Solubility Enhancement of Clarithromycin Using Solid
Dispersion and Effervescence Assisted Fusion Technique
Richa Mishra*, S.S. Gautam,
Raj K. Prasad, A. K. Patel, A. K. Sahu
Shambhunath Institute of Pharmacy, Jhalwa, Allahabad,
U. P, India.-211012
*Corresponding Author E-mail: rajdavv2007@gmail.com
ABSTRACT:
The Poor Solubility of Drugs is a major problem which
limits the development of highly potent pharmaceutics. Solubility Enhancement
is one of the important parameters which should be considered for those drugs
having poor aqueous solubility. Drugs belonging to Biopharmaceutical
Classification System (BCS) class II are characterized by low aqueous
solubility and high physiological permeability. Solid Dispersion Method
Technique and Effervescence Assisted Solid Dispersion Techniques using Modified
Fusion Method are the process to enhance the solubility of poorly water soluble
drugs. In this work, BCS class-II drugs Clarithromycin was used as a model
drugs, having poor solubility but high permeability is individually
incorporated with Mannitol, Citric acid, and Sodium bicarbonate (Hydrophilic
Carriers used as Excipients) in different ratio respectively. SDMs of Clarithromycin
were prepared melting (Fusion) method using Mannitol. EASDs of Clarithromycin
were prepared using Modified Fusion Method. Mannitol was melted and in this
molten mannitol Citric acid (organic acid) was added and uniformly mixed by
continuous stirring. Solubility of Drug Powders, Solid Dispersion, and EASDs
was determined at 25
C using shake flask method. The aqueous
solubility of Clarithromycin were estimated using a U.V. spectrophotometer at
241nm (λmax). Scanning electron Micrographs, FTIR, DSC and PXRD CLN of drug powders, solid dispersion, and EASDs
were compared. Scanning electron micrographs of EASDs showed better uniform
distribution of drug particles in the carrier matrix. The present
technique is better suitable for drugs having a low melting point or melt
without charring. Effervescence assisted fusion technique of preparing solid
dispersions can be employed for enhancing solubility of poorly soluble drugs.
KEYWORDS: EASDs,
Solid dispersion, Clarithromycin, Solubility studies etc.
INTRODUCTION:
The enhancement of oral bioavailability of poorly
water-soluble drugs remains one of the most challenging aspects of drug
development.The major goals for enhancing solubility in order to achieve the
site-specific action of the drug at the therapeutically optimal rate and dose
regimen as well as to increase
the aqueous solubility of poorly water soluble drugs1-5.
The present works deals with the preparation and characterization of Clarithromycin complex using solid
dispersion technique and effervescence assisted solid dispersion technique by
using modified fusion method for solubility enhancement. This technique is
useful for those drugs which are poorly soluble in water. Clarithromycin, Fig.
1, is a semi-synthetic macrolide antibiotic which inhibits bacterial protein
synthesis by binding to the bacterial 50s ribosomal subunit6-8.
Fig. 1: Structure of Clarithromycin
MATERIALS AND METHODS:
MATERIALS:
Clarithromycin was purchase
from Pure Chem. Pvt. Ltd.
Gujarat). Instrument were used
for characterization were Electronic balance, FTIR (Shimadzu Corporation),
UV-Vis spectrophotometer (Thermo scientific), Scanning Electron
Microscopy (JEOI Model JSM-6390 LV ), DSC (Mettler Toledo DSC 822e), PXRD
(Bruker Axs D8 Advance) and Stability
Chamber(Medical Equipment, India) etc. The best quality of entire
chemicals were used like Acetonitrile, Methanol,
Ortho phosphoric and Hydrochloric Acid (LR grade, Merck),Mannitol (Central drug
house, New Delhi).
