RESUMO
Despite contrary reports, heating inside the medication reservoir was observed for several vibrating mesh nebulizers, which may be detrimental when nebulizing biopharmaceuticals. In this study we evaluated different strategies to reduce reservoir heating during nebulization with a PARI eFlow® regarding cooling efficiency, impact on nebulizer performance and on protein stability after nebulization. Passive cooling was achieved by solution pre-cooling, overcharging of the reservoir with 1 mL additional solution or intermittent nebulization. Active cooling was realized with a micro Peltier element attached to the nebulizer reservoir. Passive cooling was most effective when the reservoir was overcharged with pre-cooled solution reducing the average reservoir temperature (TRES AVG) by 8.4°C. Active cooling enabled nebulization at a constant reservoir temperature (TRES) as low as 15°C. TRES manipulation had a linear impact on nebulizer performance. While the output rate decreased with decreasing TRES, the inhalable fraction increased resulting in an inhalable aerosol rate constant over a large TRES range. The effect on protein stability depended on the susceptibility to thermal stress and was predicted by Tm values. For lactic dehydrogenase and SM101, both exhibiting a Tm below 60°C, cooling was protective in increasing the residual activity and reducing protein aggregation. A more thermostable IgG1 did not benefit from cooled nebulization. Nebulizer cooling is a prerequisite to retain the activity and stability of thermolabile proteins during vibrating mesh nebulization. It is best achieved by micro Peltier based active cooling or by simple passive cooling strategies.
Assuntos
Temperatura Baixa , Sistemas de Liberação de Medicamentos/instrumentação , Lactato Desidrogenases/administração & dosagem , Lactato Desidrogenases/química , Nebulizadores e Vaporizadores , Receptores de IgG/administração & dosagem , Receptores de IgG/química , Administração por Inalação , Aerossóis , Animais , Química Farmacêutica , Desenho de Equipamento , Proteínas Ligadas por GPI/administração & dosagem , Proteínas Ligadas por GPI/química , Humanos , Conformação Proteica , Desnaturação Proteica , Estabilidade Proteica , Coelhos , Tecnologia Farmacêutica/métodos , Fatores de Tempo , VibraçãoRESUMO
Objetive. The acute effects of cryotherapy on creatine phosphokinase (CPK) and lactate dehydrogenase (LDH) expression, perceived pain and upper limb muscle strength in jiu-jitsu competitors were investigated. Method. Ten highly trained athletes underwent two simulated competition sessions composed by four 7-minute combats with a 15-minute interval between them. Athletes were randomly allocated to receive either cold water immersion (5 ± 1 °C for 19 minutes) or no intervention (control) after competition simulation in a crossover counterbalanced fashion. Results. For LDH, there was an effect of condition (F1,18= 7.91, P = 0.012; η2 = 0.31), with lower values being found in cryotherapy as compared to control (criotherapy = 533.2 ± 55.4 and 671.2 ± 61.0 for pre- competition and post-recuperation, respectively; control = 528.5 ± 63.7 e 759.8 ± 85.7 UI/l for pre- competition and post-recuperation, respectively). Delta CPK differed significantly between conditions (criotherapy = 138.0 ± 95.1 UI/l; control = 231.3 ± 135.8 UI/l t = -1,72; P = 0,119; effect size = 0.75). For perceived pain there was also an effect of condition (F1,18 = 12.35, P = 0.003; η2 = 0.41), with lower values being found following cryotherapy (2.4 ± 1.4 versus 4.4 ± 1.8, P = 0.003). Pre-competition skin temperature was lower than that measured after recovery (34.5 ± 1.9 oC. versus 37.6 ± 1.3 oC, P = 0.0005). There were significant correlations between perceived pain and CPK (r = 0.314) and LDH (r = 0.546). The concentrations of CPK and LDH were negatively correlated with dynamic strength (r = - 0.525). Conclusion. Recovery via cold water immersion after simulated competition resulted in less muscle damage and hypoalgesia compared to the control (AU)
Objetivo. Investigar los efectos agudos de la crioterapia en la expresión de la enzima creatina fosfoquinasa (CPK), lactato deshidrogenasa (LDH), percepción del dolor y fuerza muscular en los miembros superiores de competidores de jiu-jitsu. Método. Diez luchadores altamente entrenados fueron sometidos a dos sesiones de competición simulada (4 × 7-minutos y 15 minutos de intervalo). Después del primer día, cinco atletas fueron elegidos para la inmersión en piscina con hielo (5 ± 1 °C) durante 19 minutos, los demás fueron asignados al grupo control. Resultados. Para LDH se observó efecto de la condición (F1,18 = 7,91, P = 0,012; η2 = 0,31) con valores más bajos (P = 0,012) en la crioterapia en comparación con el control (crioterapia = 533,2 ± 55,4 y 671,2 ± 61,0, respectivamente para inicial y final; control = 528,5 ± 63,7 y 759,8 ± 85,7 UI/l; respectivamente para inicial y final). El delta del CPK fue significativamente distinto entre las condiciones (crioterapia = 138,0 ± 95,1 UI/l; t = 1,72; P = 0,119; control = 231,3 ± 135,8 UI/l; tamaño del efecto = 0,75). Para el dolor percibido también hubo efecto de la condición (F1,18 = 12,35, P = 0,003; η2 = 0,41) con valores más bajos (P = 0,003) en la crioterapia (2,4 ± 1,4 frente a 4,4 ± 1,8). La temperatura corporal posrecuperación fue más baja en grupo crioterapia (P = 0,005) que la obtenida después en el control (34,5 ± 1,9°C frente a 37,6 ± 1,3°C). Se encontró correlación significativa entre la percepción del dolor y las concentraciones de CPK (r = 0,314) y LDH (r = 0,546). Las concentraciones de CPK y LDH se correlacionaron negativamente con la fuerza dinámica (r = 0,525). Conclusión. La recuperación usando la inmersión después de la competición resulta de un menor daño muscular e hipoalgesia (AU)
