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INTERNATIONAL JOURNAL OF RESEARCH ARTICLE PHARMACEUTICAL INNOVATIONS ISSN 2249-1031
29 | P a g e Volume 3, Issue 2, March ₋ April 2013 http://www.ijpi.org
FORMULATION AND EVALUATION OF LORNOXICAM MICROSPONGE
TABLETS FOR THE TREATMENT OF ARTHRITIS
*Karthika.R , Elango.K , Ramesh Kumar.K , Rahul.K
Department of Pharmaceutics, College of Pharmacy, Madras Medical College, Chennai, India
Abstract
The purpose of this study was to design novel drug delivery system containing Lornoxicam
microsponges. Lornoxicam is a Non-steroidal anti-inflammatory drug used for the treatment
of various inflammatory diseases. Microsponges containing Lornoxicam and Eudragit RS
100 were prepared by quasi emulsion solvent diffusion method. The effects of drug to
polymer ratios on physical characteristics of the microsponges were investigated.
Compatibility of drug with adjuncts was studied by FT-IR. Production yield, loading
efficiency, particle size analysis, surface morphology and in-vitro release studies were carried
out. The microsponges were compressed into tablets. Mechanically strong tablets were
obtained owing to the plastic deformation of sponge-like structure of microsponges. The
effects of different stirring rates, amount of solvent, amount of emulsifier used on the
physical characteristics of the microsponges were investigated. All the factors studied had an
influence on the physical characteristics of the microsponges. In-vitro dissolution studies
were done on all formulations and the results were kinetically evaluated and the release rate
of Lornoxicam was found to be modified. This study presents a new approach based on
microsponge drug delivery system.
Keywords: Microsponges, Lornoxicam, Quasi-emulsion solvent diffusion method,
Morphology, Release kinetics
INTRODUCTION
Many of conventional delivery systems
require high concentrations of active
agents to be incorporated for effective
therapy because of their low efficiency as
delivery systems. Thus novel drug delivery
systems have been increasingly
investigated to achieve targeted and
controlled release of drugs. Microsponges
are highly crosslinked, patented, porous,
polymeric microspheres that acquire the
flexibility to entrap a wide variety of
active ingredients that are mostly used for
prolonged topical administration and
recently for oral administration.
Microsponges are designed to deliver a
pharmaceutically active ingredient
efficiently at minimum dose and also to
enhance stability, elegance, flexibility in
formulation, reduce side effects and
modify drug release profiles. [1, 2]
Microsponges are prepared by several
*Corresponding author
Karthika.R
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methods utilizing emulsion systems as
well as by suspension polymerization in a
liquid-liquid system. The most common
emulsion system used is Quasi-emulsion
solvent diffusion method. [2]
Lornoxicam, a congener of tenoxicam, is
a new NSAID belonging to the oxicam
class. It is a strong analgesic and anti-
inflammatory NSAID as compared to
other NSAIDs. Chemically its 6-chloro-
4-hydroxy-2-methyl-N-2-pyridyl-2H-
thieno-[2, 3-e]-1, 2-Thiazine-3-
carboxamide-1,1-dioxide. Like all
NSAIDs, it acts by inhibiting the
metabolites of COX branch of
arachidonic acid pathway. Half-life of
Lornoxicam is 3-5 hours, which increases
the dosing frequency of the drug. The
increased dosing frequency leads to side
effects. Thus the present study is aimed at
developing microsponge based novel
drug delivery system containing
Lornoxicam. The microsponges of
Lornoxicam were prepared and
characterized. They were formulated as
tablets and subjected to in-vitro
characterization for various attributes. [3]
MATERIAL AND METHODS
Lornoxicam was obtained as a gift
sample from Glenmark Pharmaceuticals
Ltd., Eudragit RS 100 was obtained from
MMC Healthcare, Chennai, Polyvinyl
alcohol was procured from S.D Fine-
Chem Limited, Mumbai, Triethyl citrate
was purchased from Himedia laboratories
Pvt.Ltd, Ethanol was from
ChangshuYangyuan Chemical, China,
Magnesium stearate from Indian
Research Products, Chennai, Micro
crystalline cellulose from Kniss
Laboratories, Chennai, Talc from S.S
Chemicals, Chennai, Lactose from
Microfine Chemicals, India. All other
chemicals and solvents were of analytical
reagent grade.
