chapter - 5 development and evaluation of alfuzosin...
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55
CHAPTER - 5
DEVELOPMENT AND EVALUATION OF ALFUZOSIN
ER TABLETS
5.1 MATERIALS AND EQUIPMENTS
Table 5.1: List of materials used in research work
Name of the Material Manufacturer
Alfuzosin Hydrochloride
Ph.Eur
Dr. Reddys laboratory, Hyderabad,
India.
Doxazosin Mesylate Ph.Eur Clearsynth labs ,India.
Microcrystalline Cellulose
( Avicel PH-101) USP/NF
FMC Bio Polymer, Ireland.
Ammonio Methacrylate
co-polymers (Eudragit RLPO)
USP/NF
Evonik industries, Germany.
Povidone(PVP K-30) USP/NF ISP Sales (UK) Limited.
Partially Pregelatinized Starch
(Starch 1500) USP/NF
Colorcon ,Goa
Hypromellose (Methocel
K100M) USP/NF
Dow chemical company, USA
Gaur Gum 8000 cps Lucid Colloids, Mumbai
Colloidal Silicon Dioxide
USP/NF
Evonik industries, Germany.
Magnesium Stearate USP/NF Ferro corporation, Cleveland.
Acetonitrile (AR Grade) Merck Specialties Pvt. Ltd, Mumbai.
Triethylamine (AR Grade) Merck Specialties Pvt. Ltd, Mumbai.
Potassium dihydrogen
Orthophosphate (ARGrade)
Merck Specialties Pvt. Ltd, Mumbai.
Hydrochloric acid (ARGrade) Merck Specialties Pvt. Ltd, Mumbai.
Orthophosphoric acid (AR
Grade)
Merck Specialties Pvt. Ltd, Mumbai.
56
Potassium coated EDTA
Tubes
Merck specialities Pvt.Ltd,
Rabbits weighing 2.8 – 3.2 Kg Saastra College of Pharmaceutical
Education and Research, Nellore
Table 5.2: List of equipments used in the research work
Equipment Name Manufactured By
Electronic Weighing Balance Mettler Toledo (AB104), Germany.
Rapid mixer granulator Diasona, Bombay.
Hot air oven Innovative instruments, Delhi.
Double cone blender Shakthi engnering, Ahemadabad
Sieves Jayant Scientific Ind., Bombay
Compression Machine (8 Station) Cadmach, Ahemadabad
Digital Vernier Calipers Mitutoyo (CD-8CSX), China.
Friability Apparatus Electrolab EF – 2W, Mumbai.
Hardness Tester Dr. Schleuniger (6D), Germany.
Dissolution Apparatus TDT-08L, Electrolab, Mumbai.
Sonicator Power sonic 505, India.
HPLC Waters, USA.
FT-IR Perkin Elmer,Japan.
Vortex Mixer Spinex, India.
Stability Chamber Mack, Mumbai.
DSC DSC21, Mettler Toledo, USA.
UV visible spectrophotometer Analytikjena Specord 210
Overhead 3-blade medium duty
stirrer Remi stirrer, Mumbai, India.
Cyclomixer Remi Instruments, Mumbai, India.
Multifuge Centrifuger Heraus, Germany.
57
5.2 ANALYTICAL METHODS
There are several reported methods for the estimation of
alfuzosin available in the literature, those are UV, Colorimetry, HPLC
&LC-MS methods.
In the present investigation we have develop a modified
Ultraviolet spectroscopic method for the estimation of alfuzosin
hydrochloride for dissolution samples*.HPLC method was developed
for estimation of drug content (Assay)*.The analytical methods (i.e
dissolution and assay) of alfuzosin hydrochloride extended release
tablets not published in official pharmacopeia.(i.e IP, BP&USP)
* The methods was developed on the basis of development and
validation of UV spectrophotometric method for estimation of alfuzosin
by Adsule Prajakta V et al.,40 for dissolution samples and New RP
HPLC method development and validation of assay for alfuzosin in
tablet dosage form by K.S.Bharathkumar et al.,44 for uniformity of
content and assay samples.
A new High performance liquid Chromatographic method was
developed and validated for the estimation of alfuzosin in rabbit
plasma.
5.2.1 Method development
The solubility of the Alfuzosin was tested in different dissolution
media like 0.01N HCl, pH 4.5 Acetate buffer, pH 6.8 phosphate
buffers, pH 10.0 phosphate buffer and Purified water. Based on the
solubility data dissolution media 0.01N HCl was selected as media
with 900mL of volume, maintained at 37 ± 0.5°C and USP Apparatus-
II (Paddle). Samples were collected at appropriate time intervals from
58
dissolution vessels and diluted the samples and measured the
absorbance at 245nm using UV-Visible spectrophotometer and
calculated using standard calibration curve.
5.2.1.1 Standard calibration curve of Alfuzosin
5.2.1.1.1 Preparation of 0.01N HCl
8.5mL of Hydrochloric Acid was diluted with water to 10 Litres.
5.2.1.1.2 Preparation of standard stock solution
25.0 mg of Alfuzosin HCl weighed in to 50ml volumetric flask
and made up the volume with 0.01N HCl. 2ml of this solution further
diluted to 100ml with 0.01N HCl.
5.2.1.1.3 Preparation of standard Calibration Curve
From the standard stock solution serial dilution were done to
obtain solutions ranging from 0.5µg/mL to 6.0µg/mL, i.e. from 10% to
120% with respect to sample concentration. The absorbance of above
solutions was measured at wavelength of 245nm using UV-Visible
spectrophotometer (Analytikjena Specord 210), against dissolution
media as blank.
The absorbance values of standard curve was represented in
Table 5.3 and a graph was plotted of concentration v/s absorbance
which was shown in Fig. 5.1
59
Table 5.3: Standard Calibration curve values of Alfuzosin
The linear equation was y = 0.1381 x - 0.0001
Where x is concentration and y is the peak absolute area.
