Piroxicam encapsulated in liposomes: characterization and in vivo evaluation of topical anti-inflammatory effect.
Liposomes of soya phosphatidylcholine, cholesterol, and stearylamine (molar ratio 6/3/1) and 0.1% alpha-tocopherol were prepared by the extrusion of multilamellar vesicles through 0.2-micron polycarbonate membrane. Liposomes were characterized by electron transmission microscopy, and the mean structure diameter was 278 nm. The encapsulation efficiency obtained was 12.73%. The topical anti-inflammatory effect was evaluated in vivo by the cotton pellet granuloma method. We analyzed free piroxicam at 4 mg/kg, piroxicam encapsulated in liposomes added to 1.5% hydroxyethylcellulose (HEC) gel at 1.6 mg/kg, and piroxicam encapsulated in liposomes added to HEC gel at 4 mg/kg; the inhibition of inflammation obtained was 21.1%, 32.8%, and 47.4%, respectively. These results showed that the encapsulation of piroxicam produced an increase of topical anti-inflammatory effect, suggesting that the inhibition of inflammation can be obtained with lower drug concentrations.
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Departamento de Farmácia Industrial, Centro de Ciências da Saúde, UFSM, Santa Maria, RS, Brasil.
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Oliveira
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D000287:Administration, Topical; D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage* / Q000627:therapeutic use; D004337:Drug Carriers; D006099:Granuloma / Q000188:drug therapy; D007249:Inflammation / Q000188:drug therapy; D008081:Liposomes; D010894:Piroxicam / Q000008:administration & dosage* / Q000627:therapeutic use; D051381:Rats; D017208:Rats, Wistar
D000894:Anti-Inflammatory Agents, Non-Steroidal; D004337:Drug Carriers; D008081:Liposomes; D010894:Piroxicam