Amiloride Hydrochloride

Adduction of amiloride hydrochloride in urea through a modified technique for the dissolution enhancement

“…IR spectra of AH shows bands characteristic of AH, the important one being at 3250 and 3150 cm À1 assigned to N-H stretching, at 1680 due to C --O stretch and at 1240 cm À1 due to N-(C 6 H 6 ) stretch. 11 The IR spectra of AHIC crystals indicate out-of-phase vibrations at 3413 cm À1 and in-phase vibrations at 3226 cm À1 which are characteristic of hexagonal channel structure of urea 35,36 (the same vibrations reported at 3445 and 3347 cm À1 for tetragonal uncomplexed form of urea 37 ). Similar observations were made regarding occurrence of four bands between 1675 and 1590 cm À1 (due to CO stretching and NH 2 bending vibrations), slight increase of the skeletal out-of-phase bending frequency at 793 cm À1 and the symmetric C-N frequency increased from 1000 to 1013.82 cm À1 , which are characteristic of hexagonal channel structure of urea.…”

“…Pure AH exhibits a water loss endotherm with a peak temperature of 132.058C and melting endotherm at 293.58C. 11 AHIC thermogram shows that the urea crystals melt incongruently in two steps, a characteristic of hexagonal form of complexed urea. 29 The first step (116.598C) involves the collapse of the hexagonal form of urea inclusion compound to yield the guest moiety and tetragonal solid urea while the second step (134.188C) is attributed to melting of tetragonal urea.…”

“…Pure AH is crystalline as demonstrated by the sharp and intense diffraction peaks, the important ones at interplanar spacings at 3.18, 3.86, 3.40 and 2.57 Å , corresponding to polymorph A of AH. 11 The diffractogram of urea crystals also exhibits peaks corresponding to tetragonal form of urea, mainly characterized by the interplanar spacing at 4.04 Å . 39 In contrast, diffractogram of crystals of AHIC inclusion compounds show peaks at interplanar spacings at 4.21, 3.42, 3.61 and 7.28 Å , which are all characteristic of the hexagonal form of urea.…”

“…10 The solubility of AH in water is typical of an organic base with limited aqueous solubility, which increases with a decrease in pH. 11 It has been shown using radiolabeled AH that approximately 50% of an oral dose administered to man is absorbed from gastrointestinal tract. 12 The remainder of the dose unabsorbed and is found in the faeces.…”

Polímeros de Impressão Molecular Obtidos Através de Polimerização por Precipitação e sua Aplicação na Técnica de Extração em Fase Sólida

“…Não foram observadas bandas características de AMI (Figura 4), principalmente na região de 3250 e 3150 cm -1 correspondente ao estiramento de N-H [10] , confirmando a eficiência na lavagem de MIP pela extração no Soxhlet.…”