Dissolution Enhancement of BCS Class 4 Dssrugs Using Quality by Design Approach with Solid Dispersion Technique

International Journal of Pharmaceutical Science Invention
ISSN (Online): 2319 – 6718, ISSN (Print): 2319 – 670X
www.ijpsi.org Volume 6 Issue 1 ‖ January 2017 ‖ PP. 21-37
www.ijpsi.org 21 | P a g e
Dissolution Enhancement of BCS Class 4 Dssrugs Using Quality
by Design Approach with Solid Dispersion Technique
Pande S.V.1
*, Biyani K.R.2
1
Research Scholar, Anuradha College of Pharmacy, Anuradha Nagar, Sakegaon Road, Chikhli, 443201, India.
2
Principal, Anuradha College of Pharmacy, Anuradha Nagar, Sakegaon Road, Chikhli, 443201, India.
Abstract: Solid dispersion is one of the vastly accepted and practically economical processes in bioavailability
enhancement study. The present investigation deals mostly with increase in solubility and dissolution rate of
BCS class 4 drugs for enhancement of oral bioavailability. For the same solid dispersion were prepared and
analyzed for appropriate concentration of drug polymer ratio by phase solubility analysis. The solvent
evaporation study widely accepted due to its efficient solid dispersion in lesser efforts. The study designs were
prepared with specific concentration of drug and polymer ratio with the help of high throughput model i.e.
Central Composite Design (by Design Expert trial copy) by specific design of experiment with full factorial
design (DOE). The fixed variables were concentration of polymers and dependant variables were dissolution
and permeability across bio-membrane in in-vitro model. The prepared dispersion investigated for dissolution
and permeability improvement using USP Type II apparatus and modified everted gut sac model which leads to
improvement of quality of whole formulation with Quality by design efficiently.
Keywords: Cefuroxime axetil, Bioavailability enhancement, Dissolution study, Solid Dispersion, Quality by
Design (QbD), Design of Experiments (DOE).
I. Introduction
BCS class 4 drugs are the drugs having low solubility and permeability according to classification
system given by Amidon et. al. in 1995. These drugs are formulated such that it is made more permeable and
more soluble with help of different formulation techniques. Solid dispersion is the technique primarily used
vastly by various researcher due to its simplicity, economical with Solvent evaporation method1
. BCS class 4
drugs used for present study are Cefuroxime Axetil, Cefpodoxime Proxetil, Furosemide. Cefuroxime Axetil is
the second generation Beta Lactam antibiotic is acted with binding to specific penicillin-binding proteins which
are generally located inside the bacterial cell wall. The proteins generally inhibit the bacterial cell wall synthesis
and causes cell lysis by interfering with an autolysin inhibitor. Cefpodoxime proxetil is an orally administered,
extended spectrum, semi-synthetic antibiotic of the cephalosporin class. It inhibits bacterial cell wall synthesis
by interfering by its ability of covalently binding to the penicillin-binding proteins. Furosemide inhibits
primarily the reabsorption of sodium and chloride not only in the proximal and distal tubules but also in the
loop of Henle these drugs are selected as they include in BCS class 4 drugs2,14
.
The DOE with full factorial design is widely used for optimization of pharmaceutical dosage
formulation process and excipients concentration depends upon response surface plot of individual polymer
responsibility in optimized result. DOE is systematic tool for increasing efficiency development of
pharmaceutical dosage forms and helps in improvement of research and development work. The Factorial
designs advantageous statistical method as all the factors are studied in all possible combinations for estimating
the influence of individual variables and their interactions using minimum experiments. The factorial design
applies relationship in dependant variables and their interrelations and study systematically its affect on
independant variable and ultimately quality of output in pharmaceutical formulation development3
. The
graphical representation can be evaluated with the help of surface response and contour plot, which generated
by statistical software gives a visual representation of the results of the desired responses and it also gives
model equation shows response as a function of the different variables. Solid Dispersion is the carrier linked
drug delivery system. The objective of the present study to design and develop highly solubilised formulation of
BCS class 4 drugs. The formulation designed such that release of the drug enhanced and was evaluated for in
vitro drug release, permeability and drug content. The known mechanism behind solid dispersion is
incorporation of drug into a water-soluble polymer matrix which can leads to increase in drug dissolution rate
and their saturation solubility in the gastrointestinal fluids. The Analysis of variance (ANOVA) can be
neglected over design of experiments as ANOVA is generally used for compare the relativity of the two
different ingradients in formulation considerations but use of factorial design experiment is indicating the
relative significance of a number of variables in the formulation. In addition, it offers way of analyzing the
results to decide on most significant variables. The maximum outcome can be drawn out of with the use of a

