Formulation of cassia didymobotrya leaf laxative tablets
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Date
2016Author
Sinidu, Mekonnen W
Type
ThesisLanguage
enMetadata
Show full item recordAbstract
Cassia didymobotrya belongs to the genus Cassia and family Fabaceae. C. didymobotrya is a
shaggy shrub and found in Eastern and Central Africa. Different parts of the plant are used in
various countries, namely Kenya, Ethiopia, Rwanda, Tanzania, Angola, Mozambique, Sudan and
Uganda for treating variety of disease conditions. The leaves are traditionally mainly used as
laxatives.
The leaves of C. didymobotrya contain chrysophanol, physcion, aloe-emodin, fallacinol, rhein,
parietinic acid, torosachrysone, sennoside B, C and D, flavonoids, α-amyrin, β-amyrin,
arachidonic acid, chrysophanic acid, catechinic tannins, kaempferol, lauric acid, myristic acid,
myristoleic acid, oleic acid, palmitic acid, rhein, glycoside, β-sitosterol stearic acid5, 1,4-
anthroquinone chrysophanic acid, daucosterol, physcion, knipholone and several anthroquinine
derivatives.
The aim of this work was to formulate and evaluate tablets from the leaf extracts of C.
didymobotrya to serve as an alternative laxative tablet.
In this study 80% ethanolic extracts of the dried leaves of C. didymobotrya were prepared
following appropriate cold maceration method. The extract was tested for presence of
hydroxyanthracene glycosides by carrying out Bontrager’s test which gave a positive result.
Total content of hydroxyanthracene glycosides in the dry leaves as well as in the leaf dry extracts
was determined using UV-visible spectrophotometric method as stated in BP 2016, which was
calculated as sennoside B. The total hydroxyanthracene glycosides percentage content was
detected to be 1.077%w/w and 3.6%w/w in the dry leaf powder and leaf extract respectively.
The dried extract of C. didymobotrya was observed to be very hygroscopic and it tends to
become sticky and liquefied. Thus handling of the extract even at normal room temperature and
relative humidity was challenging. To address this problem the C. didymobotrya leaf dry extract
was premixed with colloidal silicon dioxide. The tablet formulation was then carried out by wet
granulation using various excipients (lactose, microcrystalline cellulose, sodium starch glycolate,
sodium lauryl sulfate, colloidal silicon dioxide, talc and magnesium stearate) with different
functions. Two different formulation studies were done by varying the order of addition of the
disintegrant sodium starch glycolate. In formulation I, equivalent amount of the disintegrant was added both intra-granularly and extra-granularly, while in the case of formulation II, the
disintegrant was added only extra-granularly.
Prior to compression, the prepared granules of both batches were assessed for bulk and tap
density, Hausner’s ratio, compressibility and angle of repose according to official methods. Then
the compressed tablets were assessed for appearance, hardness, friability, thickness, uniformity
of weight, disintegration and content assay. Formulation I was found to have an average
disintegration time of 17.75 minutes and formulation II had an average disintegration time of
23.33 minutes. The assay for the percentage content of hydroxyanthracene glycosides, stated as
sennoside B was determined using UV-vis spectrophotometer (Shimadzu-1800, Japan) and it
was found to be 94.44% for formulation I and 91.78% for formulation II. The value obtained for
percentage content was found to lie within the acceptance range; reference was made to the value
stated for Senna tablets since the method for assay of Senna tablets in BP was used. In addition,
the tablets obtained from the two formulations also passed tests done for uniformity of weight,
hardness, and friability.
Publisher
University of Nairobi