The correlation coefficient was r = 1.000, indicating good linearity.
Figure:5.1 Standard Calibration curve of Alfuzosin
y = 0.1381x 0.0001 R² = 1.000
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
0 1 2 3 4 5 6 7
Ab
sorb
ance
Concentration (µg/mL)
Concentration in µg/mL Absorbance
0.5 0.0691
1.0 0.1354
2.0 0.2761
3.0 0.4201
5.0 0.6882
6.0 0.8281
Slope 0.1381
Intercept 0.0001
Correlation Coefficient 1.000
60
5.2.2 Assay by HPLC
5.2.2.1 Method development
Different columns, mobile phases, flow and column
temperatures were tested in the development of the analytical method.
C-8 and C-18 columns of the same length, different lengths and
diameters were also tested and pH of buffer variations from 3.0 to 6.5
were also tested by keeping all parameters and conditions were
constant (0.8 mL/min., injection volume of 20μL,temperature at
25°C). Then the mobile phases with different buffer concentrations
and organic content were also tested by keeping the all parameters
and conditions were constant. Finally we got the good
chromatographic peak with more than 5000 theoretical plates, tailing
factor of less than 2.0 and Relative standard deviation of less than
2.0% for six replicate standard injections.
61
5.2.2.1.1 Preparation of Dilute Orthophosphoric acid
9.3mL of 82%-Ortho phosphoric acid was diluted to 100mL with
water.
5.2.2.1.2 Preparation of Buffer
2.72g of Potassium dihydrogen phosphate weighed and
transferred into a beaker containing 1000mL of water. Sonicated to
dissolve and 2.0mL of Triethylamine was added and mixed well. pH of
the solution was adjusted to 3.0 ± 0.05 with diluted orthophosphoric
acid. Solution was filtered through 0.45μ membrane filter.
5.2.2.1.3 Preparation of mobile phase
Prepare and degassed the mixture of buffer and acetonitrile in the
ratio of 75:25%v/v.
Diluent: Mobile phase was used as diluent.
5.2.2.1.4 Chromatographic conditions
HPLC System : Waters Alliance 2695 with empower software
Column : C18, 150×4.6mm 5µ or equivalent
Flow rate : 0.8ml/min
Detection : 245nm
Injection volume : 20µL
Column temperature : 25°C
Run time : 10min
62
5.2.2.1.5 Standard preparation
50.0mg of Alfuzosin Hydrochloride standard weighed accurately
and transfer into a 200.0ml volumetric flask, dissolved and diluted
with diluent.5.0ml of this solution was transferred in to 100ml of
volumetric flask, dilute to volume with diluent and mixed well.
5.2.2.2 Method validation76
The system suitability linearity, accuracy and precision of the
method were validated.
The specificity of test method by HPLC demonstrated that the
excipients from tablets do not interfere with the analytic peak. The
linearity of the method was tested in the concentration range
1.26µg/mL to 15.08µg/mL (10.0% to 120.0%). For accuracy of the
method, standard drug was spiked from 70.0% to 130.0% and
recovery was found to be 99.2% to 100.9% and RSD 0.8%. The
precision of the method was checked were found to be relative
standard deviation 0.9%.
63
Table 5.4: Linearity
Figure 5.2: Alfuzosin assay Linearity graph
y = 331585.1 x 13706.8 R² = 0.999
0
200000
400000
600000
800000
1000000
1200000
1400000
1600000
1800000
0 10 20 30 40 50 60 70
Pe
ak a
rea
Concentration (µg/mL)
Concentration in % Concentration in
µg/ml
Peak Area
10 1.26 402135
20 2.51 839456
40 5.03 1690564
60 7.54 2584154
100 12.56 4125891
120 15.08 5023154
Slope 331585.1
Intercept 13706.8
Correlation Coefficient 0.999
64
Table 5.5: Accuracy/recovery
Table 5.6: Precision
S.No. % Assay
1 99.0
2 101.0
3 99.0
4 99.5
5 98.6
6 99.0
Avg 99.4
SD 0.86
% RSD 0.9
Figure 5.3: Alfuzosin Assay Standard
Level Actual weight added in mg
% in mg recovery
% recovery
70% 7.02 7.00 99.7
100% 10.04 9.96 99.2
130% 12.98 13.10 100.9
Mean 99.9
SD 0.8
RSD 0.8
65
5.3 PRE-FORMULATION
5.3.1 Solubility Analysis
The solubility of Alfuzosin Hydrochloride was determined in
different media as follows.
1. 0.01N HCl
2. pH 4.5 Acetate buffer
3. pH 6.8 phosphate buffer
4. pH 10.0 phosphate buffer
5. Purified Water
1.0 gm amount of the drug was weighed and transfer to 25 mL
volumetric flasks. To each of the volumetric flasks above mentioned
media were added and shaken well. The volume was made up to
volume with same media the samples were kept in constant water
bath shaker for 24 hours at temperature of 37 °C. After 24 hours the
samples were removed from bath, equilibrated for 1 hr. then the
samples were filtered through 0.45 μm filter. The dissolved drug was
measured using UV visible spectrophotometer at 245 nm after
suitable dilutions.
5.3.2 Compatibility Studies
5.3.2.1 Differential Scanning Calorimetry
Differential Scanning Calorimetry of active ingredient and
polymers were studied to investigate the compatibility of the both
materials when mixed together by observing any changes occur in
melting points of the drug. The test was performed at a rate of 5°C
66
min-1 from 25°C to 300°C temperature range under nitrogen flow of 25
ml min-1 using differential scanning calorimeter.
5.3.2.2 Fourier Transform Infra-Red (FT-IR) spectral analysis
Fourier–Transformed Infrared (FT–IR) spectrums of Alfuzosin
with HPMC K100M ,Guar gum 8000cP, Eudragit RLPO and Povidone
K-30 performed individually and in combinations at range of 400 to
4000 cm-1 and the resolution was 1 cm-1 using Fourier Transform
Infrared (FTIR) spectrophotometer, (Perkin Elmer, spectrum-100,
Japan )using the KBr disk method (2 mg sample in 200 mg KBr).
