Transcript F127-20+F68

Development of Thermoresponsive Diclofenac
Ophthalmic In Situ Gels Formulaitons
By
Rathapon Asasutjarit, Ph.D.
Department of Pharmaceutical Technology,
Faculty of Pharmacy, Rangsit University
Asira Fuongfuchat, Ph.D.
National Metal and Materials Technology center,
National Science and Technology Development Agency (NSTDA)
1
Outline
1.
Introduction
2.
Objectives
3.
Methods
4.
Results and discussion
5.
Conclusions
6.
Acknowledgements
2
Introduction
- Eye drop solution: convenient to use by instilling into conjunctival sac of
the eye with accurate dose.
- Bioavailability is very poor: blinking reflex and lacrimal secretion.
Eye drop solution
Insert
Ointment
- Inserts, ointments and suspensions.
3
temperature
temperature
- In situ gels: pH, specific ion and temperature
- The thermoresponsive in situ gel is an in situ gel system responding to a
shift in temperature.
- It is liquid at low temperature and becomes gel when in contact with
higher temperature.
4
- Diclofenac is one of non-steroidal anti-inflammatory drugs approved for
ocular use.
- Diclofenac is available in the drug market as an eye drop solution. It has
been used intensively in the case of post-op inflammatory with 3-4
times of administration.
- Thus, minimized frequency of administration, once or twice daily, is
necessary for increasing patient compliance.
5
- My previous work (Asasutjarit, 2008):
- Formulation of thermoresponsive diclofenac ophthalmic in situ gels
contained either
: Pluronic F127 (Poloxamer 407) or
: Combination of Pluronic F127 and hydroxypropylmethylcellulose
- Phase transition temperatures were lower than room temperature.
6
Objectives
The purposes of this study were to develop and to evaluate the formulation
of thermoresponsive diclofenac ophthalmic in situ gels possessing optimum
phase transition temperature.
7
Methods, Results and discussion
1. Preparation of thermoresponsive diclofenac
ophthalmic gels and products evaluation
: 0.1% w/w diclofenac sodium ophthalmic gels containing
various gelling agent contents
: prepared on a weight basis by the cold method
Formulation (Rx)
Gelling agent (%w/w)
F127
F68
Carbopol 940
1. F127-20
20
0
0
2. F127-20+F68-8
20
8
0
3. F127-20+F68-11
20
11
0
4. F127-20+F68-11+C.1
20
11
0.1
5. F127-20+F68-11+C.3
20
11
0.3
6. F127-20+F68-11+C.5
20
11
0.5
8
: Phosphate buffer pH 7.4 was used in the formulations as vehicle except
for the formulations containing carbopol 940, phosphate buffer pH 5.5
was used.
: All samples were analyzed spectrophotometrically for the content
uniformity at a wavelength of 276 nm.
: Only samples with diclofenac sodium content within 100± 10% of
labeled amount were accepted.
: They were measured their pH in triplicate by using a pH meter.
9
2. Determination of phase behavior and sol-gel
transition temperature of thermoresponsive gels
2.1 Test tube inverting method
: 2±1°C (storage temperature)
: 27±1°C (room temperature)
: 35±1°C (ophthalmic temperature).
10
2.2 Temperature sweep test : Rheometer
- storage modulus (G´) and loss modulus (G´´) at varied temperatures
100000
G'
G''
Gel phase
Tan delta
10
Phase
transition
0.1
Sol phase
0.001
0
5
10
15
25
30
35
40
45
50
Temperature oc
Semi logarithmic plot of storge modolus and tan delta againts temperature of F127-20 + F68-8(mean+SD)
Tan delta
G' G''
1000
1000000
100000
10000
1000
100
10
1
0.1
0.01
0.001
20
11
Preparation and evaluation of thermoresponsive diclofenac ophthalmic
gels (continued)
Formulation (Rx)
%Labeled
amount
*Flow ability at
various temperatures
2±1 27±1
(°C) (°C)
35±1
(°C)
Sol-gel
transition
temperature
(°C)
pH
1. F127-20
103.2±1.0
+++
-
-
20.7±0.1
7.4±0.1
2. F127-20+F68-8
103.3±1.2
+++
+
-
27.2±0.3
7.3±0.1
3. F127-20+F68-11
102.6±0.6
+++
+++
-
31.6±1.8
7.4±0.1
4. F127-20+F68-11+C.1
103.2±0.8
+++
+++
-
32.7±1.1
5.4±0.1
5. F127-20+F68-11+C.3
103.3±0.9
+++
+++
-
31.7±0.5
4.8±0.1
6. F127-20+F68-11+C.5
103.2±1.0
+++
+++
-
36.3±1.4
4.7±0.1
(n=3, mean± SD),
*Flow ability: +++ = very good; ++ = good; + = flow; - = not flow
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3. Gelling capacity test
Drop 20-μl of samples
A test tube containing 2-ml of simulated tear fluid (STF) (pH 7.4)
equilibrated at 35 °C.
The visual assessment of gel formation and dissolution
was performed in triplicate (Wu et al., 2007).
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Formulation (Rx)
Time for remaining gel in STF
(min)
3. F127-20+F68-11
20.2±0.8
4. F127-20+F68-11+C.1*
40.4±0.7
5. F127-20+F68-11+C.2
45.3±0.6
6. F127-20+F68-11+C.3
49.0±0.4
- The formulations containing carbopol 940 were eroded by STF more
slowly than the formulation without carbopol 940 markedly.
