Formulation and In vitro Percutaneous Permeation and Skin accumulation of Voriconazole Microemulsified Hydrogel

 

Mahendra Prajapati1*, Shradha Shende1, Vivek Jain1, Akhil Gupta2, Manoj Kumar Goyal2

1NRI Institute of Pharmacy, Bhopal (M.P.)

2Jai Institute of Pharmaceutical Sciences and Research, Gwalior (M.P.)

*Corresponding Author E-mail: rahuljadhav600@gmail.com

 

ABSTRACT:

The aim of the present study was to prepare and evaluate voriconazole microemulsified hydrogel. The voriconazole microemulsified is prepared by Water Titration Method. In which voriconazole microemulsified incorporated with hydrogel, Blank gels of different polymers were prepared by distilled water. Finally, the carbopol gel was prepared by dispersing 0.5% carbopol w/v and 0.5% aloe vera powder in 100 ml of water with stirring on mechanical stir. Additionally, for preservation of formulations 0.8% methyl paraben was mixed. Oil phase was selected by dissolving the voriconazole pure in different oils, oleic acid, castor oil, coconut oil, olive oil, cooten seed mineral oil and soya oil. Oleic acid was selected on the basis of higher solubility of voriconazole in it. Combination of surfactant and co-surfactant was selected on clear visual observation. Span - 40: propylene glycol in ratio 1:1 and 2:1 selected for further preparation of microemulsion. From the study F-8, F-9, F-10, F-14 and F-15 were selected for further studies. Though F-16, F-17, F-18, F-19 and F-20 formulations are also stable, but rejected due to high concentration of surfactant can cause skin irritation, skin burning and/or other complications. Characterization of selected voriconazole microemulsion formulations were evaluated under various parameters like Droplet size, Zeta potential, Poly Dispersity Index (PDI) and (%) Drug content all results showed.

 

KEYWORDS: Microemulsion, voriconazole, zeta potential, hydrogel, partition coefficient and Poly Dispersity Index (PDI).

 

 


INTRODUCTION:

Microemulsions are clear, thermodynamically stable, isotropic liquid mixtures of oil, water, and surfactant, usually in combination with a co-surfactant. The increased absorption of drugs in topical applications is attributed to enhancement of penetration through the skin by the carrier.

 

The most popular enhancer is oleic acid1 microemulsions are thermodynamically stable system and allow self-emulsification of the system. Microemulsions have low viscosity compared to emulsions2-4. Various ingredients are used in the formulation and development of microemulsions. Mainly oil and surfactants are used in microemulsion they should be biocompatible, non-toxic and clinically acceptable5.

 

A gel is a two-component, cross linked three-dimensional network consisting of sstructural materials interspersed by an adequate but proportionally large amount of liquid to form an infinite rigid network structure which immobilizes the liquid continuous phase within. A gel is an intermediate state of matter possessing property of a solid and a liquid, termed as viscoelasticity5-6. The gelling agent included in the preparation should produce a reasonable solid-like nature during storage that can be easily broken when subjected to shear forces generated by shaking the bottle, squeezing the tube, or during topical application7. Hydrogels are highly porous biocompatible three dimensional structures usually formed by cross-linked networks of hydrophilic polymer. They appear as colloidal gel with water as continuous phase absorbing substantially high amounts of water. They acquire this ability due to the presence of functional groups with hydrophilic nature on their back bone of polymer. When placed in aqueous environment cross linking of hydrophilic polymers leads to its insolubility in water due to ionic interactions and formation of hydrogen bonds. Such interactions provide integral hydrogels with essential mechanical strength which absorb water approximately 20 times to its molecular weight there by it swells8. In recent past, synthetic polymers have been largely employed in the formulation of hydrogels due to their long service life, high capacity of water absorption and high gel strength. Also, it is stable in the conditions of sharp and strong fluctuations of temperatures9.

 

Voriconazole is a triazole antifungal agent indicated for use in the treatment of fungal infections including invasive aspergillosis, esophageal candidiasis, and serious fungal infections caused by scedosporiumapiospermum (asexual form of pseudallescheriaboydii) and fusarium spp. including fusariumsolani. Iupac name (2r,3s)-2-(2,4-difluorophenyl)-3-(5-fluoropyrimidin-4-yl)-1-(1h-1,2,4-triazol-1-yl) butan-2-ol, molecular formulac16h14f3n5o, mol. Mass 349.31g/mol and melting point 127- 130 °c (248°f). Voriconazole is a triazole antifungal medication to treat serious fungal infections. It is used to treat invasive fungal infections that are generally seen in patients who are immune compromised. These include invasive candidiasis, invasive aspergillosis, and emerging fungal infections10.

