Evaluation of Antibacterial activities and Formulation of Black Mahlab Seeds Aqueous Extract
Murtada Ahmed Oshi
Department of Pharmaceutical
Technology, Faculty of Pharmacy, Omdurman Islamic University, Omdurman, Sudan
ABSTRACT:
Black mahlab is
an annual herb with a rigid, brown seeds indigenous to Sudan. Its seeds are
widely used in Sudanese traditional medicine in the treatment of diarrhea and
other abdominal upsets. The objective of the present study is to verify this
claim in scientific manner. Therefore, the seeds were tested for in-vitro
antibacterial activity and then formulated into a tablet dosage form. The water
extract of the seeds was tested against common diarrheal- causing
bacteria. Assays were performed using extract concentrations of 25, 50,
100 and 150mg/ml, and agar well diffusion method was utilized. In formulation
aspect two formulae were prepared formula-1and formula-2 by using maize starch
and polyvinyl pyrrolidine as binder respectively.
Starch paste as cost effective binder was evaluated for its binding properties
in comparison with polyvinyl pyrrolidine. The results
obtained from evaluation of granule properties and quality control tests of the
tablets for both formulae were pharmaceutically satisfactory (p ≤ 0.05).
According to pharmacopoeial specifications tablets of
formula-1 had less mechanical strength than those of formula-2, but rapidly
disintegrated and released the content more successfully than tablets of
formula-2. Therefore, tablets of formula-1 were subjected to further stability
studies and positive results were obtained. The findings of the work explored
tablets of formula-1 were cost- effective; with adequate strength to withstand
the shocks during storage, dispensing, and handling; and release its contents
for antibacterial activity successfully.
KEYWORDS: Bacteria, Black mahlab,
Tablets, Phytochemical constituents
INTRODUCTION:
Plants
and plant products have been used extensively throughout history to treat
medical problems. A number of traditional herbal medical practices have been
adopted for the diagnosis, prevention and treatment of various diseases. Many
such practices were experimentally proved depicting the scientific
insight behind their traditional uses. Low harm, high activity, patient
compliance are the reasons for choosing drug from herbal medicines.
Infections are one of the
main causes
of death
in under- developed countries
where it is associated with poverty and malnutrition. A huge number of herbal medicines
are used as antimicrobial remedies for many infectious diseases. Numerous
studies have been carried out to extract various natural products for screening
antimicrobial activity. [1]
Black mahlab
scientifically named Monechma ciliatum Jacq
belongs to Acanthaceae family is an effective antimicrobial
herb.
Its seeds (Figure 1) are used widely in
Sudanese folksy medicine by traditional healers for gastrointestinal tract
upsets e.g. diarrhea. So it was very interesting to select this plant
which can help in the treatment of infections.
Figure
1: Black Mahlab Seeds
The main objectives of the present study
were evaluation of in-vitro antibacterial activity of the dry- aqueous
extract (DAE) of seeds of Monechma ciliatum and formulation of the extract to tablet
dosage form. Beside, other general objectives were: 1) to entice the
pharmacists in particular and other healthcare professionals in general to be
active in researching about herbal medicine realm, 2) to fill the fictional
gaps between the herbal and synthetic medicines in fields of efficacy and safety,
and 3) to establish and implement the most updated scientific knowledge and
manufacturing technologies in herbal medicines formulation and
manufacturing.
In this study I selected the DAE of seeds
of Monechma ciliatum
based on a combination of ethnopharmacology and daily
healer’s practices. 2g of the seeds powder is usually soaked
in 500ml of distilled water overnight and drunk for diarrhea. Although, the
seeds were effective but it lacks of standardization and poor-quality
presentation. However, to improve its efficacy and patient acceptance, there is
need to formulate the seeds into tablet dosage form. The extract used in this research is closely resembled to traditional
preparations used by natives in Nubia Mountains
regions of Sudan to treat diarrhoea.