This spectral test was used to check the compatibility of
Alfuzosin Hydrochloride with the selected polymers. The spectrums
were shown in Fig. 5.15 to 5.31.
67
5.4 PREPARATION OF MATRIX TABLETS
5.4.1 Preparation of matrix tablets containing Alfuzosin
The wet granulation technique was chosen to prepare matrix
tablets. The compositions of the formulations were given in Table 5.7.
Matrix tablets were prepared using below technique.
Step1.Required quantity of Alfuzosin, retardant (HPMC K100 M or
Guar gum 8000 cps or Eudragit RLPO) and other excipients
(Microcrystalline Cellulose (AVCEL PH 101, Pregelatinized Starch and
Povidone) were weighed and sifted through 40# sieve.
Step 2. Step1 material was mixed in rapid mixing granulator (RMG)
for 15min and blend was granulated using purified water as the
granulating agent.
Step 3. The wet granules were sifted through 14 # sieve and dried in
hot air oven at inlet temperature of 60 ± 5°C till the moisture comes
below 3%w/w.
Step 4. The dried granules were sieved through 20 # sieve and
lubricated with Magnesium stearate and colloidal silicon dioxide
(previously shifted through # 40 mesh) for about 5 min in a double
cone blender.
Step 5. The lubricated granules were compressed into tablets using
8.8 mm round shaped with standard concave punches.(compression
machine 8 station ).
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Table5.7: Composition of matrix tablet containing Alfuzosin
Name of ingredient mg/tablet
ALF/01 ALF/02 ALF/03 ALF/04 ALF/05 ALF/06 ALF/07 ALF/08 ALF/09 ALF/10 ALF/11 ALF/12
Alfuzosin HCL 10.00 10.00 10.00 10.00 10.00 10.00 10.00 10.00 10.00 10.00 10.00 10.00
Microcrystalline Cellulose
Avicel PH 101 158.00 245.50 204.00 90.50 187.00 134.00 204.00 194.00 194.00 184.00 174.00 104.00
Eudragit RLPO 120.00 -- --- --- -- --- --- --- --- --- --- ---
Povidone K -30 9.00 --- --- --- -- --- --- --- --- --- --- ---
Starch 1500 --- --- --- 15.00 --- --- --- --- --- --- --- ---
Hydroxypropyl methyl
cellulose K100M --- --- -- --- 100.00 150.00 100.00 105.00 100.00 110.00 115.00 150.00
Guar gum 8000 cP --- 40.00 80.00 180.00 --- - 30.00 35.00 40.00 40.00 45.00 80.00
Purified Water QS QS QS QS QS QS QS QS QS QS QS QS
Collodial silicone dioxide --- 1.50 2.00 1.50 --- 2.00 2.00 2.00 2.00 2.00 2.00 2.00
Magnesium Stearate 3.00 3.00 4.00 3.00 3.00 4.00 4.00 4.00 4.00 4.00 4.00 4.00
Tablet Weight 300.00 300.00 300.00 300.00 300.00 300.00 350.00 350.00 350.00 350.00 350.00 350.00
69
5.5 EVALUATION OF TABLETS
5.5.1 Evaluation of physical parameters for granules
5.5.1.1 Flowability78,79
Flowablility of lubricated granule were tested by using Bulk
density, Tap density, Compressibility, Hausner’s ratio and Angle of
repose. Formulas are as below.
The bulk density of prepared granules were determined by
three-tap method. Weighed quantity (15gm of granules) was carefully
introduced in to a 100mL graduated cylinder. The cylinder was
dropped on to a hard wood surface 3 times from a height of 2.5cm at
an interval of 2sec. The bulk density was obtained by dividing weight
of the sample by volume of the sample.
The tap density is the ratio of weight of the dry its tapped
volume. The above weighed quantity of granules was placed on tapped
density tester (Electrolab Model:ETD-1020) and subjected to USP –
Type II method i.e, 250 drops per minute and drop height is 3 mm ±
10%. The volume of the powdered weight is measured after increment
of 250 drops until the difference of last two values mean is zero.
Bulk Density =
Tapped Density =
Compressibility Index (%) and Hausner’s Ratio Can calculated
by using the following formulas.
Compressibility Index (%) =
×100
Hausner’s Ratio =
70
Angle of repose
Take funnel stand with smooth base, keep the funnel and
adjust the funnel height such a way that the distance between the
powder pile and funnel should be approximately 2-4 cm. keep the
graph paper on base, hold the funnel orifice, pore the powder and
leave the orifice to fall down. Find the height (H) of the cone of powder
and circle of the powder carefully. Find out the angle of repose using
following equation:
Where, α is angle of the repose.
“H” is height of the powder cone
“R” is radius of the circle.
Table 5.8: Scale of flowability79
Flow Property Compressibility
Index
Hausner
Ratio
Angle of
Repose
Excellent ≤ 10 1.00-1.11 25-30
Good 11-15 1.12-1.18 31-35
Fair 16-20 1.19-1.25 36-40
Passable 21-25 1.26-1.34 41-45
Poor 26-31 1.35-1.45 46-55
Very poor 32-37 1.46-1.59 56-65
Very, Very poor >38 >1.60 >66
71
5.5.2 Evaluation of physical parameters for Tablets
5.5.2.1 Uniformity of Weight80
Ten tablets were selected randomly from each batch and
weighed individually and determine the average weight, then check for
weight variation. The average weight of tablet with % deviation as per
Indian pharmacopeia was represented in table
Table 5.9: Average weight of tablet with % deviation as per Indian
Pharmacopeia.
Average weight of Tablet % Deviation
80 mg or less 10
< 80 mg and < 250 mg 7.5
< 250 mg 5.0
5.5.2.2 Thickness
Thickness of the tablets was checked using digital vernier
calipers by placing the tablet in between the two jaws.
