Combined effect of trifluoperazine and sodium cromoglycate on reducing acute edema and limiting lasting functional impairments after spinal cord injury in rats

Edema formation is one of the very first events to occur after spinal cord injury (SCI) leading to an increase of the intrathecal pressure and consequently to serious spinal tissue and functional impairments. Current edema treatments are still symptomatic and/or non-specific. Since edema formation mechanisms are mainly described as vasogenic and cytotoxic, it becomes crucial to understand the interplay between these two subtypes. Acting on key targets to inhibit edema formation may reduce secondary damage and related functional impairments. In this study, we characterize the edema kinetic after T9-10 spinal contusion. We use trifluoperazine (TFP) to block the expression and the functional subcellular localization of aquaporin-4 supposed to be implicated in the cytotoxic edema formation. We also use sodium cromoglycate (SCG) to deactivate mast cell degranulation known to be implicated in the vasogenic edema formation. Our results show a significant reduction of edema after TFP treatment and after TFP-SCG combined treatment compared to control. This reduction is correlated with limited onset of initial sensorimotor impairments particularly after combined treatment. Our results highlight the importance of potential synergetic targets in early edema therapy after SCI as part of tissue sparing strategies.

Targeting Mast Cells: Sodium Cromoglycate as a Possible Treatment of Lipedema

Background

Mast cells are immune cells that mediate hypersensi-tivity and allergic reactions in the body, secreting histamine and other inflammatory molecules. They have been associated with different inflammatory conditions such as obesity and other adipose tissue di-sorders. Lipedema is a chronic disease characterized by an abnormal accumulation of adipose tissue on the legs and arms, pain, and other symptoms. Mast cells may play a role in the pathology of lipedema.

Objective

Pilot study to determine levels of histamine and its metabolites in lipedema subcutaneous adipose tissue (SAT) biopsy samples, and to test sodium cromoglycate for the treatment of mast cells in women with lipedema.

Methods

Biopsies from lipedema and control SAT were collected and analyzed histologically for the presence of mast cells. Mass spec-trometry was used to measure the levels of histamine, a key marker of mast cells, and its metabolites in SAT in women with lipedema and controls, and after a group of women with lipedema were administered oral and topical doses of sodium cromoglycate for two weeks.

Results

Histological examination of biopsies from lipedema patients confirmed the presence of mast cells. Metabolomic analysis revealed high levels of histamine and its metabolites in samples from women with lipedema compared to controls. Following a two-week treatment period, lipedema tissue samples exhibited reduced levels of histamine, suggesting a reduction of mast cell activity.

Conclusion

Sodium cromoglycate has the ability to stabilize mast cells and reduce histamine levels in lipedema patients, which could be useful in lowering the symptoms of lipedema.

Binding of anti-inflammatory drug cromolyn sodium to bovine serum albumin

Fluorescence spectroscopy in combination with circular dichroism (CD) and UV-vis absorption spectroscopy were employed to investigate the binding of anti-inflammatory drug cromolyn sodium (Intal) to bovine serum albumin (BSA) under the physiological conditions with Intal concentrations of 0-6.4 x 10(-5)mol L(-1). In the mechanism discussion, it was proved that the fluorescence quenching of BSA by Intal is a result of the formation of Intal-BSA complex. Quenching constants were determined using the Stern-Volmer equation to provide a measure of the binding affinity between Intal and BSA. The thermodynamic parameters Delta G, Delta H, Delta S at different temperatures (298, 304, and 310 K) were calculated and the results indicate the electrostatic interactions play a major role in Intal-BSA association. Binding studies concerning the number of binding sites (n=1) and apparent binding constant K(b) were performed by fluorescence quenching method. Utilizing fluorescence resonant energy transfer (FRET) the distance R between the donor (BSA) and acceptor (Intal) has been obtained. Furthermore, CD and synchronous fluorescence spectrum were used to investigate the structural change of BSA molecules with addition of Intal, the results indicate that the secondary structure of BSA molecules was changed in the presence of Intal.

Hsp90 is a direct target of the anti-allergic drugs disodium cromoglycate and amlexanox

Hsp90 (heat-shock protein 90) alone can act to prevent protein aggregation and promote refolding in vitro, but in vivo it operates as a part of a multichaperone complex, which includes Hsp70 and cohort proteins. Since the physiological function of Hsp90 is not yet fully understood, the development of specific antagonists might open new lines of investigation on the role of Hsp90. In an effort to discover Hsp90 antagonists, we screened many drugs and found that the anti-allergic drugs DSCG (disodium cromoglycate) and amlexanox target Hsp90. Both drugs were found to bind directly wild-type Hsp90 via the N- and C-terminal domains. Both drugs strongly suppressed the in vitro chaperone activity of native Hsp90 towards citrate synthase at 1.5-3.0 microM. Amlexanox suppressed C-terminal chaperone activity in vitro, but not N-terminal chaperone activity, and inhibited the association of cohort proteins, such as cyclophilin 40 and Hsp-organizing protein, to the C-terminal domain of Hsp90. These data suggest that amlexanox might disrupt the multichaperone complex, including Hsp70 and cohort proteins, both in vitro and in vivo. Although DSCG inhibited the in vitro chaperone activity of the N-terminal domain, the drug had no effect either on the C-terminal chaperone activity or on the association of the cohort proteins with the C-terminus of Hsp90. The physiological significance of these interactions in vivo remains to be investigated further, but undoubtedly must be taken into account when considering the pharmacology of anti-allergic drugs. DSCG and amlexanox may serve as useful tools for evaluating the physiological significance of Hsp90.

