Fighting TB: Development of microparticulate systems to target alveolar macrophages in tuberculosis therapy

Funder

Organizational Unit

Publications

Spray-drying of konjac glucomannan to produce microparticles for an application as antitubercular drug carriers

Publication . Guerreiro, Filipa; Pontes, Jorge Filipe; Rosa Da Costa, Ana; Grenha, Ana

Spray-drying is proposed in this work as the technique to produce konjac glucomannan microparticles aimed at an application in lung tuberculosis therapy. Microparticles were developed to provide direct lung delivery of an association of two first-line antitubercular drugs, isoniazid and rifabutin, by inhalation. Mannitol or leucine were incorporated as spray-drying excipients to verify their effect on the final properties of drug-loaded konjac glucomannan microparticles. The obtained results indicate that konjac glucomannan is a suitable material for the preparation of inhalable microparticles for antitubercular therapy upon processing by spray-drying. The incorporation of excipients revealed no benefit on the characterised properties. Isoniazid and rifabutin were mostly associated to microparticles with success (efficiencies of 88-104%). However, the presence of mannitol was found to decrease the capacity to associate isoniazid (efficiency of 43%). The excipients further promoted the acceleration of drug release. Moreover, general absence of toxicity was observed for microparticles in Calu-3 and A549 cells, with cell viabilities above 70%. The results of the work suggest that microparticles composed only of KGM display the most appropriate characteristics.

2019-01Journal article

Restricted

Carrageenan from red algae: an application in the development of inhalable tuberculosis therapy targeting the macrophages

Publication . Rodrigues, Susana; Cunha, Ludmylla Costa; Martins Rico, João; Rosa Da Costa, Ana; Almeida, Antonio J.; Faleiro, ML; Buttini, Francesca; Grenha, Ana

Macrophages have unique surface receptors that might recognize preferentially several moieties present on the surface of infecting organisms, including in the bacterial cell wall. Benefiting from a similar composition regarding the referred moieties, polysaccharides might be good candidates to compose the matrix of drug carriers aimed at macrophage targeting, as they can use the same recognition pathways of the infecting organisms. Carrageenan (CRG), a polysaccharide extracted from red edible seaweed, is an interesting possibility for the approach of directly targeting alveolar macrophages, as its composition is reported to be recognized by several macrophage lectin receptors. Inhalable starch/CRG microparticles were successfully produced, effectively associating isoniazid (96%) and rifabutin (74%) simultaneously. Furthermore, the produced microparticles presented adequate aerodynamic properties for pulmonary delivery with potential to reach the respiratory zone, with a mass median aerodynamic diameter (MMAD) between 3.3 and 3.9 mu m. It was further demonstrated that the antitubercular activity of the drugs remained unchanged after encapsulation. The formulation evidenced no cytotoxic effects on lung epithelial cells (A549), although mild toxicity was observed on macrophage-differentiated THP-1 cells for the drug-loaded formulation. Starch/CRG microparticles also exhibited a propensity to be captured by macrophages in a dose-dependent manner, as well as an ability to activate the target cells. This work provides indications on the potential of the starch/CRG carriers to interact with macrophages, thus providing a platform for drug delivery in the context of macrophage intracellular diseases. Additionally, if tuberculosis is focused, these microparticles can be used as inhalable drug carriers.

2020-12Journal article

Open Access

Dual antibiotherapy of tuberculosis mediated by inhalable locust bean gum microparticles

Publication . Rodrigues, Susana; Alves, Ana D.; Cavaco, Joana S.; Pontes, Jorge Filipe; Guerreiro, Filipa; Rosa Da Costa, Ana; Buttini, Francesca; Grenha, Ana