Preparation of Lornoxicam
microsponges
Lornoxicam microsponges were prepared
by quasi emulsion solvent diffusion
method. The internal phase consisted of
Eudragit RS 100 (100mg) and triethyl
citrate dissolved in 5ml ethanol. Triethyl
citrate was used as plasticizer. This was,
followed by addition of drug with gradual
stirring. The internal phase was then
poured into polyvinyl alcohol (0.5%w/v)
solution in water, the external phase.
After 2 hours of stirring the microsponges
were formed due to the removal of
ethanol from the system. The
microsponges were filtered and dried at
40˚C for 24 hours. The composition of
microsponge formulations are given in
table1.
Fourier transform infrared analysis
Infrared spectroscopy was conducted
using FT-IR spectrophotometer and the
spectrum was recorded in the wavelength
region of 4000 to 400 cm-1
. The
procedure consisted of dispersing the
sample (drug alone, mixture of drug and
excipients and the optimized formulation)
in KBr and compressed into discs by
applying a pressure of 5 tons for 5
minutes in a hydraulic press. The pellet
was placed in the light path and the
spectrum was recorded. [4]
Surface morphology of microsponges
The surface morphology of the prepared
microsponges was examined using a
scanning electron microscope, operating at
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20 kV. Dried microsponges were coated
with gold–palladium alloy for 45sec under
an argon atmosphere before observation.
SEM photograph was recorded at different
magnifications using Tescan VEGA3SBU
SEM analyzer. [5]
Determination of percentage yield [5]
The production yield of the microsponges
was determined by calculating accurately
the initial weight of the raw materials and
the weight of the microsponge obtained,
WPr
Production yield = × 100
WTh
Where-
WPr = Practical mass of microsponges
WTh = Theoretical mass (polymer + drug)
Determination of loading efficiency [5]
Lornoxicam microsponges equivalent to
50 mg of the drug was taken in a 100 ml
standard flask. 25 ml ethanol and 25ml of
6.8 pH phosphate buffer were added and
shaken for about half an hour and the
volume was made upto 100 ml with 6.8 pH
phosphate buffer. 2 ml of the solution was
taken and diluted to 100 ml with 6.8 pH
phosphate buffer. The absorbance of the
resulting solution was measured at 376 nm
and the content of LOX was calculated.
The loading efficiency (%) of the
microsponges was calculated.
DCact
Loading efficiency = × 100 DCTheo.
DCact. = Actual drug content in
microsponges
DCTheo. = Theoretical drug content
Particle size analysis
Particle size and size distribution of
microsponge particles was determined
using optical microscope. The values are
given for the formulations in the form of
mean particle size.
Micromeritic properties
The drug and blend of drug with excipients
were evaluated for bulk density, tapped
density, compressibility index, Hausner’s
ratio and angle of repose. [6, 7]
Preparation of tablet formulations
After the preparation of lornoxicam
microsponges, they were formulated as
tablets by “Direct compression method”.
All the ingredients were weighed
accurately and mixed thoroughly. The
lubricated blend was then compressed
using 8 mm flat face punch. The
composition of different formulations used
in the study is shown in Table 2.