METHODS:
Preformulation studies of
Clarithromycin (CLN) pure drug was carried out using Drug identification test,
Determination of Melting point
(capillary method), Solubility of CLN in distilled water, methanol, Ethanol,
Acetone and 0.1N HCl solution. In UV characterization, λmax.of CLN was
determined using Methanol: Water (30:70),scanning between 200-400nm and
Calibration curve was prepared. Micromeretics properties of pure CLN drug was
studies by determining of bulk density, Tapped Density, Car’s Index, Angle of
Repose and Hauser’s Ratio. The size distributions along the volume mean
diameters of the suspending particles were measured using dynamic scattering
particle size analyzer9-12.
Differential
Scanning Calorimetry (DSC)analysis
was performed using Samples (3-5 mg) were crimped in non-hermetic aluminium
pans with lids and scanned from 50 to 300ºC at a heating rate of 10ºC/min under
a continuously purged dry nitrogen atmosphere (flow rate 20mL/min). The
instrument was equipped with a refrigerated cooling system. The FT-IR spectra of CLN pure drug were obtained over the range
400- 4000cm-1 in dry KBr (50mg) and samples (1-2mg).The X-ray
diffraction (XRD) pattern of pure drug was recorded applying voltage 35 kV, 20
mA, angular range 5, divergence slit 10, and receiving slit 0.15 mm. Surface morphology of the
pure CLN was determined using a scanning
electron microscope (SEM), operated at low accelerating voltage of about 15KV
with load current about 80mA.
Preparation of CLN complex SDM:13-15
Mannitol was
melted in china dish on a heating mantle, and drug powder of CLN (10mg) was
added to the molten mannitol on the basis of stoichiometric ratio, Table 1. The
molten mixture of drug and carriers, was continuously stirred to increase
uniform distribution of components. This melted uniform mixture was quickly
solidified at low temperature under cold condition (freezer). Cooled solid
dispersions were crushed and ground gently using a mortar and pestle, Fig. 2.
The complex of solid dispersion of drug was stored in desiccators in a Petridis.
Fig 2:CLN complex using SDM
Table 1: Formula Design of the CLN complex using SDM
|
S. No.
|
Batch code
|
Drug (CLN) In mg
|
Excipient (Mannitol) in mg
|
|
1.
|
F1
|
10
|
30
|
|
2.
|
F2
|
10
|
40
|
|
3.
|
F3
|
10
|
50
|
Preparation of Clarithromycin complex using EASD
method:16-18
Carrier
(mannitol) was melted in a china dish (at175–180°C), and organic acid (citric
acid) was added to the molten mannitol. This mixture of mannitol and organic
acid was melted and uniformly mixed by continuous stirring. Drug powder of
Clarithromycin was added to this molten mixture under continuous stirring. To
the molten mixture of carrier–organic acid–drug, the sodium bicarbonate
(carbonic base)was added under rapid stirring. The ratio of carbonic base and
organic acid was according to their molar reactivity, Table 2. After addition of
sodium bicarbonate, the effervescence (micro-bubbles)was generated due to
acid–base reaction and the molten mixture turns into white froth. The froths
were cooled down and allowed to solidify at low temperature (freezer). This
cooled solid dispersion was crushed and ground gently using a mortar and
pestle, Fig. 3. The complex of EASD of drug was stored in desiccators in a
Petridis.
Fig 3:Clarithromycin complex using EASD method
Table 2: Formula
Design of the CLN complex using EASD method
|
S.NO.
|
Batch Code
|
Drug (CLN) in mg
|
Excipient (in mg)
|
|
Mannitol
|
Citric Acid
|
Sod. Bi. Carbonate
|
|
1.
|
F1
|
10
|
30
|
10
|
30
|
|
2.
|
F2
|
10
|
40
|
125
|
375
|
|
3.
|
F3
|
10
|
50
|
150
|
450
|
|
4.
|
F4
|
10
|
50
|
150
|
400
|
|
5.
|
F5
|
10
|
40
|
100
|
250
|
|
6.