MATERIALS AND METHODS:
The seeds:
The seeds were purchased from
(Omdurman Market for Herbal Products, Omdurman, Sudan) on august, 2012 and
identified at Department of Pharmacognosy, Omdurman Islamic University (voucher
number 31). The seeds were separated, dried under shedding and stored in a
covered bottle at room temperature until required for use.
Chemicals:
Ampicillin (Bristol–Mayers Squibb, USA); Crosscarmellose cellulose (A Johnson Matthey, UK); Gentamicin (Roussel, UK); Lactose
(Breckland Scientific Supplier, UK); Magnesium stearate (Breckland Scientific
Supplier, UK); Maize starch (A Johnson Matthey, UK); Microcrystalline cellulose (A Johnson
Matthey, UK); Mueller-Hinton agar and Mueller-Hinton broth (HiMedia
Laboratories Pvt. Ltd, India); Polyvinyl pyrrolidine
(Acros Oragnics, Belgium);
Talc (A Johnson Matthey, UK).
Bacteria strains used:
In this study, the Standard
bacteria Staphylococcus aureus (ATCC
25923), Bacillus subtilis (ATCC 6633), Klebsiella pneumoniae
(ATCC 53657), Escherichia coli (ATCC 25922) obtained from Department
of Pharmaceutical Microbiology, Omdurman Islamic University, Sudan.
Methods:
Extraction procedure:
100g of the coarse seed powder was
transferred to a flask containing 2000ml of distilled water. The flask was allowed
for 24h at room temperature, the content passed through a cotton wool and the
solid residue pressed (screw press). The strained and expressed liquid obtained
were mixed, put for 12h for clarification and filtrated by Whatman filter paper
No 42 (125 mm). Finally, the filtrate
was evaporated using rotary evaporator (Stuart Ltd, Germany) under reduced
pressure at 40şC, placed in a Petri dish, and left to dry to constant weight.
Preliminary phytochemical
analysis:
Qualitative screening of the seeds of Monechma ciliatum
was performed for the identification of active phytochemical
constituents using standard procedures described by Tiwari
et al. [2]
Preparation of tested bacteria:
An overnight culture of tested bacteria
were prepared in Mueller Hinton Broth and later adjusted to 0.5 Mc Farland (optical density, OD 0.5) according to method
described by Lopez et al. [3]
Preparation of the extracts for
antibacterial testing:
The sterile DAE was redissolved
in sterile distilled water and serial dilutions of the extract were
prepared (25, 50, 100, 150mg/ml).
Preparation of standard drug:
Gentamicin and ampicillin were used as standard drugs.
Serial dilutions of both were prepared (0.005, 0.01, 0.02 and 0.04 mg/ml) by
using sterile distilled water as solvent.
Evaluation of in-vitro
antibacterial activity of the extracts:
The antibacterial testing of the DAEs was
carried out using the agar diffusion method as described by Lino and Deogracious. [4]
Minimum inhibitory concentration
determination:
The Minimum inhibitory concentration of
the DAEs was determined by using the method described by Fabry
et al. [5]
Preformulation studies:
1. pH
measurement :
The pH of the aqueous solution of
DAE was measured by using pH- meter (Wagtech
International, UK).
2. Loss
on dry:
The moisture content was measured
at different points during tablets manufacturing steps by loss on dry (LOD)
method. Approximately 5g of sample was uniformly placed onto the sample pan of
moisture instrument (Kern Ltd, Germany), and the heated. The percentage of
moisture was calculated from the weight loss of the sample by heating. The
instrument was allowed to cool between tests.
3. Powder
flow estimation:
According to USP, [6] the
flow were measured at different points within the manufacturing process by
using angle of repose method. 30g of tested material was poured manually into
funnel hanged at 3cm height, and then the angle was measured.
4. Powder
Density:
According to USP, [6] the
bulk density, tapped density and Carr's index of final- blended granules were
measured. The bulk and tapped densities of final- blended granule were
determined according to the following method: a 50ml glass cylinder was weighed
and filled with 30g of powder and reweighed. The opening of the cylinder was
secured and gently reversed once, and the powder carefully levelled without
compacting. Bulk volume was determined
after one mechanical tap. Tapped volume was measured after 500taps.
