Abstract
Tobramycin I obtained from two different sources was subjected to powder X-ray diffractometry, thermal analyses, and Karl Fischer titrimetry. It was concluded to be tobramycin monohydrate (C18H37N5O9 · H2O). When heated in the differential scanning calorimeter (DSC), the dehydration of I resulted in the formation of metastable anhydrous tobramycin, which melted at 164°C. This was followed by the crystallization of the stable anhydrous tobramycin, which then melted at 217°C. The polymorphic transition was concluded to be monotropic and the calculated free energy difference between the metastable and the stable forms, at 25°C, was 348 cal · mol−1. Both the heating rate in the DSC and the sample size had a significant influence on the enthalpy values of most of the thermal events. These observations were attributed to the presence of trace amounts of moisture in the sample. No detectable decomposition of I occurred when it was heated up to 224°C.
| Original language | English |
|---|---|
| Pages (from-to) | 1159-1165 |
| Number of pages | 7 |
| Journal | Pharmaceutical Research |
| Volume | 8 |
| Issue number | 9 |
| DOIs | |
| State | Published - 1991 |
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All Science Journal Classification (ASJC) codes
- Biotechnology
- Molecular Medicine
- Organic Chemistry
- Pharmacology (medical)
- Pharmaceutical Science
- Pharmacology
- Chemistry(all)
Cite this
Solid-State Properties of Tobramycin. / Dash, Alekha K.; Suryanarayanan, Raj.
In: Pharmaceutical Research, Vol. 8, No. 9, 1991, p. 1159-1165.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Solid-State Properties of Tobramycin
AU - Dash, Alekha K.
AU - Suryanarayanan, Raj
PY - 1991
Y1 - 1991
N2 - Tobramycin I obtained from two different sources was subjected to powder X-ray diffractometry, thermal analyses, and Karl Fischer titrimetry. It was concluded to be tobramycin monohydrate (C18H37N5O9 · H2O). When heated in the differential scanning calorimeter (DSC), the dehydration of I resulted in the formation of metastable anhydrous tobramycin, which melted at 164°C. This was followed by the crystallization of the stable anhydrous tobramycin, which then melted at 217°C. The polymorphic transition was concluded to be monotropic and the calculated free energy difference between the metastable and the stable forms, at 25°C, was 348 cal · mol−1. Both the heating rate in the DSC and the sample size had a significant influence on the enthalpy values of most of the thermal events. These observations were attributed to the presence of trace amounts of moisture in the sample. No detectable decomposition of I occurred when it was heated up to 224°C.
AB - Tobramycin I obtained from two different sources was subjected to powder X-ray diffractometry, thermal analyses, and Karl Fischer titrimetry. It was concluded to be tobramycin monohydrate (C18H37N5O9 · H2O). When heated in the differential scanning calorimeter (DSC), the dehydration of I resulted in the formation of metastable anhydrous tobramycin, which melted at 164°C. This was followed by the crystallization of the stable anhydrous tobramycin, which then melted at 217°C. The polymorphic transition was concluded to be monotropic and the calculated free energy difference between the metastable and the stable forms, at 25°C, was 348 cal · mol−1. Both the heating rate in the DSC and the sample size had a significant influence on the enthalpy values of most of the thermal events. These observations were attributed to the presence of trace amounts of moisture in the sample. No detectable decomposition of I occurred when it was heated up to 224°C.
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UR - http://www.scopus.com/inward/citedby.url?scp=0025900603&partnerID=8YFLogxK
U2 - 10.1023/A:1015858503031
DO - 10.1023/A:1015858503031
M3 - Article
VL - 8
SP - 1159
EP - 1165
JO - Pharmaceutical Research
JF - Pharmaceutical Research
SN - 0724-8741
IS - 9
ER -