NANOEMULSION SYSTEM FOR TOPICAL DELIVERY OF TRETINOIN. RPA1516193015.pdf · gelling. Nanoemulsion based gel was evaluated for pH and drug content. The pH of the gel was determined

64 | P a g e International Standard Serial Number (ISSN): 2319-8141

Full Text Available On www.ijupbs.com

International Journal of Universal Pharmacy and Bio Sciences 4(2): March-April 2015

INTERNATIONAL JOURNAL OF UNIVERSAL

PHARMACY AND BIO SCIENCES IMPACT FACTOR 2.093*** ICV 5.13*** Pharmaceutical Sciences RESEARCH ARTICLE……!!!

NANOEMULSION SYSTEM FOR TOPICAL DELIVERY OF TRETINOIN

Bhavna Laxman Chauhan*1, Vijaya Avadhut Patil

1, Nilesh Mahadeo Khutle

2

1Department of Pharmaceutics, M.E.T. Institute of Pharmacy, Bandra Reclamation, Bandra (W),

Mumbai- 400 050.

2Department of Pharmaceutics, Dr. L.H. Hiranandani College of Pharmacy, Ulhasnagar,

Mumbai- 421 002.

KEYWORDS:

Nanoemulsion, Tretinoin,

Antiacne, Capmul MCM C8.

For Correspondence:

Bhavna Laxman Chauhan*

Address:

Department of Pharmaceutics,

M.E.T. Institute of Pharmacy,

Bandra Reclamation, Bandra

(W), Mumbai- 400 050.

ABSTRACT

The objective of the present study is to formulate and investigate

the potential of nanoemulsion formulation for topical delivery of

tretinoin. Tretinoin nanoemulsion was prepared by using Phase

Inversion Composition Method. In vitro drug release profile

through pig skin was studied using Franz diffusion cell. The skin

retention studies showed better retention of drug in the tissue as

compared to controls. Tretinoin nanoemulsion with droplet size in

the range of 20-200 nm showed effective antiacne activity against

Staphylococcus epidermidis. These results suggested that

nanoemulsions are potential vehicles for improved topical delivery

of tretinoin.



INTRODUCTION:

Retinoids have been used for nearly four decades as topical agents to treat acne1 and are

treatment of choice for comedonal acne, as well as for maintenance therapy2. Tretinoin is the

prototype retinoid and active metabolite product of vitamin A3. It is one of the most widely used

antiacne agent and has biological activity hundred times greater than that of vitamin A1. It helps

to regulate sebum production, collagen synthesis, epithelial cell growth and differentiation.

These qualities have led its use in various proliferative and inflammatory skin diseases such as

psoriasis, acne, epidermotropic T-cell lymphomas or epithelial skin cancer4. Despite having these

potentials, tretinoin shows several disadvantages such as low water solubility5,

photodegradation1, skin irritation and teratogenicity.

Several formulation strategies such as inclusion complexes6, liposomes

7, microspheres

8,

microemulsion9, solid-lipid nanoparticles and niosomes

10 have been recently developed in order

to enhance the delivery of topical tretinoin. The nanosized drug delivery systems may be

preferred for topical delivery of medications due to their potential of providing controlled release

rate and the small droplet size that assists in easy deposition of drug into the hair follicles, where

drug is most required8. Researchers aim at increasing the concentration of retinoids at the site of

action, diminishing local and systemic side effects and/or improving the stability of tretinoin in

the formulation11

.

Many studies have shown that nanoemulsion formulations possess better transdermal and dermal

delivery properties in vitro12

as well as in vivo13

.

Nanoemulsions are part of a broad class of multiphase colloidal dispersions and are non-

equilibrium systems14

. It is an emulsion system with the droplet size in nanometer scale in which

oil or water droplets are finely dispersed in the opposite phase using suitable surfactant to

stabilize the system15,16

. Nanoemulsions are also known as ultrafine emulsions or

miniemulsions17

. It is sized between 20-200 nm with narrow size distribution18

. The size of the

droplets varies depending on the drug particles, mechanical energy, composition and relative

amount of the surfactants19

. A cosurfactant or a cosolvent may be used in addition to the

surfactant to facilitate the stabilization process20,21

. It is a promising transdermal novel dosage

form in terms of controlling droplet size, relatively long term stability and powerful

solubilization ability.



