Inhaled sodium cromoglycate

Inhaled Medicines: Past, Present, and Future

The purpose of this review is to summarize essential pharmacological, pharmaceutical, and clinical aspects in the field of orally inhaled therapies that may help scientists seeking to develop new products. After general comments on the rationale for inhaled therapies for respiratory disease, the focus is on products approved approximately over the last half a century. The organization of these sections reflects the key pharmacological categories. Products for asthma and chronic obstructive pulmonary disease include β -2 receptor agonists, muscarinic acetylcholine receptor antagonists, glucocorticosteroids, and cromones as well as their combinations. The antiviral and antibacterial inhaled products to treat respiratory tract infections are then presented. Two "mucoactive" products-dornase α and mannitol, which are both approved for patients with cystic fibrosis-are reviewed. These are followed by sections on inhaled prostacyclins for pulmonary arterial hypertension and the challenging field of aerosol surfactant inhalation delivery, especially for prematurely born infants on ventilation support. The approved products for systemic delivery via the lungs for diseases of the central nervous system and insulin for diabetes are also discussed. New technologies for drug delivery by inhalation are analyzed, with the emphasis on those that would likely yield significant improvements over the technologies in current use or would expand the range of drugs and diseases treatable by this route of administration. SIGNIFICANCE STATEMENT: This review of the key aspects of approved orally inhaled drug products for a variety of respiratory diseases and for systemic administration should be helpful in making judicious decisions about the development of new or improved inhaled drugs. These aspects include the choices of the active ingredients, formulations, delivery systems suitable for the target patient populations, and, to some extent, meaningful safety and efficacy endpoints in clinical trials.

A Quality by Design Framework for Capsule-Based Dry Powder Inhalers

Capsule-based dry powder inhalers (cDPIs) are widely utilized in the delivery of pharmaceutical powders to the lungs. In these systems, the fundamental nature of the interactions between the drug/formulation powder, the capsules, the inhaler device, and the patient must be fully elucidated in order to develop robust manufacturing procedures and provide reproducible lung deposition of the drug payload. Though many commercially available DPIs utilize a capsule-based dose metering system, an in-depth analysis of the critical factors associated with the use of the capsule component has not yet been performed. This review is intended to provide information on critical factors to be considered for the application of a quality by design (QbD) approach for cDPI development. The quality target product profile (QTPP) defines the critical quality attributes (CQAs) which need to be understood to define the critical material attributes (CMA) and critical process parameters (CPP) for cDPI development as well as manufacturing and control.

Disodium cromoglycate inhibits asthma-like features induced by sphingosine-1-phosphate

Compelling evidence suggests the involvement of sphingosine-1-phosphate (S1P) in the pathogenesis of asthma. The systemic administration of S1P causes asthma like features in the mouse involving mast cells. In this study we investigated whether disodium cromoglycate (DSCG), administered as a preventative treatment as in human therapy, could affect S1P effects on airways. BALB/c mice, treated with DSCG, received subcutaneous administration of S1P. Bronchi and pulmonary tissues were collected and functional, molecular and cellular studies were performed. DSCG inhibited S1P-induced airway hyper-reactivity as well as pulmonary inflammation. DSCG decreased the recruitment of solely mast cells and B cells in the lung. IgE serum levels, prostaglandin D₂, mucus production and IL-13 were also reduced when mice were pretreated with DSCG. S1P induced pulmonary expression of CD23 on T and B cells, that was reversed by DSCG. Conversely, S1P failed to upregulate CD23 in mast cell-deficient Kit ^W-sh/W-sh mice. In conclusion we have shown that DSCG inhibits S1P-induced asthma like features in the mouse. This beneficial effect is due to a regulatory action on mast cell activity, and in turn to an inhibition of IgE-dependent T and B cells responses.

Effects of disodium cromoglycate on cationic exchange of deoxygenated sickle cells

In the present work, we explored the way in which cromoglycate, a drug used to treat allergies acts on ion movements in sickle cells. Cells were either slowly deoxygenated by overnight exposure to nitrogen or acutely deoxygenated by exposure to metabisulfite, a strong reducing agent which induces sickling of red blood sickle cells. Flushing the cells with nitrogen increased the intracellular concentration of Na(+) and decreased the intracellular concentration of K(+) and the sum of the concentrations of the two cations. One hundred nM cromoglycate inhibited the decrease of intracellular K(+) and the increase of intracellular Na(+) induced by deoxygenation (n=17). Metabisulfite (100mM) increased the intracellular concentration of Ca(2+) (measured by Fura Red) (n=15) and the shape of the cells (measured by light scattering) (n=9). One μM cromoglycate partially inhibited these two responses. In conclusion, cromoglycate partially inhibits abnormal K(+) loss, Ca(2+) entry pathways or Ca(2+) channels opened by cell deoxygenation and ensuing membrane modifications and prevents cell sickling.

Inhaled sodium cromoglycate for asthma in children

BACKGROUND

Sodium cromoglycate has been recommended as maintenance treatment for childhood asthma for many years. Its use has decreased since 1990, when inhaled corticosteroids became popular, but it is still used in many countries.

OBJECTIVES

To determine the efficacy of sodium cromoglycate compared to placebo in the prophylactic treatment of children with asthma.

SEARCH STRATEGY

We searched the Cochrane Airways Group Trials Register (October 2007), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 3, 2007), MEDLINE (January 1966 to November 2007), EMBASE (January 1985 to November 2007) and reference lists of articles. We also contacted the pharmaceutical company manufacturing sodium cromoglycate. In 2007 we updated the review.