- This is probably that carbopol 940 consisting in the formulations led to
more stiff gel when pH of the environment was increased.
- Since formulation Rx 4. (F127-20+F68-11+C.1) had an optimum sol-gel
transition temperature, pH and gelling capacity, it was chosen as a
representative for the further experiments.
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4. Steady shear sweep test
: The experiment was carried out at 27±1 °C and 35±1 °C by a
rheometer for determination of flow behavior of Rx 4. (F127-20+F6811+C.1)
: The initial and final shear rates were 0.05 and 100 s-1, respectively.
15
1200
shear stress (Pa)
1000
35 °C
Pseudoplastic flow
27 °C
800
600
400
200
0
0
10
20
30
40
50 60 70
shear rate (s-1)
80
90 100 110 120
Rheogram of Rx 4. (F127-20+F68-11+C.1)
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viscosity (Pas)
1.E+07
1.E+06
1.E+05
1.E+04
1.E+03
1.E+02
1.E+01
1.E+00
1.E-01
1.E-02
1E-03
35 °C
27 °C
1E-02
1E-01
1E+00
1E+01
shear rate (s-1)
1E+02
1E+03
Viscosity profile of Rx 4. (F127-20+F68-11+C.1)
- Ocular shear rate is about 0.03 s-1 during interblinking and 4,25028,000 s-1 during blinking.
17
5. Eye irritation test : 4-New Zealand white rabbit
20-µl of the sample was instilled into the conjunctival sac of
rabbit’s right eye
The left was kept as a control without manipulation.
0, 5, 10, 30 min, 1, 6, 12, 24, 48 and 72 hours
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Lesions
Grades
Cornea
No ulceration or opacity
0
Scattered or diffuse areas of opacity (other than slight dulling of normal
luster), details of iris clearly visible
1
Easily discernible translucent area, details of iris slightly obscured
2
Nacreous area, no details or iris visible, size of pupil barely discernible
3
Complete corneal opacity, iris not discernible
4
Iris
Normal
0
Markedly deepened folds, congestion, swelling, moderate circumcorneal
injection,(any o these separately or combined) iris still reacting to light
(sluggish reaction is positive)
1
No reaction to light, hemorrhage, gross destruction(any or all of these)
2
(DiPasquale and Hayes, 2001)
19
Lesions
Grades
Conjunctive
Redness (refers to palpebral and bulbar conjunctivae,
excluding cornea and iris)
Vessels normal
0
Some blood vessels definitely hyperemic (injected)
1
Diffuse, crimson color, individual vessels not easily discernible
2
Diffuse beefy red
3
Chemosis
No swelling
0
Any swelling above normal (includes nictitating membranes)
1
Obvious swelling with partial eversion of lids
2
Swelling with lids about half closed
3
Swelling with lids more than half-closed
4
(DiPasquale and Hayes, 2001)
20
a
Results of eye irritation test of
Rx 4. (F127-20+F68-11+C.1)
Lesions
Grades
Cornea
No ulceration or opacity
0
Iris
Normal
0
b
Conjunctive
Vessels normal
0
Chemosis
No swelling
0
a: the test eye
b: the controlled eye
21
6. Diclofenac absorption in the eye
- 8-New Zealand white rabbit
Group 1 : Rx 4. (F127-20-+F68-11+C.1)
Group 2 : Diclofenac eye drop solution
(Original)
- Sampling time: 5, 10, 30 min,
1, 6, and 12 hours,
- Sampling volume: 200 µl
- Zoletil 100® im
- High-performance liquid chromatrography (HPLC)
22
Concentration of diclofenac sodium in rabbit' s aqueous humor (ng/ml)
4,500
Eye drop solution
4,000
Cmax gel = 3,900 ng/ml
Rx 4. (F127-20+F68-11+C.1)
3,500
Thermoresponsive in situ gel
3,000
2,500
2,000
1,500
Cmax solution = 1,517 ng/ml
Diclofenac eye drop solution (Original)
1,000
500
0
0
60
120
180
240
300
360
420
480
540
600
660
720
Time (min)
Diclofenac concentrations in aqueous humor
23
Conclusions
- 20% w/w pluronic F127, 11% w/w pluronic F68 and 0.1% w/w
carbopol 940.
- Exhibited solution character predominantly at the storage temperature
and room temperature and became gel at the ophthalmic temperature.
- Sol-gel transition temperature was 32.7±1.1 °C.
- It was convenient to use without keeping in a refrigerator.
- It did not cause eye irritation in rabbits.
- It increased concentration of diclofenac in aqueous humor and
prolonged the contact time of diclofenac in the eye.
- This formulation had a potential for the further study in patients
suffering from inflamed eye.
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Acknowledgements
The authors gratefully acknowledge
- Mr. Chanwit Kammat,
- Mr. Thumrongrat Pukpinyo,
- Ms. Watunya Witisil,
- Ms. Suthira Thansanchokpibull
- Ms. Susiri Preedasuttichit
- Ass. Prof. Aree Thayananuphat, DVM, Ph.D.
- Research Institute, Rangsit University
for the research grant No. 33/50.
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Thank you
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