|
F6
|
10
|
40
|
200
|
250
|
CHARACTERIZATION / EVALUATION
OF ERYTHROMYCIN COMPLEX:
Micromeretics
properties prepared complex were studies by determining of bulk density, Tapped
Density, Car’s Index, Angle of Repose and Hauser’s Ratio.The percentage yield was determined using following formula-
The FT-IR spectra of prepared CLN complex
were obtained over the range 400- 4000cm-1 in dry KBr (50mg) and
samples (1-2mg). DSC analysis
was performed using Samples (3-5 mg) by crimped in non-hermetic aluminium pans
with lids and scanned from 50 to 300ºC at a heating rate of 10ºC/min under a
continuously purged dry nitrogen atmosphere (flow rate 20mL/ min). The
instrument was equipped with a refrigerated cooling system. The XRD pattern of both drug complex were recorded under the
conditions: voltage 35 kV, 20 mA, angular range 5, divergence slit 10, and
receiving slit 0.15 mm. Surface morphology was determined using a scanning
electron microscope (SEM), operated at low accelerating voltage of about 15KV
with load current about 80mA19-22. The solubility studies of CLN,
and their prepared complex were carried out in water and Menthol/water (70:30)
solution and analyzed using a UV spectrophotometer and compare23.
The pH values of solubility media (water), mannitol solution (30 mg/ml), and
solutions of EASDs (30 mg/ml) of individual drugs were measured at 22°C using a
pH meter (Seven Easy pH; Mettler).
Stability Studies of CLN
complex:
Stability study
of optimized formulation batch of prepared complex were stored at 40C
± 20C and 75% ± 5% RH for 3 months to access their
stability were compliance with WHO guidelines for stability testing. After 30, 60, 90 days sample were withdrawn
and determined solubility efficiency, color, M.P., and percentage assay24-25.
RESULTS:
CLN was found to be
similar to the organoleptic properties standard reported in I. P.M. P. of CLN Pure drug was found 225-228
ºC (Reported 222-231oC,
IP-2014). Results of Solubility studies reported in Table 3. λmax for CLN was found 270 nm, Fig.
4. All Micrometric Property values were found to be in range, indicating
good flow property of the API, Table 4. Results of particle size distribution
reported in Table 5 and Fig. 5.
Table 3: Solubility of CLN pure drug
|
S. No.
|
Clarithromycin PureDrug
|
|
|
Solvent
|
Inference
|
|
1.
|
Distilled water
|
Insoluble (0.33mg/ml)
|
|
2.
|
0.1 N HCL
|
soluble
|
|
3.
|
Methanol
|
Freely soluble
|
|
4.
|
Acetone
|
Freely soluble
|
|
5.
|
Ethanol (95%)
|
Slightly soluble
|
|
|
|
|
|
Fig. 4: Lambda max pure clarithromycin
Table 4:Values of
Micrometric Property for CLN pure
|
S. No
|
Micromeretics parameters
|
CLN Pure Drug
|
|
Reported values
|
Observed values
|
|
1.
|
Angle of
repose(◦)
|
31º-35º
|
35º± 2.01
|
|
2.
|
Bulk density (gm/cm3)
|
0.31-0.37
|
0.35±
0.02
|
|
3.
|
Tapped Density (gm/cm3)
|
0.35-0.44
|
0.38±
0.02
|
|
4.
|
Hausner’s Ratio
|
1.25-1.5
|
1.26±0.2
|
|
5.
|
Compressibility (%)
|
15-19
|
17±0.24%
|
Table 5: Particle Size Distribution
of CLN pure
|
Code
|
Frequency (µm)
|
0-10
|
10-20
|
20-30
|
30-40
|
40-50
|
50-60
|
60-70
|
70-80
|
80-90
|
90-100
|
|
CLN
|
Count(no.)
|
12
|
25
|
77
|
190
|
230
|
350
|
168
|
120
|
30
|
20
|
Fig 5: Particle Size distribution of CLN(pure)
Results of
Characterization/Evaluation for CLN complex:
M. P. of prepared complex
was found with in rang as per reported M. P. Micrometric studies was found good
flow properties of complex reported in Table 6. Results of %yield reported in
Table 7.FTIRspectra’s of
prepared complexes (SDMs and EASDs) with pure drug, it was found a change in
the spectra of both SDMs (F2) and EASDs (F4) as compared to the pure drug,
Fig.6. DSCresult, Fig. 7, indicated that the melting point of CLN complex (SDM and
EASDM) is greater than clarithromycin pure drug; whereas the EASDs show good
melting peaks as compare to SDMs peaks. PXRD analysis of clarithromycin complex of SDMs and EASDM show several weak peaks, Fig.
