The absorption and clearance of disodium cromoglycate from the lung in rat, rabbit, and monkey

Development of an In Vivo Ovine Dry Powder Inhalation Model for the Evaluation of Conventional and Controlled Release Microparticles

“…Previous studies by Moss et al (10) indicated that urinary excretion of DSCG had decreased to negligible proportions after 8 hours post administration in humans, and the authors suggested that no further absorption from the lungs was taking place. Interestingly, similar urinary excretion rates of DSCG in rats, rabbits, monkeys and humans was also observed by Moss et al, which suggested that lung clearance mechanism of DSCG in humans would follow the same pattern as found in mammalian species (14).…”

“…Table I shows the pharmacokinetic parameters calculated from both the DSCG and DSCG/PVA controlled release formulation (AUC 0À1 , apparent t 1/2 and F %). Since a value of only 8% bioavailability for inhaled DSCG from DPIs was reported in humans (15) and since the percentage excreted in faeces would be attributed to bile excretion more than GI absorption (14), it comes as no surprise that the percent bioavailability for DSCG microparticles was 2.58%±0.31 (SD). In addition, it is expected that the polar nature of the DSCG molecule and the defence clearance mechanisms (mucociliary clearance and alveolar macrophages) of the airways may have contributed to the rapid clearance of the bulk of the drug from the lungs before being subject to absorption.…”

The nasal absorption of sodium cromoglycate in the albino rat

“…The ionized compound has negligible lipophilicity. These physicochemical properties prevent the drug from being well absorbed from the gastrointestinal tract (Moss et al 1970;Smith & Fisher 1980). In contrast, the drug is rapidly absorbed from the lung (Moss & Ritchie 1970) and after subcutaneous administration (Smith & Fisher 1980).…”

“…These physicochemical properties prevent the drug from being well absorbed from the gastrointestinal tract (Moss et al 1970;Smith & Fisher 1980). In contrast, the drug is rapidly absorbed from the lung (Moss & Ritchie 1970) and after subcutaneous administration (Smith & Fisher 1980). The rapid absorption of the compound through the nasal mucosa suggests that the permeability of this tissue is governed by similar factors to those controlling absorption from the lung or subcutaneous sites.…”