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Journal of Drug Delivery and Therapeutics

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Open Access   Full Text Article                                                                                                                                         Research Article 

Development and Evaluation of Micro Emulsion Formulations of Nebivolol for Solubility Enhancement

Gurleen Kaur*, Alfisha Saifi, Kapil Kumar, Deepak Teotia

Department of Pharmaceutics, Global Institute of Pharmaceutical Education & Research, Kashipur-244713, India

Article Info:

_________________________________________

 Article History:

Received 08 July 2021      

Reviewed 29 August 2021

Accepted 07 September 2021  

Published 15 September 2021  

_________________________________________

Cite this article as: 

Kaur G, Saifi A, Kumar K, Teotia D, Development and Evaluation of Micro Emulsion Formulations of Nebivolol for Solubility Enhancement, Journal of Drug Delivery and Therapeutics. 2021; 11(5):84-89. DOI: http://dx.doi.org/10.22270/jddt.v11i5.5005   

______________________________________________

*Address for Correspondence:  

Gurleen Kaur, Department of Pharmaceutics, Global institute of pharmaceutical and research, Kashipur - 244713, Uttarakhand, India.                                ORCID ID: https://orcid.org/0000-0001-7753-6880

Abstract

______________________________________________________________________________________________________

Nebivolol HCl is a newer drug of β1-adrenergic blocker category, basically used as anti-hypertensive. It is a 3rd generation, antagonist, having NO (nitric oxide) enhancing vasodilator properties. It has 12% oral bioavailability, because of its pre systemic metabolism by the means of cytochrome P450 2D6 enzymes. Its log P value is 4.03 and 5mg is its daily dose. It is highly lipophilic drug and belongs to class BCS II, with slow dissolution. Bioavailability of any drug can be improved by avoiding its first pass metabolism and promoting solubility.  Several researchers have worked on the development of ME formulations on different poor water-soluble drugs, to increase their solubility. The purpose of this study is an attempt to enhance the solubility to improve the bioavailability of nebivolol drug by developing a novel delivery system that is microemulsion (ME) .ME formulations were developed using different oil, surfactant and co-surfactants in different ratio and studied on various parameters. Different preformulation tests done on received sample of Nebivolol. FTIR study was performed in order to find out any interactions between the ingredients. Based on the solubility Capmul Pg-12 was finalized oil, Tween 80 as surfactant, propylene glycol as the cosurfactant based on solubility and emulsification efficiency. Five Nebivolol ME formulations were successfully developed by use of oil, water, SA and Co-SA different ratio. Prepared formulations were studied for different properties- transmittance (%), pH, refractive index, viscosity, drug content, and solubility. It was seen that after 4 hours of diffusion, the drug released from the formulation ME5 is faster and more than that of the other i.e., 90.2±0.06%. It was found that ME5 was more stable and Soluble than other prepared formulations. With the better solubilty the bioavailability of Nebivolol will increased and helps in faster absorption and High diffusion in systemic circulation with lower or no risk of degradation. It somehow also reduced frequent intake of drug. 

Keywords: Nebivolol, micro emulsion, Ternary phase diagram, surfactant, co-surfactant.

 


 

1. INTRODUCTION:

Microemulsions (ME) basically are made up of oil, surfactant (SA) and water, with a co surfactant (Co-SA) in different ratio. This mixture is clear and stable. The resulting   fluid possesses low viscosity.  ME are isotropic, stable& transparent systems of droplets of immiscible liquids with diameter>500 nm1. Due to smaller droplets, they act as an excellent carrier for drugs having poor water solubility. Nebivolol HCl is a newer drugβ1-adrenergic blocker category, basically used in the management of hypertension. It is a 3rd generation, antagonist, having NO (nitric oxide) enhancing vasodilator properties.Used in the initial management of hypertension.

Peak plasma concentration achieved after its oral administration (0.5-2 h) 2-4.

It has 12%oral bioavailability, because of its pre systemic metabolism by the means of cytochrome P450 2D6 enzymes. Its log P value is 4.03 and 5mg is its daily dose. It is highly lipophilic drug and it belongs to class BCS II, with slow dissolution5-6. Bioavailability of any drug can be improved by avoiding its first pass metabolism and promoting solubility. 

Several researchers have worked on the development of ME formulations on different poor water-soluble drugs, in order to increase their solubility7

Current study is an attempt to increase solubility of Nebivolol. For this purpose, ME formulations were developed using different oil, surfactant and co-surfactants in different ratio and studied on various parameters.