Interaction of S100 proteins with the antiallergic drugs, olopatadine, amlexanox, and cromolyn: identification of putative drug binding sites on S100A1 protein

S100 proteins are a multigenic family of low-molecular-weight Ca(2+)-binding proteins comprising 19 members. These proteins undergo a conformational change by Ca(2+)-binding and consequently interact with their target proteins. Recently, we reported that two antiallergic drugs, Amlexanox and Cromolyn, bind to S100A12 and S100A13 of the S100 protein family. In the present study, we used a newly developed antiallergic drug, Olopatadine, as a ligand for affinity chromatography and examined binding specificity of the drug to S100 protein family. Olopatadine binds specifically to S100 proteins, such as S100A1, S100B, S100L, S100A12, and S100A13, in a Ca(2+)-dependent manner but not to calmodulin. Mutagenesis study showed that amino acid residues 76-85 in S100A1 are necessary for its binding to Olopatadine. In contrast, residues 89-94 were identified as an Amlexanox-binding site in S100A1. Moreover, Olopatadine did not competitively inhibit S100A1-binding site of Amlexanox. Furthermore, we showed that Olopatadine inhibited the binding of S100A1 target protein's binding site peptides to S100A1. These results indicate that C-terminal region of S100A1 is important for antiallergic drug binding, although the drug binding sites are different according to each antiallergic drug. Differences in the binding sites of S100A1 to antiallergic drugs suggest that the regulatory functions of S100 proteins may exist in several regions. Therefore, these drugs may serve as useful tools for evaluating the physiological significance of S100 protein family.

Three distinct anti-allergic drugs, amlexanox, cromolyn and tranilast, bind to S100A12 and S100A13 of the S100 protein family

To investigate the roles of calcium-binding proteins in degranulation, we used three anti-allergic drugs, amlexanox, cromolyn and tranilast, which inhibit IgE-mediated degranulation of mast cells, as molecular probes in affinity chromatography. All of these drugs, which have different structures but similar function, scarcely bound to calmodulin in bovine lung extract, but bound to the same kinds of calcium-binding proteins, such as the 10-kDa proteins isolated in this study, calcyphosine and annexins I-V. The 10-kDa proteins obtained on three drug-coupled resins and on phenyl-Sepharose were analysed by reversed-phase HPLC. It was found that two characteristic 10-kDa proteins, one polar and one less polar, were bound with all three drugs, although S100A2 (S100L), of the S100 family, was bound with phenyl-Sepharose. The cDNA and deduced amino acid sequence proved our major polar protein to be identical with the calcium-binding protein in bovine amniotic fluid (CAAF1, S100A12). The cDNA and deduced amino acid sequence of the less-polar protein shared 95% homology with human and mouse S100A13. In addition, it was demonstrated that the native S100A12 and recombinant S100A12 and S100A13 bind to immobilized amlexanox. On the basis of these findings, we speculate that the three anti-allergic drugs might inhibit degranulation by binding with S100A12 and S100A13.

Binding of disodium cromoglycate to human serum albumin

The binding of several benzopiranone derivatives to human serum albumin was determined. The antiallergic drug disodium cromoglycate binds weakly to serum albumin. However, its precursors, chromones of smaller size, were able to bind in a hydrophobic pocket in the protein, and are carried by serum albumin in blood.

Two distinct anti-allergic drugs, amlexanox and cromolyn, bind to the same kinds of calcium binding proteins, except calmodulin, in bovine lung extract

In order to explore candidates for proteins required in exocytosis, we used two anti-allergic drugs, amlexanox and cromolyn, which inhibit IgE mediated degranulation of mast cells and basophils, as molecular probes in affinity chromatography. These two drugs chiefly bound to the same kinds of calcium binding proteins in bovine lung. These proteins were as follows: bovine calgranulin C homolog, an 8-kDa unknown protein, S-100L, calgranulin B, calcyphosine, and annexins I-V. The homologous affinity of the two drugs to these proteins is in accord with the similar anti-allergic property of both drugs. From these findings it is presumed that these drugs interact with these proteins and affect pharmacologically the degranulation.

Morphine and muscle relaxants are receptor-independent G-protein activators and cromolyn is an inhibitor of stimulated G-protein activity

Morphine and muscle relaxants are classical mast cell activators and cromolyn is a mast cell inhibitor. However, the mechanisms underlying the effects of these drugs are obscure. We asked the question whether morphine and muscle relaxants may activate heterotrimeric guanine nucleotide-binding proteins (G-proteins), and whether cromolyn may prevent this activation. Morphine activated Gi-proteins in HL-60 membranes and purified transducin (TD) at concentrations above 1 mM, but the effects on morphine did not reach saturation up to 10 mM. d-Tubocurarine activated Gi-proteins and TD in a saturable manner, with EC50 values of 0.3 mM and 4.2 mM, respectively. Gallamine and succinylcholine were less effective activators of TD than d-tubocurarine, Morphine and d-tubocurarine were about similarly effective activators of Gi-proteins, whereas d-tubocurarine was a more effective activator of TD than morphine. Cromolyn at 10 microM and 100 microM had little effect on TD activity but reduced the stimulatory effect of morphine by 50% and 80%, respectively. Our data suggest the following: (1) Receptor-independent G-protein activation by morphine and muscle relaxants presumably accounts for their mast cell-activating properties. (2) Cromolyn may act by preventing G-protein activation. (3) The variability in responsiveness of mast cells towards morphine and muscle relaxants could be due to differential expression of G-proteins with different sensitivity to activation by these drugs.