Dissolution Enhancement of BCS Class 4 Drugs Using Quality by Design Approach with Solid ..
small number of experiments possible due to factorial design. In addition, they allow a means of assessing
interactions which exist between different variables over the response4-6
.
The wetting and water solubilising carrier is Polyvinylpyrolidone K30 adsorbs on surface of drug and
enhance the bioavailability13
.
The other used amphiphilic chemical polymeric solubilizer is Soluplus, which was particularly
developedforsolidsolutions. The action of soluplus of increased in bioavailability is due to formation of amatrix
polymerforsolidsolutions on the other, it is capable of solubilizing poorlysoluble drugs in aqueous media. Soluplus is
a polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol graft co- polymer7
Materials
Cefuroxime Axetil, Cefpodoxime Proxetil, Furosemide was a generous gift from Swapnroop Drugs. PVPK and
soluplus was obtained from Anuradha College of Pharmacy, Chikhli. All excipients and solvents used were of
analytical grade.
Methods
Determination of drug content
The percent drug content of each solid dispersion, was determined using powder equivalent to 10 mg
API and was dissolved in minimum amount of methanol and volume was made up to mark 100 ml using buffer.
The solution was then filtered through Whatman filter paper and required dilution were being made and assayed
for drug content using UV double beam spectrometer (Shimadzu Corporation, Japan. UV -1601). Three
replicates were prepared and average value was reported8, 9
.
FTIR studies
The FTIR spectra of the drug, polymers and solid dispersion in specific ratio were recorded with FTIR
spectrophotometer. The FT-IR spectra of the agglomerates and the pure drug were recorded on Shimadzu
IRAffinity-1S spectrophotometer (Shimadzu Corporation, Kyoto, Japan). Background spectrum was obtained
under identical conditions. Each spectrum was derived from single scan collected in the region 400 – 4000 cm-1
at a spectral resolution of 2 cm-2
and rationed against background scan of KBr. The samples also mixed and
trturated with KBr and forms a mass in DRS unit attached to IR spectrophotometer.
DSC Studies
Differential scanning calorimetric (DSC) analysis of the samples was carried out with a DSC analyzer
(SIIO, Japan, Model: SIIO 6300 with Auto-sampler). A sample (3-7 mg) was sealed in an aluminum pan with a
perforated lid and heated under nitrogen atmosphere at a heating rate of 10°C/min over the temperature range of
40 – 400°C. The thermograms were obtained and recorded with heat flow and temperature with empty pan as
reference.
XRD Studies
The XRPD patterns of the samples were monitored with an X-ray diffractometer (Model: D8 Advance Make:
BRUKER, Germany) using Ni filtered CuKα radiation. The samples were analyzed over 2 range of 5.010-
39.990o
with scanning step size of 0.020° (2θ) and scan step time of one second.9
Mathematical kinetic assessment for drug release mechanism
Release kinetics is an integral part for the development of a dosage form because if the kinetics of drug
release is known, one can also established in vivo in vitro (IVIVC) correlation. Mathematical approach is one of
scientific methods to optimize and evaluate the error in terms of deviation in the release profiles of formulated
products during the formulation development stage. Mathematical model approach important in research and
development because of its simplicity and their interrelationships may minimize the number of trials in final
optimization, thereby improving the formulation development process. The dissolution profile of the optimized
batch was fitted to the different kinetic models.
In vitro drug release data were fitted to kinetic models Qt versus t (zero order) Log (Q0-Qt) versus t
(first order) Qt versus square root of t (Higuchi) log %Qt versus log %t (Korsmeymer-Peppas) Where Qt is the
amount of drug released at time t. The criteria for selecting the most appropriate model are highest R2
value.
Highest R2
value indicates linearity of dissolution data.13
Phase solubility Studies
Solubility measurements were performed in triplicate using the method reported by Higuchi and Connors. An
excess amount of drug of about (100 mg) was added to 25 ml distilled water containing increasing
concentrations of the Polymer (i.e., 0.1%, 0.2%, 0.3%, 0.4%, 0.5% w/v). The flasks were sealed and shaken at

