Development of Aerosol Dry Powder Chemotherapeutic-Loaded Microparticles for the Treatment of Lung Cancer

Lung cancer is the leading cause of cancer-related deaths worldwide, resulting in the highest mortality rates among both men and women with respect to all other types of cancer. Difficulties in treating lung cancer arise from late-stage diagnoses and tumor heterogeneity and current treatment involves a combination of chemotherapeutics, surgery, and radiation. Chemotherapeutics administered systemically can lead to undesirable side effects and severe off-site toxicity. For example, chronic administration of the chemotherapeutic doxorubicin (DOX) leads to cardiotoxicity, thereby limiting its long-term use. Systemic administration of the highly lipophilic molecule paclitaxel (PTX) is hindered by its water solubility, necessitating the use of solubilizing agents, which can induce side effects. Thus, in this investigation, formulations consisting of spray-dried microparticles (MP) containing DOX and PTX were produced to be administered as dry powder aerosols directly to the lungs. Acetalated dextran (Ac-Dex) was used as the polymer in these formulations, as it is a biocompatible and biodegradable polymer that exhibits pH-responsive degradation. Solid-state characterization revealed that DOX and PTX remained in solubility favoring amorphous states in the MP formulations and that both drugs remained thermally stable throughout the spray drying process. In vitro release studies demonstrated the pH sensitivity of the formulations due to the use of Ac-Dex, as well as the release of both therapeutics over the course of at least 48 h. In vitro aerosol dispersion studies demonstrated that both formulations exhibited suitable aerosol dispersion properties for deep lung delivery.