This study aims to formulate the nanoemulsion containing tretinoin as a model drug and evaluate

the release of tretinoin by in vitro permeation studies through pig skin using Franz diffusion cell.

The results obtained could be used to predict the suitability of the dosage form formulated for

topical drug delivery. This new drug delivery system is also developed with the intention of

enhancing the antibacterial activity of drug when incorporated in nanoemulsion.

MATERIALS AND METHODS

Materials

Tretinoin was a gift sample from Shalaks Pharmaceutical Pvt. Ltd. (New Delhi). Capmul MCM

C8 was a gift sample from Abitec Corporation (United State). Triton X-100, n-butanol, ethanol,

isopropyl alcohol and carbopol 934 were purchased from S. D. Fine Chemicals (Mumbai, India).

S. epidermidis (MTCC 6810) was purchased from MTCC, Chandigarh and Nutrient agar from

Himedia, Mumbai. Retin-A® is a commercial preparation and was purchased from local medical

shop. All other chemicals used in the study were of analytical reagent grade.

Formulation of nanoemulsion

Solubility of tretinoin

The solubility of tretinoin in various oils (capmul MCM C8, isopropyl myristate, labrafac

lipophilic, maisine and oleic acid), surfactants (labrasol, span 80, triton X-100, tween 20 and

tween 80) and cosurfactants (ethanol, n-butanol and propylene glycol) was determined by

dissolving an excess amount of tretinoin in 2 ml each of the selected oils, surfactants and

cosurfactants in 5 ml capacity stoppered vials. An excess amount of tretinoin was added to 5 ml

capacity stoppered vial and mixed using a vortex mixer (Remi Cyclomixer, CM-101). The vials

were then kept at 37ºC ± 1.0ºC in an isothermal shaker (Remi waterbath, RSB-12) for 72 hours

to get equilibrium. The equilibrated samples were removed from the shaker and centrifuged at

3000 rpm for 15 minutes. The supernatant was diluted with methanol and quantified

spectrophotometrically (UV, Jasco V-630) at 342 nm. The experiment was repeated in triplicates

and results were represented as mean value (mg/ml) ± standard error of mean.

Pseudoternary phase diagram study

Pseudoternary phase diagrams were constructed using Triplot software version 4.1.2. to find the

concentration range of each component for the existing range of nanoemulsions. On the basis of

solubility studies, surfactant and cosurfactant (Smix) were mixed in different weight ratios (1:1,

2:1 and 3:1). Nine different combinations of oil and Smix (1:9, 2:8, 3:7, 4:6, 5:5, 6:4, 7:3, 8:2 and

9:1) were prepared to delineate the boundaries of phases precisely formed in phase diagrams.



Distilled water was used as an aqueous phase. Pseudoternary phase diagrams of oils, Smix and

aqueous phase were developed using the water titration method. Slow titration with aqueous

phase was done to each weight ratio of oil and Smix. The formulations were observed visually for

transparency and their flowability. The physical state of nanoemulsion was marked on a pseudo-

3-component phase diagram with one axis representing the aqueous phase, second representing

oil and the third representing a mixture of surfactant and cosurfactant at fixed weight ratios (Smix

ratios).

Selection of nanoemulsion formulations and prepartion

Large amount of surfactants causes skin irritation, therefore it is necessary to determine the

optimum surfactant concentration from the phase diagram. Exactly 0.05% w/w of tretinoin was

dissolved in the oil phase of the nanoemulsion formulations. The clear nanoemulsion containing

tretinoin was obtained by diluting the weighed amount of mixture containing oil and Smix.

Aqueous phase was added drop wise to this mixture and mixed continuously using a magnetic

stirrer at room temperature.