Inhaled histamine increases the rate of absorption of sodium cromoglycate from the lung

Since many factors may alter lung epithelial permeability (LEP) to water soluble molecules, the effect of histamine on the absorption and clearance of inhaled sodium cromoglycate was examined in seven mildly asthmatic patients with hyperresponsive airways and eight normal subjects. The subjects underwent histamine challenge to determine the provocative concentration of histamine required to reduce the forced expiratory volume in one second (FEV1) by 20% (PC20) from baseline. On two further visits they inhaled either saline placebo or histamine and 5 min later inhaled an aerosol containing sodium cromoglycate. Measurements of FEV1 were made and blood samples taken for analysis of plasma sodium cromoglycate concentration at intervals for 3 h. In the asthmatic group histamine inhalation led to a 24 +/- 4% reduction in FEV1 but had no effect on the normal subjects. When compared with inhaled saline, histamine increased the initial pulmonary absorption of SCG without influencing the total amount of drug absorbed in both asthmatics and normals. These observations suggest that the pharmacokinetics of inhaled sodium cromoglycate may be altered significantly by inflammatory mediators present at the site of drug absorption from the airways.

Digestive permeability to different-sized molecules and to sodium cromoglycate in food allergy

Intestinal absorption of mannitol (used as a marker of normal monomer passage) and intestinal absorption of lactulose (used as a marker of macromolecule exclusion) were measured in 15 healthy subjects and in 20 patients with food allergy. When studied in the fasting state, there was no apparent difference in the absorption of mannitol between control subjects and allergic patients although the absorption of lactulose was more marked, but not significantly, in the latter group. Ingestion of an allergen by these patients led to a significant increase in the absorption of lactulose (intestinal passage increased by a factor of two). Administration of 300 mg cromoglycate 1/4 hour before the provocation test completely averted abnormal intestinal permeability. Digestive absorption of cromoglycate was also studied in the same 15 control subjects and 20 allergic patients. The peak plasma concentration and area under the curve were significantly greater in healthy subjects when the study was carried out in the fasting state. The application of an oral provocation test with an allergen also significantly increased the plasma concentration of cromoglycate in allergic patients. Contact between an allergen and the digestive tract in allergic patients therefore leads to an increased intestinal absorption of macromolecules but also to cromoglycate passage, which inhibits allergic reactions.

A novel cell-permeable cromoglycate derivative inhibits type I Fc epsilon receptor mediated Ca2+ influx and mediator secretion in rat mucosal mast cells

Type I Fc epsilon receptor (Fc epsilon RI) mediated Ca2+ uptake and secretion of rat serosal mast cells have been shown to be inhibited by disodium 1,3-bis [(2'-carboxylatochromon-5'-yl) oxy]-2-hydroxypropane (disodium cromoglycate, DSCG), which is widely employed in the treatment of allergic asthma [Foreman et al. (1977) Br. J. Pharmacol. 59, 473P-474P; Cox (1967) Nature (London) 216, 1328-1329]. This drug was also found to modify the protein phosphorylation pattern of these mast cells. [Theoharides et al. (1980) Science 207, 80-82]. We have isolated by affinity chromatography on a water-insoluble cromoglycate-carrying matrix a cytosolic enzyme recently identified as a nucleoside 5'-diphosphate kinase. In order to examine a possible intracellular activity of the drug, a cell-permeant cromoglycate derivative, 1,3-bis [[2'-[[(acetoxymethyl)oxy]carbonyl]chromon-5'- yl]oxy]-2-hydroxypropane [bis(acetoxymethyl) cromoglycate, CG/AM], has been synthesized, and its uptake and effect on the Fc epsilon RI-mediated exocytosis of mast cells was investigated. A tritium-labeled CG/AM derivative, used as radioactive tracer, was found to permeate mucosal mast cells of the rat line RBL-2H3 and accumulate intracellularly up to 40-fold its extracellular concentration following hydrolysis by cytoplasmic hydrolases. A CG/AM dose dependent inhibition of the Fc epsilon RI-induced mediator secretion was observed in RBL-2H3 cells loaded with this compound (I50 approximately 40 microM extracellular CG/AM). A similar dose-dependent inhibition was observed for both the Fc epsilon RI-mediated transient rise in the concentration of cytosolic free Ca2+ ions [( Ca2+]i) and the net Ca2+ influx, as monitored by the fluorescent indicator Quin2 and the radioactive tracer 45Ca2+, respectively. These results clearly show that cell-permeant cromoglycate inhibits the Fc epsilon RI-mediated Ca2+ influx into the cell and further underscore the dominant role of this process in the coupling of stimulus to secretion in RBL cells. Furthermore, with the identification of nucleoside 5'-diphosphate kinase as a potential intracellular target for CG activity, distinct mechanisms of action may be inferred for cell-permeant and nonpermeant forms of CG.

