Table 3.
Examples of frequently studied pharmaceutical compounds and their basic properties.
| Compound | CAS | Formula | Solubility | Solubility in water | pKa |
|---|---|---|---|---|---|
| Sulfathiazole | 72-14-0 | C9H9N3O2S2 | Slightly soluble in ethanol (0.5 mg/ml) | Insoluble (<1 mg/ml) | 7.2 |
| Sulfamethoxazole | 723-46-6 | C10H11N3O3S | Soluble in ethanol or acetone | Insoluble (0.1 mg/ml) | 5.60 |
| Sulfameter | 651-06-9 | C11H12N4O3S | Sparingly soluble in methanol | Insoluble (0.47 mg/ml) | 7.02 |
| Sulfapyridine | 144-83-2 | C11H13N3O2S | Slightly soluble in methanol | Insoluble (<1 mg/ml) | 8.48 |
| Sulfadimethoxine | 122-11-2 | C12H14N3O2S | Soluble in NH4OH (50 mg/ml) | Insoluble | 5.94 |
| Sulfamethazine | 57-68-1 | C12H14N4O2S | Soluble in dilute acid or base | Soluble (1.5 mg/ml) | 7.4/2.65 |
| Sulfadiazine | 68-35-9 | C10H10N4O2S | Soluble in dilute acid or base | Soluble (13 mg/100 ml) | 2.21 |
| Sulfamerazine | 127-79-7 | C11H12N4O2S | Slightly soluble in DMSO, methanol | Slightly soluble (0.2 mg/ml) | 2.29 |
| Sulfamonomethoxine | 1220-83-3 | C11H12N4O3S | Soluble in ethanol or methanol | Soluble (10 mg/ml) | 5.94 |
| Sulfachloropyridazine | 80-32-0 | C10H9N4CLO2S | Soluble in DMSO (56 mg/ml), in 0.5 M NaOH (50 mg/ml) | Insoluble | 6.10 |
| Sulfanilamide | 63-74-1 | C6H8N2O2S | Soluble in acetone | Soluble (7.5 mg/ml) | 10.6 |
| Norfloxacin | 70458-96-7 | C16H18FN3O3 | Soluble in dilute acid or base | Slightly soluble (0.28 mg/ml) | 6.34/8.75 |
| Ciprofloxacin | 85721-33-1 | C17H18FN3O3 | Insoluble in DMSO (<1 mg/ml) | Soluble (30 mg/ml) | 6.43/8.68 |
| Enrofloxacin | 93106-60-6 | C19H22FN3O3 | Soluble in dilute acid or base; Very slightly soluble in DMSO (1 mg/ml) | Slightly soluble | 6.43 |
| Ofloxacin | 82419-36-1 | C18H20FN3O4 | Soluble in acetic acid, in 1 M NaOH (50 mg/ml) | Slightly soluble | 5.19 |
| Levofloxacin | 100986-85-4 | C18H20FN3O4 | Soluble in glacial acetic acid or dichloromethane | Slightly soluble | 5.19 |
| Nalidixic acid | 389-08-2 | C12H12N2O3 | Soluble in DMSO, in chloroform (20 mg/ml), in 0.5 M NaOH (50 mg/ml) | Insoluble (0.1 mg/ml) | 6.11 |
| Tetracycline | 60-54-8 | C22H24N2O8 | Soluble in ethanol (＞20 mg/ml) | Soluble (1.7 mg/ml) | 8.3/10.2 |
| Oxytetracycline | 79-57-2 | C22H24N2O9 | Soluble in alcohol or ether | Insoluble (0.2 mg/ml) | 3.27/7.32/9.11 |
| Chlortetracycline | 57-62-5 | C22H23ClN2O8 | Soluble in DMSO, ethanol, methanol | Slightly soluble (0.63 mg/ml) | 3.3 |
| Tylosin | 1401-69-0 | C46H77NO17 | Soluble in DMSO (25 mg/ml), in ethanol (30 mg/ml) | Soluble (50 mg/ml) | 7.73 |
| Erythromycin | 114-07-8 | C33H67NO13 | Soluble in ethanol | Soluble (2 mg/ml) | 8.8 |
| Clarithromycin | 81103-11-9 | C41H76N2O15 | Soluble in DMSO | Insoluble (0.1 mg/ml) | 8.99 |
| Amoxicillin | 26787-78-0 | C16H25N3O8S | / | Soluble (4 mg/ml) | 2.4 |
| Chloramphenicol | 56-75-7 | C11H12Cl2N2O5 | Soluble in alcohol (5–20 mg/ml) | Insoluble | 11.03 |
| Thiamphenicol | 15318-45-3 | C12H15Cl2NO5S | Soluble in DMSO (66 mg/ml), in ethanol (50 mg/ml) | Insoluble | 11.05 |
| Clindamycin | 18323-44-9 | C18H33ClN2O5 | Soluble in DMSO (≥15.3 mg/ml) | Slightly soluble （0.3 mg/ml） | 7.6 |
| Trimethoprim | 738-70-5 | C14H18N4O3 | Soluble in DMSO (40 mg/ml) | Insoluble (<1 mg/ml) | 6.6 |
| Monensin | 17090-79-8 | C36H62O11 | Soluble in organic solvent | Slightly soluble | 4.26 |
| Atenolol | 29122-68-7 | C14H22N2O3 | Soluble in DMSO (53 mg/ml), in ethanol (53 mg/ml) | Slightly soluble (0.3 mg/ml) | 9.6 |
| Metoprolol | 37350-58-6 | C15H25NO3 | soluble in methanol (>500 mg/ml) | Soluble (>1000 mg/ml) | / |
| Nalidixic acid | 389-08-2 | C12H12N2O3 | Soluble in chloroform (20 mg/ml) | Insoluble (0.1 mg/ml) | 6.11 |
| Carbamazepine | 298-46-4 | C15H12N2O | Soluble in DMSO (47 mg/ml), in ethanol (18 mg/ml) | Slightly soluble (<1 mg/ml) | 13.94 |
| Bisphenol A | 80-05-7 | C15H16O | Soluble in methanol, acetone | Insoluble | 10.29 |
| 17β-Estradiol | 50-28-2 | C18H24O2 | Soluble in acetone | Insoluble | 10.71 |
| azithromycin | 83905-01-5 | C38H72N2O12 | Soluble in anhydrous ethanol and in methylene chloride | Insoluble | 8.74 |
| Citalopram | 59729-33-8 | C20H21FN2O | Soluble in DMSO | Slightly soluble | 9.38 |
| Fexofenadine | 83799-24-0 | C32H39NO4 | Soluble in DMSO (12 mg/ml) | Insoluble | / |
| Irbesartan | 138402-11-6 | C25H28N6O | Soluble in DMSO (>25 mg/ml) | Insoluble | 4.16 |
Notes: Data from "Chemical Book" (https://www.chemicalbook.com/ProductIndex_EN.aspx; Solubility of <1 mg/ml refers to the product slightly soluble or insoluble.