INTRODUCTION:

To treat intraocular or surface problems there we are having several marketed formulations which can be formulated as a kind of eye drops either in a form of solutions or suspensions as ocular drug. To reach a therapeutic agent the main challenge in ocular disease may involve narrow topical absorption of the active ingredient. Such kind of problem mainly occurs due to the corneal impermeability of the drug and also the less residence time. This problem is mainly due to limited capacity for instilled volumes inside the eye. (Narmeen Adel Elkasabgy 2014)¹.

When a drug solution is applied in the eye the factors like tear drainage as well as the blinking nature of the eye reduces 10-fold of drug concentration in 4-20 minutes. (Rahul Tiwari 2017)²

Eye drops formulations with less water-soluble drug have the benefit to transvers lipophilic cornea, but as they have less aqueous solubility which leads to their low ocular bioavailability. (Duxfield L, 2015)³.

To improve the drug solubility as wall as retention time and absorption of a drug the approach called self-emulsifying drug delivery system is used. (Kakkar S, 2015) ⁴.

SEDDS contains a mixture of an oil, surfactant, co-surfactant, and drug these has the capability to form an oil-in-water (o/w) emulsion. SEDDS are useful to increase the bioavailability for drugs having low water solubility. This more useful for ocular delivery since the formulation for spontaneous emulsion over dilution besides tear secretion on the ocular surface. (Reddy S, 2011) ⁵.

For better drug absorption smaller droplet size gives a wide interfacial surface area. For the formulation of SEDDS there is need of solubility of drug in various components as well as the area in phase diagram with an emulsifying region. And the distribution of droplet size. (Vilas PC et al, 2013) ⁶.

Ketoconazole (KET) is a broad-spectrum antifungal drug it is a synthetic derivative of phenylpiperazine. Which prevents the synthesis of the fungal ergosterol by suppressing the activity of the cytochrome P450 14α-demethylase. Ketoconazole is an antifungal drug with low aqueous solubility, restricting its application in ocular fungal infection. Though the drug is having high efficacy, its limited solubility compromises its proper therapeutic utilization. Thus, there is need to develop an ophthalmic formulation of the ketoconazole which will increase its solubility and thus improve its therapeutic utilization. (Ahmed TA 2021) ⁷.

The goal of the study to formulate the ketoconazole SEDDS using oleic acid (oil phase), cremophore RH 40(surfactant) propylene glycol (co-surfactant) to increase the solubility and the therapeutic utilization.

MATERIALS AND METHOD:

Materials:

Ketoconazole was purchased from Yarrow Chem Products. PEG-400 and Cremophor RH 40 were purchased from Himedia Laboratories Pvt. Ltd. Span-80, Tween-20, Methanol, Castor Oil, olive oil, oleic acid, Isopropyl palmitate were purchased from Loba chemicals Pvt. Ltd. Mumbai. Captex-200 and Capmul-MCM were obtained as gift samples from ABITEC Corporation Mumbai. Cremophor EL, Isopropyl myristate were purchased from Ozone International, Mumbai. Cod liver oil was purchased from Universal medicare Pvt ltd, Gujarat. Propylene glycol was purchased from Nice chemicals, Kerala.

Method:

Equilibrium solubility studies for Ketoconazole:

Solubity studies of ketoconazole were performed by mixing an excess amount of drug with various non-aqueous solvents (oils, surfactant, and cosurfactants) using a water bath shaker at room temperature (37° ± 2°C) for 72 h to reach equilibrated and then samples were centrifuged at 3000 rpm for 15 min. The supernatant was filtered through a 0.45 µ membrane filter and the amount of Ketoconazole solubilized was analyzed using UV–visible spectrophotometer at 205nm. Shown in table no 1 (Shrestha H 2014) ⁸.

Construction of Pseudo Ternary Phase Diagram:

The pseudo ternary phase diagram of oil, surfactant / co-surfactant (smix) and water were constructed using the water titration method. Based on the results of the solubility study, the selected oils (oleic acid), surfactant (cremophor RH 40) and co-surfactant/co-solvent (propylene glycol) were chosen to construct pseudo-ternary phase diagrams. Smix was made by mixing Surfactant and co-surfactant in n proportion of 1:1, 2:1 and 1:2 ratio. Smix and oil were mixed at ratios of 1:9, 2:8, 3:7, 4:6, 5:5, 6:4, 7:3, 8:2, and 9:1 in a volumetric flask. To the resultant mixtures, distilled water was added dropwise till the first sign of turbidity and then a clear solution to identify the endpoint after equilibrium, if the system became clear then the water addition was stopped. The resultant emulsion with a clear or slightly blush appearance, exhibits good stability and flowability as a nanoemulsion. (Gursoy RN 2004) ⁹.