5.5.2.3 Hardness81
Hardness is main criteria for tablets and should have enough to
withstand mechanical stress like coating, packaging, shipment, and
handling by the consumer. The crushing strength test of tablet
diametrically was performed on 10 tablets from each formulation by
using Dr.Schleuniger, Hardness tester.
72
5.5.2.4 Friability82
The friability test is to evaluate the ability of the tablet to
withstand abrasion in coating, packaging, handling and shipping.
Friability of each formulation tested using 20 tablets was
determined using a Roche type friability tester.20 tablets were
weighed, transferred to friabilator and performed the test with 100
rotations at speed of 25 rpm. After completion of rotations tablets
were removed, dedusted and weighed. Friability of tablet should not
be more than 1.0 %. Friability percentage was calculated using the
following equation:
× 100
5.5.3 Drug content by HPLC
Accurately weighed 20 tablets and determined the average tablet
weight in mg. Tablets were crushed into fine powder. Weighed the
sample equivalent to 10.0mg of Alfuzosin and transferred it into
individual 200ml volumetric flask with the aid of 120ml diluent.
Solution was sonicated for 15min, dissolved and diluted to volume
with diluent. Portion of sample was centrifuged for about 15min prior
to dilution. 5.0ml of sample solution was transferred into individual
20.0ml volumetric flask, made up the volume with diluent and mix
well. Alfuzosin was estimated by HPLC using developed method
step:5.2.2.
73
5.5.4 Uniformity of drug content test77
Ten tablets were selected randomly, weigh the tablet
individually and place it into individual 200ml volumetric flask with
the aid of 120ml diluent. Solution was sonicated for 15min, dissolved
and diluted to volume with diluent. Portion of sample was centrifuged
for about 15min prior to dilution. 5.0ml of sample solution was
transferred into individual 20.0ml volumetric flask, made up the
volume with diluent and mix well and inject to the HPLC System as
followed as per assay method. (5.2.2)
5.5.5 In-vitro Dissolution Study: (By UV)
Dissolution Parameters
Medium : 0.01N HCl
Volume : 900mL
Apparatus : USP-II (Paddle)
Revolutions(RPM) : 100
Temperature : 37 ± 0.5° C
Time Points : 1,2,3,6,12 and 20 hours
Lambda √ : 245nm
5.5.5.1 Test Solution
All the bowls were filled with 900 mL of dissolution medium and
maintained at 37±0.5 °C. Dropped one tablet in to each dissolution
vessel and start the dissolution test. 10.0 ml of aliquot were
withdrawn at specific time intervals and same quantity of fresh
dissolution media was replaced. Aliquots were filtered through 0.45 μ
(Millipore) nylon membrane filter.5ml of this solution was diluted to
74
10ml with dissolution medium .Samples were estimated by developed
method step: 5.2.1.
5.5.6 Effect of Hardness on dissolution
To study the effect of hardness on the tablet formulation, we
have compressed the formulation (B.No: ALF/10) at different hardness
levels i.e low hardness (8.1 to 9.3kp), optimum hardness (10.7 to 12.2
kp), high hardness (14.4 to 15.7 kp). The dissolution studies were
performed arrive the effect of the hardness on the drug release.
All the samples were analysing for in-vitro drug release by using same
mentioned method (5.2.1).
For comparison, marketed samples also analysed by using same
method (5.2.1)
5.5.7 Statistical approach to difference and similar factor83
The model independent method is most suitable for dissolution
profile comparison when 3 to 4 or more dissolution time points are
available.
Statistical models such as Difference factor (f1) and similar
factor (f2) both were constructed for optimized batch and marketed
product dissolution profile by using following equations. Difference
factor measures the % difference between 2 curves at each time point
and the relative error between the two curves, similarity factor is a
measurement of % dissolution similarity between the two curves.
Difference Factor f1={[∑t=1n (Rt-Tt)]/[ ∑t=1
n Rt]} x 100
Similar Factor f2=50xlog{[1+(1/n)∑t=1n (Rt-Tt)2]-0.5 x 100
75
Where,
n is number of time points.
R(t) is the mean % drug dissolved of Marketed product at time t.
T(t) is the mean % drug dissolved of test product.
f1 value should be close to 0 (0 to 15) to prove the both the
formulations are not different.
f2value should be between 50 to 100 to prove the both the
formulations are similar.
5.5.8 Kinetic modeling system for In-vitro release84
5.5.8.1 Zero Order
Drug dissolution from dosage forms that do not disaggregate
and release the drug slowly (a constant release rate) can be
represented by zero order equation. To study the release kinetics, in
vitro data of drug release studies were plotted as cumulative amount
of percentage drug released versus time. It describes the rate of drug
release is independent of the concentration of dissolved substance.
C = Kot
Where, Ko is zero-order rate constant expressed in units of
concentration/time and t is the time.
Application: This equation can be used to describe the drug
dissolution of matrix tablets with low soluble drugs, osmotic systems
andtransdermal systems,
5.5.8.2 First Order
This model useful in the determination of drug absorption
and/or elimination. Drug release depending on the concentration.
76
LogC=LogCo-kt /2.303
Where, Co = The initial concentration of drug and K is first order
constant.
Application: This equation can be used to describe the drug release in
porous matrices those containing water-soluble drugs.
5.5.8.3 Erosion model85
This equation defines the drug release based on erosion alone.
Q = 1-(1-k3t) 3
Where, Q is the fraction of drug released at time t, k3 is the release
rate constant. Thus, a plot between [1-(1-Q) 1/3] against time will be
linear if the release obeys erosion equation.
5.5.8.4 Korsmeyer-Peppas model
To find the drug release mechanism first 60% drug release data
were fitted in Korsmeyer-Peppas model, which described drug release
from a polymeric system equation. To study release kinetics, in vitro
drug release data was plotted as log cumulative % drug release versus
log time.