Formulation of the tablets:
Technique of tablets preparation
Two formulae were prepared by using wet
granulation tabletting technique. Formula- 1 by using
starch as binder and formula- 2 by using polyvinyl pyrrolidine
as binder.
Calculation of the extract dose
per tablet:
150mg of the extract was incorporated into
the tablet, depending on the traditional use of the seeds for diarrheal and
abdominal upsets.
·
100g of the seed powder give 9.5g
of the extract (Table 2)
·
2g (the weight of seed powder used
in traditional preparations) gives 150mg of the extract.
Procedure of tablets preparation:
For tablets of formula-1:
According to formula in table 1, DAE was
weighed precisely, transferred to a beaker and labelled (A). A specified amount
of mixture of lactose, MCC and half amount of maize starch was transferred to
another beaker and labelled (B). Both (A) and (B) were mixed together
adequately by mortar and kneaded to a wet mass by using starch paste 10% (w/v).
The wet mass was forced manually through a No. 10 mesh screen to form granules,
which were placed in a hot air oven at 40şC for 12h. The dried granules were
resized using No. 32 mesh screen to get uniform- sized granules. The dried
granules were remixed with reminder of maize starch, magnesium stearate and talc for 5min. The final lubricated- granule
was transferred to a hopper of a single- punch tabletting
machine (Erweka, Germany) and tabletted
using die No. 10. The weight and the pressure of the machine were adjusted to
obtain a tablet of 500 mg.
For tablets of formula-2:
For tablets of formula-2, polyvinyl
pyrrolidine solution 1% (w/v) was used instead of
starch paste 10% (w/v) and the same procedure steps were carried out.
Table
1:
Constituent of tablet formula
Composition |
Formula-1 |
Formula-2 |
||
Weight in tablet (g) |
Conc. in tablet (Wt %) |
Weight in tablet (g) |
Conc. in tablet (Wt %) |
|
DAE (active ingredient) |
150 |
30 |
150 |
30 |
Lactose (filler) |
142 |
28.4 |
125 |
25 |
MMC (filler) |
125 |
25 |
142 |
28.4 |
Starch paste 10% w\v (adhesive) |
q.s. |
- |
- |
- |
PVP 2% w\v (adhesive) |
- |
- |
- |
q.s. |
Maize starch (disintegrant) |
50 |
10 |
50 |
10 |
Mg stearate (lubricant) |
5 |
1 |
5 |
1 |
Talc (glidants) |
25 |
5 |
25 |
5 |
Total weight |
500 |
100 |
500 |
100 |
Evaluation of prepared tablets:
1. Weight
variation test
According to USP, [6] 20
tablets were selected randomly from each batch and weighed individually. The
average weight and deviation of each tablet from the mean were calculated. The
standard deviation and percentage deviation were calculated and compared with
standard.
2. Hardness
test
The test was done according to
method described by Kiran et al., [7] 10 tablets were placed between jaws
of hardness test apparatus (Erweka, Germany) and the
force required breaking the tablet was noted.
3. Friability
The friability test was carried
out according method described in USP. [6] 20 tablets were weighed, placed in
friability tester (Erweka, Germany) and rotated up to
100 revolutions. The tablets were reweighed after removal of fines and the
percentage of weight loss was calculated.
4. Disintegration
test
The disintegration test was
carried out according method described in USP, [6] under
botanical dosage forms. Six tablets were placed individually in each tube of
disintegration test apparatus (G.B. Caleva, England).
The water was maintained at a temperature of 37°±2°C and time taken for the
entire tablet to disintegrate completely was noted.
5. Dissolution
test
5.1. Screening of the extract
The whole extract was selected as a marker. 0.2g of the
extract was placed in two a 100ml flasks and 100ml of 0.1M HCl
and distilled water was added separately. The flasks were shaken, and then
filtered through a Whatman filter paper. The absorption spectrum of the both
solutions of the extract was recorded using a UV spectrophotometer (Jenway Ltd, UK) and the wavelength for maximum absorption was determined.
