Therapeutic equivalence of three metered-dose inhalers containing salbutamol (Albuterol) in protecting against methacholine-induced bronchoconstriction in children with asthma

Effect of different accessory devices on the dose delivered from pressurised metred-dose inhalers

INTRODUCTIONS

Improved aerosol delivery of bronchodilators to chronic obstructive pulmonary disease (COPD) subjects is a cornerstone in the treatment approach. Drug delivery and response are improved with the use of accessory devices [spacers and valved holding chambers (VHCs)] with metred-dose inhalers (pMDIs). However, different accessory devices are available in the market with different properties that could affect aerosol delivery. Thus, this study aimed to assess the relative lung deposition and systemic bioavailability and compare bronchodilator response of salbutamol delivered using different accessory devices attached to pMDIs.

METHODS

Twelve healthy subjects and twelve COPD subjects inhaled 300 μg salbutamol (3 pMDI puffs) using five different accessory devices with either masks or mouthpieces (Able, Aerochamber plus flow Vu, Dolphin chamber, Tipshaler spacer, and modified Drink bottle spacer). Urine samples were collected thirty minutes post-dosing and cumulatively for the next twenty-four hours, to determine and compare the relative lung deposition [0-0.5 hour excretion of urinary salbutamol (USAL0.5)] and systemic bioavailability [0.5-24 hours excretion of urinary salbutamol (USAL24)] of salbutamol from the selected accessory devices. Also, the difference between pre and post-inhalation forced expiratory volume in one second (ΔFEV₁ %) of predicted was determined for each accessory device.

RESULTS

Urinary excretion of salbutamol (both USAL0.5 and USAL24 samples) in COPD subjects was significantly (P < .05) lower than in healthy subjects for all accessory devices. USAL0.5 and USAL24 in non-antistatic spacers (modified Drink bottle spacer and Dolphin chamber spacers) were significantly lower (P < .05) than that for antistatic spacers (Aerochamber plus flow Vu, Able and Tips-haler). No significant difference in USAL0.5 and USAL24 was observed between facemasks and mouthpieces. There was a significant difference (P < .05) in ΔFEV₁ % of predicted values between COPD subjects and healthy subjects. However, within the COPD group and the healthy group there was no significant difference in ΔFEV₁ % of predicted values between all accessory devices or between with mouthpiece or with a mask.

CONCLUSIONS

COPD subjects had lower aerosol delivered compared with healthy subjects. Anti-static accessory devices delivered a higher amount of aerosol compared with non-antistatic accessory devices. Even though the presence of a significant difference in aerosol delivery between non-antistatic and antistatic accessory devices no significant difference was found in the ΔFEV₁ % between all accessory devices.

A Study of Patient Responses to a Perceived Change in Salbutamol Metered Dose Inhalers

Experience in the clinic reveals that some patients have attributed negative changes in their respiratory health status to generic substitution of inhaled medications, even though — from a pharmacological perspective — therapeutic equivalence would be expected. The objective of this study was to evaluate patient-reported changes in efficacy or toxicity following a perceived switch of an inhaled drug product. Forty-eight patients with air flow limitation had their usual brand of salbutamol metered-dose inhaler (MDI) replaced for one week with a new MDI. Patients were not informed that the replacement MDI was exactly the same brand as their usual MDI, and the product identity was disguised by a label. Forced expiratory volume in one second, respiratory symptoms and MDI use were compared between the week when the patients knew they were using their usual brand of MDI and the week they were using the perceived new MDI. Patient MDI preference was assessed at the end of the study. Even though there was no change in the brand of salbutamol MDI, 46 per cent of patients thought that the new MDI was better at managing their symptoms, 27 per cent thought that the new MDI was worse and 27 per cent perceived no difference (p<0.05 for rejecting the null hypothesis that all responses would be for no difference). Seventy per cent of patients stated that they had a preference for one MDI over the other, even though there had been no change in inhaler. Factors other than product differences are likely to be responsible for patient claims of changes in respiratory health status subsequent to generics substitution with inhaled medications when equivalent products are used. If such changes are reported following the introduction of a new generic product, the changes may be incorrectly attributed to the new product, confounding the ability to assess the quality of the new product in post-marketing evaluation.