Formulation and optimization of SEDDS:

Once the pseudo- ternary diagrams identified the self-emulsifying region, the formulations were prepared by addition of 2%w/v (20 mg/ml) ketoconazole in mixtures of each oil, surfactant, co-surfactant with varying component ratio shown in table no 2 The microemulsion of ketoconazole was obtained by stirring the mixture using a magnetic stirrer at 25⁰C at 100 rpm. (Kumar R 2016) ¹⁰.

Optimization study for Ketoconazole:

The optimal mixture design was used to optimize the composition of the SEDDS formulation. Levels of independent factors were selected from area of self-emulsification found in the ternary phase diagram. Smix (Cremophor RH40: Propylene glycol) and oil (oleic acid) were selected as independent variables X1andX2 respectively. The concentration of X1 was set within the range of 10-20-30% and the concentration of X2 was set within the range of 5-10-15% respectively. Two response factors were selected as independent variables partial size (Y1) and zeta potential (Y2) respectively. Nine experimental runs were determined according to the mixture design method.

Self-emulsification time: It is a time for accumulation to form a homogenous mixture upon dilution of formulated SNEDDS. The 1 ml of SEDDS formulation was introduced in 300 ml purified water. (Basalious EB, 2010) ¹¹.

Globule size: The average globule size of microemulsions were determined by photon correlation spectroscopy. Measurements were made using Zetasizer 1000 HS (Nano ZS, Malvern Instruments), Drug content of microemulsions was analyzed by UV–visible spectrophotometer (Shimadzu 1700, Japan) at 205 nm. (Akula S,2014).¹²

Determination of zeta potential: Zeta potential was measured by photon correlation spectroscopy using Zetasizer (Nano ZS, Malvern Instruments) equipped with, which measures the potential ranged from −120 to 120 V. Nano emulsion formulation was diluted 100 times using double distilled water and analysed for zeta potential. All measurements were carried out at 25°C. (Nagaraju R,2019).¹³

Appearance, pH and Drug content:

Appearance: Clarity is one of the most of important characteristics of ophthalmic preparations. The developed formulations were observed against black and white background for clarity and colour of the formulation. (Yousry C, 2020).¹⁴

pH: pH is considered as one of the most important parameters involved in ophthalmic formulation. The two main principles are as of interest are the effect of pH on both solubility and stability. The developed formulations should be stable at a particular pHand meanwhile, at the same time there should be no irritation upon instillation of the formulation. Ophthalmic formulations should have a p^H range between 5 to 7.4. The developed formulations were evaluated for p^H by using Equitoxic digital pH meter. (Kawakami K, 2002).¹⁵

Drug Content:

The drug content of the formulation was determined by taking sample(5ml) in 10ml of volumetric flask and diluted with Saturated tear fluid of p^H -7.4 to get the concentration of 10μg/ml(approximately). Then the absorbance was determined at λmax (205nm) using UV-Spectrophotometer to calculate the percentage of drug content. (Sirish V, 2010).¹⁶

In-vitro Drug Release Studies:

In-vitro drug release was carried out using Franz Diffusion Cell. Cellophane membrane was used which was soaked overnight using freshly prepared STF. The developed formulation was placed in donor compartment and the receptor compartment was filled with 50 ml freshly prepared STF. The temperature was maintained at 37⁰C and rotating speed was kept at 50 rpm. 0.1 ml aliquots were withdrawn at time interval of 1hr and replaced by equal quantity of the receptor medium. The withdrawn aliquots were diluted using freshly prepared STF. The absorbance was measured at 272 nm using UV-Visible Spectrometer. The percent drug release was calculated by using calibration curve equation. (Zhang P,2008).¹⁷

RESULTS AND DISCUSSION:

Solubility studies and component selection

Based on solubility studies (Table 1), oleic acid was selected as the oil carrier while Cremophore RH 40 and propylene glycol was selected as surfactant and co-surfactant, respectively, for formulation of o/w microemulsion. The microemulsion was prepared by drop-wise addition of the required amount of water into the pre-mixed solution of oil, surfactant and co-surfactant under magnetic stirring.