 

MATERIAL AND METHODS:

Material: Voriconazole was gifted by Ipca Laboratories. Aloe vera powder, Carbopol, Mineral oil, Oleic acid, Methyl paraben, Methanol, Potassium dihydrogenortho phosphate and NaOH were purchased HiMedia Laboratories Pvt Ltd., Mumbai.Triethanolamine, Propylene Glycol, Span- 40 and Tween-80 were obtained Oxford Laboratories, Mumbai. HCl, Ethyl acetate, n- Octanol were obtained Finar Chemical (India) Pvt Ltd., Ahmedabad.Ethanol was purchased Jiangsu Huaxi International Trade Co. Ltd and Coconut oil purchased from Parasute coconut oil.

 

METHODS:

Formulation Development9

Selection of Oils:

On the basis of solubility of drug in the oils, we selected the oils/surfactants/co surfactants for microemulsion. 10ml oil taken in 25ml of beaker and dissolve the drug with stirring at ambient temperature until saturation. Drug concentration in saturated oils was measured by UV visible spectroscopy at 256nm.

 

Selection of surfactants and co-surfactants:

Various type of surfactant and co-surfactants are available. Different ratios of surfactants and co-surfactants tried to mix well with stirring and observed the resultant mixture if it is clear solution, can be selected.

 

Preparation method of Microemulsions by Water Titration Method:

O/W type microemulsions prepared by water titration method with selected oil and selected surfactant co-surfactant ratios. At the room temperature, particular ratio of surfactant and co-surfactant (Smix), mix with oil then this prepared mixture was subjected for titration with water until the clear solution obtained. Volume of water and final volume of the mixture was calculated all the quantities should be taken in %w/w.

 

Characterization of voriconazole loaded microemulsion10

Thermodynamic stability:

Microemulsions are thermodynamically stable systems and formed at particular composition (concentration) of oil, surfactant, co-surfactant and water. In addition no creaming or cracking and phase separation as compared to regular emulsion have kinetic stability results ultimately phase separates, thus selected regions of microemulsions also characterized to prove thermodynamic stability. The microemulsion formulations subjected to stress tests like heating cooling cycle, centrifugation, and those formulations passed these stress tests were subjected to dispersibility test.

 

Heating Cooling Cycle:

The prepared microemulsion formulations are tested against heating-cooling cycle. In this test, sample stored at refrigerator temperature 4°C for 48 hrs then at 45°C for 48 hrs, studied in six cycles. Those formulations, which were stable at these temperatures, were subjected to centrifugation test.

 

Centrifugation:

The passed formulations from heating cooling cycles were centrifuged using centrifuge at 3500rpm for 30 min. Those formulations which did not show any phase separation were taken for the Dispersibility test.

% Drug Content determination:

The %drug content of microemulsion was determined by dissolving required quantity (2ml) of Microemulsions (equivalent to 2mg VCZ) in mixture of methanol. After suitable dilutions with distilled water, absorbance was determined using double beam UV-spectrophotometer keeping blank microemulsion at wavelength 256nm.

 

Droplet size, Zeta potential and Polydespersibility index measurement:

The droplet size, zeta potential and polydispersity index (PDI) of the Microemulsions determined by zeta sizer which work on light scattering due to brownian motion of particles. All the experimental analysis repeated in triplicate.

 

Incorporation of microemulsion into the Gel:

Blank gels of different polymers were prepared by distilled water. Finally, the carbopol gel was prepared by dispersing 0.5% carbopol w/v and 0.5% aloe vera powder in 100ml of water with stirring on mechanical stir. Additionally, for preservation of formulations 0.8% methyl paraben was mixed.

 

Evaluation of Microemulsified Voriconazole Hydrogel111

Physical examination:

Prepared gel formulations inspected visually for their color change, homogeneity, clearance and phase separation.

 

Viscosity:

A cone and plate viscometer with spindle C75-2 (Brookfield) was used to determine viscosity of different Microemulsions gels.

 

Determination of pH:

The pH of Microemulsified gel was determined by using digital pH meter (Systronics), at ambient room temperature. Microemulsified gel was accurately weighed and dispersed in 50ml purified water to make 10% solution. The calibration of pH meter was done with buffered solution before each use.

