Clinical Pharmacology of Cilomilast

Human total clearance values and volumes of distribution of typical human cytochrome P450 2C9/19 substrates predicted by single-species allometric scaling using pharmacokinetic data sets from common marmosets genotyped for P450 2C19

Common marmosets (Callithrix jacchus) are small non-human primates that genetically lack cytochrome P450 2C9 (CYP2C9). Polymorphic marmoset CYP2C19 compensates by mediating oxidations of typical human CYP2C9/19 substrates.Twenty-four probe substrates were intravenously administered in combinations to marmosets assigned to extensive or poor metaboliser (PM) groups by CYP2C19 genotyping. Eliminations from plasma of cilomilast, phenytoin, repaglinide, tolbutamide, and S-warfarin in the CYP2C19 PM group were significantly slow; these drugs are known substrates of human CYP2C8/9/19.Human total clearance values and volumes of distribution of the 24 test compounds were extrapolated using single-species allometric scaling with experimental data from marmosets and found to be mostly comparable with the reported values.Human total clearance values and volumes of distribution of 15 of the 24 test compounds similarly extrapolated using reported data sets from cynomolgus or rhesus monkeys were comparable to the present predicted results, especially to those based on data from PM marmosets.These results suggest that single-species allometric scaling using marmosets, being small, has advantages over multiple-species-based allometry and could be applicable for pharmacokinetic predictions at the discovery stage of drug development.

Oleic acid as the active agent and lipid matrix in cilomilast-loaded nanocarriers to assist PDE4 inhibition of activated neutrophils for mitigating psoriasis-like lesions

Both phosphodiesterase (PDE4) inhibitors and omega-9 fatty acids show anti-inflammatory activity for treating inflamed skin diseases, but their efficacy remains low. Combinatorial agents are anticipated to offer an advanced strategy for efficient therapy. We prepared cilomilast-loaded oleic acid (OA) nanocarriers to test the inhibitory capability against human neutrophil stimulation and a murine psoriasis model. OA played dual roles in the nanocarriers as both the active ingredient and lipid matrix in the nanoparticulate core. OA nanoparticles but not free OA could restrain calcium mobilization in activated neutrophils. The inhibition level of superoxide anion and elastase by cilomilast-loaded OA nanocarriers approximated that of free forms. In the mouse model, the intradermal nanosystems reduced imiquimod-induced epidermal thickening from 230.4 to 63.1 μm. Transepidermal water loss was decreased from 30.2 to 11.3 g/m²/h by integrated nanocarriers. The nanosystems mitigated neutrophil infiltration and hyperproliferation in the psoriasiform lesion via decreased expression of cytokines and chemokines. STATEMENT OF SIGNIFICANCE: The long-term therapy for psoriasis is unsatisfactory due to the possible adverse effects and inefficiency after prolonged use. Both phosphodiesterase (PDE4) inhibitors and omega-9 fatty acids such as oleic acid (OA) show anti-inflammatory activity for treating inflamed skin diseases. Combinatorial agents are anticipated to offer an advanced strategy for efficient therapy. OA is also ideal for incorporation into nanoparticles to enhance particulate emulsification, drug entrapment, and biocompatibility. We prepared cilomilast-loaded oleic acid (OA) nanocarriers to test the inhibitory capability against human neutrophil stimulation and a murine psoriasis lesion. OA nanocarriers are indigenous to prevent neutrophil activation and the deterioration of psoriatic lesion. Cilomilast incorporation in OA nanocarriers could further mitigate the clinical score and suppressing proinflammatory mediators.

Use of cilomilast-loaded phosphatiosomes to suppress neutrophilic inflammation for attenuating acute lung injury: the effect of nanovesicular surface charge

Background

Cilomilast is a phosphodiesterase 4 (PDE4) inhibitor for treating inflammatory lung diseases. This agent has a narrow therapeutic index with significant adverse effects on the nervous system. This study was conducted to entrap cilomilast into PEGylated phosphatidylcholine-rich niosomes (phosphatiosomes) to improve pulmonary delivery via the strong affinity to pulmonary surfactant film. Neutrophils were used as a cell model to test the anti-inflammatory activity of phosphatiosomes. In an in vivo approach, mice were given lipopolysaccharide to produce acute lung injury. The surface charge in phosphatiosomes that influenced the anti-inflammatory potency is discussed in this study.

Results

The average diameter of the phosphatiosomes was about 100 nm. The zeta potential of anionic and cationic nanovesicles was − 35 and 32 mV, respectively. Cilomilast in both its free and nanocapsulated forms inhibited superoxide anion production but not elastase release in activated neutrophils. Cationic phosphatiosomes mitigated calcium mobilization far more effectively than the free drug. In vivo biodistribution evaluated by organ imaging demonstrated a 2-fold ameliorated lung uptake after dye encapsulation into the phosphatiosomes. The lung/brain distribution ratio increased from 3 to 11 after nanocarrier loading. The intravenous nanocarriers deactivated the neutrophils in ALI, resulting in the elimination of hemorrhage and alveolar wall damage. Only cationic phosphatiosomes could significantly suppress IL-1β and TNF-α in the inflamed lung tissue.

Conclusions

These results suggest that phosphatiosomes should further be investigated as a potential nanocarrier for the treatment of pulmonary inflammation.

Drug interactions

Drugs for allergy are often taken in combination with other drugs, either to treat allergy or other conditions. In common with many pharmaceuticals, most such drugs are subject to metabolism by P450 enzymes and to transmembrane transport. This gives rise to considerable potential for drug-drug interactions, to which must be added consideration of drug-diet interactions. The potential for metabolism-based drug interactions is increasingly being taken into account during drug development, using a variety of in silico and in vitro approaches. Prediction of transporter-based interactions is not as advanced. The clinical importance of a drug interaction will depend upon a number of factors, and it is important to address concerns quantitatively, taking into account the therapeutic index of the compound.