room temperature (28°C) for 24 h on a shaker, and the samples were filtered through a 0.22-μm whatman filter
paper. The filtrate was suitably diluted and analyzed at UV-Vis. spectrophotometer (model no: 1601, Shimadzu,
Japan) at specified wavelength 15
.
Formulation with 32
factorial design (central composite design)
A central composite design is used to systematically study the influence of the individual and
combined effect of independent variables i.e. numeric factors which can control by us in formulation. They are
X1 and X2. From this independent variables affect on dependant variables i.e. drug dissolution after 2 hrs (D2)
and Permeability after 4 hours (P4). In present study, two independant factors are evaluated, and experimental
trials are performed at all nine possible combinations and record their dependant variables. Statistical model
central composite design was selected as two independant variable to study in development of the dosage form
in order to find their individual and combined effects on the dependent variables. Response surface and contour
plots shows the interaction between different variables. A mathematical quadratic regression model was
developed for predicting system responses within selected experimental conditions. Experimental data were
fitted according to the following polynomial equation calculated by multiple regression analysis:
Y= b0+ b1X1 +b2X2+ b12X1X2 + b11X1
2
+ b22X2
2
Where Y is the dependent variable, b0 is the arithmetic mean response of the 9 runs; and b1 and b2 are
the estimated coefficients for the independent factors X1 and X2, respectively. The main effects (X1 and X2)
represent the average result of changing one factor at a time from its low to high value. The interaction term
(X1X2) shows how the response changes when factors are simultaneously changed. The polynomial terms (X1
2
and X2
2
) are including investigating nonlinearity. A statistical model, which consists of interactive and
polynomial terms, was utilized to evaluate the responses. The responses were analyzed using analysis of
variance (ANOVA) and the individual response parameters were evaluated using F test and polynomial
equation was generated for each response using multiple linear regression analysis.15
Preparation of solid dispersion
Physical mixtures were prepared by mixing accurate weight of API with PVPK, Soluplus in drug:
polymer ratio of 1:1 (1:2 for polymers ratio) as per table 1. The powder blend was passed through sieve no 40.
The resultant mixture was further kept for evaporation by stirring under mechanical stirrer using a three blade
propeller to form a thick and high viscous form and transferred into petri plate, then dried under reduced
pressure. The dried mass was pulverized, passed through 60 mesh sieve size, then weighed, transferred to sealed
pouch. Stored in a desiccators. The procedure was repeated with different concentration of polymers according
to the factorial design.17
Optimization of solid dispersion using 32
full factorial designs
Response surface methodology (RSM) is characteristically employed to relate a response variable to the levels
of the input
Code Polymer -1 0 +1
X1 PVPK 30 116.66 166.66 216.66
X2 Soluplus 33.33 83.33 133.33
API Cefuroxime Axetil, / Cefpodoxime Proxetil/ Furosemide 250
Table 1: Batch code Variable levels in coded form Drug: Polymer Actual quantity of drug and polymer
Taking drug polymer ratio 1:2 at middle step (i.e at position “0” and ±10 for PVPK and ±10 for
SOLUPLUS (2:1 polymer ratio in complex). A 32
full factorial design(central composite design) was employed
to study the effect of independent variables, i.e., PVPK 30 (X1) and Soluplus (X2) on dependent variables
permeability; drug released up to 2 h. Contour or RSM plots for each response were generated using the
DESIGN EXPERT (STAT-EASE) demo version software. Variables level Low (−1) Medium (0) High (+1).
Run Number Trial Code Run
1 -1 0
2 -1 1
3 -1 -1
4 0 1
5 0 -1
6 0 0
7 1 0
8 1 -1
9 1 1
Table 2: Runs for Coded levels of factors

In vitro drug release studies
In vitro drug release profile of the drug from Solid dispersion carried out by the dissolution test
according to USP 23. Dissolution studies performed using USP apparatus type-I i.e., basket type at a
temperature of 37 ± 0.5°C. Studies were carried out in 900 ml of phosphate buffer pH 7, at 50 rpm and for
cefuroxime axetil. 900ml of Glycine Buffer pH 3.0, RPM 75 prepared for cefpodoxime proxetil. For
Furosemide dissolution media was phosphate buffer pH 5.8, volume 900 mL. at 50 rpm. The dissolution was
continued in phosphate buffer till 2 h. Samples were withdrawn at a predetermined time intervals and replaced
with fresh media. Samples were filtered and then analyzed using ultraviolet-visible spectrophotometer at λmax
280 nm, 233 nm, 274 nm for cefuroxime axetil , cefpodoxime proxetil, furosemide respectively for
determination of drug content.
Drug permeability study
Drug permeability study was performed using Modified Wilson and Krane apparatus. Solid dispersion
containing 50 mg drug were taken and the powdered dispersion were dispersed in 5ml of respective buffer
solution and added in the outer receiver compartment, prepared gut sac of chicken ileum which tied to thread at
one end and glass canula at other. It was suspended in receiver compartment having canula at the top filed with
buffer above 1-2 cm from height in canula the whole assembly maintained at 37°±0.5°C and. After specific time
period the samples were collected and analyzed for the drug content 16
.
II. Results And Discussion
Actual Drug Content
The percent drug content of each solid dispersion was determined to measure the dose uniformity of the
formulation using powder equivalent to 10 mg API and assayed by UV spectrophotometer for drug
concentration and reported in table.
Sr. No. PVPK SOLUPLUS Actual Drug Content (%)
Cefuroxime Axetil Cefpodoxime proxetil Furosemide
1 0 -1 99.53±0.686 98.47±0.729 96.6± 0.636
2 0 1 98.87±0.729 98.47±0.569 97.76±0.177
3 -1 1 99.51±1.090 99.7±0.6497 100.45±0.578
4 1 1 100.58±0.654 100.67±0.663 98.57±0.7
5 1 -1 98.32±1.026 99.68±0.519 99.77±0.559
6 -1 0 99.92±0.971 99.33±0.505 100.64±0.41
7 -1 -1 99.29±1.236 97.49±1.050 100.54±0.661
8 1 0 98.99±1.0154 99.36±0.2325 100.17±0.428
9 0 0 99.62±1.141 98.28±1.28 98.29±0.690
Table 3: Actual Drug Content
FTIR studies
Fig 1. Overlay FTIR Spectra of Cefuroxime Axetil Solid Dispersion

