Published:Journal of Chromatographic Science,
ISSN 0021-9665 Volume
45, Number 9, October 2007, pp. 623-628
Thermostability Testing and Degradation Profiles
of Doxycycline in Bulk, Tablets, and Capsules by HPLC
Rade Injac[1,2], Vukosava Djordjevic-Milic[2],
and Branislava Srdjenovic[2]
[1] Faculty of Pharmacy, Department of Pharmaceutical Biology,
University of Ljubljana, Askerceva 7, 1000 Ljubljana, Slovenia
and
[2] Medical Faculty, Department of Pharmacy, University of Novi
Sad, Hajduk Veljkova 3, 21000 Novi Sad, Serbia
A high-performance liquid chromatography (HPLC)
method for the quantitation of doxycycline in bulk, tablets,
and capsules after storage at –20, 5, 25, 40, 50, 60, and
70°C, has been developed and validated. The samples are eluted
from a μ-Bondapak C8 column (4.6 ×× 150-mm, i.d.,
5-μm particle size) at 27°C, with a mobile phase of acetonitrile–water–THF
(29.5:70:0.5, v/v/v), adjusted to pH 2.5 with 1.0M HCl. The flow
rate is 1.0 mL/min and detection by UV is at 350 nm. The stability
of doxycycline in bulk and in pharmaceuticals is checked over
90 days. Doxycycline shows thermo-degradation after exposure
to high temperature; tablets are more stable than capsules. The
shelf lives (t90%) are determined to be 1.00, 2.84, and 5.26
years in bulk, capsules, and tablets, respectively, at 25°C.
Metacycline and 6-epidoxycyline are identified as degradation
products at high temperatures. Amounts of doxycycline, metacycline,
and 6-epidoxycycline in all samples are determined by HPLC, and
the results compare with those from micellar electrokinetic capillary
chromatography. After 90 days, metacycline and 6-epidoxycyline
are almost equal in test samples from standard bulk form, tablets,
and capsules. It is 27.8 ± 0.3%, 13.7 ± 0.1%, and
18.8 ± 0.2%, respectively.
Reproduction
of editorial content of this journal is prohibited without publisher’s
permission.
This
article is available in its entirety by fax for $40.00.
Visa, MasterCard & Amex accepted.
To
order electronicallyclick here or call: 847-647-2900 ext. 1323 or fax request to: 847-647-1155.