 

Spreadability study:

Spreadability of Microemulsified gel was determined by placing 0.5g of gel within a circle of 1cm diameter pre-marked on a glass plate. Another glass plate was kept over it and 500gm weight was placed on this upper for 5 min. The gel spreading was noted from the change in diameter of gel placed.

 

In-vitro drug release:

The in-vitro drug release studies were carried out in the modified USP dissolution apparatus (37°C±0.5°C) containing a two-sided open glass cylinder for 8 hours. The diffusion barrier was cellophane membrane as a release barrier. A pre-soaked dialysis membrane was adapted to the terminal portion of the glass cylinder. In each case, microemulsified gel (5ml i.e. 0.2mg/ml) was accurately introduced into the glass cylinder from the open side and this cylinder was fixed on the stirrer. The stirrer was suspended in 50ml dissolution fluid (pH 7.4 phosphate buffer) medium maintained at 37°C±0.5°C at 50rpm. Aliquots of samples (3ml) were withdrawn at predetermined time intervals with volume replacement. The withdrawn samples were analyzed for drug content, by measuring absorbance at 256nm in the double beam UV/Visible spectrophotometer. Sink conditions were maintained throughout the release period. The comparative release study of voriconazole from microemulsion formulations were carried out. Data obtained in triplicate were analyzed graphically in different type of kinetic model plots.

 

Results and Discussion:

Span-40: propylene glycol in ratio 1:1 and 2:1 selected for further preparation of microemulsion. Different trial formulations were prepared and studied for their physicochemical characterization and visual observation and finally got the optimized formulations. The trial formulations of microemulsion were prepared in two batches, formulations prepared according to following formulae. In first trial batch, drug voriconazole and oil concentration percentage remains constant and the percentage of Smix (1:1) will gradually increase. In second trial batch, drug voriconazole and oil concentration percentage remains constant and the percentage of Smix (1:1) will gradually increase. From the study reported in above table, F-8, F-9, F-10, F-14 and F-15 were selected for further studies. Though F-16, F-17, F-18, F-19 and F-20 formulations are also stable, but rejected due to high concentration of surfactant can cause skin irritation, skin burning and/or other complications.

 

Prepared selected formulations of microemulsion were incorporated in prepared gel with stirring on magnetic stir in the ratio of 1:1. The codes added G for gel, now the changed codes are GF-8, GF-9, GF-10, GF-14 and GF-15.

 

By the preformulation studies it is observed that voriconazole is a white, odorless powder. Solubility determined in various solvents extract was freely soluble in ethanol and methanol, slightly soluble in Distilled Water, sparingly soluble in ethyl acetate, soluble in 0.1N HCl and poorly soluble in 0.1N NaOH. Melting point was observed at 1300C.lmax 256nm was determined by scanning sample from 200-400nm and also calibration curve was obtained by absorbance of aliquots from 5-30 µg/ml with following linear equation y=0.024x-0.01 R² = 0.999. Partition coefficient was 1.797 obtained. Drug: Excipient Compatibility Studies at room temperature, 20C-80C and 450C -500C says it is stable. Stability also confirmed by FT-IR studies.

 

Oil phase was selected by dissolving the voriconazole pure in different oils, oleic acid, castor oil, coconut oil, olive oil, cooten seed mineral oil and soya oil. Oleic acid was selected on the basis of higher solubility of voriconazole in it. Combination of surfactant and co-surfactant was selected on clear visual observation. Span- 40: propylene glycol in ratio 1:1 and 2:1 selected for further preparation of microemulsion.

 

20 different type formulations formed using different concentration of oil and Smix on trial basis. Then observed visually and Thermo dynamic Stabilityfor optimization of microemulsion. From the study F-8, F-9, F-10, F-14 and F-15 were selected for further studies. Though F-16, F-17, F-18, F-19 and F-20 formulations are also stable, but rejected due to high concentration of surfactant can cause skin irritation, skin burning and/or other complications. Characterization of selected voriconazole microemulsion formulations were evaluated under various parameters like Droplet size, Zeta potential, Poly Dispersity Index (PDI) and (%) Drug content all results showed in table.