Characterization of the human peripheral lung adenosine receptor

Because adenosine narrows asthmatic airways, is released during hypoxia and by mast cells, and is antagonized by theophylline, it may play a role in asthma. I characterized the first step in pulmonary responses to adenosine: its adenosine receptor. Plasma membranes, prepared from macroscopically normal human peripheral lung, were incubated with 10 nM 5'-N-ethylcarboxamido[3H]adenosine ([3H]NECA) and various concentrations of competing ligand under experimentally determined optimal conditions: 4 degrees C, pH 7.4, 5 mM MgCl2, 1.8 mg protein/ml, 30-min incubation time. Bound and free ligand were separated by rapid vacuum filtration, and the radioactive counts were analyzed using a weighted, non-linear, least-squares curve-fitting program, LIGAND. Analyzed together, the data from the lungs of 6 patients revealed a single binding site with a dissociation constant (Kd) for NECA of 200 nM +/- 14% and a receptor concentration of 543 fmol/mg protein +/- 13%. Analyzed separately, the individual Kds ranged from 133 to 430 nM and the receptor concentrations from 338 to 811 fmol/mg protein. Adenosine receptor ligands competed with NECA in an A2 rank order of potency: NECA greater than 8-phenyltheophylline greater than 3-isobutyl-1-methylxanthine greater than theophylline greater than N6-L-phenylisopropyladenosine greater than N6-D-phenylisopropyladenosine greater than N6-cyclohexyladenosine. Theophylline bound to the receptor with an inhibition constant (Ki = 70.9 microM +/- 28%) near the therapeutic range (28 to 56 microM). Cromolyn also bound with high affinity (Ki = 5.42 microM +/- 47%). I conclude that human lung adenosine receptors: (1) are single-site receptors, probably of the A2 subtype and (2) bind to both theophylline and cromolyn.

Isolation and purification of an Fc epsilon receptor activated ion channel from the rat mast cell line RBL-2H3

Derivatives of the antiallergic drug cromolyn [disodium 5,5'-[(2-hydroxy-1,3-propanediyl)-bis(oxy)]bis [4-oxo-(4H-1-benzopyran)-2- carboxylate]], which can be conjugated covalently at the propane 2-position to macromolecules and to insoluble matrices, were synthesized. Conjugates of these derivatives with macromolecules were examined for their binding to cells of the rat basophilic leukemia line RBL-2H3, which is widely employed as a model for immunologically induced mast cell degranulation. Only those drug-protein conjugates in which the cromolyn analogue with an amino group at the propane 2-carbon instead of the hydroxyl was linked to the carrier by glutaraldehyde were found to exhibit specific and saturable binding to these cells. Analysis of the binding data for these conjugates yielded an apparent binding constant of 3.8 +/- 0.2 X 10(8) M-1 and an apparent number of binding sites for the probe of 4000-8000 per cell. The conjugates found to bind specifically to the cells were also immobilized on agarose matrices and employed in an affinity-based isolation of the membrane component responsible for the observed binding. A single labeled polypeptide was eluted from these columns, onto which either whole cell lysates or solubilized purified plasma membranes of surface-radioiodinated RBL-2H3 cells had been adsorbed. This membrane protein appears on autoradiograms of nonreducing SDS-PAGE as a single broad band of approximately 110,000 daltons (Da) apparent molecular mass. On autoradiograms of reducing gels, the only band detected has an apparent mass of approximately 50,000 Da and appears narrower. Elution of the columns with the drug and disulfide-reducing agents or with the latter alone resulted in significantly higher yields of the 50-kDa polypeptide. Both the intact and reduced proteins bind strongly to immobilized concanavalin A and less so to immobilized wheat germ agglutinin, suggesting that the isolated intact protein is probably a dimer of two glycosylated subunits of similar molecular mass. Treatment of the reduced protein with endoglycosidase F leads to a decrease in its apparent molecular mass by approximately 12 kDa, suggesting that the extent of glycosylation of this polypeptide is approximately 25%. As shown in the following paper, the intact protein constitutes a Ca2+ channel that is activated upon IgE-Fc epsilon receptor aggregation.

[The relationship between Ca++ ions and a protein specific to cromolyn in the degranulation of mast cells and basophils in the rat]

Previous research has shown that cromolyn (disodium cromoglycate) binds specifically to the membrane of rat mast and basophil leukemia (RBL) cells, forming a ternary complex with Ca++, blocking of the Ca++ results in inhibition of histamine release upon immunologic triggering. The specific cromolyn binding protein (CBP) has been isolated by using its high affinity form cromolyn. Specific monoclonal anti CBP antibodies have been obtained in mice and polyclonal anti-cromolyn antibodies in rabbits. These antibodies have been used for further purification and characterization of the CBP. Experiments on RBL cell lines have shown that CBP is essential for Ca++ influx and histamine liberation upon immunologic triggering by these cells. Variant CBP deficient RBL do not take up Ca++ and do not degranulate in response to immunologic triggering but their ability to respond normally can be induced by incorporating CBP into their membranes with help of Sendai virus carrier vesicles. This shows that CBP plays a crucial role for the RBL cells Ca++ influx and histamine release following IgE crosslinking.

The pharmacokinetics of sodium cromoglycate in man after intravenous and inhalation administration

The pharmacokinetics of sodium cromoglycate in four healthy volunteers after slow intravenous infusion have been evaluated following measurement of plasma concentrations by radioimmunoassay. The results confirm earlier findings that sodium cromoglycate is rapidly eliminated from the body and that the data can be fitted to a two compartment open model. The pharmacokinetic parameters derived from the intravenous administration were used to evaluate the pharmacokinetics after inhalation administration via the Spinhaler. A model for absorption from the lungs is described which involves absorption at two different rates; this gives a better fit to the observed data than a single absorption rate. A fast absorption rate constant with a mean value of 0.54 min-1 and a slower rate constant with a mean value of 0.0097 min-1 were found. Of a mean total of 2.84 mg absorbed from a 20 mg inhaled dose, 0.68 +/- 0.15 (s.e. mean) mg were absorbed at the fast rate and 2.17 +/- 0.37 mg at the slower rate. These rates probably reflect absorption from different sites within the lungs. The results may have important implications for interpretation of clinical findings.

