Cromolyn sodium toxicity studies in primates

Ameliorative effects of type-A procyanidins polyphenols from cinnamon bark in compound 48/80-induced mast cell degranulation

Allergic diseases are a significant health concern in developing countries. Type-A procyanidin polyphenols from cinnamon (Cinnamomum zeylanicum Blume) bark (TAPP-CZ) possesses antiasthmatic and antiallergic potential. The present study was aimed at the possible anti-allergic mechanism of TAPP-CZ against the compound 48/80 (C48/80)–induced mast cell degranulation in isolated rat peritoneal mast cells (RPMCs). TAPP-CZ (1, 3, 10, and 30 µg/ml) was incubated for 3 hours with isolated, purified RPMCs. The C48/80 (1 µg/ml) was used to induce mast cell degranulation. The mast cell viability was assessed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay whereas histamine, β-hexosaminidase (β-HEX), and interleukin-4 (IL-4) levels were determined in RPMCs. TAPP-CZ (3, 10, and 30 µg/ml) showed significant and dose-dependent decrease in a number of degranulated cells and levels of markers (histamine, β-HEX, and IL-4) as compared with C48/80 control. In conclusion, TAPP-CZ stabilizes mast cell and cause inhibition of the allergic markers such as histamine, IL-4, and β-HEX in IgE-mediated manner. The present study supports mast cell stabilization as a possible mechanism of action of TAPP-CZ against immune respiratory disorders such as asthma and allergic rhinitis.

Disodium cromoglycate stabilizes mast cell degranulation while reducing the number of hemoglobin-induced microvascular leaks in rat mesentery

Blood substitutes, such as diaspirin cross-linked Hb (DBBF-Hb), have been considered for use during blood transfusions. Unfortunately, bolus injection of modified Hb has been shown to rapidly increase the leakage of microvessels to plasma albumin. This effect may result from production of excess reactive oxygen species (ROS) and could be linked to the observed increase in degranulated mast cells (DMC). Disodium cromoglycate (cromolyn) stabilizes mast cells and therefore might minimize the venular permeability in the rat mesentery. In 10 anesthetized Sprague-Dawley rats, the mesenteric preparation was continuously suffused with cromolyn while the microvasculature was filled with DBBF-Hb solution (10 mg/ml) for 10 min. Six animals received cromolyn pretreatment [two intravascular injections over 30 min (experiment A)] and four animals received pretreatment with 2% HEPES-buffered saline (HBS)-BSA (experiment B). Two more animals were pretreated with HBS-BSA without DBBF-Hb infusion but with cromolyn suffusion (experiment C). Another set of experiments was performed on five animals without cromolyn suffusion or any pretreatment but with DBBF-Hb infusion (experiment D). All groups then received a 1-min perfusion of FITC-albumin, fixation for 60 min, and microscopic examination. Experiments A and B demonstrated a significant reduction in the number of venular leaks and DMC compared with experiment D, but not in the area of venular leaks. These results suggest mast cell degranulation is not a major contributor to microvascular leakage induced by DBBF-Hb.

Hyaluronidase inhibitors (sodium cromoglycate and sodium auro-thiomalate) reduce the local tissue damage and prolong the survival time of mice injected with Naja kaouthia and Calloselasma rhodostoma venoms