 

All five voriconazole microemulsion formulations were incorporated in clear, odorless, washable, homogeneous, stable and free from grittiness aloe vera hydrogel and was evaluated under the various parameters, pH of all formulations were observed between 5.9 to 7.1 and Spreadability between 4.326 to 5.341gcm/sec. and viscosity between 40.23 to 76.38 centi poise and all were observed yellowish clear gel. In-vitro drug Release of microemulsified gel preparations were studied and found GF-8 = 87.61, GF- 9 = 94.18, GF- 10 = 91.27, GF- 14 = 90.74 and GF-15=90.62. GF-9 was excellent microemulsified gel preparation on the basis of drug release profile.

 

Table No. 1: Formulation of carbopolgel

S. No.

Ingredients

Quantity in (w/v)

01.

Carbopol 940

0.5 %

02.

Aleo Vera (powder)

0.5%

03.

Triethanol amine

1 %

04.

Water

100ml

05.

Methyl paraben

0.8 %

 

Table no. 2: Optimization of surfactant and co-surfactant ratio

Name of surfactant and co- surfactant

Ratio

Visual observation

sTween -80: propylene glycol

1:1

2:1

Clear

Cloudy

Tween -80: n-butanol

1:1

2:1

Translucent Cloudy

Translucent Cloudy

Span- 40: propylene glycol

1:1

2:1

Clear

Clear

Span - 40 : n- butanol

1:1

2:1

Translucent Cloudy

Translucent Cloudy

 


 

Table No. 3: Formulations of trial batch- 01 (Smix 1:1)

S. No.

Ingredients

F-1

F-2

F-3

F-4

F-5

F-6

F-7

F-8

F-9

F-10

1

Voriconazole (mg)

10

10

10

10

10

10

10

10

10

10

2

Oleic acid (%w/v)

5

5

5

5

5

5

5

5

5

5

3

Span-40: Propylene glycol(1:1)(%w/v)

5

10

15

20

25

30

35

40

45

50

4

Distilled water (%w/v)

90

85

80

75

70

65

60

55

50

45

5

Final volume

25

25

25

25

25

25

25

25

25

25

 

Table No. 4: Formulations of trial batch- 02 (Smix 2:1)

S. No.

Ingredients

F-11

F-12

F-13

F-14

F-15

F-16

F-17

F-18

F-19

F-20

1

Voriconazole (mg)

10

10

10

10

10

10

10

10

10

10

2

Oleic acid (%w/v)

5

5

5

5

5

5

5

5

5

5

3

Span-40: Propylene glycol (2:1) (%w/v)

5

10

15

20

25

30

35

40

45

50

4

Distilled water (%w/v)

90

85

80

75

70

65

60

55

50

45

5

Final volume

25

25

25

25

25

25

25

25

25

25

 

Table No. 5: Optimization of all prepared formulation

S. No.

Code of formulation

Visual observation

Thermo dynamic Stability

1

F-1

White, Cloudy

Phase separation

2

F-2

White, Coludy

Phase separation

3

F-3

White, Coludy

Phase separation

4

F-4

White, Coludy

Phase separation

5

F-5

White, Coludy

Phase separation

6

F-6

White, Slight Coludy

Phase separation

7

F-7

White, Slight Coludy

Phase separation

8

F-8

Light yellow, Clear

Stable

9

F-9

Light yellow, Clear

Stable

10

F-10

Light yellow, Clear

Stable

11

F-11

White, Coludy

Phase separation

12

F-12

White, Coludy

Phase separation

13

F-13

White, Slight Coludy

Phase separation

14

F-14

Light yellow, Clear

Stable

15

F-15

Light yellow, Clear

Stable

16

F-16

Light yellow, Clear

Stable

17

F-17

Light yellow, Clear

Stable

18

F-18

Light yellow, Clear

Stable

19

F-19

Light yellow, Clear

Stable

20

F-20

Light yellow, Clear

Stable

 

Table No. 6: Characterization of selected voriconazole microemulsion formulations

Formulation Code

Droplet size (nm)

Zeta potential (mV)

Poly Dispersity Index (PDI)

Drug content (%)

F-8

231.3 ± 4.24

14.2 ± 1.42

0.402 ± 0.03

93.21 ± 1.22

F-9

173.2 ± 2.53

13.2 ± 1.45

0.329 ± 0.04

95.42 ± 1.13

F-10

183.3 ± 1.39

12.4 ± 2.66

0.424 ± 0.01

89.32 ± 2.13

F-14

141.7 ± 1.02

14.6 ± 1.37

0.299 ± 0.05

94.52 ± 1.41

F-15

243.5 ± 2.33

13.5 ± 1.86

0.443 ± 0.03

93.31 ± 2.13

Note: All the values are mean of triple reading ± standard deviation

 