Mt / M∞= Ktn
Where Mt / M∞ =a fraction of drug released at time t,
K = The release rate constant and n is the release exponent. The n
value is used to characterize different mechanism of drug release for
cylindrical shaped matrices.
5.5.8.5 Higuchi’s Model
The first mathematical model which describes drug release from
a matrix system proposed by Higuchi in 1961. It is applicable for
77
planar systems initially; it was then extended to different geometrics
and porous systems.
Q=KH x T1/2
KH = The Higuchi dissolution constant
The values of cumulative percentage drug release versus square root
of time.
Application: This can be used to describe the drug release from matrix
tablets with water soluble drugs and transdermal systems.
5.6 Stability Studies86
Stability study of selected formulation was tested according to
international conference of harmonization guidelines. The tablets was
stored in Alu-Alu blister for 3 months in stability chamber at 40°C ±
2°C & 75% ± 5 % RH. Stability samples were tested for Physical, drug
content and in vitro dissolution.
78
5.7 RESULTS
5.7.1 Solubility Analysis
Solubility of Alfuzosin in different media at 37 °C ± 0.5 °C.
Table 5.10: Solubility of Alfuzosin
Media Solubility “mg/mL”
pH 2.0 0.01N HCL 192( mg/mL)
pH 4.5 Acetate buffer 172( mg/mL)
pH 6.8 Phosphate buffer 159( mg/mL)
pH 10.0 Phosphate buffer 123( mg/mL)
Purified Water 123( mg/mL)
Figure 5.4: Solubility Study of Alfuzosin in Different media
0
50
100
150
200
250
pH 2.0
0.01N HCL
pH 4.5
Acetate
buffer
pH 6.8
Phosphate
buffer
pH 10.0
Phosphate
buffer
Purified
Water
mg
/mL
Media
Solubility “mg/mL”
79
5.7.2 Compatibility Studies
5.7.2.1 Differential Scanning Calorimetry
Figure 5.5:DSC of Alfuzosin
Figure 5.6: DSC of Alfuzosin with HPMC K100M
80
Figure 5.7: DSC of Alfuzosin with Guargum 8000 cP
Figure 5.8:DSC of Alfuzosin with Eudragit RLPO
81
Table 5.11: DSC characteristics of pure drug and Combination
with Polymers
Parameters Alfuzosine
HCl (API)
API+HPM
C K100M API+Gaurgum
API+Eudragit
RLPO
On Set (°C) 228.2 226.1 223.0 215.6
Peak (°C) 234.7 232.4 230.1 227.7
Delta H (J/g) -16.53 -7.60 -17.01 -5.59
5.7.2.2 Fourier Transform Infra-Red (FT-IR) spectral analysis
Figure 5.9: IR spectrum of Alfuzosin
82
Figure 5.10: IR spectrum of HPMC K100M
Figure 5.11: IR spectrum of Guargum 8000 cP
83
Figure 5.12: IR spectrum of Eudragit RLPO
Figure 5.13: IR spectrum of Alfuzosin with HPMC K100M
84
Figure 5.14: IR spectrum of Alfuzosin with Guargum 8000 cP
Figure 5.15: IR spectrum of Alfuzosin with Eudragit RLPO
85
Table 5.12: Characteristic peaks of Alfuzosin
Frequency (cm-1) Functional Group
1503,1530,1552 C-C stretching
3183 C-H stretching
1213 C-O stretching
2954 Aromatic ring attached to C-H
stretching
3345 NH2 stretching
1307 C-N
Table 5.13: Characteristic peaks of HPMC K100M
Frequency (cm-1) Functional Group
1039 C-C stretching
2923 C-H stretching
1279 C-O stretching
3500 CH2CH(OH) CH3 Stretching value -OH
stretching
Table 5.14:Characteristic peaks of Guargum 8000 cP
Frequency (cm-1) Functional Group
870 to1022 C-C stretching
2922 -CH stretching
1154 C-O stretching
3400 OH stretching
Table 5.15: Characteristic peaks of Eudragit RLPO
Frequency (cm-1) Functional Group
1262 C-C stretching
2925 C-H stretching
1020 C-O stretching
1734 C=O stretching
86
Table 5.16: Characteristic peaks of Alfuzosin + HPMC K100M
Frequency (cm-1) Functional Group
Alfuzosin HCl
1530 C-C stretching
1240 C-O stretching
2924 Aromatic ring attached to C-H stretching
3400 NH2 stretching
1395 C-N stretching
HPMC K100 M
1067 C-C stretching
2920 C-H stretching
1277 C-O stretching
3400 CH2CH(OH) CH3 Stretching value -OH
stretching
Table 5.17: Characteristic peaks of Alfuzosin+Guargum 8000 cP
Frequency (cm-1) Functional Group
Alfuzosin HCl
1504,1531 C-C stretching
1241 C-O stretching
2924 Aromatic ring attached to C-H stretching
3400 NH2 stretching
1395 C-N stretching
Guargum 8000 cps
872 C-C stretching
2924 -CH stretching
1155 C-O stretching
3400 OH stretching
87
Table 5.18: Characteristic peaks of Alfuzosin+ Eudragit RLPO
Frequency (cm-1) Functional Group
Alfuzosin HCl
1529 C-C stretching
2925 C-H stretching
1245 C-O stretching
2853 Aromatic ring attached to C-H stretching
3400 NH2 stretching
1348 C-N stretching