Construction of Pseudo ternary phase diagram

These pseudo-ternary phase diagram (consisting oil, Smix and water) demonstrated an extensive region of microemulsion formation. In addition, phase diagrams also help in determination of concentration range of components used for formulation of microemulsion. Table 1.

VCZ solubility in various non-aqueous (oily) components

Solubility in different oil:

Tabel no 1: Solubility in different surfactant/ cosurfactants:

Sr no	Oil	Solubility in mg/mL (mean ±SD, n = 3)
1	Castor oil	20
2	oleic acid	85
3	Isopropyl myristate	48
4	Olive oil	56
5	Isopropyl palmitate	35
6	Capmul MCM EP/NF	18
7	Captex 200	15.5

Tabel no: 2 Solubility of Ketoconazole in different oils.

Sr no	Surfactant/co-surfactant	Solubility in mg/mL (mean ±SD, n = 3)
1	Tween 20	23
2	Tween 80	48
3	Cremophor RH 40	65
4	Cremophor RH EL AR	16
5	PEG 400	23
6	Propylene glycol	79
7	PEG 600	42
8	Glycerine	48

Fig no: 1Solubility of Ketoconazole in different surfactants

Fig no: 2Solubility of Ketoconazole in different Co-surfactants.

Fig no: 3Pseudo-ternary phase diagram for Smix ratio 1:2

Fig no: 4 Formulation selection and stability studies.

Composition of the selected SEDDS

Tabel no:3 Optimization study Mixture design for optimization of Ketoconazole SEDDS formulation.

S. No	Composition
	Oil (oleic acid)	Surfactant (cremophor RH 40)	Co-surfactant (propylene glycol)
1	10	16.66	33.34
2	10	18.33	36.67
3	10	20	40
4	20	16.66	33.34
5	20	18.33	36.67
6	20	20	40
7	30	16.66	33.34
8	30	18.33	36.67
9	30	20	40

Tabel no: 4 Fit Summary

Response 1: Zeta potential

Fit summary for zeta potential.

Mixture number	S mix%	oil	Particle size (nm) (Y1)	Zeta potential (mV) (Y2)
P1	10	5	160.7	-21.3
P2	10	10	490.8	-23.1
P3	10	15	643.7	-25.8
P4	20	5	175.9	-14.6
P5	20	10	494.1	-18.5
P6	20	15	689.5	-24.5
P7	30	5	147.7	-19.8
P8	30	10	368.8	-22.3
P9	30	15	666.7	-24.6

Sum of squares is Type III - Partial

The Model F-value of 93.71 implies the model is significant. There is only a 0.01% chance that an F-value this large could occur due to noise.

P-values less than 0.0500 indicate model terms are significant.

Final Equation in Terms of Coded Factors

PS = +426.43-18.67A+252.60B

Contour plot of particle size:

Fig no: 7 3D response surface plot for the effect of independent variable particle size (Y1)

Fig. no: 8 Overlay plot

Fig. no: 9 Self-emulsification time test for Ketoconazole

It is a time for accumulate to form a homogenous mixture upon dilution of formulated SNEDDS. The 1 ml of SNEDDS formulation was introduced in 300 ml purified water. That content was mixed gently using a magnetic stirrer at 37^oC. The time needed to emulsify spontaneously and progression of emulsion droplet was observed for triplicate time.

Table no: 9 Globule size and Zeta potential

Sr no	Formulation code	Self-Emulsification Time (Second)
1	K1	10
2	K2	12
3	K3	11
4	K4	9
5	K5	16
6	K6	15
7	K7	8
8	K8	10
9	K9	12

Globule size analysis and Zeta potential: Aliquots (1 mL each) of the formulation, serially diluted 100-fold with purified water, Analyses the fluctuations in in light scattering due to Brownian motion of the particles were employed to determine the globule size using particle size analyser based on dynamic laser scattering.

