Inhaleables gastrointestinal tract problems

Fourth, inhaling instead of taking pills can help avoid gastrointestinal tract problems such as poor solubility, low bioavailability, gut irritability, unwanted metabolites, food effects and dosing variability. 

During inhalation exposure of human volunteers to low levels of toluene (200-300 mg/mty, approximately 50% of the inhaled toluene was absorbed (Lbf et al., 1993). Such studies at low toluene exposure are complicated by the presence of toluene from other sources, in blood or in urine (Pierce et al., 1996). If the deuterated [ Hgjtoluene is used for exposure, this problem is avoided [but an isotope effect may reduce the rate of the metabolism of deuterated toluene compared to normal toluene, possibly by 30-50%]. When toluene is administered orally, it is virtually completely absorbed from the gastrointestinal tract (Baelum et al., 1993). 

HUMAN HEALTH RISKS Inhalation human TCLo 100 ppm Acute Risks irritation of eyes, skin, mucous membranes and respiratory tract abdominal cramps confusion CNS depression narcosis vomiting headache dizziness dermatitis gastrointestinal problems Chronic Risks Effects on CNS, liver and respiratory system skin defattening dermatitis. 

---