Characterization of Nanoemulsion

Nanoemulsions have some interesting physical properties that distinguish them from ordinary

microscale emulsions. The parameters used to characterise nanoemulsion are as follows

1. Droplet size, zeta potential and polydispersity index of nanoemulsion formulations

The average droplet size, polydispersity index and zeta potential can be determined using

Malvern Zetasizer. It analyses the fluctuations in intensity of scattering by droplets due to

Brownian motion22

. The measurement was performed using He-Ne laser at 633 nm. Light

scattering was monitored at an angle 90º at 25º C.

2. pH of nanoemulsion formulations

The pH of the nanoemulsion formulations can be determined by using digital pH meter

(Elico model LI 120).

3. Drug content of nanoemulsion formulations

The drug content of nanoemulsion was analyzed by using UV-visible spectrophotometer.

Known quantity of formulation was dissolved in methanol by sonication and absorbance

was measured at 342 nm after suitable dilution.

4. Drug loading capacity of nanoemulsion formulations

It was studied by adding excess amount of tretinoin to the nanoemulsion formulation and

stirred for 48 hours at 25ºC. The formulations were centrifuged and the supernatants were



collected. These supernatants were diluted appropriately with methanol and tretinoin

concentration was determined at 342 nm.

Formulation of nanoemulsion based gel

The formulation that showed no phase separation, having small droplet size and the one showing

good agreement with respect to pH, drug content and drug loading was selected for further

development of nanoemulsion based gel. As nanoemulsions have low viscosity and are difficult

to apply on the skin, it should be gelled with suitable gelling agent. For present study, gel was

prepared using carbopol 934 (1.5%). Required quantity of carbopol 934 was directly dispersed in

the nanoemulsion formulation. Neutralization was performed using triethanolamine to attain

gelling. Nanoemulsion based gel was evaluated for pH and drug content.

The pH of the gel was determined by dispersing 2.5 g of gel (0.05%) in 25 ml of distilled water.

The pH of this dispersion was detected using digital pH meter23

.

To determine drug content of nanoemulsion based gel, 0.5 g of tretinoin loaded nanoemulsion

based gel (0.05%) was accurately weighed and adjusted to 10 ml with methanol. The mixture

was centrifuged and the supernatants were collected. Tretinoin concentration was determined at

342 nm after appropriate dilution using UV-visible spectrophotometer.

Stability studies

The physical stability of nanoemulsion was studied by visual observation of clarity and phase

separation. Chemical stability was studied by keeping the nanoemulsion at 40°C and 75%

relative humidity as well as at room temperature for 3 months. Formulations were then analysed

for tretinoin content using UV-double beam spectrophotometer at 342 nm.

In vitro skin permeation study

In vitro skin permeation of tretinoin loaded nanoemulsion formulations was carried out through

pig skin by using Franz diffusion cell. Hair was shaved carefully from abdominal skin of the pig.

The subcutaneous fat and other extraneous tissues were removed. The dermis side was wiped

with isopropyl alcohol to remove the adhering fat. The cleaned skin was washed with distilled

water and stored at 4ºC for 24 hours in phosphate buffer saline pH 7.4 and used for the

permeation experiments. The skin was thawed and mounted between the donor and receiver

compartments of the Franz diffusion cell having a capacity of 11 ml and surface area of 1.327

cm2. The assembly was thermostated by circulating warm water at 37±2ºC in the external jacket

of Franz diffusion cell to stimulate the body temperature. The formulation equivalent to 1 gm

was placed uniformly on the epidermal surface of skin in the donor compartment, while receptor



compartment contained hydroalcoholic solution (ethanol: PBS in 50:50). The diffusion medium

in the receptor compartment was constantly stirred by means of magnetic stirrer. The aliquot of 2

ml was withdrawn through the sampling port of diffusion cell at predetermined time intervals of

0.5, 1, 2, 3, 4, 5, 6, 7 and 8 hours and replaced immediately with the same volume of the receptor

medium. The samples were immediately analyzed for drug content spectrophotometrically at 338

nm. Three replicates of each experiment were performed.