Table No.7: Physical Examination, pH, Viscosity and Sreadability of Microemulsified Gels

Gel formulation Code

Physical Examination

pH

Viscosity (cP)

Spreadability gm.cm/sec

GF-8

Yellowish, clear

6.2

40.23

5.334

GF-9

Yellowish, clear

6.8

55.43

4.334

GF-10

Yellowish, clear

7.1

54.55

5.341

GF-14

Yellowish, clear

6.6

68.32

4.326

GF-15

Yellowish, clear

5.9

76.38

5.265

 

Table No.8: In-vitroVoriconazole Release Profile of Microemulsified gel Formulation

Time (hr.)

GF-8

GF-9

GF-10

GF-14

GF-15

0

0

0

0

0

0

1

06.9

15.00

12.91

11.04

08.75

2

17.9

27.43

28.78

25.55

21.37

3

30.60

40.59

38.20

38.81

32.65

4

46.20

51.45

52.60

53.01

45.91

5

58.76

61.59

62.31

63.37

58.86

6

69.84

74.02

76.93

78.08

71.71

7

80.60

86.34

84.99

83.43

79.25

8

87.61

94.18

91.27

90.74

90.62

 


 

Fig. No. 1: Zero Order plots for voriconazole microemulsified hydrogels

 

Fig. No. 2: First Order plots for voriconazolemicroemulsified hydrogels

 

Fig. No. 3: Higuchi model plots for voriconazolemicroemulsified hydrogels

 

Fig. No. 4: Peppas model plots for voriconazolemicroemulsified hydrogels

 

CONCLUSION:

The prepared microemulsifiedvoriconazole hydrogel preparations had shown excellent promising results for all the evaluated parameters. Based on the in-vitro drug release and drug content results, GF-9 formulation was better drug release as compare to GF-8, GF-10, GF-14 and GF-15 which shows higher percentage of drug release.

 

ACKNOWLEDGEMENT:

I extend my sincere thanks Dr. Vivek Jain, Head Department of NRI Institute of Pharmacy, Bhopal for his timely help throughout the research work as well as providing instrumental facilities for carrying out of my work. I consider myself the luckiest to work under the guidance of Ms. Shradha Shende, Assistant Professor of Pharmaceutics, Department of NRI Institute of Pharmacy, Bhopal (M.P.).

 

REFERENCE:

1.      Anna Kogan, Nissim Garti (2006). “Microemulsions as transdermal drug delivery vehicles” Advances in Colloid and Interface Science Volumes 123–126, 16 November, Pages 369-385.

2.      Kumar. K. Senthil et al. (2011). Microemulsions as Carrier for Novel Drug Delivery: A Review. International Journal of Pharmaceutical Sciences Review and Research; 10: 37-45.

3.      Patel R. Mrunali (2007). Microemulsions: As Novel Drug Delivery Vehicle; 5.

4.      Madhav. S and Gupta. D. (2011). A review on microemulsion based system. International Journal of Pharmaceutical Sciences and Research; 2 (8): 1888.

5.      Vyas S P (2009). Theory and practice in novel drug delivery system. CBS Publishers New Delhi.; p115.

6.      Prince L. M. (1976). A theory of aqueous emulsions I. Negative interfacial tension at the oil/water interface. Journal of Colloid and Interface Science; 23: 165- 173.

7.      Carter SJ (2000). Disperse system In: Cooper and Gunn’s Tutorial Pharmacy. 6thed. New Delhi: CBS Publishers and Distributors; 68-72.

8.      Todd RH, Daniel SK. (2008). Hydrogels in drug delivery: progress and challenges. Polymer; 49: 1993-3007.

9.      Ahmed EM. (2013). Hydrogel: Hydrogel: Preparation, characterization, and applications, J Adv Res .07.006.

10.   Rangasamy et al (2013)., International Current Pharmaceutical Journal, September, 2(10): 165-169

 

 

 

Received on 05.06.2021          Modified on 28.06.2021

Accepted on 10.07.2021   ©Asian Pharma Press All Right Reserved

Asian J. Pharm. Tech. 2021; 11(4):267-272.

DOI: 10.52711/2231-5713.2021.00044