Table 4: FTIR Cefuroxime Axetil
Sr No Functional Group Range Actual Value
1 Aromatic- CH(Streching) 3000-3100 cm-1
3037.89 cm-1
2 Aliphatic –CH(Streching) 2850-2900cm-1
2885.51 cm-1
3 Amide 1750-1800cm-1
1780.30 cm-1
4 -COOR 1725-1750cm-1
1732.08 cm-1
5 Carbonyl Group 1650 – 1700 cm-1
1685.79 cm-1
6 -C=O (out of plane) 1200-1400 cm-1
1300.02 cm-1
7 -C-N 1080-1200 cm-1
1155.36 cm-1
8 -C-S 600-700 cm-1
669.30 cm-1
Table 5: FTIR Solid Dispersion of Cefuroxime Axetil
From above peak positions distinct peaks of hydroxyl group and aromatic group is low intense which
can conclude that the formation of solid dispersion i.e physical complex between excipient and cefuroxime
axetil. Also other than above characteristic peaks are absent which suggest no interaction between cefuroxime
axetil and excipients in formulation.
Fig. 2: Overlay Spectra of Cefpodoxime Proxetil Solid Dispersion
1 -NH (pri. Amine) 3500-3600cm-1
3560.59 cm-1
2 -NH (sec amine) 3250-3300cm-1
3229.14 cm-1
3 Aromatic- CH 3000-3100 cm-1
3057.17 cm-1
4 Aliphatic –CH 2850-2900cm-1
2893.22 cm-1
5 Amide (cefum ring) 1750-1800cm-1
1786.08 cm-1
6 -COOR 1725-1750cm-1
1737.86 cm-1
1680.00 cm-1
8 -C=O (out of plane) 1200-1400cm-1
1346.31 cm-1
9 -C-N 1080-1200 cm-1
1145.72cm-1
10 -C-S 600-700 cm-1
665.44 cm-1
Table 6: FTIR of Cefpodoxime Proxetil
1 -OH 3500-3650cm-1
3649.32 cm-1
2 -NH Streching 3450-3500cm-1
3491.16 cm-1
3 Aromatic- CH(Streching) 3000- 3100cm-1
3041.74cm-1
4 Aliphatic –CH(Streching) 2850-2900cm-1
2825.72 cm-1
5 Amide (cefum ring) 1750-1800cm-1
1786.08 cm-1
6 -COOR 1725-1750cm-1
1734.01 cm-1
7 Carbonyl Group 1650–1700 cm-1
1681.93 cm-1
8 -C=O (out of plane) 1200-1400cm-1
1303.88 cm-1
9 -C-N 1080-1200 cm-1
1151.50 cm-1
10 -C-S 600-700 cm-1
673.16cm-1

1 Amine (pri. and sec.) 3500-3600 cm-1
3585.67 cm-1
2 Aromatic -CH(Streching) 3000-3100 cm-1
3066.82 cm-1
2883.58 cm-1
4 Amide 1750-1800cm-1
1786.08 cm-1
5 -COOR 1725-1750cm-1
1726.29 cm-1
1681.93 cm-1
7 -C-N 1080-1200 cm-1
1145.72 cm-1
8 -C-S 600-700 cm-1
688.59 cm-1
Table 7: FTIR Solid Dispersion of Cefpodoxime Proxetil
No other characteristic peaks were observed in the IR spectra of formulations which indicated the absence of
any interaction between drug and polymers
Fig.3: Overlay FTIR Spectra of Furosemide Solid Dispersion
1 -NH (pri. And sec.) 3300-3400cm-1
3348.42 cm-1
2 Aromatic- CH 3000-3100 cm-1
3041.74 cm-1
2835.36 cm-1
1674.21 cm-1
5 C-O-C 1050-1150cm-1
1074.35 cm-1
6 S=O 1030-1060 cm-1
1053.13 cm-1
7 -C-Cl 600-700 cm-1
644.22 cm-1
Table 8: FTIR Furosemide
1 Amine (pri. and sec.) 3300-3400 cm-1
3356.14 cm-1
2 Aromatic –CH(Streching) 2900-3100 cm-1
2958.80 cm-1
2854.65 cm-1
4 -COOR 1725-1750cm-1
1745.58 cm-1
1674.21 cm-1
6 C-O-C 1050-1150cm-1
1089.78 cm-1
7 S=O 1030-1060 cm-1
1035.77 cm-1
8 -C-Cl 600-700 cm-1
684.73 cm-1
Table 9: FTIR Solid Dispersion of Furosemide
All the above characteristic peaks appear in the spectra of all binary systems at same wave number indicating no
modification or interaction between the drug and carrier.