Drug deposition studies

The skin surface was washed three times with PBS and dried with filter paper after 8 hrs of

permeation study. The skin samples were minced and soaked in a flask with 20 ml of methanol

for 24 hours. The methanolic samples were shaken in an ultrasound bath for 4 times in order to

extract the drug accumulated in the skin pieces. The concentration of drug in skin sample is an

index of topical delivery, whereas the concentration in the receptor phase is an index of

transdermal delivery7.

Determination of flux and permeability

The cumulative amount of drug permeating across the pig skin was plotted against time. The

steady state flux of tretinoin was calculated by dividing the slope of the linear portion of the

curve by the area of the exposed membrane surface. Permeability coefficient was calculated by

dividing the flux obtained by the initial concentration of drug in the donor compartment. The

experiment was carried out in triplicate. The results of drug permeation, drug retention, flux and

permeability coefficient of nanoemulsion formulation was compared with that of hydroalcoholic

drug solution and marketed formulation.

Antibacterial activity

Staphylococcus epidermidis is universally found inside affected acne vulgaris pores, whereas

Propionibacterium acnes is normally the sole resident. The optimised formulation was tested

against S. epidermidis (MTCC 6810) to investigate antiacne activity.

The agar well diffusion method was used for the determination of antibacterial activity against S.

epidermidis. Test bacterial suspension (100µl of 108cfu/ml) was swabbed on the surface of

nutrient agar plates. Agar wells were made using cork borer at equal distance. Each sample was

added in the well after 10 minutes setting. After preincubation at 4ºC for 2 hours, plates were

further incubated at 37ºC for 24 hours. The average diameter of the zone of inhibitions produced

was measured in millimetres. Diameter of the inhibition zone of nanoemulsion formulation was

compared with that of plain drug solution in DMSO. All tests were performed in duplicate.



RESULTS AND DISCUSSION

Formulation of nanoemulsions

Solubility study

Oil phase is the most important component of nanoemulsion formulation as it can solubilize

lipophilic drug. Solubilizing capacity of an oil phase is crucial for development of nanoemulsion,

as it determines the drug loading efficiency. In the present study, solubility of tretinoin in five

different oils was assessed. Result of solubility study in different oil phase is depicted in Table 1

and is represented graphically in Figure 1. The tretinoin showed highest solubility in a capmul

MCM C8 (14.37±0.03 mg/ml) as compared with other oils. Therefore capmul MCM C8 was

selected for investigation. Regarding surfactant and cosurfactant selection, drug solubility would

come second to the main selection perspectives i.e. emulsification efficiency. In the present

investigation, various surfactants were screened for their emulsification efficiencies. Triton X-

100 exhibited the highest emulsification efficiency among the various surfactants screened and it

also showed highest solubility of tretinoin (10.77±0.14 mg/ml) as depicted in Table 1. Hence,

triton X-100 was selected as surfactant. Among the different cosurfactant screened n-butanol

showed higher emulsifying capacity for capmul MCM C8 and triton X-100 mixture and highest

solubility 4.57±0.01 mg/ml as depicted in Table 1. Thus, n-butanol was selected as a cosurfactant

for present study.

Table 1: Solubility of tretinoin in various components

Components of nanoemulsion Solubility of Tretinoin (mg/ml)

Oils

Capmul MCM C8 14.37±0.03

Isopropyl myristate 00.97±0.08

Labrafac lipophilic 02.08±0.14

Maisine 01.85±0.02

Oleic acid 12.35±0.02

Surfactants

Labrasol 03.57±0.09

Span 80 02.23±0.04

Triton X-100 10.77±0.14

Tween 20 09.16±0.03

Tween 80 08.26±0.05

Cosurfactants

Ethanol 01.24±0.10

n-Butanol 04.57±0.01

Propylene glycol 01.59±0.03



Fig. 1- Graphical representation of tretinoin solubility in various components

Pseudoternary phase diagram study

The construction of pseudoternary phase diagrams was used to determine the concentration range

of capmul MCM C8, Smix and water in the existing range of nanoemulsion using Triplot software

version 4.1.2. The pseudoternary phase diagrams with various weight ratios of triton X-100 and

n-butanol are depicted in Figure 2. The shaded area represents nanoemulsion region in the

pseudoternary phase diagram. The rest of the region on the phase diagram represents the turbid

and conventional emulsions based on visual observations. The results showed that all Smix ratios

(i.e. 1:1, 2:1 and 3:1) have almost same nanoemulsion area.