Eudragit RLPO
1277 C-C stretching
2925 C-H stretching
1020 C-O stretching
1731 C=O stretching
5.7.3 Evaluation of Matrix Tablets
5.7.3.1 Evaluation of physical parameters for granules
5.7.3.1.1 Flowability
Table 5.19: Bulk properties of blend
B.No
Parameter
Bulk Density
Tapped Density
Carr’s Index
Hausner’s ratio
Angle of repose (°)
ALF/01 0.339 0.479 29.22 1.412 46.5
ALF/02 0.325 0.482 32.57 1.483 56.7
ALF/03 0.326 0.491 33.60 1.506 56.4
ALF/04 0.345 0.490 29.59 1.420 46.3
ALF/05 0.343 0.457 24.94 1.332 42.1
ALF/06 0.362 0.459 21.13 1.267 41.8
ALF/07 0.342 0.480 28.76 1.403 46.5
ALF/08 0.361 0.500 27.71 1.383 47.1
ALF/09 0.328 0.486 32.51 1.481 56.4
ALF/10 0.399 0.471 15.28 1.180 33.6
ALF/11 0.334 0.464 27.90 1.387 46.3
ALF/12 0.334 0.488 31.55 1.461 56.4
88
5.7.3.2 Evaluation of physical parameters for tablets
5.7.3.2.1 Physical parameters of tablets
Table 5.20: Physical parameters of Tablets
B.No
Parameters
Weight of Tablet (in mg)
Hardness
(in kp)
Thickness
(in mm)
Friability
(%)
ALF/01 297-301 9.1-10.6 5.42-5.50 0.14
ALF/02 299-302 9.4-10.2 5.43-5.51 0.12
ALF/03 298-304 9.0-10.5 5.42-5.49 0.15
ALF/04 299-303 9.1-10.6 5.44-5.50 0.14
ALF/05 300-303 9.5-10.4 5.41-5.49 0.10
ALF/06 301-304 9.8-10.7 5.46-5.54 0.11
ALF/07 349-352 9.7-10.8 5.69-5.75 0.14
ALF/08 347-353 9.9-10.5 5.70-5.74 0.15
ALF/09 349-355 9.6-10.8 5.71-5.73 0.12
ALF/10 355-360 10.7-12.2 5.69-5.74 0.13
ALF/11 348-357 10.8-12.1 5.68-5.74 0.14
ALF/12 347-358 9.8-11.2 5.71-5.76 0.12
89
Figure 5.16: Photograph of prepared ALFUZOSIN extended release Tablets (B.No: ALF/10)
Figure 5.17: Shows the swelling of prepared ALFUZOSIN extended release Tablets at 12 hr (B.No: ALF/10)
90
5.7.3.3 Evaluation of Chemical parameters for Tablets
5.7.3.3.1 Drug Content
Table 5.21: Chemical parameters of tablets
Parameter B.No
ALF/01 ALF/02 ALF/03 ALF/04 ALF/05 ALF/06
Drug
content
( %)
99.2 99.5 99.9 99.8 99.6 99.9
ALF/07 ALF/08 ALF/09 ALF/10 ALF/11 ALF/12
99.7 99.9 99.9 100.1 99.9 99.9
5.7.3.3.2 In-vitro Dissolution Study
Table 5.22: Dissolution values
B.No Cumulative % Drug Release
1hr 2hr 3hr 6hr 12hr 20hr
ALF/01 26.2 92.1 99.8 --- --- ---
ALF/02 53.1 81.7 98.2 --- --- ---
ALF/03 22.3 29.6 63.2 99.2 --- ---
ALF/04 26.2 39.1 46.7 68.5 93.2 99.1
ALF/05 14.5 32.6 50.3 96.2 -- --
ALF/06 12.2 27.7 48.2 82.6 95.4 --
ALF/07 24.5 36.7 45.6 62.5 84.3 95.7
ALF/08 24.9 34.4 48.7 61.7 80.6 95.5
ALF/09 14.2 28.3 31.2 57.6 79.2 94.2
ALF/10 21.2 31.5 41.8 55.9 76.8 91.2
ALF/11 17.6 24.2 39.4 50.5 71.6 89.1
ALF/12 6.5 13.2 26.2 51.3 73.8 92.3
91
Figure5.18: In-vitro drug release of formulations contains Eudragit RLPO
Figure 5.19: In-vitro drug release of formulations
contains Guargum 8000 cP
Figure 5.20: In-vitro drug release of formulations contains HPMC K100M
0 10 20 30 40 50 60 70 80 90
100 110
0 2 4 6 8 10 12 14 16 18 20 22
ALF/01
0 10 20 30 40 50 60 70 80 90
100 110
0 2 4 6 8 10 12 14 16 18 20 22
% D
rug R
elea
se
Time (hr.)
In-vitro drug release of formulations contains Guargum 8000cps
ALF/02
ALF/03
ALF/04
0 10 20 30 40 50 60 70 80 90
100 110
0 2 4 6 8 10 12 14 16 18 20 22
% D
rug R
elea
se
Time (hr.)
In-vitro drug release of formulations contains HPMC K100M
ALF/05
ALF/06
92
Figure 5.21: In-vitro drug release of formulations contains HPMC K100M and Guargum 8000 cP
Figure 22: Photograph shows dissolution of Alfuzosin ER Tablets
Table 5.23: Dissolution profile at different hardness of tablets
(B.No: ALF/10)
Time in
(hr.)
Low Hardness
(8.1-9.3)
Medium Hardness
(10.7 -12.2)
High Hardness
(14.4-15.7)
1 21.1 21.4 18.4
2 30.5 31.8 27.4
6 52.5 55.4 50.5
12 69.6 76.4 70.6
20 82.3 91.5 85.6
0 10 20 30 40 50 60 70 80 90
100 110
0 2 4 6 8 10 12 14 16 18 20 22
% D
rug R
elea
se
Time (hr.)
In-vitro drug release of formulations contains HPMC K100M and
Guargum
ALF/07
ALF/08
ALF/09
ALF/10
ALF/11
ALF/12
93
Figure5.23: Dissolution profile at different Hardness of
Alfuzosin ER tablets
Table 5.24: Comparison of in-vitro release of ALF/10 with
Marketed Product
Time points Marketed Product
(Uroxatral) B.No: ALF/10
1 hour 20.3 21.2
2 hour 28.5 31.5
3 hour 42.9 41.8
6 hour 52.8 55.9
12 hour 80.5 76.8
20 hour 97.4 91.2
F2 value 72.05
F1 value 1.20
0
10
20
30
40
50
60
70
80
90
100
0 2 4 6 8 10 12 14 16 18 20 22
%D
rug R
elea
se
Time (hr.)
