Orlistat or tetrahydrolipstatin (Xenical, Hoffmann-La Roche) is a saturated derivative of lipstatin originally isolated from Streptomyces toxytricini. Orlistat (Xenical, Hoffmann-La Roche) is a powerful inhibitor of gastrointestinal lipase and as such, reduces fat absorption. Orlistat acts by binding covalently to the serine residue of the active site of gastric and pancreatic lipases. When administered with fat-containing foods, orlistat partially inhibits hydrolysis of triglycerides, thus reducing the subsequent absorption of monoaclglycerides and free fatty acids. Unlike other weight-reducing drugs it is minimally absorbed and has no effects in the CNS. Xenical is indicated for obesity management including weight loss and weight maintenance when used in conjunction witha reduced-calorie diet. XENICAL is also indicated to reduce the risk for weight regain after prior weight loss. XENICAL is indicated for obese patients with an initial body mass index (BMI) ≥ 30 kg/m2 or ≥ 27 kg/m2 in the presence of other risk factors (eg, hypertension, diabetes, dyslipidemia). In addition to its well established efficacy in achieving modest weight loss, orlistat has been shown to improve glycaemic parameters in obese adults with type 2 diabetes mellitus as well as some features of the metabolic syndrome.

Triphenylphosphine oxide (TPPO) is a neurotoxic very stable polar compound present in waste organic solutions from the chemical and pharmaceutical industry. The acute toxicity of TPPO LC50=12.2µg/mL, LC90=29.5µg/mL is higher than triphenyltin acetate so that a correct management in the relationship with sustainable chemistry is strongly required. TPPO was identified as a selective and potent inhibitor of transient receptor potential melastatin-5 (TRPM5), but at the same moment, it had no effect (up to 100 μM) on the membrane potential responses of TRPA1, TRPV1, or TRPM4b.