TY - JOUR
T1 - Inhaled aerosolization of all-trans-retinoic acid for targeted pulmonary delivery
AU - Brooks, Ari D.
AU - Tong, William
AU - Benedetti, Fabio
AU - Kaneda, Yoshikazu
AU - Miller, Vincent
AU - Warrell, Raymond P.
N1 - Funding Information:
Supported in part by CA-07860 from the National Cancer Institute. Presented in part at the annual meeting of the American Association of Cancer Research, San Diego, Calif., 1997.
PY - 2000
Y1 - 2000
N2 - Retinoids have shown promising activity for both cancer chemoprevention and as a treatment for emphysema. However, chronic oral administration of these drugs is limited by systemic side effects, including hepatic dysfunction, skeletal malformations, hyperlipidemia, hypercalcemia, and other reactions. In order to improve the pulmonary targeting of this potentially useful therapy, we developed a system for aerosolization of retinoids that substantially increased their local bioavailability. We compared the biodistribution and pharmacokinetics of an inhaled formulation of all-transretinoic acid (all-trans-RA), which was packaged in a metered dose inhaler, following both intratracheal (IT) and intravenous (IV) administration in male Sprague-Dawley rats. After drug administration, anesthetized animals were killed at 5 min, and at 1, 2, 4, 6 and 24 h. Plasma and emulsified samples of liver and lung tissues were dissected, extracted, and frozen prior to measurement of all-trans-RA concentration by high-performance liquid chromatography (HPLC). Aerosolization and IT injection of all-trans-RA resulted in a significantly longer pulmonary half-life of the drug (both 5-17 h), lower peak serum concentrations (aerosol 71 ± 31 ng/ml, IT 68 ± 50 ng/ml), and lower liver levels (aerosol 111 ± 28 ng/g, IT 753 ± 350 ng/g) than the same dose administered IV (2 h, 838 ± 56 ng/ml, 4258 ± 1006 ng/g, respectively; P < 0.05 for each comparison). Histologic examination of lungs and trachea showed no focal irritation attributable to the drug after single-dose administration. These results suggest that aerosolization of retinoids may offer a practical alternative to systemic oral administration for chemoprevention trials or treatment of lung diseases. This method may substantially increase the therapeutic index of these compounds by reducing systemic complications associated with long-term dosing.
AB - Retinoids have shown promising activity for both cancer chemoprevention and as a treatment for emphysema. However, chronic oral administration of these drugs is limited by systemic side effects, including hepatic dysfunction, skeletal malformations, hyperlipidemia, hypercalcemia, and other reactions. In order to improve the pulmonary targeting of this potentially useful therapy, we developed a system for aerosolization of retinoids that substantially increased their local bioavailability. We compared the biodistribution and pharmacokinetics of an inhaled formulation of all-transretinoic acid (all-trans-RA), which was packaged in a metered dose inhaler, following both intratracheal (IT) and intravenous (IV) administration in male Sprague-Dawley rats. After drug administration, anesthetized animals were killed at 5 min, and at 1, 2, 4, 6 and 24 h. Plasma and emulsified samples of liver and lung tissues were dissected, extracted, and frozen prior to measurement of all-trans-RA concentration by high-performance liquid chromatography (HPLC). Aerosolization and IT injection of all-trans-RA resulted in a significantly longer pulmonary half-life of the drug (both 5-17 h), lower peak serum concentrations (aerosol 71 ± 31 ng/ml, IT 68 ± 50 ng/ml), and lower liver levels (aerosol 111 ± 28 ng/g, IT 753 ± 350 ng/g) than the same dose administered IV (2 h, 838 ± 56 ng/ml, 4258 ± 1006 ng/g, respectively; P < 0.05 for each comparison). Histologic examination of lungs and trachea showed no focal irritation attributable to the drug after single-dose administration. These results suggest that aerosolization of retinoids may offer a practical alternative to systemic oral administration for chemoprevention trials or treatment of lung diseases. This method may substantially increase the therapeutic index of these compounds by reducing systemic complications associated with long-term dosing.
KW - All-trans-retinoic acid
KW - Chemoprevention
KW - Inhalers
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U2 - 10.1007/s002800000148
DO - 10.1007/s002800000148
M3 - Article
C2 - 11052629
AN - SCOPUS:0033774621
SN - 0344-5704
VL - 46
SP - 313
EP - 318
JO - Cancer chemotherapy and pharmacology
JF - Cancer chemotherapy and pharmacology
IS - 4
ER -