In-vitro drug release of optimised formula at diffrent hardness
Optimum Hardness
(10.7 -12.2)
High Hardness (14.4-
15.7)
Low Hardness (8.1-
9.3)
94
Table 5.25: Alfuzosin f1& f2 values
S.No B.No Dissimilarity
factor ( f1)
Similarity
factor(f2 )
1. ALF/7 8.34 61.42
2. ALF/8 7.26 63.17
3. ALF/9 5.49 61.14
4. ALF/10 1.20 72.05
5. ALF/11 9.31 62.07
Figure5.24: In-vitro drug release of ALF/10 and Marketed Product
0 10 20 30 40 50 60 70 80 90
100 110
0 2 4 6 8 10 12 14 16 18 20 22
%D
rug R
elea
se
Time (hr.)
In-vitro drug release of ALF/10 and Marketed Product
ALF/10
Reference
95
5.7.4 Kinetic modeling system for In-vitro release
Table 5.26: In vitro release kinetics of Alfuzosin ER tablets
Correlation Coefficient (r2)
k (/h)
n value B.No: Zero First Higuchi Erosion Peppas
Uroxatral 0.9711 0.9832 0.9944 0.9975 0.9925 0.1740 1.866
ALF/01 0.9097 0.9902 0.9385 0.9920 0.9492 2.9559 0.703
ALF/02 0.9882 0.9715 0.9970 0.9942 0.9970 1.6304 1.755
ALF/03 0.9780 0.9681 0.9772 0.9858 0.9671 0.3737 1.058
ALF/04 0.9320 0.9976 0.9786 0.9923 0.9904 0.1627 2.137
ALF/05 0.9991 0.9728 0.9962 0.9883 0.9983 0.2713 0.943
ALF/06 0.9164 0.9941 0.9646 0.9762 0.9643 0.2639 1.100
ALF/07 0.9512 0.9992 0.9896 0.9955 0.9938 0.1487 2.161
ALF/08 0.9535 0.9939 0.9893 0.9956 0.9903 0.1427 2.183
ALF/09 0.9562 0.9982 0.9900 0.9957 0.9864 0.1396 1.550
ALF/10 0.9625 0.9992 0.9943 0.9956 0.9948 0.1129 2.035
ALF/11 0.9674 0.9968 0.9937 0.9954 0.9888 0.1037 1.786
ALF/12 0.9605 0.9976 0.9918 0.9961 0.9797 0.1300 1.064
96
Selected formulation Kinetic models plots (B.NO: ALF/10)
Figure 5.25: Zero order plot for B. No: ALF/10
0
20
40
60
80
100
120
0 5 10 15 20 25
Co
mu
lati
ve p
erce
nt
dru
g re
leas
e (
%)
Time (hr)
Uroxatral
ALF/10
Linear (Uroxatral)
Linear (ALF/10)
97
Fig 5.26: First order plot for B.No: ALF/10
0
0.5
1
1.5
2
2.5
0 5 10 15 20 25
Log
per
cen
t re
mai
nin
g to
be
rele
ase
d
Time (hr)
Uroxatral
ALF/10
Linear (Uroxatral)
Linear (ALF/10)
98
Fig 5.27: Higuchi plot for B.No: ALF/10
0
20
40
60
80
100
120
0.000 1.000 2.000 3.000 4.000 5.000
Co
mu
lati
ve p
erce
nt
dru
g re
leas
e (
%)
Square root time (hr)
Uroxatral
ALF/10
Linear (Uroxatral)
Linear (ALF/10)
99
Fig 5.28: Erosion plot for B.No: ALF/10
0.000
0.100
0.200
0.300
0.400
0.500
0.600
0.700
0.800
0.900
1.000
0 5 10 15 20 25
(1-Q
)1/3
Time (hr)
Uroxatral
ALF/10
Linear (Uroxatral)
Linear (ALF/10)
100
Fig 5.29: Korsmeyer-Peppas plot for B.No: ALF/10
0.000
0.500
1.000
1.500
2.000
2.500
0 0.2 0.4 0.6 0.8 1 1.2 1.4
log
frac
tio
n r
ele
ase
Log Time (hr)
Uroxatral
ALF/10
101
5.7.5 Stability Studies:
Stability studies for FormulationB.N0:ALF/10 revealed that
there was no significant change in appearance, assay, and drug
release profile at 40°C± 2° & 75% RH till 3 months.
Table 5.27: Stability study parameters
Parameters Time period
Initial 1 Month 2 Month 3 Month
Description Complies Complies Complies Complies
Drug content
(%)
100.1 99.9 99.8 99.9
Uniformity of dosage units ( %)
Tablet -1 98.2 99.2 99.6 98.7
Tablet -2 99.5 98.1 98.7 99.4
Tablet -3 99.7 99.6 100.2 99.7
Tablet -4 99.0 100.1 99.5 100.7
Tablet -5 101.2 99.7 99.8 99.6
Cumulative % Drug Release
1Hr 21.2 20.5 20.8 21.1
2Hr 31.5 30.7 30.9 31.3
3Hr 41.8 41.1 41.5 42.2
6Hr 55.9 56.1 55.5 56.3
12Hr 76.8 76.9 77.1 77.3
20Hr 91.2 90.9 91.5 92.5
102
5.8 DISCUSSION
5.8.1 The solubility results are shown in Table 5.10. Alfuzosin
Hydrochloride was soluble in pH 2.0-0.01N HCl, pH4.5 Acetate buffer,
pH6.8 Phosphate buffer, pH10 Phosphate buffer and purified water.
Comparatively all the media alfuzosin was more soluble in 0.01NHcl.