DSC Studies
Fig.5: DSC of Cefuroxime Axetil Fig. 6: DSC of SD (Cefuroxime Axetil, PVPK and
Soluplus)
The DSC studies performed to understand heat effect on given dispersion. The DSC thermogram of
CA exhibited a sharp endothermic peak at 88.80° and 180.73°. Whereas, solid dispersion exhibited an
endothermic peak at 131.41° and 177.28° indicates the formation of Solid Dispersion and drug shows
exothermic peak at 250.02° and solid dispersion shows broad exothermic peak 260.48°. This suggests drug
might formed complex with carrier.
Fig. 7: DSC of Cefpodoxime Proxetil Fig. 8: DSC of SD (Cefpodoxime Proxetil, PVPK
and Soluplus)
The results of DSC of pure cefpodoxime proxetil shows broad endotherm at 95.55°, whereas in case
formulation shift of melting endotherm to 60.93°, and 216.95° and exotherm could not be differentiated after
larger endotherms appeared which shows the formation of solid dispersion.
Fig. 9: DSC of Furosemide Fig. 10: DSC of SD (Furosemide, PVPK and
Soluplus)

The DSC plot of pure furosemide drug powder shows a sharp endothermic peak 222.95°C followed by
endotherm at 275.94° C, in the formulaton endothermic peaks were observed at the temperature 96.15°C and
218.66° C which results the solid dispersion formation confirmation.
XRD Studies
Fig 11: XRD of Cefuroxime Axetil Fig 12: XRD of Cefuroxime Axetil, PVPK-30
and Soluplus
The XRD study performed for determination of crystal habit of pure drug and effect of solid dispersion
on drug and polymer. The XRD patterns of drug, showed presence of significant sharp peaks indicated that the
drug is in somewhat crystalline state. However, the XRD pattern of SDs showed characteristic reduced intensity
of peaks no new intensity peaks were observed. This confirmed that the drug is present in amorphous state in
SD.
Fig.13 : XRD of Cefpodoxime Proxetil Fig. 14: XRD of SD (Cefpodoxime Proxetil,
PVPK and Soluplus)
The diffraction spectra of Cefpodoxime Proxetil doesn’t show any intense peaks which leads to conclusion that
the drug is present in amorphous state and solid dispersion with soluplus,
Fig. 15: XRD of Furosemide Fig. 16: XRD of SD (Furosemide, PVPK and
Soluplus)

The XRD pattern of furosemide shows intense and sharp peaks that prove the crystalline nature of the
compound. The solid dispersion of furosemide with PVPK and soluplus show undefined, broad, diffuse peaks
of low intensities. This feature indicates the formation of a significant amount of amorphous material.
Standard Calibration Curve
The drug evaluated for formulation before their formulation. The absorbance maxima of the individual drug
determined with their respective buffer solutions. Standard Calibration Curve of Cefuroxime Axetil was prepared in
7.0 pH phosphate buffer at λmax 280 nm. Standard Calibration Curve of Cefpodoxime Proxetil was prepared in 3.0 pH
phosphate buffer at λmax 233nm.Standerd Calibration Curve of Furosemide was prepared in 5.8 pH phosphate buffer
λmax 274nm. Using UV-Visible spectrophotometer. For this stock solution of 1000 µg/ml was prepared. Serial
dilutions of 5, 10, 15, 20, 25 µg/ml were prepared and absorbance was taken. Averages of 3 sets of values were taken
for standerd calibration curve, and solutions were scanned in the range 200-400 nm against blank. The calibration
curve was plotted.
Fig. 17: Absorbance Maxima of Cefuroxime
Axetil at 280 nm
Fig. 18: Absorbance maxima of Cefpodoxime
Proxetil at 233 nm
Fig. 19: Absorbance maxima of Furosemide at 274 nm
Standard Calibration Curve of Cefuroxime Axetil
Concentration (µg/ml) Absorbance (nm)
0 0
5 0.7905±0.012
10 1.6078±0.05
15 2.3699±0.11
20 3.0679±0.15
25 3.9133±0.008
Table 10: Standard Calibration Curve of
Cefuroxime Axetil
Fig. 20: Standard Calibration Curve of Cefuroxime Axetil

Standard Calibration Curve of Cefpodoxime Proxetil
Concentration (µg/ml) Absorbance(nm)
0 0
5 0.7905±0.082
10 1.3944±0.157
15 2.1072±0.021
20 2.7445±0.089
25 3.3876±0.28
Table 11: Standard Calibration Curve of
Cefpodoxime Proxetil
Fig. 21: Standard Calibration Curve of Cefpodoxime Proxetil
Standerd Calibration Curve of Furosemide
Concentration (µg/ml) Absorbance (nm)
0 0
5 0.5926±0.0362
10 1.312±0.0046
15 1.9876±0.035
20 2.608±0.179
25 3.1937±0.138
Table 12: Standerd Calibration Curve of
Furosemide
Fig. 22: Standerd Calibration Curve of Furos
Fig. 22: Standerd Calibration Curve of Furosemide
Solid Dispersion Formulations
Phase Solubility Study
Sr.
No.
Polymer Conc.
(% w/v)
Drug
Concentration
(µg/ml)
1 0.1 1.254± 0.32
2 0.2 2.283± 0.83
3 0.3 3.4553± 0.11
4 0.4 5.1047± 0.25
5 0.5 7.8386± 0.093
Table 13: Phase Solubility Study of PVPK-
30 and Cefuroxime Axetil
Fig.23 : Phase Solubility Study of PVPK 30 and Cefuroxime
Axetil

