EBRANTIL ® Capsules are a drug product of urapidil, an alpha-1 adrenergic receptor antagonist, in the form of enteric/sustained-release granule filled capsules. This product can be administered as a solution prepared by the simple suspension method (SSM) to patients with gastrostomy through tubes; however, there is no information on the elution behavior of the drug administered by SSM. In this study, one EBRANTIL ® Capsules 15 mg was put in 20 mL of purified water or Japanese Pharmacopoeia (JP) 1st fluid for the dissolution test (pH 1.2) of 55 and 37℃. The test container was left for 10 minutes, then the content was suspended. The dissolution test was carried out in JP 1st fluid. The elution of urapidil from EBRANTIL ® Capsules untreated by SSM was 30％ or less in 60 minutes. Ninety percent or greater of urapidil eluted in 30 minutes treated with water of 55℃. The elution rate of urapidil treated with water of 37℃ was relatively slower than that; however, 60％ or greater urapidil eluted in 60 minutes. The elution behavior of urapidil from the capsule treated with JP 1st fluid was almost the same as that of the untreated EBRANTIL ® Capsules. These data suggest that the granules in the capsules were slightly dissolved in JP 1st fluid, but they dissolved immediately in water of 55 and 37℃. In conclusion, EBRANTIL ® Capsules should not be administered by SSM to avoid lowering blood pressure when treating patients.

The simple suspension method (SSM) is a method of administering drugs via feeding or gastrostomy tubes to those who have difficulty swallowing. In the SSM, solid formulations (eg, tablets, capsules) are immersed in hot (55℃) water. This promotes the disintegration and dissolution of the drugs and changes their solubility. However, pharmaceutical companies have not issued test results on the solubility and dissolution behaviors of suspended drugs prepared according to the SSM. For this study, we chose 10 drugs, 8 listed and 2 not listed in the Japanese Orange Book, to compare the dissolution behaviors of each drug, treated vs untreated with the SSM. Dissolution was classified into three patterns: rapid (gliclazide and famotidine), moderate (propranolol, pindolol, metoprolol), and slow (furosemide, ibuprofen, glimepiride). The initial dissolution rates of the moderate-dissolution drugs increased markedly by employing the SSM. In this study, hydroxyzine capsules and phenytoin tablets, neither of which is listed in the Japanese Orange Book, were compared with different dosage/administration forms of those drugs listed in the book (ie hydroxyzine tablets and phenytoinphenobarbital combination tablets).