8, compared to pure clarithromycin. The disappearance of diffraction peak is
attributed to the reduced particle. SEM images of pure CLN with its complexes F2 (SDM) and F4 (EASDM)
reported in Fig. 9, 10 and 11.
Table 6: Micrometric properties of CLN complex
|
S. No
|
Code
|
SDM method
|
|
Bulk
Density
|
Tapped
Density
|
Carr’s
Index (%)
|
Hausner’s Ratio
|
Angle of Repose(◦)
|
|
1.
|
F1
|
0.34±0.01
|
0.36±0.01
|
15 ± 1.12%
|
1.25
|
32º ± 1.01
|
|
2.
|
F2
|
0.35±0.02
|
0.38±0.02
|
17±0.24%
|
1.26
|
35º±2.02
|
|
3.
|
F3
|
0.36±0.01
|
0.42±0.01
|
15 ± 0.99%
|
1.25
|
34º ± 1.01
|
|
|
|
EASD method
|
|
1.
|
F1
|
0.32±0.01
|
0.36±0.02
|
15 ± 0.27%
|
1.25
|
32º ± 1.01
|
|
2.
|
F2
|
0.34±0.02
|
0.41±0.01
|
15 ± 0.43%
|
1.25
|
34º ± 1.01
|
|
3.
|
F3
|
0.32±0.01
|
0.36±0.02
|
15 ± 0.42%
|
1.24
|
33º ± 1.02
|
|
4.
|
F4
|
0.35±0.02
|
0.38±0.02
|
17±0.24%
|
1.26
|
35º±2.02
|
|
5.
|
F5
|
0.33±0.01
|
0.40±0.01
|
15 ± 0.43%
|
1.25
|
34º ± 1.02
|
|
6.
|
F6
|
0.36±0.02
|
0.43±0.01
|
15 ± 0.27%
|
1.26
|
34º ± 1.01
|
Table 7:Percentage Yield of CLN complex
|
S. NO.
|
Batch Code
|
SDM method
|
|
Theoretical
Yield (mg)
|
Practical
Yield(mg)
|
% Yield
|
|
1.
|
F1
|
40
|
33
|
82.5%
|
|
2.
|
F2
|
50
|
34
|
68%
|
|
3.
|
F3
|
60
|
57
|
95%
|
|
|
EASD Methods
|
|
1.
|
F1
|
800
|
682
|
85.25%
|
|
2.
|
F2
|
550
|
480
|
87.27%
|
|
3.
|
F3
|
660
|
402
|
60.90%
|
|
4.
|
F4
|
610
|
430
|
70.49%
|
|
5.
|
F5
|
400
|
297
|
74.25%
|
|
6.
|
F6
|
500
|
280
|
56%
|
FTIR spectra of Clarithromycin (pure)
FTIR spectra
of CLN complex using SDM [F2]
FTIR spectra of CLN complex F4 [EASDM]
Fig 6. FTIR spectra of
pure CLN and optimized complex [F2 and F4]
DSC
Spectraof CLN (Pure)
DSC
spectra of CLN complex using SDM [F2]
DSC
spectra of CLN complex using (EASD)
[F4]
Fig 7:DSC spectra of CLN and
Optimized complex
PXRD
spectra of clarithromycin (pure)
PXRD of Clarithromycin
complex using SDM [F2]
PXRD of Clarithromycin
complex F4 [EASDM]
Fig 8. PXRD spectra of pure CLN and optimized complex [F2 and F4]
Fig. 9:SEM structure of Clarithromycin (pure)
Fig. 10:SEM structure of Clarithromycin complex using
SDM (F2)
Fig. 11: SEM structure of Clarithromycin complex using
EASD (F4)
Solubility of clarithromycin complexusing SDM and EASD
method, indicated that solubility of both SDM (F2) and EASD (F4) was increased
as compare to the pure drug. Results are reported in Table 8 and Fig 12.The
percent (%) drug content of all batches of SDMs and EASDs of CLN complex was
found within range between 60%-97.5% which was within the limits of IP
specifications, Table 8 and Fig. 13. Results of stability studies and assay
reported in table 9.
