subject: An injectable ivermectin composition [print this page] An injectable ivermectin composition An injectable ivermectin composition
An injectable ivermectin composition having a programmable release rate and providing multiple concentration peaks of active ivermectin to produce a sequence of ivermectin release pulses into the blood of cattle and horses. The composition comprises a solution of 0.2%-10% w/w of ivermectin in a solvent selected from propyleneglycol and a mixture of glycerile caprylate, caproate and caprate, such as glycerides of caproic, caprilic and capric acids in equal parts. The solution is used as a vehicle for suspending microspheres 100 nm-200 m in diameter of a degradable polymer containing between 0.5% and 50% of ivermectin. The microspheres may be formed from polylactic acid, polyglycolic acid or a copolymer of polylactic-polyglycolic acid. The programmable multi-pulse release system may also be obtained with a biodegradable matrix selected from hardenable natural polymers, such as gelatin or albumin, apart from the copolymers of lactic and gycolic acids. SUMMARY OF THE PRIOR ART
It is known that injectable ivermectin dissolved in propyleneglycol solvent releases into the blood during a period up to 14 days. Reference may be made to European Patent (EP) application 0045 655 (filed on 10 Feb. 1982) which discloses a preparation of ivermectin in glicerol-formal and propyleneglycol to increase the duration of the pesticide activity.
Reference may be made to other attempts at extending the activity of ivermectin in injectable formulations. For instance, EP application 00413 538 filed on 9 Feb. 1991 discloses using triacetine in injectable ivermectin formulations. This document claims that said formulations last 42 days and furthermore confirms that the activity of preexistent formulations lasted 14 days only.
None of the prior art documents known to us has claimed activity for injectable formulations lasting more than the 42-day period claimed by the aforesaid EP application 00413 538. Moreover, although the most diverse solvents as well as implantable matrices and ruminal boli having extended duration have been suggested, we know of no injectable preparation that may provide ivermectin from the solvent during an extended period of time and, in addition, provide release peaks lasting 15 to 20 days, the beginning of which may be programmed to follow the moment that the active drug reserve is practically completely exhausted in the solvent.