Table 14: Phase solubility Study of Soluplus and
Cefuroxime Axetil
Fig. 24: Phase Solubility Study of Soluplus and
Cefuroxime Axetil
Sr No Polymer Conc
(% w/v)
Drug
Concentration
(µg/ml)
1 0.1 1.081 ± 0.112
2 0.2 1.483± 0.111
3 0.3 2.655± 0.048
4 0.4 4.504± 0.174
5 0.5 6.738± 0.30
Table 15: Phase Solubility Study of PVPK 30 and
Cefpodoxime Proxetil Fig. 25: Phase Solubility Study of PVPK 30 Cefpodoxime Proxetil
Sr No
Polymer Conc
(% w/v)
Drug
Concentration
(µg/ml)
1 0.1 1.081± 0.112
1 0.2 1.776± 0.19
2 0.3 2.872± 0.22
3 0.4 4.268± 0.31
4 0.5 5.526± 0.14
Table 16: Phase solubility Study of Soluplus
and Cefpodoxime Proxetil
Fig. 26: Phase Solubility Study of Soluplus and Cefpodoxime
Proxetil
Sr.
No.
PolymerConc
(% w/v)
Drug
Concentration
(µg/ml)
1 0.1 1.254± 0.32
2 0.2 2.276± 0.051
3 0.3 4.594± 0.11
4 0.4 5.412± 0.24
5 0.5 6.58± 0.16

Sr.
No.
Polymer Conc
(% w/v)
Drug
Concentration
(µg/ml)
1 0.1 0.891± 0.072
2 0.2 1.665± 0.138
3 0.3 2.555± 0.085
4 0.4 3.914± 0.124
5 0.5 5.988± 0.145
Table 17: Phase Solubility Study of PVPK-30
and Furosemide
Fig. 27: Phase Solubility Study of PVPK 30 and
Furosemide
Sr
No
Polymer
Conc
(% w/v)
Drug
Concentration
(µg/ml)
1 0.1 0.891± 0.072
2 0.2 1.666± 0.137
3 0.3 2.763 ± 0.124
4 0.4 3.748± 0.081
5 0.5 4.586± 0.112
Table 18: Phase solubility Study of Soluplus and Furosemide Fig. 28: Phase Solubility Study of Soluplus and
Furosemide
The phase solubility study determines capacity of polymer for drug entrapment. The different polymers
are used in solubility enhancement are according to their drug entrapment capacity.
The polymers gives here two types of phase solubility curve they are AL typre where every polymer
shows the increase in solubility of the drug by adding polymer which gives straight line in phase solubility
curve. Another type is AP in this curve due to the formation of secondary complexes of drug and polymer
which is more solubilised than the primary complexes hence the ratio of drug to polymer was selected higher in
concentration. In above curves the PVPK gives the curve of this type which suggests that the final concentraton
to be decided for PVPK-30 is double as it tends to forms secondary complex. Hence in formulation
concentration was decided 1:2 (Soluplus : PVPK-30) in drug polymer ratio previously decided 1:1 in solid
dispersion preparation.
Solid Dispersion
The solid dispersion of drug Cefuroxime axetil,/ Cefpodoxime Proxetil/ Furosemide and polymer
PVPK and soluplus were prepared by solvent evaporation method. The polymer as selected from the phase
solubility study for determination of solubility. The complex nature evaluated using hydrophilic polymers, due
to formation of soluble complexes and/or wetting action carrier. The stability constant determined by equation
S= slope/Ks(1-slope)
where S is apperant stability constant , Ks is solubility of drug in vehicle without carrier. the stability
constant of Cefuroxime axetil is 482.76 mg/mol. in PVPK , 1567.89 mg/mol in soluplus, Cefpodoxime proxetil
is 563.90 mg/mol in PVPK, 1391.87 mg/mol in soluplus , And furosemide is 940.83 mg/mol in PVPK, 2399.25
mg/mol in soluplus. The apperant stability constant should be more than 100 for prediction of stability of
complex in solution. Solubility of Cefuroxime Axetil in buffer is 0.0671mg/ml without carrier, while