Despite the existence of effective oral therapy, tuberculosis remains a deadly pathology, namely because of bacterial resistance and incompliance with treatments. Establishing alternative therapeutic approaches is urgently needed and inhalable therapy has a great potential in this regard. As pathogenic bacteria are hosted by alveolar macrophages, the co-localisation of antitubercular drugs and pathogens is thus potentiated by this strategy. This work proposes inhalable therapy of pulmonary tuberculosis mediated by a single locust bean gum (LBG) formulation of microparticles associating both isoniazid and rifabutin, complying with requisites of the World Health Organisation of combined therapy. Microparticles were produced by spray-drying, at LBG/INH/RFB mass ratio of 10/1/0.5. The aerodynamic characterisation of microparticles revealed emitted doses of more than 90% and fine particle fraction of 38%, thus indicating the adequacy of the system to reach the respiratory lung area, thus partially the alveolar region. Cytotoxicity results indicate moderate toxicity (cell viability around 60%), with a concentration-dependent effect. Additionally, rat alveolar macrophages evidenced preferential capture of LBG microparticles, possibly due to chemical composition comprising mannose and galactose units that are specifically recognised by macrophage surface receptors. (C) 2017 Elsevier B.V. All rights reserved.

2017-08Journal article

Open Access

Hybrid nanosystems based on natural polymers as protein carriers for respiratory delivery: stability and toxicological evaluation

Publication . Rodrigues, Susana; Cordeiro, Clara; Seijo, Begona; Remunan-Lopez, Carmen; Grenha, Ana

Chitosan/carrageenan/tripolyphosphate nanoparticles were previously presented as holding potential for an application in transmucosal delivery of macromolecules, with tripolyphosphate demonstrating to contribute for both size reduction and stabilisation of the nanoparticles. This work was aimed at evaluating the capacity of the nanoparticles as protein carriers for pulmonary and nasal transmucosal delivery, further assessing their biocompatibility pattern regarding that application. Nanoparticles demonstrated stability in presence of lysozyme, while freeze-drying was shown to preserve their characteristics when glucose or sucrose were used as cryoprotectants. Bovine serum albumin was associated to the nanoparticles, which were successfully microencapsulated by spray-drying to meet the aerodynamic requirements inherent to pulmonary delivery. Finally, a satisfactory biocompatibility profile was demonstrated upon exposure of two respiratory cell lines (Calu-3 and A549 cells) to the carriers. A negligible effect on cell viability along with no alterations on transepithelial electrical resistance and no induction of inflammatory response were observed. (C) 2015 Elsevier Ltd. All rights reserved.

2015-06Journal article

Open Access

Engineering of konjac glucomannan into respirable microparticles for delivery of antitubercular drugs

Publication . Guerreiro, Filipa; Swedrowska, Magda; Patel, Roshnee; Floréz- Fernández, Noelia; Torres, María Dolores; Rosa Da Costa, Ana M.; Forbes, Ben; Grenha, Ana

Few medically-approved excipients are available for formulation strategies to endow microcarriers with improved performance in lung drug targeting. Konjac glucomannan (KGM) is a novel, biocompatible material, comprising mannose units potentially inducing macrophage uptake for the treatment of macrophage-mediated diseases. This work investigated spray-dried KGM microparticles as inhalable carriers of model antitubercular drugs, isoniazid (INH) and rifabutin (RFB). The polymer was characterised and different polymer/drug ratios tested in the production of microparticles for which respirability was assessed in vitro. The swelling of KGM microparticles and release of drugs in simulated lung fluid were characterised and the biodegradability in presence of beta-mannosidase, a lung hydrolase, determined. KGM microparticles were drug loaded with 66-91% association efficiency and had aerodynamic diameter around 3 mu m, which enables deep lung penetration. The microparticles swelled upon liquid contact by 40-50% but underwent size reduction (>62% in 90 min) in presence of beta-mannosidase, indicating biodegradability. Finally, drug release was tested showing slower release of RFB compared with INH but complete release of both within 24 h. This work identifies KGM as a biodegradable polymer of natural origin that can be engineered to encapsulate and release drugs in respirable microparticles with physical and chemical macrophage-targeting properties.

2021Journal article

Open Access