SELECTION CRITERIA

All double-blind, placebo-controlled randomised trials, which addressed the effectiveness of inhaled sodium cromoglycate as maintenance therapy, studying children aged 0 up to 18 years with asthma.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data. We pooled study results.

MAIN RESULTS

Of 3500 titles retrieved from the literature, 24 papers reporting on 23 studies could be included in the review. The studies were published between 1970 and 1997 and together included 1026 participants. Most were cross-over studies. Few studies provided sufficient information to judge the concealment of allocation. Four studies provided results for the percentage of symptom-free days. Pooling the results did not reveal a statistically significant difference between sodium cromoglycate and placebo. For the other pooled outcomes, most of the symptom-related outcomes and bronchodilator use showed statistically significant results, but treatment effects were small. Considering the confidence intervals of the outcome measures, a clinically relevant effect of sodium cromoglycate cannot be excluded. The funnel plot showed an under-representation of small studies with negative results, suggesting publication bias.

AUTHORS' CONCLUSIONS

There is insufficient evidence to be sure about the efficacy of sodium cromoglycate over placebo. Publication bias is likely to have overestimated the beneficial effects of sodium cromoglycate as maintenance therapy in childhood asthma.

Inhaled sodium cromoglycate for asthma in children

BACKGROUND

Sodium cromoglycate has been recommended as maintenance treatment for childhood asthma for many years. Its use has decreased since 1990, when inhaled corticosteroids became popular, but it is still used in many countries.

OBJECTIVES

To determine the efficacy of sodium cromoglycate compared to placebo in the prophylactic treatment of children with asthma.

SEARCH STRATEGY

We searched the Cochrane Airways Group Asthma trials register (November 2002), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 3, 2002), MEDLINE (January 1966 to November 2002), EMBASE (January 1985 to November 2002) and reference lists of articles. We also contacted the pharmaceutical company manufacturing sodium cromoglycate

SELECTION CRITERIA

All double-blind placebo-controlled randomised trials, which addressed the effectiveness of inhaled sodium cromoglycate as maintenance therapy, studying children aged 0 up to 18 years with asthma.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed trial quality and extracted data. Study results were pooled.

MAIN RESULTS

Of 3500 titles retrieved from the literature, 25 papers reporting on 24 studies could be included in the review. The studies were published between 1970 and 1997 and together included 1074 participants. Most were cross-over studies. Few studies provided sufficient information to judge the concealment of allocation. Four studies provided results for the proportion of symptom-free days. Pooling the results did not reveal a statistically significant difference between sodium cromoglycate and placebo. For most of the other outcomes, the results were similar: small effect size and a confidence interval including the point of no difference. The funnel plot showed an under representation of small studies with negative results, suggesting publication bias.

REVIEWER'S CONCLUSIONS

The evidence of the efficacy of sodium cromoglycate over placebo is not proven. Publication bias is likely to have overestimated the beneficial effects of sodium cromoglycate as maintenance therapy in childhood asthma.

Inhaled disodium cromoglycate (DSCG) as maintenance therapy in children with asthma: a systematic review

BACKGROUND

Disodium cromoglycate (DSCG) is included in the BTS guidelines on the treatment of asthma for use in children, but is now used only infrequently. We have identified and interpreted the findings of all published randomised, placebo controlled trials of DSCG in the prophylactic treatment of children with asthma.

METHODS

Several databases were searched to identify trials. Studies were included if they investigated subjects with asthma aged 0-18 years old, addressed maintenance treatment with inhaled DSCG, and were published in English. The methodological quality of the studies was assessed independently by three reviewers. The 95% confidence intervals (CI) of differences in the treatment effect for cough and wheeze between placebo and treatment with DSCG were computed. The estimates were pooled and tested for homogeneity and, to assess possible publication bias, a funnel plot was made and tested for symmetry.

RESULTS

Of the 24 randomised, placebo controlled trials identified, the methodological scores varied widely. The null hypothesis of homogeneity was rejected. Under the assumption of heterogeneity the overall CI for wheeze was 0.11 to 0.26 and for cough was 0.13 to 0.27. The overall tolerance intervals (-0.11 to 0. 48 and -0.04 to 0.43 for wheeze and cough, respectively) both included zero, so it cannot be concluded that future studies will show an effect of DSCG compared with placebo. Older studies were more often in favour of DSCG. The funnel plots suggest publication bias; small studies with negative or equal outcomes are lacking.

CONCLUSION

Given the apparent publication bias, the small overall treatment effect, and the tolerance interval including zero, there is insufficient evidence that DSCG has a beneficial effect as maintenance treatment in children with asthma.

Recent developments in respiratory care pharmacology

Bronchoactive inhaled aerosol drugs target the respiratory tract directly and seek to minimize systemic exposure and reduce side effects. Common delivery devices such as the metered dose inhaler, the small volume nebulizer, or the dry powder inhaler each deliver approximately the same fraction of dose (10%) to the lungs, although their dose amounts are not equivalent. Major respiratory drug groups are reviewed, and include the beta-adrenergic and anticholinergic bronchodilators, mucolytic agents, corticosteroids, mediator antagonists, anti-infective agents, and exogenous surfactants. New agents in each group are identified and briefly described, along with the clinical use and most commonly observed side effects for each class of drugs.