Cefpodoxime Proxetil it is 0.0893 mg/ml and Furosemide it is 0.0436 mg/ml, the solubility constant of drug and
carrier complex was above 100 for each complex hence can be said as stable complex of drug and polymer in
solution. The phase solubility results indicated a linear increase of Cefuroxime axetil (r2
=0.991, slope=6.214),
Cefpodoxime Proxetil (r2
=0.992,slope=7.614), Furosemide (r2
=0.992,slope=6.92) solubility as a function of
polymer PVPK-30 concentration indicative of a AL type solubility diagram. In general, if the rise of
concentration of phase diagram linear i.e coefficient of line (R2
) value below near to 1, the complex
stoichiometry will be assumed to be 1:1 and such profiles according to Higuchi and Connors are of AL type.
Further in formulation study the central composite design was employed to study the effect of independent
variables (PVPK [X1] and Soluplus [X2]) on dependent variables dissolution study for 2 hours and permeability
up to 4 h. The polynomial equations for each response with their high magnitude of the coefficients and
mathematical sign indicate about the fit of the model. The final results were confirmed by outcome of the result
in vitro drug release and permeability study of optimised batch and its comparison with pure drug.
Factorial equation for dissolution study
Batch Run X1 X2 Dissolution(%) after 2 hrs Permeability (mg/ml)
1 1 0 19.71±0.04 1.3313±0.12
2 1 1 18.48±0.04 1.4371±0.17
3 0 0 17.05±0.1 1.1302±0.27
4 0 -1 19.9±0.26 0.6731±0.07
5 -1 1 15.9±0.06 2.1321±0.20
6 1 -1 21.4±0.255 1.2805±0.2
7 -1 0 16.7±0.10 1.3963±0.3
8 -1 -1 18.5±0.36 0.7169±0.1
9 0 1 17.8±0.35 1.5247±0.2
All values are expressed as mean±SD, (number of terms) n=3
Table 19: Characteristics of solid dispersion of Cefuroxime Axetil
Dependent
variables
Source of variation Sum of
squares
Degree of
freedom
F value P value
Source Std.
Deviation
R-
Square
Predicted R-
Square
Dissolution (T2) Linear 0.66 0.8925 0.8294 21.69 2 24.92 0.0012
Permeability Quadratic 0.032 0.9980 0.9810 0.15 2 74.76 0.0028
Table 20: ANOVA of independent variables
Final Equation in Terms of Coded Factors
The model proposes the following polynomial equation for percentage drug entrapment (Cefuroxime Axetil) by
Polymer:
Dissolution (Y) = 18.38 + 1..41X1 - 1.27X2
Permeability = 1.10-0.033X1+0.40X2-0.31X1X2+0.27X1
2
+8.133E-003X2
2
Design-Expert® Software
Factor Coding: Actual
Desirability
Design Points
X1 = A: PVPK
X2 = B: Soluplus
-1 -0.5 0 0.5 1
-1
-0.5
0
0.5
1
Desirability
A: PVPK
B:Soluplus
0 00
0.1
0.1
0.2
0.2
0.3
0.3
0.4
0.5
Prediction 0.616373
Figure 29: Contour and response surface methodology plot for Desirability study for optimization of the batch
indicating graphical and numerical optimization.

Batch Run X1 X2 Dissolution (%) after 2 hrs Permeability (mg/ml)
1 1 0 20.39 ± 0.19 1.2597± 0.16
2 1 1 20.06 ± 0.09 1.898 ± 0.201
3 0 0 18.71 ± 0.09 1.411 ± 0.255
4 0 -1 22.02 ± 0.76 0.7688± 0.179
5 -1 1 18.31 ± 0.06 2.257 ±0.213
6 1 -1 22.49 ± 0.38 1.093 ± 0.099
7 -1 0 18.22 ± 0.06 1.617 ± 0.108
8 -1 -1 20.21 ± 0.09 0.6298 ± 0.088
9 0 1 19.46 ± 0.04 1.5407 ± 0.178
Table 21: Characteristics of solid dispersion of Cefpodoxime Proxetil
Dependent
variables
squares
Degree of
freedom
F value P
valueSource Std. Deviation R-Square Predicted R-
Square
Dissolution (T2) Quadratic 0.43 0.9693 0.7563 3.5 2 9.28 0.0519
Permeability Linear 0.27 0.7996 0.4701 1.72 2 11.97 0.0081
Table 22: ANOVA of independent variables
Final Equation in Terms of Coded Factors
The model proposes the following polynomial equation for percentage drug entrapment (Cefpodoxime Proxetil)
by Polymer:
Dissolution (Y) = 19.18+ 1.03X1 - 1.15X2 – 0.13 X1X2 – 0.12 X1
2
+1.32 X2
2
Permeability (Y) = +1.39 - 0.042X1 + 0.53X2
Desirability
Design Points
X1 = A: PVPK
X2 = B: Soluplus
-1 -0.5 0 0.5 1
-1
-0.5
0
0.5
1
Desirability
A: PVPK
B:Soluplus
0
0
0
0.1
0.2
0.3
0.4
0.5Prediction 0.587
Figure 30: Desirability plot for optimization of the batch indicating graphical and numerical optimization.
Batch Run X1 X2 Dissolution (%) after 2 hrs Permeability (mg/ml)
1 1 0 16.53± 0.167 0.9568± 0.29
2 1 1 17.1± 0.77 1.224± 0.81
3 0 0 15.22 ± 0.55 1.047 ± 0.40
4 0 -1 18.21 ±0.286 0.6493 ± 0.47
5 -1 1 13.68± 0.236 1.83± 0.012
6 1 -1 17.81 ± 0.355 0.8322± 0.42
7 -1 0 14.34 ± 0.285 1.4272 ± 0.29
8 -1 -1 12.084 ± 0.304 0.6034±0.38
9 0 1 15.76 ± 0.477 1.271±0.83
Table 23: Characteristics of solid dispersion of Furosemide