Characterization of the ion channel activity in planar bilayers containing IgE-Fc epsilon receptor and the cromolyn-binding protein

Electric conductance was studied across micropipette-supported planar lipid bilayers, reconstituted with IgE-Fc epsilon receptor and the cromolyn-binding protein (CBP) isolated from membranes of rat basophilic leukemia cells (RBL-2H3). Currents were observed following the addition of aggregating agents, specific for either of the two proteins. The results show that the two proteins are necessary and sufficient for the opening of cation channels. Both aggregation of Fc epsilon receptor via IgE with a specific antigen and of CBP by anti-CBP induce channels with similar conductances and open-time distributions. In the presence of 1.8 mM calcium, the most frequently observed channels have a conductance of 1-2 pS. At 100 mM calcium conductance increased to 4-5 pS. Channels induced by antigen were susceptible to blocking by the anti-allergic drug cromolyn. These results suggest that CBP acts as the core of the cation channel and that the channel conductance and open-time characteristics are independent of the mode of aggregation.

Current concepts in clinical therapeutics: asthma

The epidemiology, etiology, pathophysiology, diagnosis, and treatment of asthma are reviewed, and the major drugs used in treating asthma are discussed in depth. In terms of morbidity, mortality, and economic impact, asthma is a serious disease. About nine million Americans suffer from it, and in a recent year nearly 2000 people died from it. The underlying mechanism of asthma appears to be a hyperreactivity of the airways to certain stimuli, including environmental irritants, exercise, and psychological factors. The symptoms of asthma are caused by spasm of airway smooth muscle, increased mucus secretion, and inflammation. Asthma may be classified as intermittent (patients with extended symptom-free periods) or chronic (patients with frequent exacerbations). Diagnosis of asthma relies heavily on a comprehensive patient history confirmed with objective physiologic data. Acute or intermittent asthma should be treated first with inhaled beta 2 agonists such as albuterol or terbutaline. Corticosteroids should be started if the response to the beta 2 agonists is inadequate, and theophylline may be used while waiting for the steroids to exert an effect. Adequate hydration, correction of metabolic acidosis, and oxygen are essential supportive measures. Theophylline appears to be the best noncorticosteroid for chronic asthma, although cromolyn is an acceptable alternative. Sympathomimetic bronchodilator therapy and corticosteroids may be needed adjunctively. Immunotherapy is indicated in patients with chronic asthma caused by specific allergens and poorly controlled on theophylline or cromolyn. Asthma is best managed using multiple pharmacologic agents in response to specific events and symptoms, making optimal therapy difficult to achieve and sometimes difficult to define.

Ocular sodium cromoglycate. An overview of its therapeutic efficacy in allergic eye disease

Sodium cromoglycate stabilizes mast cell membranes and prevents the release of histamine and other biochemical mediators. When topically applied to the eye before allergen exposure, ocular sodium cromoglycate prevents many of the signs and symptoms associated with type I allergic reactions (which includes hayfever, acute allergic and chronic allergic conjunctivitis, and vernal keratoconjunctivitis) and giant papillary conjunctivitis. Although difficulties exist in evaluating clinical trials in allergic eye disease, both open and controlled studies have shown ocular sodium cromoglycate to be very effective in relieving the subjective symptoms and clinical signs of the above ocular disorders. In addition, ocular sodium cromoglycate may decrease the need for supplementary oral antihistamines and, more importantly, the need for ocular corticosteroids, thus decreasing the incidence of steroid-induced ocular side effects. However, in severe cases and in instances of acute exacerbation of symptoms, the combined ocular application of sodium cromoglycate and corticosteroids may be very effective. No systemic or severe adverse reactions have been attributed to ocular sodium cromoglycate, which is not surprising since systemic drug absorption from the eye is minimal. However, transient local stinging and burning have been reported. Thus, although further studies in giant papillary conjunctivitis and comparative studies with corticosteroids in allergic conjunctivitis and vernal keratoconjunctivitis are needed to more clearly define the extent of benefits that may be obtained from ocular sodium cromoglycate, it is clear that the safety and efficacy of the drug in type I allergic eye diseases is such that it should be considered as a first-line agent when drug therapy of these disorders is indicated.

Influence of ophthalmic formulations on sodium cromoglycate disposition in the albino rabbit eye

The effect of different ophthalmic vehicles on the disposition of sodium cromoglycate in tears and ocular tissues of the rabbit eye has been studied over 6 h. The vehicles contained sodium cromoglycate, 2% in an aqueous solution, 2 and 4% in an oleaginous formulation of polyethylene and mineral oil (Plastibase 5W), and 4% in an absorption ointment base of 10% hypoallergenic acetylated lanolin (Modulan) in paraffins. The last formulation was superior to all others studied over 6 h in prolonging the retention of sodium cromoglycate in the precorneal area and the conjunctiva. The concentration of sodium cromoglycate in the tears, conjunctiva and cornea 6 h after administration of the acetylated lanolin base equalled or exceeded the concentrations obtained with the aqueous solution 1 h post-instillation.