Fig. 2- Pseudoternary phase diagrams indicating nanoemulsion (shaded area) region of Capmul

MCM C8 (oil), Triton X-100 (surfactant) and n-Butanol (cosurfactant) at different Smix ratios

indicated in (A) Smix=1:1, (B) Smix=2:1 and (C) Smix=3:1

Selection of nanoemulsion formulations and its preparation

Nanoemulsion formulations were selected from nanoemulsion regions, using pseudoternary

phase diagrams. The formulations where the oil phase completely dissolved the drug and

accommodated the optimum quantity of Smix and distilled water were selected for further

investigation. Composition of nanoemulsion formulations are described in Table 2.



Table 2: Composition of nanoemulsion formulations

Components Sm= 1:1 Sm= 2:1 Sm= 2:1 Sm= 2:1

F1 (%) F2 (%) F3 (%) F4 (%)

Drug 0.05 0.05 0.05 0.05

Oil 05.56 13.64 16.67 22.22

Smix 50.00 31.82 30.95 33.33

Water 44.44 54.54 52.38 44.44

Evaluation of nanoemulsion

The nanoemulsion formed was transparent against strong light when observed for visual clarity.

No flocculation and phase separation were found at the time of preparation. Results of

physicochemical parameters of all four nanoemulsion formulations such as droplet size,

polydispersity index, pH, drug content and drug loading are described in Table 3.

Droplet size and surface charge on the droplets of nanoemulsion has marked effect on the

stability of the emulsion system. The droplet size of nanoemulsion determines the rate, extent of

drug release and absorption. The polydispersity index of the nanoemulsion formulation indicates

uniformity of droplet size within the formulation. Least droplet size of 81.69 nm was shown by

formulation F2 having polydispersity index 0.407. Zeta potential of formulation F2 was found to

be 0.891. The low value of zeta potential is indicative of the absence of a charge on the particles.

This may be due to the use of nonionic surfactant in the nanoemulsion formulation which

stabilize the particles sterically and thus act as stabilizer. The other possible mechanisms of

origin of charge on the particles are may be due to different ion absorption from any electrolyte

solution or ionization of surface functional groups present in the drug molecule. However, this

does not take place to a great extent with already stabilized particles, thus giving a very low

value for zeta potential24

(Marsalek, 2012). The average droplet size of the other nanoemulsion

formulations was found to be in the range of 80-130 nm as shown in the Table 3.

The nanoemulsion formulations showed pH values varying from 5.80 to 6.30. All the pH values

lie within the normal pH range of the skin as shown in Table 3. It was also observed that

incorporation of tretinoin did not significantly affect the pH value of the formulations. The drug

content of the nanoemulsion formulation was within the range of 98-100% as depicted in Table

3. The solubility of drug in the nanoemulsion was found to increase with increasing surfactant:

cosurfactant concentrations. This could be attributed to higher solubility of tretinoin in triton X-



100 as depicted in Table 3. However, there was no significant difference in solubility of tretinoin

in various nanoemulsion formulations.

Table 3: Physicochemical parameters of nanoemulsion formulations

Formulation

code

Droplet size

(nm)

Polydispersity

index pH values

Drug content

(%w/w)

Drug loading

(mg/gm)

F1 118.7 0.441 5.82±0.091 99.48±0.31 20.54±0.15

F2 81.69 0.407 5.85±0.037 99.79±0.05 25.15±0.52

F3 117.6 0.548 6.21±0.023 98.94±0.22 24.92±0.06

F4 126.8 0.384 6.07±0.012 99.02±0.03 27.30±0.03

Evaluation of Nanoemulsion based gel

Since the droplet size of nanoemulsion formulation F2 was smallest amongst the various

formulations and showed good agreement with respect to pH, drug content and drug loading, it

was incorporated in gel base. The pH of the nanoemulsion based gel formulation was found to be

6.45±0.023, which was within the acceptable limits for topical formulation. Assay of gel was

carried out to determine the drug content in the formulation and was found to be 99.74± 0.35%

for F2 gel formulation.