Various preformulation studies were made in order to receive sample of Nebivolol. FTIR study was done to find out the interactions between the ingredients. Depending upon the solubility Capmul Pg-12 was selected as oil phase, Tween 80 as surfactant, propylene glycol as the co surfactant based on their solubility and emulsifying efficiency Ternary diagrams were constructed for differentaspected ratio of oil, water, SA and Co-SA. Here, five Nebivolol ME formulations were successfully developed by using CapmulPg-12, water, SA and Co-SA in different ratio. Developed formulations were studied for different properties such as transmittance (%), pH, refractive index, viscosity, drug content, and solubility.

The significance of the study is toincrease the solubiltyof Nebivolol by preparing a novel Drug delivery system of the drug, consequently increasing its bioavailability. This development reduces the risk of drug degradation and frequent dose administration& also makes drug more stable and highly soluble that possesshigh degree of Diffusion and better absorption in systemic circulation in sustained and controlled manner. 

Description: Nebivolol.svg

Figure 1: Structure of Nebivolol16


 

 

Table 1: Composition of batches for Nebivolol ME formulations.

Code

image

 

image

% Oil

image

image

ME1

1:1

30

60

10

ME2

1:2

60

35

5

ME3

1:3

35

60

10

ME4

2:1

50

40

10

ME5

3:1

40

55

5

 

 


 

2. METHOD 

2.1 Materials Used: Nebivolol Hydrochloride is received from Cadila pharmaceuticals, Gujarat. Capmul Pg-12 was obtained from CDH, Delhi. Castor Oil, linseed oil, Soyabean oil, Peanut oil, Castor oil are received from Jindal refinery, Uttarakhand.Tween-80, Tween-60, Span-40 and others are brought from sweta scientific, Lucknow.

2.2Preparation:

Pseudo- Ternary phase diagrams (PTPD):

PTPD Diagrams were plotted using water titration method. For the ME area under plot and estimation of the resulting possibility of formed ME formulations with selected oil, SA, and Co-SAThe amount of SA and Co-SA used were 1:1, 2:1 and 3:1, while 5 % oil was used in exact amount.These ingredients were admixed with oil, to get different ratio of weight i. e., 9:1, 8:2, 7:3, 6:4, 5:5, 4:6, 3:7, 2:8 and 1:9. Add water drop wise water with stirring through a magnetic stirrer. A constant temperature was maintained until a homogeneous dispersion or solution starts appearing. 

image

Figure 2: Pseudo Ternary phase diagram17-19

Physical appearance can be observed by visual evaluation after adding each drop. At end point the titration was declared to be completed where, the resulting solution was converted into a transparent one. The total amount of water, pre-owned to make this formulation turbid was noted.  The total % of each phase was determined. The same process was acquired for the other SA and Co-SA ratio. All the SA and Co-SA ratio come UP with dotted area in the PTPD8.

Preparation of Nebivolol loaded ME formulations

Total Five ME formulations were formulated through water titration method. Nebivolol (100) mgwaswa blended with selected oil (Capmul Pg-12), SA (Tween-80) and Co-SA (Propylene glycol). Additon of water was done gradually through stirring. Finally, crystal clear ME formulations were attained. 

2.3 Preformulation Studies:

Physical Appearance: Examine the authenticity of the received Nebivolol gift sample. 

M.P. determination

Melting point of Nebivolol was determined by the means of Thiels tube method. Three hundred ml of paraffin was Poured to Thiels tube, and sealed with the flame. Melting temperature of Nebivolol was recognized using thermometer9.

FTIR analysis

Fourier Transform Infra Red analysis (FTIR) was used to consider drug-excipient interaction by detecting the samples in the range of 400-4000 cm-1. The pure drug was combined with surfactant, co-surfactant and oil and the mixture was analyzed. Spectral comparison was done with FTIR of pure drug to eliminate the possibility of important functional groups of the drug that interacts with the excipients10.

Determination of λmax

10 mg of Nebivololwas placed in 2 volumetric flasks of 100ml. Buffer of pH 7.4 is used as the diluents to make stock solution A. Exact ten ml was removed from it and transfered to 100ml volumetric flask (mention stock solution B).  Sample from stock solution B was used and detected under UV Spectrophotometer. 250 nm was the point where λmaxwasobtained11.


 

 

image

Figure 3: FTIR Spectra of Nebivolol

image

Figure 4: FTIR Spectra of Nebivolol with capmul-pg12, tween-80 &PEG

 


 

Standard curve 

Exact 2.38 g di-sodium hyd.  Phosphate (Na2HPO4) was alloyed with 0.19 g KH2PO with .0 g NaCl to get 1000ml total volume. Exact 10 mg Nebivolol was lay hold and dissolved in buffer to obtain 1000 µg/ml concentration. 1 ml sample of it is dilute with 10 ml buffer (known to be stock solution). Different concentration were prepared from this stock solution and detected by UV spectrophotometer at 638.2   nm12.

