Aminophylline

The candidate drugs used were as follows: serotonin (Sigma-Aldrich), 5-hydroxy -L-tryptophan (Sigma-Aldrich), tryptophan (Sigma-Aldrich), melatonin (Sigma-Aldrich), cisapride (Sigma-Aldrich), citalopram (Sigma-Aldrich), escitalopram (Sigma-Aldrich), fluoxetine (Sigma-Aldrich), fluvoxamine (Selleckchem), paroxetine (Sigma-Aldrich), sertraline (Sigma-Aldrich), clomipramine (Sigma-Aldrich), imipramine (Sigma-Aldrich), amitriptyline (Sigma-Aldrich), moclobemide (Sigma-Aldrich), pirlindole (Santa Cruz Biotechnology), toloxatone (Sigma-Aldrich) and aminophylline (Sigma-Aldrich) (Table 1). Each candidate compound was dissolved in 0.1% DMSO and tested at the initial doses of 16.5 μM, 33 μM, and 66 μM, which were then expanded upon based on efficacy and toxicity to doses ranging from 4.12 μM–132 μM. Doses that elicited greater than 50% mortality were considered toxic and each dose was tested a minimum of three times and up to 16 times.

In this work, two APIs were tested. Pure theophylline and aminophylline were purchased from Sigma-Aldrich company. Pure APIs were used as standards to obtain thermograms. The analysis was comprised of commercial pharmaceutical preparations containing theophylline and aminophylline. In the study, Euphyllin^® long 200 mg, and 300 mg (zr pharma&GmbH company, Wien, Austria), Theospirex^® retard 150mg, and 300 mg (BIOFARM company, Poznan, Poland), aminophylline 100 mg and 200 mg (advacare pharma, Cheyenne, WY, USA) were used. Additionally, the work also uses microcrystalline cellulose and lactose monohydrate as excipients. Samples of excipients were purchased from Sigma-Aldrich company.

Sodium chloride (NaCl), potassium chloride (KCl), magnesium sulfate (MgSO₄), potassium phosphate (KH₂PO₄), calcium chloride (CaCl₂), glucose, sodium bicarbonate (NaHCO₃), monobasic sodium phosphate (NaH₂PO₄) and dibasic sodium phosphate NaH₂PO₄ were obtained from Êxodo Científica (Sumaré, São Paulo, Brazil). Carbamylcholine hydrochloride (CCh), aluminum hydroxide [Al(OH)₃], ovalbumin (OVA) (grade II and V), nifedipine, aminophylline and dibasic sodium phosphate (Na₂HPO₄) were obtained from Sigma-Aldrich (São Paulo, São Paulo, Brazil). Arachidonic acid (AA) and isoprenaline were purchased from Cayman Chemical (Ann Arbor, Michigan, USA). Dexamethasone disodium phosphate injection was purchased from Aché Laboratórios Farmacêuticos (Guarulhos, São Paulo, Brazil).
Absolute alcohol was purchased from Neon (Suzano, São Paulo, Brazil), and xylol and paraffin were purchased from Dinâmica Química Contemporânea LTDA (Indaiatuba, São Paulo, Brazil). Formaldehyde, hematoxylin, eosin and Masson's trichrome were obtained from different brands.

Glucose (C₆H₁₂O₆), monobasic potassium phosphate (KH₂PO₄), hydrochloric acid (HCl), and magnesium sulfate heptahydrate (MgSO₄.7H₂O) were obtained from Nuclear (Brazil). Sodium chloride (NaCl) was purchased from Dinâmica (Brazil). Potassium chloride (KCl), calcium chloride dihydrate (CaCl₂.2H₂O), and sodium bicarbonate (NaHCO3) were acquired from Vetec (Brazil) and acetylcholine chloride (ACh) from Merck (Brazil). Phenylephrine (PHE) was obtained from Pfizer (United States) and aminophylline and indomethacin from Sigma Aldrich (Brazil). Ethylenediaminetetraacetic acid (EDTA) (1:250) was purchased from BioTécnica-Advanced Biotechnology (Brazil) and carbogen mixture (95% O₂ and 5% CO₂) from White Martins (Brazil). The weighing of the substances was done with a GEHAKA analytical balance model AG 200 (Brazil).