Cromolyn sodium in the treatment of asthma: coming of age in the United States

Cromolyn sodium has matured as a first-line drug in the management of asthma in the United States. New pharmacokinetic assays reveal that it exerts classic dose-response effects both in vitro and in vivo. The protective effect of cromolyn sodium is due chiefly to its ability to inhibit mediator release from mast cells, but there is considerable evidence that it may affect reflex-induced asthma and bronchial hyperreactivity. It may also reduce the number of inflammatory effector cells such as eosinophils and decrease the IgE-mediated local immune response. Two formulations are currently available in the United States: the powdered Spinhaler apparatus and a solution that can be aerosolized by a nebulizer. A metered-dose aerosol preparation containing 1 mg/drug per activation is being investigated in other parts of the world and appears to be equally as effective as the powdered and nebulized forms of cromolyn. Recent controlled studies reveal that cromolyn sodium and theophylline have equal efficacy in the first-line management of asthma, but troublesome cardiovascular and psychoneurologic side effects are often observed after theophylline therapy. If used properly, cromolyn sodium is a valuable agent in the pharmacologic treatment of asthma.

Topical sodium cromoglycate in the management of atopic eczema--a controlled trial

A double-blind, group comparison trial of a topical cream containing 4% sodium cromoglycate (SCG) was undertaken in forty-six patients with chronic atopic eczema. A statistically significant improvement was seen after 9 weeks in the actively treated patients compared with the placebo group. However, in general, no benefit was observed in severe eczema, perhaps due in some part to the seemingly late onset of action of SCG. Measurement of total serum IgE before and after the trial showed an increase in levels which was apparently unrelated to treatment with SCG or placebo or to a change in severity of the eczema. The amount of SCG in the urine was small and very variable, indicating low percutaneous absorption. The calculated bioavailability ranged from 0.01% to 2.75% of the applied dose. These results together with follow-up studies suggest that topical SCG as a long-term measure may be useful in the management of mild or moderately severe eczema, reducing the frequency of acute exacerbations.

The nasal absorption of sodium cromoglycate in the albino rat

The intranasal absorption of sodium cromoglycate has been investigated in the adult male COBS/Wistar rat. Sodium cromoglycate (1 mg kg-1) was instilled into the nasal cavities and for comparison animals were also similarly dosed intravenously or sub-lingually. Serial samples of blood or bile were collected. After intravenous administration, the area under the plasma concentration curve (AUC0-infinity) was 32 micrograms min ml-1 corresponding to a plasma clearance of 13 ml min-1 and an elimination rate constant of 0.049 min-1. Plasma concentrations of radioactivity after intranasal administration rose to a mean peak of 0.3 micrograms ml-1 approximately 20 min after dosing and fell to 0.03 micrograms min ml-1 at 3 h. The AUC0-3 was 19 micrograms min ml-1 corresponding to an absorption of 60% over 3 h. The absorption rate constant (ka) was 0.059 min-1. The total amount of sodium cromoglycate excreted in bile after intravenous administration was 56%. The amount of compound excreted in the bile was 30% after intranasal administration corresponding to an absorption of 53%. Plasma and bile data therefore show good agreement. Total excretion in the bile over 3 h after sub-lingual administration was 3%, demonstrating that this route made no significant contribution to the intranasal results. The absorption of sodium cromoglycate is independent of variations in the technique including changes in the orientation of the rat or blocking of the nasopalatine. The techniques used minimized other competing nasal clearance processes such as mucociliary clearance.

Cromolyn sodium

Cromolyn sodium is a valuable agent in the pharmacologic management of asthma. In addition to its established effects of inhibiting mediator release, it now appears that it is a useful drug for diminishing the effects of reflex-mediated asthma, nonspecific bronchial hyperreactivity, and diurnal swings of bronchial lability. Because of these unique prophylactic properties, the availability of a nebulized aqueous solution delivery system and recent clinical reports showing that its efficacy is comparable to theophylline, cromolyn sodium should be reconsidered as a first-line antiasthmatic drug in the United States.

Identification of calcium antagonist receptor binding sites using (3H)nitrendipine in bovine tracheal smooth muscle membranes

(3H)Nitrendipine binding to the bovine tracheal muscle membrane at 25 degrees C was rapid, saturable (Bmax = 14.8 +/- 3.9 fmol/mg protein) and of high affinity (Kd = 0.15 +/- 0.04 nM). The rank order of Ca2+ antagonists competing for airway (3H)nitrendipine binding was nitrendipine not equal to nisoldipine not equal to nifedipine much greater than verapamil. Cromolyn, however, neither inhibited nor increased the binding.

[Cromoglycic acid (disodium cromoglycate) and inhibitors of mast cell degranulation]

Cromoglycic acid (disodium cromoglycate) is a diacromone derived from khelline whose chief action in asthma is preventive, through inhibition of mastocyte degranulation. Since its digestive absorption is poor, it is given locally as a pulverulent aerosol. Cromoglycic acid is also used successfully in certain forms of ocular and nasal allergy. An oral preparation of cromoglycic acid is beginning to be used in food allergy and certain rectocolites. Trials are ongoing with several other substances, which have comparable properties and are active orally.

The prolonged retention of sodium cromoglycate in the rabbit eye

The retention of sodium cromoglycate in the rabbit eye over a 6 h period following its administration in two different vehicles is reported. When formulated as a dispersion in a hypo-allergenic acetylated lanolin/paraffins base, prolonged retention was observed. Thus, the concentration of sodium cromoglycate in the tears, conjunctiva and cornea 6 h after administration equalled or exceeded the concentration obtained with an aqueous solution 1 h post-instillation.

Non-enhancement of sodium cromoglycate intestinal absorption by quaternary ammonium ions. An effect of salt on ion-pair formation?

Studies on the nature of rat small intestine perfusates indicate that this environment is thermodynamically unfavourable for the production of ion pairs between cromoglycate and alkylbenzyldimethylammonium ions. This is suggested as being the reason why, unlike previously found for ocular absorption of cromoglycate, these quaternary ammonium ions do not alter cromoglycate intestinal absorption.