Once versus twice daily budesonide metered-dose inhaler in children with mild to moderate asthma: effect on symptoms and bronchial responsiveness

BACKGROUND

Simplifying dosing regimens could improve both adherence and asthma-related morbidity. However, there is little information on the effectiveness of once-daily budesonide, administered through a metered dose inhaler (MDI) plus spacer, on asthma symptoms and pulmonary function in asthmatic children.

METHODS

The aim of this study was to compare the effect of once-daily versus twice-daily doses of inhaled budesonide on symptoms, lung function and bronchial hyperresponsiveness (BHR) in asthmatic children. This study was a randomized, single-blind, parallel clinical trial. Patients received budesonide from an MDI either 800 microg as a daily dose or fractionated in 400 microg twice a day for 12 weeks. Statistical analysis was performed using tests for independent and paired samples.

RESULTS

In both groups, asthma symptoms significantly decreased. However, the improvement in asthma symptoms, decrease in BHR and treatment adherence were significantly greater in the once-daily group than in the twice-daily group (p < 0.05). No significant differences were found between the two groups in spirometric parameters, morning peak expiratory flow or plasma cortisol values.

CONCLUSIONS

Once-daily administration of 800 microg of inhaled budesonide administered by MDI plus spacer was more effective in controlling symptoms and improving BHR than fractionating the dose to 400 microg twice daily. The differences observed in this study could have been due to the greater adherence to treatment in patients in the once-daily group.

The effect of reducing the fine-particle mass of salmeterol from metered-dose inhalers on bronchodilatation and bronchoprotection against methacholine challenge: a randomized, placebo-controlled, double-blind, crossover study

OBJECTIVE

This study examined the clinical relevance of fine-particle mass (FPM) delivered from metered dose inhalers (MDIs) to bronchodilatation and bronchoprotection against methacholine challenge by comparing a marketed chlorofluorocarbon (CFC) formulation of salmeterol with an investigational hydrofluoroalkane (HFA)formulation.

METHODS

This was a randomized, double-blind, placebo-controlled, 3-way crossover study in patients with mild to moderate asthma who had a forced expiratory volume in 1 second (FEV (1)) of > or =60% predicted and a base-line provocation dose of inhaled methacholine required to produce a 20% decrease in FEV(1) (PD (20) [methacholine]) of < or =3.2 mg. On separate occasions, patients received 2 inhalations of salmeterol 25 microg from either the CFC MDI (FPM 14 microg), the investigational HFA MDI (FPM 7 microg), or placebo via CFC MDI. Serial measurements of FEV(1) were made over 90 minutes after dosing, followed by methacholine challenge. Efficacy end points were PD(20) (methacholine) and FEV(1) AUC (inc) (incremental area under the FEV(1) curve) over 15 to 90 minutes. The study was designed to demonstrate non-inferiority of the investigational HFA formulation to the CFC formulation in terms of protection against methacholine-induced bronchial hyperresponsiveness; for PD(20) (methacholine), noninferiority was predefined as 1.0 doubling dose of methacholine.

RESULTS

The study enrolled 40 patients (65% men; mean age, 36.9 years). Both active treatments were significantly better than placebo in terms of PD(20) (methacholine) (P < 0.001). In the per-protocol population, the mean (SE) difference in bronchoprotection between the CFC MDI and placebo was 2.7888 (0.3432) doubling doses of methacholine (n = 32), and the difference between the investigational HFA MDI and placebo was 1.8268 (0.3418) doubling doses(n = 33). The adjusted mean (SE) treatment difference between the CFC MDI and HFA MDI was 0.9621 (0.3454) doubling doses. The upperlimit of the 95% CI (0.2714-1.6527) was greater than the predefined limit for noninferiority. There was no significant difference in FEV(1) AUC(inc) between formulations (mean treatment difference, 1.895 L . min; 95% CI, -4.893 to 8.684); however, both active treatments were significantly different from placebo (P < 0.001).