5.2. Drawing of the calibration curve of the extract
Different concentrations of the extract were
prepared to contain between 0.01 to 0.2mg/ml of extract in 0.1M HCl and distilled water separately. The absorbance of each
concentration in each case was taken at wavelength 275nm (maximum absorption
wavelength) and plotted against the various concentrations to obtain the
calibration curve for the extract for both solvents.
5.3. Dissolution test procedure
The dissolution test was carried out
according method described in USP, [6] under botanical dosage
forms. The dissolution tester (G.B. Caleva, England)
was filled with 900ml of 0.1M HCl and water
separately as medium, and allowed to warm up to 37±0.5şC. 6 tablets were
selected randomly and individually introduced into dissolution tester
(apparatus 2, 75rpm). Then the machine was operated for 60min. 10ml of sample
was withdrawn in different time intervals (10, 20, 30, 40, 60 min), filtered
and assayed using UV method with reference to the standard.
Stability study of tablets of formula-1
Both disintegration and dissolution tests
were done after 3, 6, 9 and 12 months of storage of the tablets in glass bottle
at room temperature 30± 2°C and relative humidity 60 ± 5.
Statistical Evaluation
The data were statically analyzed by
Students t-test and values were considered significant. And value were
expressed as p<0.05.
RESULTS
The results of antibacterial activity of
the extract were summarized in table 2.
The minimum inhibitory concentrations of
the extract were 12.5mg/ml for Bacillus subtilis
and 25mg/ml for Staphylococcus aureus, Klebsiella pneumoniae and Escherichia
coli. The results were detailed in table 3.
Table 2: Bioactivity of DAE and standard
antibiotics against standard bacteria
Extract |
Yield (±0.5) |
Conc. (mg/ml)
|
Mean diameter of growth inhibition zone (MDIZ) |
||||
S. aureus |
B. subtilis |
K. pneumoniae |
E. coli |
P. aeruginosa |
|||
Water |
9.50 |
25 |
- |
16 |
12 |
- |
– |
|
|
50 |
13 |
16 |
15 |
15 |
– |
|
|
100 |
18 |
25 |
18 |
17 |
– |
|
|
150 |
20 |
33 |
21 |
18 |
– |
Gentamicin |
|
0.005 |
12 |
16 |
12 |
11 |
– |
|
|
0.01 |
14 |
16 |
15 |
15 |
– |
|
|
0.02 |
16 |
22 |
19 |
18 |
– |
|
|
0.04 |
20 |
30 |
33 |
22 |
– |
Ampicillin |
|
0.005 |
– |
12 |
– |
– |
– |
|
|
0.01 |
– |
13 |
– |
– |
– |
|
|
0.02 |
– |
14 |
– |
– |
– |
|
|
0.04 |
– |
16 |
– |
– |
– |
D. Water |
|
– |
– |
– |
– |
– |
– |
Data are presented as mean MDIZ (mm) of
three replicates; Inhibition zone 15mm: sensitive; 14-15mm: intermediate;
<15mm: resistant; - : no inhibition zone
Table 3: Minimum inhibitory concentration of the DAE
Conc. mg/ml |
Medium (ml) |
Inoculum (ml) |
Water extract |
|||
Sa
Bs Kp Ec
|
||||||
3.125 |
20 |
0.01 |
+ |
+ |
+ |
+ |
6.25 |
20 |
0.01 |
+ |
+ |
+ |
+ |
12.5 |
20 |
0.01 |
+ |
* |
+ |
+ |
25 |
20 |
0.01 |
* |
- |
* |
* |
50 |
20 |
0.01 |
- |
- |
- |
- |
(+): Growth; (-): No growth; (*): MIC; All determinations
were done in triplicates. Sa: Staphylococcus
aureusBs: Bacillus
subtilis;
Kp: Klebsiella pneumoniae;
Ec: Escherichia coli
Phytochemical analysis of the Monechma ciliatum seeds
showed the presence of flavonoids, tannins, anthraquinones, unsaturated sterols and triterpens
(Table 1). These phytochemical compounds
have been reported in other studies to elicit antimicrobial and
astringent effects.
