EFFECT OF ULTRA VIOLET RADIATION ON THE STABILITY OF PROGUANIL AND PYRIMETHAMINE
EFFECT OF ULTRA VIOLET RADIATION ON THE STABILITY OF PROGUANIL AND PYRIMETHAMINE
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Date
1985-09
Authors
UKO, NNENNA OYIDIA
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Abstract
The influence of UV radiation (366nm) on the
stability of proguanil hydrochloride and pyrimethamine
sulphate in tablet formulations and in phosphate
buffer solutions of different pH values has been
evaluated in the present study, UV spectroscopic
method for estimating drug content in the various
dosage forms was employed. The effect of pH on the
UV spectrum of the drugs was investigatedĀ» The
influence of reaction vessel and pH on the irradiated
phosphate buffer solutions was also studied,
In-vitro dissolution rate studies of the drugs
were carried out including those tablets that had
been subjected to UV irradiation.
The UV spectrum of proguanil hydrochloride was
found to be stable at pH values above 2.0 in phosphate
buffer solutions. Below pH 2,0 the spectral peak at
232nm disappeared while the peak at 253nm flattened
out giving a plateau.
Proguanil hydrochloride was found to enter into
photochemical reaction in phosphate buffer solution
when subjected to continuous UV irradiation at 366nm.
Evidence of photochemical reaction was shown by loss
of spectral peaks in phosphate buffer, appearance of
a precipitate, colour change of solution, spectral
shift and increase in absorbance of the irradiated
solution. The photochemical reaction was found to be
influenced by the pH of the solution and the type of glassware in which the reaction was performed.
Assay of irradiated proguanil hydrochloride tablets
indicated loss of drug content with time.
Dissolution rate studies of the irradiated tablets
showed decrease in dissolution rate: with time
The UV spectrum of pyrimethamine sulphate remained
stable at different Values. Pyrimethamine sulphate
appeared not to readily enter into photochemical
reaction. The formulations used showed signs of
degradation by colour change of tablets but there was
no loss of drug content on assay.
The dissolution rate of the irradiated pyrimethamine
tablets produced by Wellcome Nig. Ltd. increased with
time in phosphate buffer solution pH 4.5 while the
dissolution rate of irradiated pyrimethamine tablets
produced by Quality Control Unit A.B.U. Zaria decreased
with time in phosphate buffer solution pH 4.5. This
difference observed in the dissolution rates of the
formulations has been attributed to the influence of
the different excipients used by the different
manufacturers.
Description
A THESIS SUBMITTED TO THE POSTGRADUATE
SCHOOL, AHMADU BELLO UNIVERSITY, IN PARTIAL
FULFILMENT OF THE REQUIREMENTS FOR THE
AWARD OF THE DEGREE OF MASTER OF SCIENCE.
DEPARTMENT OF PHARMACEUTICAL CHEMISTRY
FACULTY OF PHARMACEUTICAL SCIENCES
AHMADU BELLO UNIVERSITY, ZARIA.
Keywords
ULTRA VIOLET RADIATION,, PROGUANIL,, PYRIMETHAMINE, STABILITY