Table 8: Water Solubility sand %drug content of CLN
complex
|
Batch code
|
Pure CLN (mg/ml)
|
Complex SDM
|
% Drug Content
± SD (n=3)
|
|
Pure Drug
|
0.33mg/ml
|
-----
|
----
|
|
F1
|
----
|
0.43
|
60 ± 0.48
|
|
F2
|
----
|
1.14
|
96 ± 0.70
|
|
F3
|
----
|
1.05
|
72 ± 0.46
|
|
|
|
EASD complex
|
|
|
F1
|
----
|
0.42
|
60 ± 0.46
|
|
F2
|
----
|
1.10
|
69 ± 0.39
|
|
F3
|
----
|
0.38
|
76±0.48
|
|
F4
|
----
|
2.3
|
97±0.44
|
|
F5
|
----
|
0.45
|
81±0.36
|
|
F6
|
----
|
1.10
|
85±0.46
|
Fig. 12:Solubility of CLN complex SDM (F2) and EASD
(F4) methods
Fig. 13: %Drug
content of CLN complex SDM (F2) and EASDM (F4)
Table 9: Stability Study and %assay of CLN complex SDM
(F2) and EASDM (F4)
|
Time
|
Solubility
Efficiency of F2 (SDM)
|
Color
|
Melting Point
|
% Assay
|
|
Initial
|
1.14
|
White-off-white
|
167-169ºC
|
99
|
|
After Storage
|
|
1months
|
1.14
|
White-off-white
|
167-169ºC
|
98
|
|
2months
|
1.13
|
White-off-white
|
164-166ºC
|
97
|
|
3months
|
1.12
|
White-off-white
|
161-163ºC
|
97
|
|
Time
|
Solubility
Efficiency of F4 (EASDM)
|
Color
|
Melting Point
|
% Assay
|
|
Initial
|
2.3
|
White-off-white
|
189-191ºC
|
99
|
|
After Storage
|
|
1months
|
2.3
|
White-off-white
|
189-191ºC
|
98
|
|
2months
|
2.2
|
White-off-white
|
186-188ºC
|
97
|
|
3months
|
2.1
|
White-off-white
|
183-185ºC
|
97
|
DISCUSSION:
Micrometric properties of pure drugs as well as for
SDMs and EASDs complex indicate god flow properties.The
result shows that the melting point of clarithromycin complex (SDM and EASD) is
greater than clarithromycin pure drug; whereas the EASDs show good melting
peaks as compare to SDMs peaks. These fact simply that complex of SDMs and
EASDs of clarithromycin are crystalline in nature. XRD analysis of clarithromycin
complex show several weak peaks compared to pure clarithromycin, it is cleared that particle size will
decreased. SEM image indicate good shape and size. Solubility of CLN complex was
increased as compare to the pure drug but SDMs [F2] and EASDM [F4] show good
solubility, in which F4 (EASDM) have more solubility than F2 (SDM). Stability
studies indicating that optimized formulation is stable.
CONCLUSIONS:
Effervescence
assisted solid dispersion technique (EASD) provides an increase in the
solubility of poorly water soluble drugs Clarithromycin. This technique can
also be exploited for other poorly soluble drugs to enhance their solubility.
ACKNOWLEDGEMENT:
The authors very
sincere thankful to Shambhunath Institute of Pharmacy, Allahabad for providing the
facilities of this research work.
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