Table 4: Phytochemical test results of seeds of Monechma
Ciliatum
Test Name |
Observation |
Result |
Test for alkaloids |
No color change |
- |
Test for anthraquinones |
Pink precipitate |
++ |
Test for coumarins |
No color change |
- |
Test for cyanogenic
glycosides |
No color change |
- |
Test for flavonoids |
Red colouration |
++ |
Test for saponins |
No color change |
- |
Test for tannins |
Green precipitate |
+ |
Test for triterpens |
Pink to purple precipitate |
+++ |
Test for unsaturated sterols |
Green to purple precipitate |
+++ |
(+ + +): appreciable amount; (+ +): moderate amount; (+): minute amounts; (-):
not detected
The granules obtained for the both
formulae were satisfactory. No rat holing was observed during the flow of
granules from the hopper and no capping and sticking was not observed. The
results were provided in table 5.
Table 5: Precompression (Preformulation) study results
Measured properties |
Formula-1 |
Formula-2 |
pH of the DAE |
7.5 |
7.5 |
Moisture content (%) of wet- mass |
18.8 |
13.7 |
Moisture content (%) of dry-
granule |
1.2 |
1.4 |
Moisture content (%) of final-
granule |
1.5 |
1.6 |
Angle of repose (°) of dry-granule |
20.47 |
16.38 |
Angle of repose (°) of final-
granule |
19.62 |
16.64 |
Bulk density (g/ml)
|
0.52 |
0.53 |
Tapped density (g/ml) |
0.61 |
0.62 |
The tablet post- compression parameters
(weight variation, friability, hardness and disintegration tests) were measured
and the results were given in table 6 and figures 2 and 3.
Table 6:
Post- Compression study results
Test name |
Formula-1 |
Formula-2 |
% Weight Variation |
1.2 |
2.1 |
% Friability
|
0.1 |
0.4 |
Hardness (kg/cm2) |
6.5 |
8.4 |
Disintegration time
(min: sec) |
8.3 |
11.7 |
Figure 2:
Weight variation statistical analysis tablets of both formulae by SPSS-
computer- program
Figure 3:
Hardness statistical analysis for tablets of both formulae by SPSS- computer-
program
As a drug efficiency depend upon its
bioavailability, which is affected by dissolution of the formulated drug
tablet. [8] Formula-1 tablets were selected for further
dissolution and stability studies. As the formulated material was from natural
plant origin that needs unusual methods to assay as stated in USP, [6]
under the article of botanical origin require more vigorous procedure, marker
selection method was used for the dissolution test using the UV
spectrophotometer at wavelength 275nm for the calibration curve. The
absorbencies obtained from the tablets were referred to the curves (Table 7 and
Figure 4, 5 and 6), and the percent dissolved was calculated in different time
intervals (Table 8).
Table 7: The absorbance data by using HCl
and water as dissolution medium
No. |
Concentration
(mg/ml) |
Absorbance
in 0.1HCl |
Absorbance in
distilled water |
1 |
0.03 |
0.179 |
0.164 |
2 |
0.06 |
0.319 |
0.301 |
3 |
0.09 |
0.474 |
0.422 |
4 |
0.12 |
0.621 |
0.601 |
5 |
0.15 |
0.763 |
0.671 |
Figure 4:
Computerized calibration curve of the fresh extract using 0.1N HCl as medium
Figure 5:
Computerized calibration curve of the fresh extract using distilled water as
medium
Figure 6:
Drug dissolved with time for both HCl and water
Ongoing stability studies were carried out
for tablets of formula-1 up to nine months (0, 3, 6, 9 and 12 months); no
considerable changes in disintegration and dissolution of tested tablets were
detected (Tables 9 and 10).