Disposition of topically applied sodium cromoglycate in the albino rabbit eye

The influence of pH, tonicity, preservatives, polymers and instilled drop size on the disposition of sodium cromoglycate, an agent used in the prophylaxis of vernal keratoconjunctivitis, in the tear chamber of the albino rabbit eye has been examined. Radiotracer techniques were used throughout. The initial decline in concentration in the tear chamber was found to be unaffected by the presence of preservatives, pH, and tonicity over the ranges studied. However, significant increases in the residence time of sodium cromoglycate in the precorneal area were noted when a smaller instilled drop size was used and when 5% polyvinyl alcohol (PVA) was added to the aqueous vehicle. Tissue uptake was found to be greatest in the conjunctiva, followed by the cornea, the iris-ciliary body and the aqueous humor. In both the conjunctiva and the cornea, the addition of 5% PVA produced an elevation in the peak concentration of sodium cromoglycate and an increase in the time at which the peak concentration was achieved, indicating improved drug delivery to these sites.

Basophil variants with impaired cromoglycate binding do not respond to an immunological degranulation stimulus

Cromoglycate, which inhibits IgE-mediated degranulation of mast cells and a basophilic rat tumour cell line (RBL-2H3) (ref.3), is a drug widely used in the treatment of allergic asthma. We have demonstrated the presence of specific binding sites for that drug on the membranes of basophils and mast cells and more recently, we have succeeded in isolating the cromoglycate-binding protein from the membranes of RBL-2H3 cells. These findings together with the chelation by cromoglycate of alkaline-earth ions in low polarity medium, suggest that the binding site of the drug may either be part, or closely related to the calcium gate. To further investigate this, we have selected variants of the RBL-2H3 cell line that are defective in cromoglycate binding but bind IgE normally. In these variants, which have similar histamine content to the parental cells, IgE-mediated challenge did not lead to Ca2+ influx, degranulation and histamine release. In contrast, these cells were able to release histamine on exposure to the Ca2+ ionophore A23187, indicating that the degranulation mechanism distal to the Ca2+ gating step is unaffected. Taken together, these findings suggest that cromoglycate-binding protein has a role in the transmembrane calcium influx which induces degranulation.

The pharmacokinetic assessment of sodium cromoglycate

The plasma concentration of sodium cromoglycate (SCG) was measured in four healthy subjects by radioimmunoassay after a 4 mg intravenous dose and after inhaling from 20 mg capsules, and from 10 and 30 mg ml-1 nebulizer solutions. The mean absorption constant (K1) after inhalation was 0.43 h-1. The mean elimination constant from the plasma (Kelim) after intravenous administration was 11.5 h-1, and that after inhalation was similar. The apparent volume of distribution of SCG (Vd beta) was 0.2 litre kg-1 and the mean plasma clearance was 0.35 litre h-1kg-1. The amount of SCG absorbed after inhalation varied according to the method of inhalation and dose. After the inhalation of powder from 20 mg capsules, 1.30-3.96 mg reached the plasma, after inhalation of SCG produced by nebulizing a 10 mg ml-1 solution for 5 min at 10 psi using a Minineb nebulizer 0.19-0.31 mg reached the plasma and when the solution was increased to 30 mg ml-1 the figure was 0.33-0.45 mg.

Further studies on the effects of disodium cromoglycate on guinea pig ileum

Transmural electrical stimulation was carried out on innervated strips of the longitudinal muscle of guinea pig ileum. Disodium cromoglycate (DSCG) inhibited the electrically induced contractions. Five minutes later, prostaglandin E2 (2.5 ng/ml) was added to the bath and it reversed the action of DSCG. Furthermore, DSCG inhibits significantly the guinea pig ileum contractions induced by nicotine and also those induced by histamine and acetylcholine on ileum denervated by cooling. These results suggest that DSCG effects on guinea pig ileum contraction are mediated by membrane-stabilizing properties of this drug on smooth muscle fibres as well as on myenteric plexus.

Isolation of a basophilic membrane protein binding the anti-allergic drug cromolyn

The membrane protein component in basophils, responsible for the specific, Ca2+-dependent, binding of the anti-allergic drug cromolyn [disodium cromoglycate, DSCG; the disodium salt of 1,2 bis(2- carboxychromon -5- yloxy )-2-hydroxy propane] was isolated by two procedures based on affinity for the drug. In the first procedure, involving immunoprecipitation, rat basophilic leukemia cells (RBL-2H3), surface labeled by 125I were reacted with a polyvalent conjugate of DSCG and bovine serum albumin and then subjected to solubilization by the non-ionic detergent Nonidet P-40 (NP-40). From these lysates, precipitation was specifically attained by subsequent addition of rabbit anti-DSCG antibodies. In an SDS-polyacrylamide gel electrophoresis (SDS-PAGE), a single radioactive band was observed, having an apparent mol. wt. of 60 000 daltons. Competitive inhibition of the immunoprecipitation in the presence of free drug or excess of EDTA demonstrated the specificity of the isolation. Furthermore, this particular membrane component could not be isolated from several other cell types examined. The second isolation from several other cell types examined. The second isolation procedure employed affinity chromatography on DSCG immobilized on polyacryl- hydrazido agarose beads. The DSCG-binding protein was eluted from the affinity column with either DSCG or with EDTA and also migrated on SDS-PAGE as a single band of 60 000 mol. wt., similar to that obtained by the immunoprecipitation procedure. These and other results suggest that this newly isolated protein is the one responsible for the Ca2+-dependent binding of the drug to the basophil membrane.