Experiments have been carried out to find potent inhibitors of hyaluronidases of Naja kaouthia (NK) and Calloselasma rhodostoma (CR) venoms with the aim of reducing local tissue damage and systemic toxicities caused by the venoms. Seven drugs/chemicals known to inhibit hyaluronidases were tested for their activity on venom enzymes. These were: sodium cromoglycate (SC), sodium aurothiomalate (SAT), apigenin, kaemferol, phenylbutazone, oxyphenbutazone and fenoprofen. The results showed that SC or SAT at 10 mM, completely inhibited the enzymes of both venoms. In in vivo experiments, SC or SAT, when incubated with NK venom prior to injection, significantly reduced edema and myonecrosis. In the case of CR venom, hemorrhage, in addition to edema and myonecrosis, was also significantly reduced. In the independent type experiment, SC or SAT were effective if injected within 1 min after the injection of venom. At longer time intervals of 3 and 10 min the inhibitors were effective in reducing some parameters of local tissue necrosis but the extent of inhibition was lower. SC and SAT at 256 and 195 microg/mouse, respectively, significantly prolonged the survival time of mice receiving lethal doses of NK. In the case of CR venoms, the two inhibitors not only prolonged the survival time but also prevented death of mice receiving lethal doses of the venom. The other inhibitors were poorly soluble in water and were studied only on enzyme inhibition and prolongation of survival time; they were mostly ineffective. Thus, SC and SAT when injected immediately at the sites of bites can reduce the systemic and local toxicity of NK and CR venoms. These results suggest that administration of these drugs at the site of venom injection may be useful in reducing venom-induced local tissue damage.

Toxicologic testing of inhaled pharmaceutical aerosols

This paper reviews technical issues related to the toxicologic testing of inhaled pharmaceuticals. Although there are commonalities between approaches to general and inhalation toxicity testing, there also are specific challenges in the toxicity testing of inhaled pharmaceuticals. A major issue is that of dose; inhaled dose is more difficult to determine than intravenous or oral doses. Also, it is harder to relate dose in laboratory animals to that in man for inhalation exposure than for other routes of administration. Additionally, in the case of inhaled pharmaceuticals, people generally inhale through the mouth, whereas most laboratory animals inhale primarily through the nose. This presents significant challenges in exposure methodology and technology that often need innovative approaches involving alteration to particle size of the agent or dosing procedure. Because the respiratory tract is the site of deposition, local respiratory toxicity and possible damage to lung cells need to be assessed. Systemic toxicity also needs to be evaluated and may be an issue in some cases. Special studies on pulmonary function, mucociliary clearance, or immune response may be needed, depending on the nature of the inhaled pharmaceutical. This review explores the main issues involved in toxicity testing of inhaled pharmaceuticals, the approaches that have been used, and the current and future challenges.

Ocular allergy and mast cell stabilizers

The role of the mast cell in ocular allergy is becoming understood. As a result, the therapeutic effects of agents that stabilize the mast cell have been evaluated in the treatment of seasonal allergic conjunctivitis, vernal keratoconjunctivitis, atopic keratoconjunctivitis, and giant papillary conjunctivitis. At present, cromolyn sodium is the only available mast cell stabilizer of known effectiveness. Clinical and laboratory investigations of the effectiveness of cromolyn sodium in the treatment of ocular allergy are reviewed in the present article.

Cromolyn sodium: a review

Cromolyn is a white crystalline powder which is poorly absorbed from the gastrointestinal tract. Its therapeutic value lies in its functions as an inhaled or topically applied agent. Cromolyn has been approved in the United States for asthma therapy since 1973. It was marketed at that time as a drug to reduce the corticosteroid requirements of severe asthmatics. It clearly did not live up to that claim. Initial enthusiasm for cromolyn was replaced by disillusionment. In the last few years, investigators have taken another look at cromolyn and have a renewed interest in it. Cromolyn's mechanisms of action remain only partially understood. It appears to block allergic mediator release from certain mast cells. It may also decrease bronchial hyperreactivity. The frequency of drug toxicity at customary dosages is extremely low. Adverse effects tend to be mild, short-lived and without sequelae. Currently, cromolyn is a first line therapy for mild to moderate asthma requiring chronic treatment. It is also of proven efficacy in the treatment of allergic rhinitis, allergic conjunctivitis and vernal keratoconjunctivitis.

Disodium cromoglycate inhibits allergic patch test reactions

Disodium cromoglycate was applied before patch testing in patients with contact allergy to propipocaine hydrochloride, nickel and formaldehyde. The responses obtained were mitigated to a high degree when compared with similar effects due to corticoids.