Table 8: The mean absorbance of six
tablets in different time intervals by using 0.01N HCl
and distilled water as dissolution medium
Time of dis. test |
Hydrochloric acid |
Distilled water |
||||
Average absorbance
|
Extract amount |
Percent dissolved |
Average absorbance
|
Extract amount |
Percent dissolved |
|
After 10 min |
0.572 |
0.747 |
74.77 |
0.490 |
0.724 |
66.97 |
After 20 min |
0.580 |
0.758 |
78.86 |
0.518 |
0.737 |
71.41 |
After 30 min |
0.598 |
0.781 |
81.21 |
0.588 |
0.745 |
72.78 |
After 40 min |
0.601 |
0.792 |
82.87 |
0.590 |
0.764 |
84.57 |
After 60 min |
0.700 |
0.936 |
90.21 |
0.600 |
0.779 |
85.41 |
Table 9:
Ongoing study (disintegration test results)
Test no. |
Time of disintegration the
test
|
Time (min: sec) |
1 |
At zero time |
7.4 |
2
|
After three month |
10.41 |
3 |
After six month |
12.61 |
4 |
After nine month |
14.58 |
Table 10: Ongoing study (dissolution test
results)
No. |
Time of the test |
Absorbance
after 1h |
Amount of
the drug |
Percent dissolved |
1 |
At zero
time |
0.610 |
0.8357 |
83.57 |
2 |
After 3
months |
0.605 |
0.82885 |
82.85 |
3 |
After 6
months |
0.598 |
0.81926 |
81.92 |
4 |
After 9
months |
0.580 |
0.7946 |
79.46 |
5 |
After 12
months |
0.576 |
0.7679 |
77.57 |
DISCUSSION:
The bacteria selected in the study were
common diarrheal- causing pathogens. The extract inhibited Staphylococcus aureus, Bacillus subtilis,
Klebsiella pneumoniae
and Escherichia coli
with inhibition zone diameter 13 to 20, 16 to 33, 12 to 21 and 15 to 18mm
respectively. The antibacterial activity of the extract showed the highest
activity against Bacillus subtilis compared to
the other bacteria used. Collectively, the growth of all bacteria used was
inhibited effectively and to different extent by the extract at different
concentrations; and were comparable to that exhibited by reference antibacterial
drug (as positive control) and distilled water (as negative control).Wendakoon et al., [9] report the
greater the inhibition zone (measured in mm) indicates the higher antibacterial
effect. Pseudomonas aeruginosa neither was
sensitive to the extract nor to standard antibiotics used gentamicin
and ampicillin. Omolola,[10] state resistance of Pseudomonas aeruginosa to extracts may be due to its the
permeability barrier afforded by its outer membrane lippolysaccharide
and its tendency to colonize surfaces in the biofilm
form makes the cells impervious to therapeutic concentrations of antibiotics.
The relatively low MIC values against
tested bacteria means that the extract has the potential to treat any ailments
associated with these bacterial pathogens effectively and with high potency.
From the MIC results, it can be observed that Gram positive bacteria are more
susceptible than Gram negative bacteria to the extract. In Gram negative
bacteria, the outer phospholipidic membrane carrying
the structural lipopolysaccharide components makes
the cell wall impermeable to lipophilic solutes.
[11] Gram positive bacteria having only an outer peptidoglycan layer, thus is not an effective permeability
barrier. [12]
The antibacterial activity test results were coincided
with phytochemical screening results (Table 4) and
with the native people traditional practices that use primarily water as the
solvent for extraction of the plant seeds for diarrhea. This study found that
water provided more consistency in antibacterial activity. The antibacterial
activity of the extract was attributed to flavonoids
and tannins, that acted by different mechanisms comparable to the standard
antibiotics, and with large margin of safety. Doss et al.,[13]
report tannins have antibacterial activity against Staphylococcus aureus and Pseudomonas aeruginosa.