CONCLUSIONS

FPM from different MDI formulations may affect the bronchoprotective properties of salmeterol. In this study, the formulation with the smaller FPM was associated with less-effective bronchoprotection, although there was no difference in bronchodilatation. This study did not demonstrate noninferiority of the investigational HFA formulation to the CFC formulation in terms of protection against methacholine-induced bronchial hyperresponsiveness.

Comparison of bronchoprotective and bronchodilator effects of a single dose of formoterol delivered by hydrofluoroalkane and chlorofluorocarbon aerosols and dry powder in a double blind, placebo-controlled, crossover study

BACKGROUND

In response to the phasing out of chlorofluorocarbon (CFC) inhalers, a metered dose hydrofluoroalkane (HFA) formulation, Modulite (Chiesi Farmaceutici S.p.A, Parma, Italy), to be delivered with a pressurized metered dose inhaler (pMDI), has been developed. Modulite is a HFA formulation technology that has been designed to provide stable and uniform dose delivery of HFA-based formulations to enable an easy transition from CFC to HFA inhalers.

OBJECTIVES

The aim of this study was to compare the bronchoprotective and bronchodilator effects of a single dose of 12 microg of formoterol from the HFA Modulite inhaler with the Foradil Aerolizer (dry powder inhaler, DPI) and the Foradil CFC inhalers (Novartis Health Consumer, Basel, Switzerland).

METHODS

This was a double blind, double dummy, randomized, placebo-controlled, crossover study conducted in 38 subjects with mild to moderate asthma (mean forced expiratory volume in 1 s [FEV1] 87.5% predicted). The primary endpoint was methacholine challenge provocative dose required for 20% fall in the FEV1 (PD20) 90 min post dose. Bronchodilation was assessed with spirometry (FEV1, FVC, FEF25-75) and impulse oscillometry (resistance at 5 and 20 Hz, reactance at 5 Hz and resonant frequency) over the 90 min post dose. In a subset of 12 subjects formoterol plasma levels, serum potassium and glucose were determined up to 480 min post dose.

RESULTS

The three formoterol formulations demonstrated significant (P < or = 0.05) improvements in bronchoprotection compared to placebo and non-inferiority of the HFA preparation compared to the CFC and DPI preparations was demonstrated. Geometric mean PD20 values were 0.51 mg with HFA, 0.62 mg with DPI, 0.62 mg with CFC and 0.2 mg with placebo. The log transformed mean differences in PD20 doubling dose between HFA and (a) DPI was -0.28 (95% CI -0.84-0.29, P = 0.57) (b) CFC was -0.28 (95% CI -0.84-0.28, P = 0.57) and (c) placebo was 1.38 (95% CI 0.82-1.94, P < 0.001). Serum potassium, glucose and formoterol plasma profiles were comparable for the CFC, HFA and DPI devices.

CONCLUSION

Our findings of similar efficacy, pharmacokinetics and systemic effects of the HFA formoterol inhaler compared to the CFC and DPI preparations supports the potential use of this novel formulation in the treatment of asthma.

Dose-response relationship and reproducibility of urinary salbutamol excretion during the first 30 min after an inhalation

AIMS

To determine the reproducibility and dose-response relationship for urinary salbutamol excretion post inhalation.

METHODS

Fifteen volunteers inhaled either one, two, three, four or five doses of 100 micro g salbutamol on separate days and then seven of these also repeated each of the one, three and five doses on five occasions. After each study dose urine was collected 30 min post inhalation.

RESULTS

The mean (SD) 30 min urinary salbutamol after one, two, three, four and five doses was 2.61 (1.0.), 5.47 (1.59), 8.68 (2.73), 12.34 (3.96) and 15.99 (4.50) micro g, respectively. Statistical analysis revealed a linear relationship (P < 0.001). Mean (SD) coefficient of variation after one, three and five doses was 10.5 (3.6), 10.1 (2.7) and 9.4 (2.3)%.

CONCLUSIONS

The 30 min salbutamol urinary excretion post inhalation pharmacokinetic method, to compare inhaled products, is linear with inhaled dose and reproducible.