Preparation and Preclinical Evaluation of Inhalable Particles Containing Rapamycin and Anti-Tuberculosis Agents for Induction of Autophagy.
Mycobacterium tuberculosis (Mtb) inhibits host defense mechanisms, including autophagy. We investigated particles containing rapamycin (RAP) alone or in combination with isoniazid (INH) and rifabutin (RFB) for: targeting lung macrophages on inhalation; inducing autophagy; and killing macrophage-resident Mtb and/or augmenting anti-tuberculosis (TB) drugs.



PLGA and drugs were spray-dried. Pharmacokinetics, partial biodistribution (LC-MS/MS) and efficacy (colony forming units, qPCR, acid fast staining, histopathology) in mice following dry powder inhalation were evaluated.



Aerodynamic diameters of formulations were 0.7-4.7 μm. Inhaled particles reached deep lungs and were phagocytosed by alveolar macrophages, yielding AUC0-48 of 102 compared to 0.1 μg/ml × h obtained with equivalent intravenous dose. RAP particles induced more autophagy in Mtb-infected macrophages than solutions. Inhaled particles containing RAP alone in daily, alternate-day and weekly dosing regimens reduced bacterial burden in lungs and spleens, inducing autophagy and phagosome-lysosome fusion. Inhalation of particles containing RAP with INH and RFB cleared the lungs and spleens of culturable bacteria.



Targeting a potent autophagy-inducing agent to airway and lung macrophages alone is feasible, but not sufficient to eliminate Mtb. Combination of macrophage-targeted inhaled RAP with classical anti-TB drugs contributes to restoring tissue architecture and killing Mtb.
Pharmaceutics Division, CSIR-Central Drug Research Institute, Sector 10A, Jankipuram Extension, Lucknow, 226031, India.
Anuradha
A
Gupta
Pharmaceutics Division, CSIR-Central Drug Research Institute, Sector 10A, Jankipuram Extension, Lucknow, 226031, India.
Deepak
D
Sharma
National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi, 110067, India.
Jairam
J
Meena
Pharmaceutics Division, CSIR-Central Drug Research Institute, Sector 10A, Jankipuram Extension, Lucknow, 226031, India.
Sanketkumar
S
Pandya
Pharmaceutics Division, CSIR-Central Drug Research Institute, Sector 10A, Jankipuram Extension, Lucknow, 226031, India.
Madhur
M
Sachan
Pharmaceutics Division, CSIR-Central Drug Research Institute, Sector 10A, Jankipuram Extension, Lucknow, 226031, India.
Sadan
S
Kumar
Pharmaceutics Division, CSIR-Central Drug Research Institute, Sector 10A, Jankipuram Extension, Lucknow, 226031, India.
Kavita
K
Singh
Pharmaceutics Division, CSIR-Central Drug Research Institute, Sector 10A, Jankipuram Extension, Lucknow, 226031, India.
Kalyan
K
Mitra
Pharmaceutics Division, CSIR-Central Drug Research Institute, Sector 10A, Jankipuram Extension, Lucknow, 226031, India.
Sharad
S
Sharma
National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi, 110067, India.
Amulya K
AK
Panda
National JALMA Institute for Leprosy and Other Mycobacterial Diseases, ICMR, Tajganj, Agra, 282001, India.
Pushpa
P
Gupta
National JALMA Institute for Leprosy and Other Mycobacterial Diseases, ICMR, Tajganj, Agra, 282001, India.
Umesh Datta
UD
Gupta
Pharmaceutics Division, CSIR-Central Drug Research Institute, Sector 10A, Jankipuram Extension, Lucknow, 226031, India. amit_misra@cdri.res.in.
Amit
A
Misra
D000280:Administration, Inhalation; D000818:Animals; D000995:Antitubercular Agents / Q000008:administration & dosage* / Q000138:chemical synthesis / Q000378:metabolism; D001343:Autophagy / Q000187:drug effects* / Q000502:physiology; D004353:Drug Evaluation, Preclinical / Q000379:methods; D004359:Drug Therapy, Combination; D006801:Humans; D019344:Lactic Acid / Q000008:administration & dosage / Q000138:chemical synthesis / Q000378:metabolism; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism; D008297:Male; D051379:Mice; D009000:Monocytes / Q000187:drug effects / Q000378:metabolism; D009169:Mycobacterium tuberculosis / Q000187:drug effects* / Q000378:metabolism; D011100:Polyglycolic Acid / Q000008:administration & dosage / Q000138:chemical synthesis / Q000378:metabolism; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D020123:Sirolimus / Q000008:administration & dosage* / Q000138:chemical synthesis / Q000378:metabolism
D000995:Antitubercular Agents; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; D020123:Sirolimus
autophagy; biodistribution; dry powder inhalation; macrophage targeting; microparticles; microspheres; pharmacokinetics; pulmonary drug delivery; tuberculosis