Evaluation of Lornoxicam microsponge
tablets
The tablets of lornoxicam were evaluated
for uniformity of weight. Thickness and
diameter were measured by vernier
calipers. Hardness was determined using
Monsanto hardness tester and friability of
tablets was determined by Roche
friabilator. [7]
Disintegration test
One tablet was placed in each of the six
tubes of basket, the assembly was
suspended in water, maintained at
temperature 37˚C±2˚C and the apparatus
was operated. The time taken to
disintegrate the tablet completely was
noted. [7]
Drug content
Ten tablets were weighed and ground. The
weight equivalent to 8 mg of drug was
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taken and transferred to a 100 ml standard
flask. 25 ml of ethanol and 25 ml of 6.8
pH phosphate buffer were added and
shaken for about half an hour and the
volume was made up to 100 ml with 6.8
pH phosphate buffer. The above solution
was filtered and 5 ml of filtrate was taken
and diluted to 100 ml with 6.8 pH
phosphate buffer. The absorbance of the
resulting solution was measured at 376 nm
and the content of Lornoxicam was
calculated. [7, 8]
Uniformity of content
Six tablets were randomly selected and
tested for their drug content. The content
of active ingredients of various
formulations was calculated by measuring
the absorbance of diluted solutions using
UV-Visible Spectrophotometer at 376 nm. [7]
In-vitro drug release studies
Two step dissolution conditions was used
in USP Type II (paddle) dissolution
apparatus to simulate the physiological
conditions of GIT – 2 hours in 900 ml of
simulated gastric fluid (SGF, pH 1.2) and
10 hours in 900 ml of simulated intestinal
fluid (SIF, pH 6.8). The stirring rate was
100 rpm and the temperature was
maintained at 37 ± 0.5˚C. Aliquots of
dissolution medium were withdrawn at
predetermined time intervals and the same
volume of medium was replenished to
maintain the constant volume. The
absorbance of the solutions was measured
at 376 nm and the release was calculated. [8]
Drug release kinetics
The dissolution profile of optimized
formulation was subjected to various
models such as Zero order kinetics
(percentage drug release against time),
First order kinetics (log percentage drug
unreleased against time), Higuchi
(percentage drug released against square
root of time), Korsemeyer-Peppas (log
percent drug released against log of time)
and Hixson-Crowell (cube root of
cumulative percentage of drug remaining
against time) to assess the kinetics of drug
release from prepared Lornoxicam
microsponges.
RESULTS AND DISCUSSION
Compatibility studies
FT-IR spectra were recorded to assess the
compatibility of the drug and excipients.
FT-IR spectra of drug, physical mixture of
drug and excipients were examined. In FT-
IR spectra of Lornoxicam powder,
characteristic O-H stretching band at
3448.47 cm-1
, C-Cl stretching band at
794.61 cm-1
, SO2 streching band at
1427.22 cm-1
and aromatic C=S stretching
band at 1188.06 cm-1
were seen. These are
the major peaks of the spectra of the drug.
All these peaks were present in the spectra
of formulation and thus confirm that the
drug did not interact with the excipients.
Evaluation of microsponge
Particle size and shape
The SEM photographs of the
microsponges are shown in figure 4.
Particle size analysis showed the particle
size ranging from 75.6 to 45.5 µm and
spherical in shape. Mean particle size of
formulations M1 to M5 is given in table 4.
Production yield and loading efficiency
Production yield and loading efficiency of
Lornoxicam microsponge formulation are
given in table 4. Batch M1 to M5 shows
production yield in the range of 69.35 to
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89.65 % and loading efficiency in the
range of 89.25 to 96.39 % as shown in
table 4.
Evaluation of tablets
Micromeritic properties
The Lornoxicam microsponge blends were
free flowing as indicated by the values of
bulk density (0.479 to 0.510 g/ml), tapped
density (0.534 to 0.585 g/ml),
compressibility index (10.29 to 12.82%)
and Hausner’s ratio (1.11 to 1.14). Angle
of repose ranged from 29.11 to 31.16. The
values are given in Table 3.
Physical evaluation and Drug content
The Lornoxicam microsponge tablets were
uniform in weight (0.178 to 0.181g). The
thickness (2.5 mm) and diameter (8.00
mm) of the tablets were uniform. The
hardness of tablets was found to be
between 4.25 and 4.75 kg/cm2, while the
friability of the tablets ranged between
0.44 and 0.6 %. The tablets have enough
hardness to withstand stress during
transport and handling. The disintegrating
time of the various formulations were
found to be between 2.12 and 3.0 min.
