LIPID EMULSIONS OF PALMITOYLRHIZOXIN: EFFECTS OF PARTICLE SIZE ON BLOOD DISPOSITIONS OF EMULSION LIPID AND INCORPORATED COMPOUND IN RATS

✍ Scribed by Atsushi Kurihara; Yoko Shibayama; Akiko Yasuno; Masarua Ikeda; Masafumi Hisaoka

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 580 KB
• Volume: 17
• Category: Article
• ISSN: 0142-2782
• DOI: 10.1002/(sici)1099-081x(199605)17:4<343::aid-bdd958>3.0.co;2-7

✦ Synopsis

Emulsion formulations of various particle sizes for the highly lipophilic antitumour agent, RS-1541 (1 3-O-palmitoylrhizoxin), were prepared using dioctanoyldecanoylglycerol (ODO) as lipids and polyoxyethylene-(60)-hydrogenated castor oil (HCO-60) as a surfactant. These emulsions were evaluated as injectable drug carriers and compared with a colloidal solution.

Both in vitro and in vivo after i.v. administration, RS-1541 was distributed into lipoproteins from the colloidal solution. When applied as emulsions of various particle sizes (124-419 nm) in vitro, RS-1541 was retained and stabilized within the emulsions. In the in vivo study, however, retention of RS-1541 in the emulsions after i.v. injection depended on their size. The smd-particle emulsions (94-1 12nm) resulted in long retention, and the large-particle emulsions (41 5-474 nm) led to short retention.

Lipolysis rates of emulsion particles by lipoprotein lipase also depended on their sue, indicating rapid lipolysis for small-particle emulsions (1 33 nm). However, the lipolysis was not such an extensive one, showing 10-30% release of capric acid from OD0 within 6 h. Blood dispositions of capric acids approximately paralleled those of RS-1541 after i.v. injection of various particle size emulsions (130-368 nm) to rats, although relatively rapid eliminations of capric acids compared with RS-1541 were observed for the smallparticle size emulsions (1 30 nm).

These results suggest that when injected as emulsion formulations, the highly lipophilic antitumour agent, RS-1541, has behaviour similar to that of the emulsion particles in the body, which is dependent on the size of the latter. Thus, by properly selecting the particle size, lipid emulsions consisting of O D 0 and HCO-60 are expected to be effective and useful DDS carriers for RS-1541.