Dependent
variables
squares
Degree of
freedom
F value P value
Source Std.
Deviation
R-
Square
Predicted R-
Square
Dissolution (T2) Linear 1.34 0.6694 0.2167 21.83 2 6.07 0.0367
Permeability Linear 0.14 0.9197 0.7321 0.17 2 8.83 0.0311
ANOVA: Analysis of variance
Table 24: ANOVA of dependent variables
Final Equation in Terms of Coded Factors:
The model proposes the following polynomial equation for percentage drug entrapment (Furosemide) by
Polymer:
Furosemide Dissolution = 15.64+1.89X1 -0.26X2
Permeability = 1.09 - 0.14X1 + 0.37X2 - 0.21X1X2
Desirability
Design Points
X1 = A: Pvpk
X2 = B: Soluplus
-1 -0.5 0 0.5 1
-1
-0.5
0
0.5
1
Desirability
A: Pvpk
B:Soluplus
0.2
0.3
0.4
0.5
0.6
Prediction 0.624379
Figure 31: Contour and response surface methodology plot for Desirability study for optimization of the batch
indicating graphical and numerical optimization.
The results of the equation showed that X1 (pvpk-30) has a positive effect on the drug release as shown
by the positive coefficient as compared to the X2 (soluplus) which showed a positive effect on the drug transport
across intestinal membrane as shown by the Constraints were set according to the formulation of solid
dispersion using the minimum amount of excipients, which would give desired response values i.e., good
dissolution and permeability across intestinal membrane. In optimization [Figure 30] maximum desirability was
achieved at (1 0.36) coded batch drug polymer ratio. Over lay plot of the desirability give the details of the
optimized batch giving the optimum results of the optimized batch, which were very closer to the results
obtained by the batch
Drug Goal Batch
Predicted
Dissolution
Actual
Dissolution
Predicted
Permeability
Actual
Permeability
Cefuroxime Axetil High Drug Release,
High Permeability,
In Range PVPK-30,
In Range Soluplus
1 -1 21.0672 21.4 1.263 1.2805
Cefpodoxime
Proxetil
1 1 20.1286 20.06 1.877 1.898
Furosemide 0.36* 1 16.06 16.11 1.34 1.31
*by taking 0.36=181.66 pvpk frm number line of code
Table 25: Constraints for responses

In vitro Drug Release Study of Pure Drug and Optimised batch
The In vitro drug release study of drug after solid dispersion with optimised batch and pure drug is as follows
Time (min) CA CP Fur CA (1 -1) CP (1 1) Fur (0.36 1)
0 0 0 0 0 0 0
10 0.0034±0.027 0.0048±0.0088 0.0036±0.0091 1.974± 0.254 2.833±0.191 1.086±0.057
20 0.0077±0.054 0.0083±0.010 0.0072±0.0096 4.2 ± 0.293 4.97± 0.155 3.98±0.128
30 0.0115±0.037 0.0126±0.014 0.0103 ±0.021 7.214 ± 0.55 8.26± 0.532 6.04± 0.170
60 0.0779±0.035 0.0894±0.111 0.0762± 0.013 11.98±0.6433 12.98±0.111 10.48±0.103
90 0.0829± 0.15 0.0983±0.104 0.0722± 0.064 17.347±0.510 17.99±0.444 13.07±0.519
120 0.0967± 0.11 0.1893±0.154 0.0783± 0.046 21.4 ± 0.498 20.06±0.121 16.1±0.0283
Table 26: In vitro Drug Release Profile of Optimised Formulation and Drug
Fig 32: In vitro Drug Release profile of Formulation comparing with pure drug.
Model
Formulation
Zero Order First Order
Korse Mayer
Peppas
Hickson
Krowell
Higuchi
CA R2
0.9050 0.9051 0.9050 0.9050 0.7629
CP R2
0.9165 0.9164 0.9609 0.9165 0.6886
Furo R2
0.8417 0.8417 0.8458 0.8417 0.7412
CA (1 -1) R2
0.9879 0.9949 0.9969 0.9930 0.9020
CP (1 1) R2
0.9442 0.9635 0.9912 0.9577 0.9440
Furo (0.36 1) R2
0.9736 0.9736 0.9871 0.9703 0.9167
Table 27: Model Fitting of Drug release profile
The above table shows model fitting which suggest the drug release kinetics follows Korsemayer peppas model
showing R2
value close to one than other. Hence model with R2
value near to 1 showing Korsemayer Peppas
best fit model for drug release.
III. Conclusion
The results of a 32
full factorial design (Central Composite Design) revealed that the pvpk-30 and
soluplus significantly affected the dependent variables dissolution after 2 hrs. And drug permeability across
intestinal membrane. The solid dispersion of the best batch exhibited a dissolution and permeability is increased
(preclinically). The in vitro release studies indicate that the solid dispersion formulation could increase the drug
bioavailability due to rise in solubility and permeability of drug.
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