5.8.2 Differential Scanning Calorimetry (DSC) results are shown in
Table 5.11. The DSC thermograph for Alfuzosine showed melting
peak starts at 228.2°C ending at 234.7°C and the mixer of the
Alfuzosin + HPMC K100M, Alfuzosin + Guar gum & Alfuzosin +
Eudragit RLPO showed melting points starting at 226.1°C, 223.0°C &
215.6°C ending at 232.4°C, 230.1°C & 227.7°C respectively. The
endothermic energy of Alfuzosine was -16.53 J/g and the mixer of the
Alfuzosin + HPMC K100M, Alfuzosin + Guar gum & Alfuzosin +
Eudragit RLPO were -7.60J/g, -17.01J/g& -5.59 J/g respectively.
From the obtained results concluded that there is no interaction
between the selected polymers and drug substance.
5.8.3 Fourier Transform Infra-Red (FT-IR) spectral results are shown
in Table 5.12 – 5.18. The FT-IR spectra of pure drug showed
characteristic peaks at 1503 cm-1, 1530 cm-1, 1552 cm-1,3183 cm-1,
1213 cm-1,2954 cm-1, 3345 cm-1& 1307 cm-1. The mixer of drug
substance and polymers of the selected in the formulations also
showed same characteristic peaks with linear and shift so these
values supported that there is no interaction between the selected
polymer and the drug substance.
103
5.8.4 The results of bulk properties are shown in Table 5.19.
The bulk density of the prepared formulations are in the range of
0.325g/mL to 0.399g/mL.
The tapped density was found to be in the range of 0.457g/mL to
0.500g/mL.
The Carr’s index and Hausner’s ratio varies in the range of 15.28 %,
1.180 to 33.60 %, 1.506 respectively.
Angle of repose was found to be in the range of 33.6° to 56.7°. The
bulk properties of B.No: ALF/10 was showed flow properties (15.28
%,1.18, 33.6°)respectively.
So the results clearly indicate that the preferred blend have good
flowability and compressibility.
5.8.5 Results of tablet weight variation are shown in Table 5.20.
All batches were found within specified range ±5.0% as per
Indian Pharmacopeia.
5.8.6 Tablet Thickness results are shown in Table5.20.
Thickness of tablet containing total weight 300 mg was found
in the range of 5.41 to 5.54 mm. Thickness of tablet containing total
weight 350 mg was found in the range of 5.68 to 5.76 mm
5.8.7 Hardness results are shown in Table 5.20.
Hardness of all tablets were found in the range of 9.0 to 12.2 kp.
Selected batch (B.No: ALF/10) found with 10.7 to 12.2kp.
104
5.8.8 Friability results are shown in Table 5.20.
Friability of all tablets was found in the range of 0.10 - 0.15% w/w,
which found within the specified limit. Friability of selected batch
(B.No: ALF/10) was found to be 0.13%.
5.8.9 The results of the assay shown in Table5.21.
The assay results are found within the pharmacopeial limits which
indicate uniformity in drug content for all the prepared formulations.
5.8.10 The results of Dissolution studies are shown in Table5.22.
The formulation prepared with Eudragit RLPO (40 % w/w
concentration) alone (B.No: ALF/01) able to control drug release
99.8% at 3 hours.
Those formulations containing guar gum alone (B.No: ALF/02,
ALF/03, ALF/04) contain in the concentration of 13.33, 26.67& 60.00
% w/w respectively are able to control drug release 98.2% at 3 hours,
99.2% at 6 hours and 99.1% at 20 hours respectively.
The formulations contain HPMC K100M alone (B.No: ALF/05,
ALF/06) in the 33.33%, 50.0% concentrations released the drug in
96.2% at 6 hours, 95.4% at 12 hours respectively.
The formulation containing the combination of HPMC K 100M
and Guar gum 8000 cp (B.No: ALF/07, ALF/08, ALF/09, ALF/10,
ALF/11 & ALF/12) at the concentrations of 28.57 & 8.57, 30 & 10,
28.57 & 11.49, 31.429 & 11.429, 32.857 & 12.857, 42.857 & 22.857
respectively controls drug release 95.7% at 20 hours, 95.5% at 20
hours, 94.2% at 20 hours, 91.2% at 20 hours, 89.1% at 20 hours and
92.3% at 20 hours respectively.
105
Among all the formulations B.No: ALF/10 are shown able to
drug release over 24 hours.
Marketed formulation also evaluated for the comparison of the
drug release which shows 97.4% released in 20 hours and found that
the B.No: ALF/10 is shows similar release of the drug as that of the
marketed formulation.
5.8.11 The similarity and dissimilarity factor values are shown in
Table5.25.
The f1, f2 are calculated by using the equation proposed by More
et al, the results of formulation (B.No: ALF/10) f1= 1.20, f2= 72.05 so,
it indicates the proposed formulation is similar to that of the marketed
formulation.
5.8.12 The results of kinetic profile are shown in Table5.26.
The release profile was studied for kinetics of the drug release
by zero order and first order kinetics. The correlation coefficient value
(r2) of zero order and first order for all formulation were found to be in
the range of 0.9097-0.9991 and 0.9681-0.9992. These results indicate
that the release follows first order kinetics.
The mechanism of drug release was studied by using Higuchi’s,
Erosion and Peppas model. The correlation r2 values found to be
(0.9385 – 0.9970),(0.9762 – 0.9975) and (0.9492 – 0.9983)
respectively, this results indicates the release mechanism follows with
super case II transport.(As the n value more than1) From the observed
results indicate the drug release follows first order kinetics with
diffusion mechanism.
106
5.8.13 The results of stability studies are shown in Table No: 5.27.
The stability studies were conducted on the selected formulation
(B.No: ALF/10) at 40°C/75% RH for 3 months. The tablets were
evaluated for Description, Assay, uniformity of dosage units and
Dissolution.
There is no significance difference between the initial and final
exposed samples with required physical stability and chemical
stability like assay and dissolution. So this indicates the formulation
is stable.