Disintegrating time was found to be within
the limits as the maximum time for
uncoated tablets is 30 min. The drug
content in various formulations varied
between 91.22 and 100.6% w/w. (Table 5) [8]
Uniformity of Drug content
The percentage of drug content of all the
formulations ranged from 96.85 and 100.7
% w/w. All the formulations comply with
the test for uniformity of content.
In-vitro drug release
The release profiles obtained for the
microsponge tablets are presented in figure
1. The profiles showed a bi-phasic release
with an initial burst effect. In the first 2
hrs, about 13 to 27% of the drug was
released. Cumulative release for the
microsponges after 12 hrs ranged from 86-
96%. Drug release from the formulations
decreased with increase in the amount of
polymer in the microsponges. [9]
Release Kinetics of the Optimized
formulation
The R2 values for various release models
are 0.919 for Zero order, 0.994 for First
order, 0.966 for Higuchi, 0.948 for
Korsemeyer-Peppas and 0.991 for Hixson-
Crowell kinetics. The drug release follows
first order kinetics and the mechanism
followed is Hixson-Crowell.
Effect of stirring rate on microsponges
The effect of stirring rate on the size of
microsponges was studied. As the stirring
speed was increased, microsponges of
smaller size were obtained. When the rate
of stirring was increased from 200 to 400
rpm, the mean particle size decreased from
59.67 µm to 35.81µm. It was also
observed that at higher stirring rates
employed, turbulence was created within
the external phase, polymer then adhered
to the stirrer and the production yield
decreased, but the drug content increased,
as shown in table 6. [9]
Effect of volume of internal phase on
microsponges
It was observed that on increasing the
volume of internal phase from 5 to 15 ml
microsponges were not formed. This may
be due to the decrease in viscosity of
internal phase. It was observed that the
particle size, production yield and drug
content decreased on increasing internal
phase volume. The result suggests that the
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amount of ethanol need to be controlled
within an appropriate range to affect not
only the formation of quasi-emulsion
droplets at the initial stage but also the
solidification of drug and polymer in the
droplets. The good microsponges were
produced only when 5 ml of internal phase
was used, as shown in table 7. [10]
Effect of amount of emulsifying agent
on microsponges
The production yield and mean particle
size were greatly affected by the amount of
emulsifying agent. The increase in the
amount of emulsifying agent resulted in
larger microsponges. This could be due to
the increased viscosity. The increased
amount of emulsifying agent decreased the
production yield and drug content but
increased the mean particle size as shown
in the table 8. [10]
Conclusion
This study presents a new approach for the
preparation of modified microsponges with
prolonged release characteristics. The
prepared microsponges exhibited
characteristics of an ideal delivery system.
The unique compressibility of
microsponges offers a new alternative for
producing mechanically strong tablets.
References
1. Swetha A, Gopal Rao M, Venkata
Ramana K, Niyaz Basha B, Koti
Reddy V. Formulation and In-vitro
evaluation of Etodolac entrapped in
Microsponge based drug delivery
system. International Journal of
Pharmacy 2011; 1(2): 73-80.
2. Markand Mehta, Amish Panchal,
Viral H Shah, Umesh Upadhyay.
Formulation and In-vitro
evaluation of controlled release
Microsponge gel for topical
delivery of Clotrimazole.
International Journal of Advanced
Pharmaceutics 2012; 2(2): 93-101.
3. Prasad Byrav D S, Medhi B,
Prakash A, Patyar S, Wadhwa S.
Lornoxicam : A Newer NSAID.
IJPMR 2009; 20(1): 27-31.
4. Afsar C Shaikh, Sayyed Nazim,
Shaikh Siraj, Tarique Khar, Siddik
Patel M, Mohammad Zameeruddin,
Arshad Shaikh. Formulation and
evaluation of sustained release
tablets of Aceclofenac using
hydrophilic matrix system. IJPPS
2011; 3(2): 145-148.
5. Sarat Chandra Prasad M, Ajay M
B, Nagendra Babu, Prathyusha P,
Audinarayana N, Bhaskar Reddy
K. Microsponge Drug Delivery
System : A Review. Journal of
Pharmacy Research 2011; 4(5):
1381-1384.