Table no: 10 Appearance, pH and Drug content

Sr no	Zeta potential (mV)	Particle size (nm)
1	-21.3	160.7
2	-23.1	490.8
3	-25.8	643.7
4	-14.6	175.9
5	-18.5	494.1
6	-24.5	689.5
7	-19.8	147.7
8	-22.3	368.8
9	-24.6	666.7

1. Appearance:

All the prepared in SEDDS were evaluated for preliminary steps such as visual appearance, P^Hand drug content. These SEDDS formulation were transparent and clear.

2. Ph:

The pH values were found in the acceptable range and thus would cause No irritation. The pH was found in the range of 6.6 – 7.8. The values obtained are given in Table no (25)

3. Drug content:

The drug content was found to be in the acceptable range of all formulations. Drug content of formulated SEDDS ranging from 90.15- 95.25%. Formulation K7 showed high drug content 95.25%. This indicates that drug uniformly distributed throughout system.

Table no: 11 In-vitrodrug release studies

Formulations	Visual Appearance	Clarity	pH	Drug content
K1	Transparent	Clear	6.11	90.15
K4	Transparent	Clear	6.03	94.3
K7	Transparent	Clear	6.15	95.25

In-vitro diffusion studies were carried out for K1, K2 and K4 formulation using STF as diffusion medium. In the Franz diffusion cell.

Table no- 12

Time(min)	%CDR of
Time(min)	K1	K4	K7	API
0	0	0	0	0
5	18	17.2	15	2.3
10	25.8	26.7	27.2	5.5
15	38.9	33.6	35.2	15.6
20	55.5	524	52.3	20.2
25	70.4	66.6	70.8	25.5
30	79.8	77	75.2	31.7
45	89.5	84.7	88.5	36.9
60	93.9	90.2	91.2	44.3

Fig. no: 10

CONCLUSION:

The developed SEDDS would demonstrate advantage over topical drug delivery system. These observations led us to the conclusion that SEDDS seem to be promising drug delivery systems, which can provide an effective and practical solution to the problem associated with drugs with low aqueous solubility and poor systemic bioavailability. SEDDS approach enhanced the bioavailability by efficient drug delivery and by altering physiological phenomena during absorption. The present study demonstrated a systematic approach for the development of SEDDS which can be very useful for the ophthalmic delivery of many emerging hydrophobic drugs with good therapeutic potential.

ACKNOWLEDGMENT:

The presenters are very thankful to KLE College of Pharmacy, Nipani for their constant support and help to carry out this research.

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Received on 27.03.2025 Revised on 23.05.2025

Accepted on 30.06.2025 Published on 25.07.2025

Available online from July 31, 2025

Res. J. Pharma. Dosage Forms and Tech.2025; 17(3):172-178.

DOI: 10.52711/0975-4377.2025.00024

This work is licensed under a Creative Commons Attribution-Non Commercial-Share Alike 4.0 International License. Creative Commons License.

Source	Sequential p-value	Lack of Fit p-value	Adjusted R²	Predicted R²
Linear	0.0480		0.5154	0.2403	Suggested
2FI	0.9577		0.4188	-0.4695
Quadratic	0.1370		0.7425	-0.1608
Cubic	0.1880		0.9727	0.3782	Aliased

Source	Sum of Squares	df	Mean Square	F-value	p-value
Model	63.48	2	31.74	5.25	0.0480	significant
A-S mix	2.04	1	2.04	0.3380	0.5822
B-Oleic acid	61.44	1	61.44	10.17	0.0189
Residual	36.25	6	6.04
Cor Total	99.73	8

Source	Sequential p-value	Lack of Fit p-value	Adjusted R²	Predicted R²
Linear	< 0.0001		0.9586	0.9346	Suggested
2FI	0.7283		0.9517	0.8677
Quadratic	0.3549		0.9596	0.8224
Cubic	0.3120		0.9882	0.9882	Aliased

Source	Sum of Squares	df	Mean Square	F-value	p-value
Model	3.849E+05	2	1.925E+05	93.71	< 0.0001	significant
A-S mix	2090.67	1	2090.67	1.02	0.3519
B-Oleic acid	3.828E+05	1	3.828E+05	186.41	< 0.0001
B-Oleic acid	3.828E+05	1	3.828E+05	186.41
Cor Total	3.973E+05	8

Final Equaton in Terms of Coded Factors

Final Equation in Terms of Coded Factors