Table 2: Nebivolol standard curve (Medium= buffer, pH 7.4)

S.N.

image

Absorbance 

1

0

0

2

2

0.025±0.08

3

3

0.0471±0.09

4

4

0.052±0.03

5

5

0.066±0.11

6

6

0.084±0.04

7

7

0.091±0.08

8

8

0.114±0.05

9

9

0.125±0.08

10

10

0.136±0.06

 

Description: rat cal curv phot

Figure 5: Standard Curve of Nebivolol at pH 7.

Selection of the oil phase

Maximum solubility of Nebivolol was considered to be obtained using different oils. Oils like castor oil, soybean oil, Kollisolv GTA, MCT, and Capmul Pg-12 were used for solubility consideration. Capmul Pg-12 was selected as the oil phase13 due to High solubility.

Selection of SA and Co-SA

The solubility of Nebivololwas determined in SA and Co-SA The efficiency of emulsifying of SA and Co-SA was determined in order to know their capability of emulsification in selected oil.Nebivolol was admix in equal ratio of SA, and diluted properly and examined for transmittance at 638 nm by using UV-Vis spectrophotometer. The effortlessness formation of preparation was detected by inversing the volumetric flask, which is used to obtained uniform emulsion. Similarly, transmittance of Co-SA and Nebivolol was evaluated. The main observations were determined which of them was able to produce more clearly ME formulations at the minimum concentration14.

 

Solubility analysis

Weigh10 gm oil in a beaker, alloy with 100 mgNebivolol. They were mixed properly by using stirring through a magnetic stirrer. After complete dissolution of Nebivolol, Again add 10mg Nebivolol further in the same way. The addition process was continued until, a saturated solution is achieved. The resulting Final solution was checked by usingUV-spectrophotometer at 250 nm. Similarily, the solubility of Nebivolol is estimated in SA and Co-SA15.


 

 

image

Figure 6: Solubility of Nebivolol in different oils

 


 

2.4Evaluation parameters for ME of Nebivolol

  1. General physical characteristics
  2. Percentage Transmittance: 

It was determined by using UV spectrophotometer (638 nm). It lies within the range of 98.57 ±0.09 to 99.42±0.23% for all the ME formulations prepared with Nebivololwhich confirms good transparency nature of formulations.

Table 3: Emulsification efficiency with surfactants and selected oil (Capmul Pg-12).

Surfactant

% Transmittance

HLB Value

Tween-60

85.147±0.0172

14.9

Tween-80

88.127±0.0241

15

Labrasol

74.271±0.0218

14

 

For the ME formulations of Nebivolol, the pH value lies in between3.44 ± 0.08 to 4.12 ± 0.09.

image

Figure 7: Comparative pH values of micro emulsion formulations.

The Viscosity of formulated ME formulations of Nebivolol, lies inbetween64.23±2.1 to 70.56±5.77 %.

  1. In-Vitro Drug release.
  2. Kinetic modeling for ME formulations :

In current study PCP disso Version 2 software was used in for the estimation of drug release pattern. Different Models for the release kinetic profile are shown in Table 9. First kinetic order and Korsemeyerpeppas models were used for plotting of kinetic data. Drug Release was monitored through diffusion process.

Drug release data was evaluated through PCP disso software for the kinetic models. First order kinetics along with Peppas and Korsmeyer model were studied.

Table: 4Kinetic release Data

Batch 

Kinetic model

Parameters

ME1

Peppas and Korsmeyer

R = 0.965, K1 = 4.234, n = 0.750

ME2

Peppas and Korsmeyer

R = 0.974, K1 = 3.147, n = 0.854

ME3

First order 

R = 0.952, K1 = 5.61, n = 0.750

ME4

Peppas and Korsmeyer

R = 0.934, K1= -0.070

ME5

Peppas and Korsmeyer

R = 0.963, K1 = 6.812, n = 0.772


 

 

 

Table 5: Evaluation parameters of prepared Nebivolol micro emulsion formulations

Batch

Transmittance (%) 

pH 

Refractive index 

Viscosity (cp) 

Drug content (%)

Solubility mg/ml

ME1 

99.3 ± 0.08 

3.56 ± 0.08 

1.3548±0.007 

64.23±2.1 

98.37± 0.08

27.87±0.08

ME2

99.27 ± 0.11 

3.76 ± 0.12

1.3420 ± 0.008 

65.46±3.7 

99.32 ± 0.34

28.87±0.11

ME3

99.42 ± 0.23 

3.82 ± 0.07 

1.3718 ± 0.004 

70.56±5.77 

99.61 ± 0.03

29.87±0.08

ME4

98.57 ±0.09 

3.44 ± 0.08 

1.3620 ± 0.008 

68.43±3.34 

99.52 ± 0.02

25.87±0.09

ME5

98.63 ± 0.21 

4.12 ± 0.09 

1.3518±0.016 

69.36±4.74 

98.43 ± 0.04

31.87±0.07

 


 

3. RESULTS AND DISCUSSION

I) Transmittance

Transparency of formulated ME formulations of Nebivolol were detected by using U.V. Spectrophotometer to determine % transmittance at 638 nm. As regards blank is concerned, distilled water was used as blank. 