6. Debajyoti Ray, Amresh K Prusty.
Designing and In-vitro studies of
Gastric floating tablets of Tramadol
Hydrochloride. International
Journal of Applied Pharmaceutics
2010; 2(4): 12-16.
7. Indian Pharmacopoeia (2010) :
Ministry of Health and Family
Welfare, Government of India,
Controller of Publication, New
Delhi, India.
8. Uma Maheswari A, Elango K,
Daisy Chellakumari, Saravanan K,
Anglina Jeniffer Samy.
Formulation and Evaluation of
Controlled Porosity Osmotic
INTERNATIONAL JOURNAL OF RESEARCH ARTICLE PHARMACEUTICAL INNOVATIONS ISSN 2249-1031
35 | P a g e Volume 3, Issue 2, March ₋ April 2013 http://www.ijpi.org
Tablets of Lornoxicam. IJPSR
2012; 3(6): 1625-1631.
9. Vikas Jain, Ranjit Singh.
Dicyclomine loaded Eudragit based
Microsponge with potential for
Colonic Delivery: Preparation and
Characterization. Tropical Journal
of Pharmaceutical Research 2010;
9(1): 67-72.
10. Manoj Kumar Mishra, Mukesh
Shikhri, Rishikesh Sharma,
Mahesh Prasad Goojar.
Optimization, formulation
development and characterization
of Eudragit RS 100 loaded
Microsponges and subsequent
colonic delivery. IJDDHR 2011;
1(1): 8-13.
Table 1: Composition of Lornoxicam microsponge containing eudragit RS 100
Ingredient M 1 M 2 M 3 M 4 M 5
Lornoxicam(g) 0.1 0.3 0.5 0.7 0.9
Eudragit RS 100 (g) 0.1 0.1 0.1 0.1 0.1
Polyvinyl Alcohol (g) 0.5 0.5 0.5 0.5 0.5
Triethyl citrate (ml) 0.5 0.5 0.5 0.5 0.5
Ethanol (ml) 5 5 5 5 5
Water (ml) 200 200 200 200 200
Table 2: Composition of Lornoxicam tablets
Formulation
code
Lornoxicam
microsponges (mg)
Micro crystalline
cellulose (mg)
Magnesium
stearate (mg)
Talc
(mg)
Lactose
(mg)
F1 16.00 30 5.4 9 119.60
F2 10.66 30 5.4 9 124.94
F3 9.60 30 5.4 9 126.00
F4 9.14 30 5.4 9 126.45
F5 8.88 30 5.4 9 126.72
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Table 3: Micromeritic properties of Lornoxicam and powder blend
Drug and
Blends
Bulk density*
(g/ml)
Tapped
density* (g/ml)
Compressibility
index* (%)
Hausner’s
ratio*
Angle of
repose*
Drug 0.312±0.012 0.454±0.014 31.2±0.16 1.452±0.06 47.57˚±0.34
MB1 0.51±0.006 0.585±0.004 12.82±0.21 1.14±0.03 30.2˚±0.19
MB2 0.489±0.002 0.560±0.003 12.67±0.24 1.14±0.07 29.7˚±0.69
MB3 0.479±0.003 0.534±0.006 10.29±0.28 1.11±0.05 31.16˚±0.68
MB4 0.489±0.005 0.560±0.008 12.67±0.34 1.14±0.09 30.1˚±0.83
MB5 0.492±0.04 0.558±0.017 11.82±0.19 1.13±0.05 29.11˚±0.20
* Mean of three readings
Table 4: Evaluation of Lornoxicam microsponges
Formulation Production yield (%) Loading efficiency (%) Mean particle size (µm)
M1 69.35 89.25 75.60
M2 79.3 90.00 64.20
M3 84.77 93.38 62.20
M4 78.20 96.95 54.40
M5 89.65 96.39 45.50
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Table 5: Physical evaluation and drug content
Formu
-lation
Uniformity