Rhama and Madhavan,
[14] report flavonoids
have antibacterial activity against Escherchia
coli, Klebsiella pneumoniae
and Pseudomonas aeruginosa.
The granules produced were of acceptable
quality. The goals of preformulation studies are to
choose the correct form of the drug substance, evaluate its physical and
chemical properties, and generate a thorough understanding of the material’s
stability under the conditions that will lead to the development of a practical
drug delivery system. [15]
In the process of formulation of an
effective tablet dosage form from the DAE, the wet granulation technique was
used. Wet granulation technique was used due to the extract high dose and poor
compatibility of its powder. These two factors are not favourable for
the manufacture of tablet by other techniques (direct and dry granulation). Majekodunm et al., [16] report
in preparation of tablet from natural products wet granulation appears to
produce tablets of acceptable mechanical and drug release properties than those
prepared by direct compression. The whole
plant extract was chosen for the formulation due to the probability of
synergistic action. Plant metabolites are present in complex mixtures, each
containing various functional groups; a phytochemical
matrix will exhibit multiple functionalities and bioactivities. [17]
Two formulae were designed, one containing
maize starch as a binder (formula- 1), and other containing PVP (formula-2).
Both formulae contain MCC/maize starch, magnesium stearate,
and talc as the disintegrant, lubricant, and glidant respectively at recommended levels. The batch size
was maintained at 250g for each trial. Each granulation batch used the same
quantity of water for granulation, theoretically, 16% or 40ml. The use of
colouring and flavouring agents were not needed as the extract was mutually
coloured and flavoured (brown colour with aromatic flavour), and the presence
of high content of lactose in the both formulae masked the bitter taste of
extract. The tablets were compressed at the specified weight (500mg).
The higher weight variation of the tablets
was 2% for tablets of formula-2 but still within the acceptable weight
variation range of ± 5%. Tablets of both formulae passed the weight variation
test with p<0.05 (Table 6 and Figure 2). The variation of the weight of
individual tablet is a valid indication of the corresponding variation in the
drug content. [18] Hardness
of tablets of both formulae was complied with the requirements stated in
official pharmacopeias with p<0.05 (Table 6 and
Figure 3). Hardness indicates the capability of a tablet to withstand
mechanical shocks during handling in manufacturing, packaging and shipping.
[19] The tablets of both formulae disintegrated before 20min. The
high hardness value and long disintegration time of formula-2 tablets was
attributed to polymer used. Hirasawa et al., [20]
conclude their research use of PVP as tablets binder increase the
hardness of tablets.
0.01M HCl was
better than distilled water as dissolution medium (Table 8 and Figure 6), this
may be attributed to the relatively weak alkalinity of the extract (pH 7.5).
Therefore, 0.01M HCl was proposed as dissolution
medium for further stability tests. Both disintegration and dissolution tests
were carried out after storage at room temperature, for three months, six
months, and nine months. Tablets of formula- 1 were stable for nine months as
shown in tables 9 and 10. The increasing of disintegration time (Table 9) and
decreasing of percent dissolved in dissolution test (Table 10) may be
attributed to the increase of hardness of tablets by loss of moisture via
evaporation.
Tablet of both formulae complied with the
standard requirements regarding their weight variation, friability, hardness,
disintegration, and dissolution. A cost effective formulation was adopted using
starch as binder. The dissolution test of tablets of formula-1 was carried out
to assay the amount of the dissolved ingredients, by measuring the amount of
the dissolved ingredients in different time intervals, which gave positive
scientific prediction about the pharmacokinetics and bioavailability. Tablets
of formula- 1 were stable for twelve months as shown in the ongoing stability
results.
ACKNOWLEDGEMENT:
I thankful to Omdurman Islamic University,
Department of Pharmaceutical Technology for providing the laboratory facilities
to perform the research work.
REFERENCES:
1.
Abu- Shanab
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Received on 26.03.2013
Modified on 20.04.2013
Accepted on 28.04.2013
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Research Journal of Pharmaceutical Dosage Forms and Technology. 5(3):
May- June, 2013, 131-138