preparing a micellar solution comprising: from 0.02 mg/ml to 10 mg/ml of at least one anionic surfactant selected from the group consisting of alkylphosphates, alkylsulfates and alkylsulfonates; from 0.1% to 30% by weight on the total weight of the micellar solution of at least one alkaline soap; from 0.1% to 30% by weight on the total weight of the micellar solution of at least one non-ionic amphiphilic polymer selected from the group consisting of partially hydrolyzed polyvinyl acetate, polyoxyethylene/polyoxypropylene copolymers, polyacrylamides, polyvinylpyrrolidone and derivatives thereof, dextrane derivatives and agarose derivatives with various molecular weights, cellulose derivatives, non-ionic rubbers, cyclodextrins and derivatives thereof; said micellar solution being prepared by means of the following steps: (i) solubilizing in water the at least one anionic surfactant; (ii) adding the at least one alkaline soap, heating to a temperature comprised between 35°C and 90°C; and (iii) adding the at least one non-ionic amphiphilic polymer; (b) adding to the micellar solution prepared in step (a) a solution that contains at least one antibody of interest at a concentration comprised between 0.1 mg/ml and 10 mg/ml with respect to the final solution resulting from step (b); (c) adding to the solution obtained in step (b) at least one acid at a concentration comprised between 0.01M and 5M with respect to the final solution resulting from step (c); (d) cooling in an ice bath the suspension obtained in step (c) down to ambient temperature.