of weight *
(g)
Diameter
# (mm)
Thickness
# (mm)
Hardness#
(kg/cm2)
Friability
^ (%)
Drug
content #
(%w/w)
Uniformity
of content ҂
(%w/w)
Disintegration
time # (min)
F1 0.179±
0.006
8±0.0 2.5±0.0 4.4±0.45 0.44±
0.023
100.6±0.02
3
100.69±0.52
3
2.12±0.06
F2 0.179±
0.005
8±0.0 2.5±0.0 4.25±0.25 0.47±
0.012
96.38±0.05
4
100.60±1.07
6
2.19±0.05
F3 0.180±
0.002
8±0.0 2.5±0.0 4.75±0.25 0.60±
0.025
91.22±0.01
8
96.85±0.859 2.78±0.01
F4 0.181±
0.003
8±0.0 2.5±0.0 4.25±0.25 0.53±
0.019
93.09±0.03
2
100.7±0.632 2.52±0.05
F5 0.178±
0.005
8±0.0 2.5±0.0 4.35±0.33 0.47±
0.015
95.9±0.027 99.76±0.927 3.0±0.02
*mean of 20 readings. # mean of 5 readings. ^mean of 3 readings. ҂mean of 6 readings
Figure1: Release study of various formulations
0
20
40
60
80
100
120
0 2 4 6 8 10 12 14
% D
RU
G R
ELEA
SE
TIME IN HOURS
F1
F2
F3
F4
F5
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Table 6: Effect of stirring rate on Lornoxicam microsponges
Formulation
Internal phase composition External
phase
Stirring
rate
(rpm)
Production
yield (%)
Mean
particle
diameter
* (µm)
%Drug
content
*
F5
Drug
(g)
Polymer
(g)
Ethanol
(ml)
water PVA
(%)
0.9 0.1 5 200 0.5 200 80.07 59.67±
3.15
84.17±
1.3
0.9 0.1 5 200 0.5 300 75.18 48.19±
6.89
90.02±
2.4
0.9 0.1 5 200 0.5 400 73.96 35.81±
4.56
94.23±
1.7
* Mean of 5 readings
Table 7: Effect of internal phase composition on Lornoxicam microsponges
Formulation
Internal phase composition External
phase
Stirring
rate
(rpm)
Production
yield (%)
Mean
particle
diameter
* (µm)
%Drug
content
*
F5
Drug
(g)
Polymer
(g)
Ethanol
(ml)
water PVA
(%)
0.9 0.1 5 200 0.5 300 79.29 45.5±
5.39
93.95±
1.6
0.9 0.1 10 200 0.5 300 68.34 41.99±
6.89
86.21±
0.9
0.9 0.1 15 200 0.5 300 66.85 38.25±
7.24
80.05±
0.5
* Mean of 5 readings
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Table 8: Effect of emulsifying agent on Lornoxicam microsponges
Formulation
Internal phase composition External
phase
Stirring
rate
(rpm)
Production
yield (%)
Mean
particle
diameter
* (µm)
%Drug
content
*
F5
Drug
(g)
Polymer
(g)
Ethanol
(ml)
water
(ml)
PVA
(%)
0.9 0.1 5 200 0.25 300 82.3 46.49±
7.11
92.81±
0.8
0.9 0.1 5 200 0.5 300 78.69 50.17±
6.45
90.23±
0.4
0.9 0.1 5 200 0.75 300 69.05 66.25±
5.67
85.87±
0.6
* Mean of 5 readings
Figure 2: A plot of First order kinetics
y = -0.115x + 2.057R² = 0.994
0
0.5
1
1.5
2
2.5
0 2 4 6 8 10 12
Log
Cu
m %
Dru
g R
emai
nin
g
Time
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Figure 3: A plot of Hixson-Crowell kinetics
Figure 4: SEM image of Lornoxicam Microsponges
y = -0.266x + 4.628R² = 0.991
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
0 2 4 6 8 10 12 14
Cu
be
ro
ot
of
% d
rug
rem
ain
ing
Time in Hours
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