Altered ocular absorption and disposition of sodium cromoglycate upon ion-pair and complex coacervate formation with dodecylbenzyldimethylammonium chloride

Ion-pair formation between the dianionic drug sodium cromoglycate and dodecylbenzyldimethylammonium chloride has been found to alter the extent and rate of corneal penetration of both large ions upon their coadministration. Additionally, using a complex coacervate of the two large ions as the applied dose form (in which the complex is in equilibrium with the ion pairs), a change in the overall disposition of both large ions to the various components of the eye is observed.

Age related changes in the clearance and oral absorption of sodium cromoglycate in the developing albino rat

A dual radioisotope method was used to investigate the clearance and oral abso***rption of sodium cromoglycate. Radiolabelled sodium cromoglycate was administered orally at a dose of 100 mg kg 1 (14 C-labelled) and simultaneously subcutaneously at a dose of 2 mg kg−1 (3 H-labelled) to rat pups 5, 9, 14, 20, 29 and 75 days old. Blood concentrations of 14 C and 3 H were measured at intervals for 24 h after dosing. Since the compound is not metabolized the blood concentrations of 14 C were taken as a measure of the sodium cromoglycate absorbed orally and the blood concentrations of 3 H as a measure of the subcutaneously administered material. Using the area under the oral 14 C blood curve (AUC) as an index of bioavailability, the calculated bioavailability of sodium cromoglycate (692·9−945·9 min μg ml−1) in 5, 9 and 14 day old pups was 4–8 times greater than that observed (61·0-118·8 min μg ml−1) in 20, 29 and 75 day old pups. The blood clearance of sodium cromoglycate was increased four-fold in 75 day old animals (43·9 ml min−1 kg−1) and three-fold in 20 and 29 day old pups when compared to the clearance in 5, 9 and 14 day old pups. The clearance in 5, 9 and 14 day old pups was relatively constant (10·8 − 9·9 ml min−1 kg−1). In rats less than 14 days old the systemic absorption of sodium cromoglycate after oral administration was 2–3 times greater (6·8-9·2%) than in rats aged 20, 29 or 75 days old (2·7-3·3%). The reduction in oral bioavailability of sodium cromoglycate as the pups grew older was, therefore, due to both an increased blood clearance and a decreased absorption of the compound.

A binding site on mast cells and basophils for the anti-allergic drug cromolyn

Calcium permeability of basophil and mast cell membranes is stimulated on allergen binding to its specific membrane-bound IgE. This entry of Ca2+ ions into the cell triggers the degranulation and secretion process. Disodium cromoglycate (cromolyn DSCG), the disodium salt of 1,3-bis(-2-carboxychromon-5-yloxy)-2-hydroxypropane, inhibits the degranulation and release of anaphylactic mediators, and has found wide application in the treatment of allergic bronchial asthma. Accumulated evidence indicates that this inhibition takes place by blocking the calcium uptake. To localize its site of action, the drug has been covalently conjugated to fluorescent polyacrylamide and polyglutaraldehyde beads (0.7 and 0.2 microns in diameter, respectively). We show here that these drug-bead conjugates (DBC) do prevent the drug penetrating into the cell without reducing its ability to inhibit histamine release (Table 1). Furthermore, we show a specific Ca2+-dependent binding of the DBC to the membranes of rat peritoneal mast cells (RPMC) and basophils.

Therapy with cromolyn sodium

Cromolyn is a prototype of a new series of drugs, the pharmacologic activities of which may offer an entirely new approach in the treatment of asthma. Whereas bronchodilator drugs and steroids act primarily at tissue sites to counteract the effects of various toxic mediators released from tissue mast cells, cromolyn prevents the release of such mediators from mast cell membranes. The advent of cromolyn sodium therapy has been recognized as a significant advance by the pharmaceutical industry, which is rapidly developing a series of cromolyn-like drugs with similar properties. Many of these compounds are active orally, and some preliminary investigations suggest that they also could be clinically effective. Cromolyn has therapeutic value in immunologic and nonimmunologically induced bronchospasm, being particularly suited for conditions amenable to long-term prophylactic therapy. The risk-to-benefit ratio of cromolyn sodium therapy is excellent. Cromolyn sodium is an important adjunct in the treatment of asthma. By topical administration the drug has been effective in seasonal and perennial rhinoconjunctivitis and in selected cases of gastrointestinal allergy to foods.

Liver disease and vasculitis in a patient taking cromolyn

Hypersensitivity reactions to cromolyn sodium occur rarely. On several occasions they have been associated with peripheral eosinophilia and granulomatous inflammation. Liver disease has not been reported previously as a complication of inhaled cromolyn. We describe here a woman in whom marked peripheral eosinophilia, liver disease, and systemic vasculitis developed while taking cromolyn and resolved or improved on discontinuation of the drug and treatment with corticosteroids. The liver disease was similar to primary biliary cirrhosis except that marked eosinophilic infiltration and granulomas were present initially. Studies of the patient's serum for binding of carbon 14-labeled cromolyn, the skin for deposits of the drug, and the circulating lymphocytes for stimulation by cromolyn failed to demonstrate any abnormalities. However, the elevated IgG and IgM levels, the positive rheumatoid factor and antimitochondrial antibody, and the reduced serum complement, which returned to normal on discontinuation of the drug therapy, suggests that immunologic mechanisms may have played a role in the pathogenesis of this patient's illness.