Tadalafil-loaded PLGA microspheres for pulmonary administration: preparation and evaluation

Tadalafil, a long-acting PED-5 inhibitor, is commonly used for the treatment of pulmonary arterial hypertension (PAH). However, its efficacy and clinical application are severely limited by the poor water solubility, low bioavailability and a series adverse effects (e.g. headaches, indigestion). In this study, tadalafil was prepared and loaded into biodegradable PLGA (poly(lactic-co-glycolic acid)) microspheres (TDF-PLGA-MS) via emulsification-solvent evaporation. The resulting microspheres were processed into pulmonary inhalant by freeze drying. The TDF-PLGA-MS was spherical and uniform, with an average particle diameter ~10.29 µm. The encapsulation efficiency and drug loading yield of TDF-PLGA-MS were 81.68% and 8.52%, respectively. The investigation of micromeritics showed that the TDF-PLGA-MS had low moisture content. The fluidity of powders was relatively good. The aerodynamic diameter and emptying rate of microspheres powders were 3.92 µm and 95.41%, respectively. Therefore, the microspheres powders were easy to be atomized, and can meet the requirements of pulmonary administration. In vitro release results showed that the microspheres group released slowly. The cumulative release in 24 h and 10 d was 46.87% and 84.06%, respectively. The in vitro release profile of TDF-PLGA-MS was in accordance with the Weibull model. The results of Pharmacokinetics showed that tadalafil from microspheres slowly released into the blood after intratracheal instillation. The pulmonary drug residue in 0.5 h was 3.5 times compared with solution group. The residual concentration in lung after 10d was still higher than that of solution group in 48 h. The t1/2β and MRT0-∞ were 3.10 times and 3.96 times that of solution group, respectively. Moreover, the Cmax and AUC of drug residues in lung ​​were 3.48 times and 16.36 times that of solution group, respectively. The results of tissue distribution showed that the Re in lung was 16.358, which indicated the lung targeting. In conclusion, the TDF-PLGA-MS for pulmonary administration in this study can significantly improve the pulmonary targeting, increase efficacy of tadalafil and reduce other non-target organs toxicity. This study will have an important clinical significance for PAH patients who need long-term drug therapy.

Surdez súbita em paciente em uso de tadalafil: um relato de caso clínico / Sudden deafness in a patient with tadalafil use: a clinical case report

Introdução: a Surdez Súbita (SS) é uma emergência médica de baixa prevalência, porém com potencial de perda auditiva irreversível para o paciente. Possui diversos e ainda incertos mecanismos etiopatológicos. Recentemente a literatura vem trazendo a associação da SS com a classe dos inibidores da fosdodiesterase-5 (IPDE-5), a qual inclui medicamentos para tratamento de impotência sexual. Objetivo: relatar caso clínico de paciente idoso que apresentou SS após fazer uso de medicamento da classe dos IPDE-5, pesquisando na literatura qual a provável fisiopatologia. Metodologia: trata-se de estudo qualitativo, descritivo do tipo relato de caso clínico, realizado através da coleta de dados do prontuário médico, que foram comparados com literatura especializada. Resultado: paciente masculino, 72 anos, engenheiro, procurou atendimento referindo hipoacusia e plenitude aural à direita notados subitamente há três dias. Relata ter feito uso de Tadalafil 5mg, anteriormente aos sintomas. Anamnese e exame físico direcionaram para hipótese diagnóstica de SS, de modo que exames complementares foram solicitados. À audiometria evidenciou-se perda auditiva sensorioneural moderada a severa em orelha direita. Após tratamento com prednisolona oral e mesilato de codergocrina, paciente apresentou melhora, com audiometria evidenciando perda sensorioneural leve em orelha direita. Conclusão: a relação entre SS e o uso de IPDE-5 está cada vez mais evidente de acordo com a literatura. É provável que possa haver ativação de vias de estresse celular, contribuindo para patologia