Ultrasound-mediated release of calcein from echogenic liposomes

Echogenic liposomes (ELIP) have been developed for drug encapsulation. The gas contents in ELIP present a potential mechanism for ultrasound-triggered release of drug contents. Calcein, a fluorescent dye, was loaded in ELIP as a drug substitute (C-ELIP) and ultrasound-induced release was quantified...

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Bibliographic Details
Published in:The Journal of the Acoustical Society of America 2007-11, Vol.122 (5_Supplement), p.3007-3007
Main Authors: Kopechek, Jonathan A., Chrzanowski, Stephen M., Smith, Denise A. B., Gaskins, Whitney B., Abruzzo, Todd A., Huang, Shaoling L., McPherson, David D., Holland, Christy K.
Format: Article
Language:English
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Summary:Echogenic liposomes (ELIP) have been developed for drug encapsulation. The gas contents in ELIP present a potential mechanism for ultrasound-triggered release of drug contents. Calcein, a fluorescent dye, was loaded in ELIP as a drug substitute (C-ELIP) and ultrasound-induced release was quantified with fluorescence spectrophotometry. Pulsed 6.0-MHz color Doppler from a clinical diagnostic ultrasound scanner (CL15-7 transducer, Philips HDI 5000, MI of 1.3, 150 Hz pulse repetition frequency) was applied to samples of C-ELIP in an in vitro flow phantom (2.2 ml/min). For comparison, Triton X-100 was added to C-ELIP to release calcein. Control samples of C-ELIP were not treated with ultrasound or Triton X-100. The echogenicity of C-ELIP (expressed as mean digital intensity in a 0.5 cm2 region of interest) decreased by 9.6±2.1 dB after exposure to ultrasound. The observed calcein concentration (μg/ml) was 3.1±0.1 for the untreated sample, 4.5±0.1 after Triton X-100 treatment, and 4.2±0.2 after ultrasound exposure. 65.6% of encapsulated calcein was released with ultrasound. These results demonstrate that ultrasound-mediated release of drugs from ELIP using a clinical diagnostic ultrasound scanner is feasible. [Work supported by an AIUM Education and Research Grant and NIH 1R01 HL074002, and NIH 1RO1 NS047603-01S1.]
ISSN:0001-4966
1520-8524
DOI:10.1121/1.2942739