Alternate Interpretation of the Role of Water in the Erythromycin Structure

Bauer, John F.; Quick, John; Oheim, Robert

doi:10.1002/jps.2600740823

Cited by 16 publications

(11 citation statements)

References 2 publications

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“…Structural rearrangement is not required for desolvation to occur, as is evident from the diffraction pattern, which is one explanation for the low activation energy for desolvation, as observed by Bauer, Quick, and Oheim. 3 The solid-state NMR spectrum of erythromycin A dihydrate, after drying over P 2 O 5 , was dramatically different from the fully hydrated sample. As shown in Figure 9, the solid-state NMR spectrum of the dehydrated-dihydrate has broadened resonances resulting from a distribution of chemical environments in the solid.…”

Section: Resultsmentioning

confidence: 98%

“…Hygroscopicity of Erythromycin A FormssThe existence of a true dihydrate form of erythromycin A has been questioned. 3 It has been observed that the water content of erythromycin A can be highly variable, while the crystalline lattice of the compound is retained. 3 Furthermore, it has been proposed that the dihydrate is very hygroscopic in nature, 3 yet it is rather insoluble in water.…”

Section: Resultsmentioning

confidence: 99%

“…3 It has been observed that the water content of erythromycin A can be highly variable, while the crystalline lattice of the compound is retained. 3 Furthermore, it has been proposed that the dihydrate is very hygroscopic in nature, 3 yet it is rather insoluble in water. Therefore, we examined the water uptake curves of the dihydrate, anhydrate, and the amorphous forms of erythromycin A (see Figure 7).…”

Section: Resultsmentioning

confidence: 99%

“…Furthermore, the activation energy for desolvation was shown to be very low. 3 We reinvestigated this phenomenon by storing erythromycin A dihydrate over P 2 O 5 for 3 days. A complete X-ray powder diffraction pattern of the material was acquired within 4 min, and the powder pattern resembled the crystalline dihydrate form.…”

Section: Resultsmentioning

confidence: 99%

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Solid-State Investigations of Erythromycin A Dihydrate: Structure, NMR Spectroscopy, and Hygroscopicity

StephensonX

Stowell

Toma

et al. 1997

Journal of Pharmaceutical Sciences

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The crystal structures of the commercially available form of erythromycin A dihydrate and clarithromycin anhydrate, in addition to the structure of erythromycin B dihydrate, are reported in this paper. In light of the crystallographic data, analysis of the structural information provides insight into the physical properties of these pharmaceuticals. The propensity of these pharmaceuticals to form solvated structures is discussed and the hygroscopicity of erythromycin A dihydrate is investigated. Solid-state 13C NMR was used to monitor changes that occur when the dihydrate form of erythromycin A is stored under conditions of low relative humidity. Although erythromycin A dihydrate retains its crystallographic order at low humidity, as indicated by its X-ray powder diffraction pattern, the local chemical environment is dramatically influenced by the loss of the water molecules and results in dramatic changes in its solid-state 13C NMR spectrum.

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Section: Resultsmentioning

confidence: 98%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

See 2 more Smart Citations

Solid-State Investigations of Erythromycin A Dihydrate: Structure, NMR Spectroscopy, and Hygroscopicity

StephensonX

Stowell

Toma

et al. 1997

Journal of Pharmaceutical Sciences

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“…A number of studies on these forms have been reported. [4][5][6][7][8][9][10][11] At the same time, a literature review showed that similar information on commercially marketed lots of Em raw material is often lacking, and significant variations in the physical properties of the bulk drug are encountered among material supplied by some manufacturers and among different lots supplied by the same manufacturer. 6 Additionally, the intricate molecular structure of Em (Figure 1) suggests the variety of possible supramolecular motifs in crystals, resulting in the formation of different polymorphic modifications.…”

Section: -3mentioning

confidence: 99%