2) Refractive index:

For the formulated ME formulations of Nebivolol, the refractive index lies in between1.3420 ± 0.008 to 1.3718 ± 0.004. 

3) Solubility:

A solubility profile indicates that the sample received by the company was Nebivolol. The solubility of Nebivololwas estimated in various oils to select the one having high solubility. Capmul Pg-12 has shown maximum solubility, thus selected as the oil to formulate ME formulations. Similarly, Tween 80 was selected as SA, Propylene glycol as the Co-SA based on their solubility and emulsification efficiency.

4) Drug Content 

The drug content formulated ME formulations of Nebivolol was determined by dissolving 1 ml (=10mg) in methanol (10ml). The measurement of Drug Content is done using UV spectrophotometer at 250 nm16.ME5 was found to be with highest drug content.

image

Figure 8: Comparative % drug content of micro emulsion formulations.

5) In-Vitro Drug release:

For estimating in-Vitro release Franz diffusion Cell (20ml) was used. The prepared ME formulations of Nebivolol undergoes diffusion process through Franz diffusion Cell, with a capacity of 20ml.  20 ml Buffer (pH7.4) is filled in receptor chamber. Donor compartment holding NebivololME formulations is attached with Cellophane membrane. All the samples were examiner using UV spectrophotometer at 250nm.Data collected shows Formulation with Capmul-pg12 have better in-vitro drug release in given span of time.


 

 

Table 6: In vitro study of prepared Nebivolol micro emulsion formulations

 (min)

Percentage drug released±SDa

ME1

ME2

ME3

ME4

ME5

0

0

0

0

0

0

20

6.4±0.08

6.8±0.15

11.5±0.29

19.2±0.08

21.8±0.53

40

11.36±0.01

12.8±0.47

19.6±0.18

30.7±0.09

33.5±0.32

60

16.9±0.07

21.5±0.25

29.7±0.17

35.5±0.11

41.6±0.28

80

23.3±0.05

27.4±0.55

37.4±0.18

40.6±0.15

47.2±0.50

100

32.43±0.13

35.6±0.26

42.9±0.33

48.2±0.21

54.3±0.48

120

38.64±0.17

41.1±0.34

51.2±0.33

53.5±0.08

62.6±0.35

140

41.68±0.08

47.1±0.21

57.7±0.09

66.3±0.07

69.7±0.32

160

46.41±0.09

53.8±0.15

62.6±0.08

70.2±0.15

77.2±0.15

180

47.15±0.11

54.8±0.32

68.3±0.12

75.4±0.21

82.3±0.09

200

49.56±0.14

55.7±0.09

69.4±0.21

79.09±0.35

84.8±0.08

220

50.49±0.06

58.4±0.11

72.8±0.06

81.5±0.06

86.1±0.05

240

53.41±0.08

60.2±0.23

75.43±0.08

83.6±0.09

90.2±0.06

   Mean+ SD, N=3

image

Figure 9: Different release models for Nebivolol micro emulsion formulations.

 


 

4. CONCLUSION:

Preformulations and evaluation studies shows Nebivolol solubility has been enhanced using Capmul-Pg12.Total five ME formulations were developed in current study.

ME formulations of ME5 batch was found to be optimum, on the basis of performed tests. After the incorporation of the drug, the microemulsion systems remained stable and optically clear showing no phase separation. The solubility of the drug was confirmed using conductivity measurements which indicated that the drug may be present at the interface of the oil and aqueous phases. UV-visible spectroscopic studies indicated that the system was optically clear. We can conclude that our microemulsion system helps increase the solubility

Of the hydrophobic drug with the help of hydrophobic component of microemulsion and lipophilic part of the surfactant. ME showed higher in vitro drug release when compared with commercially available drug. Hence, on the basis of developed formulation characterization and spectroscopic studies it may be concluded that the ME formulation can be employed to improve the bioavailability of a poorly soluble drug like Nebivolol using a suitable & compatible medium.

CONFLICT OF INTEREST: 

The authors have no conflicts of interest regarding this investigation.

ACKNOWLEDGMENTS:  Authors acknowledges to Global Institute of Pharmaceutical education and research for all support and encouragement for writing this research article.

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