Pharmaceutical composition containing anionic drug, and preparation method therefor

A composition for delivering an anionic drug, comprising:

• the anionic drug as an active ingredient;
• a cationic compound which is a cationic lipid represented by Formula 7 as recited below;
• an amphiphilic block copolymer;
• and
• at least one salt of a polylactic acid selected from the group consisting of the compounds
• of Formulae 5 and 6 as below,
• wherein the anionic drug forms a complex with the cationic compound by electrostatic interaction,
• wherein the complex is entrapped in a micelle structure of the amphiphilic block copolymer and the salt of polylactic acid,
• wherein an anion of carboxylic acid in the salt of polylactic acid is bound to the complex in order to reduce the zeta potential of the micelle, and
• wherein the zeta potential of the micelle is from −20 to 20 mV:
• wherein R′is -PAD-O—C(O)—CH2CH2—C(O)—OM, wherein PAD is selected from the group consisting of D,L-polylactide, D-polylactide, polymandelic acid, copolymer of D,L-lactide and glycolic acid, copolymer of D,L-lactide and mandelic acid, copolymer of D,L-lactide and caprolactone, and copolymer of D,L-lactide and 1,4-dioxane-2-one, Mis Na, K or Li;
• and a is an integer from 1 to 4;
• and
• YO-[—C(O)—(CHX)a—O—]m—C(O)—R—C(O)—[—O—(CHX′)b—C(O)—]n—OZ [Formula 6]
• wherein X and X′ are independently hydrogen, C1-10 alkyl or C6-20 aryl;
• Y and Z are independently Na, K or Li;
• m and n are independently an integer from 0 to 95, with the proviso that 5<m+n<100;
• a and b are independently an integer from 1 to 6;
• and R is —(CH2)k−, C2-10 divalent alkenyl, C6-20 divalent aryl or a combination thereof, wherein k is an integer from 0 to 10,
• wherein the salt of polylactic acid has a number average molecular weight of at least 500 Daltons,
• wherein n and m each are 0 to 12 with the proviso that 2≤n+m≤12, a and b each are 1 to 6, R1 and R2 each are independently selected from the group consisting of saturated and unsaturated C11-25 hydrocarbons.