PubMed · 11399680
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B J Lipworth. 2001. Optimizing bronchodilator therapy for copd.. https://doi.org/10.1378/chest.119.6.1628
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The effects of carriers, the drug:carrier ratio and a 1 month storage period of a formulation in permeable polystyrene tube at 40 degrees C/75% RH on the in vitro pulmonary deposition of model drugs from dry powder inhaler (DPI) were evaluated. Budesonide (hydrophobic) and salbutamol sulphate (hydrophilic) were used as model drugs. Mannitol and glucose were used as the carriers. In addition, lactose 110M was used as the carrier for budesonide. The novel multiple dose Taifun was used as a DPI; Taifun is a breath-actuated inhaler that contains the powder formulation in a reservoir chamber. The respirable fractions (RF%) values of the drugs were determined by the "Andersen" sampler. The RF% values of salbutamol sulphate increased with an increase in the drug:carrier ratio before storage, whereas the drug:carrier ratio did not affect the RF% values after storage. In the case of budesonide, the drug:carrier ratio did not affect the RF% values before storage, instead the RF% values of budesonide increased with an increase in the drug:carrier ratio after storage. The RF% values of salbutamol sulphate decreased after storage of the formulation, this was not dependent on the carrier and the drug:carrier ratio. However, with budesonide the effect of the storage on its RF% values was dependent on which carrier was used and also the drug:carrier ratio. Overall, storage had less effect on the RF% values of budesonide than those of salbutamol sulphate. The highest RF% values of budesonide were obtained when mannitol was used as the carrier. Furthermore, the RF% values of salbutamol sulphate tended to be higher when mannitol was used as the carrier instead of glucose.
OBJECTIVE: This open randomized study examined differences between the effects of an equal dose of salbutamol administered via the Diskus, Turbuhaler, and pMDI plus Volumatic. Measurements included dose response curves, dynamic and static lung volumes, respiratory muscle strength, and systemic effects. METHODS: The cumulative dose-response study compared the biological effects (pulmonary function, respiratory muscle function, systemic effects) of an equal dose of salbutamol delivered via four different devices in 23 patients with asthma and 21 patients with moderate or severe chronic obstructive pulmonary disease (COPD). RESULTS: Salbutamol via Volumatic showed significantly better bronchodilation than via pMDI or Turbuhaler in both patient groups. No significant difference was found between salbutamol via Volumatic and Diskus. However, the advantage of Volumatic is of marginal clinical relevance since the additional bronchodilation was a maximum of 140 ml FEV(1) and did not exceed the minimal patient-perceivable improvement. In the asthma group a more evident plasma K(+) decrease was found after salbutamol delivered via pMDI and pMDI plus Volumatic. Furthermore, especially in the COPD patients a significant decrease was observed in hyperinflation and consequently an improvement in maximal inspiratory pressure as a result of salbutamol via all devices. CONCLUSIONS: Bronchodilation by salbutamol was slightly more effective via Volumatic than via pMDI or Turbuhaler. No significant difference in bronchodilation was found between salbutamol via Volumatic and Diskus. The advantage of Volumatic is not of clinical relevance.
Antibodies directed against the second extracellular loop of G protein-coupled receptors were shown to possess functional activities. Using a functional monoclonal antibody against the human beta2-adrenergic receptor, a scFv fragment with high affinity for the target epitope was constructed and produced. The fragment recognized the beta2-adrenergic receptors on A431 cells, blocked cAMP accumulation induced by the beta2-agonist salbutamol, and decreased basal cAMP accumulation in the same cells. Their in vitro activity was tested on neonatal rat cardiomyocytes. The antibody fragments blocked the chronotropic activity induced by the beta2-agonist clenbuterol. They also decreased the in vivo heart beating frequency of mice pretreated with bisoprolol (a beta1-adrenergic receptor antagonist) for 4 min after injection. The immunological approach presented here may serve as a strategy for the synthesis of a new class of allosteric modulators for G protein-coupled receptors.