Stability studies of the nanoemulsion formulation

Stability studies of the nanoemulsion formulation were carried out by subjecting them to visual

inspection and drug content. Nanoemulsion formulations F2 and F3 did not show any evidence

of phase separation, flocculation or precipitation while formulations F1 and F4 showed phase

separation and became milky/turbid as shown in Table 4. The drug content of the nanoemulsion

formulations after 3 months was found to be in the range 86-88% at accelerated condition 40±2°

C and 75± 5% RH.



Table 4: Results of stability studies of the nanoemulsion formulation

Stability study results at room temperature

Formulation code Appearance pH Drug content (%)

F1 Slight yellow, milky/turbid 6.23±0.05 90.05±0.015

F2 Clear, yellow, transparent 6.29±0.04 92.73±0.01



Stability study results at accelerated condition 40±2° C and 75± 5% RH

Formulation code Appearance pH Drug content (%)





In vitro permeation studies

In vitro permeation studies was carried out using pig skin and vertical Franz diffusion cell to

evaluate the tretinoin accumulation into the skin and its permeation through the skin. Permeation

data of nanoemulsion formulation was compared with those of control (Hydroalcoholic drug

solution) having same concentration. Furthermore, a commercial topical formulation of tretinoin

(Retin-A®, 0.05%) was also used as a control. The amount of tretinoin permeated from various

formulations and control was determined for 8 hours. The formulation codes for different

formulations used for permeation study are listed in Table 5. The permeation profiles (percentage

cumulative drug release versus time) of tretinoin through the skin from different formulations

and controls are shown in Figure 3.

The highest drug permeation was obtained with the hydroalcoholic drug solution. Amount of

tretinoin permeated from hydroalcoholic drug solution, nanoemulsion formulation (NE2) and

marketed preparation was found to be 2.00±0.039%, 1.5±0.131% and 0.95±0.06% respectively

as shown in Figure 3. Nanoemulsion based gel form (NEG2) showed no skin permeation as

compared to fluid state nanoemulsion.



Table 5: The formulation codes for different formulations

HDAL Hydroalcoholic drug solution

NE2 Nanoemulsion formulation

NEG2 Nanoemulsion based gel

MRKT Marketed preparation

Fig. 3- Graphic representation of cumulative amount of tretinoin permeated from

nanoemulsion (NE2), marketed preparation (MRKT) and hydroalcoholic drug solution

(HDAL)

Drug deposition studies

The concentration of drug retained in skin sample is an index of topical delivery. The amount of

drug accumulated in the pig skin is reported in Table 6. Nanoemulsion formulation showed a

drug accumulation of 32.86±0.43 µg/cm2

which was found to be higher as compared to control.

Drug retained by the hydroalcoholic drug solution and marketed preparation was found to be

27.33±0.26 µg/cm2 and 24.75±0.22 µg/cm

2 respectively.

Table 6: Study of drug retention into the pig skin

Formulation code Amount of drug retained

(µg/cm2)

HDAL 27.33±0.26

NE2 32.86±0.43

NEG2 30.37±0.13

MRKT 24.75±0.22



Fig. 4- Comparative study of skin deposition of tretinoin from various formulations

Flux and permeability parameters

The permeation flux of drug formulation was compared with the hydroalcoholic drug solution

and marketed preparation. Maximum flux was obtained with hydroalcoholic drug solution

(1.30±0.08 mg/cm2/h). Flux of the nanoemulsion formulation (1.02±0.15 mg/cm

2/h) was found

to be higher than the marketed preparation (0.64±0.04 mg/cm2/h). The results of steady state

flux and permeation coefficient are depicted in Table 7.

Table 7: Permeability parameters of different formulations

Formulation

code

Steady state flux

Jss (mg/cm2/h)

Permeation coefficient

Kp (cm/h)

HDAL 1.30±0.08 0.02±0.11

NE 1.02±0.15 0.02±0.24

MRKT 0.64±0.04 0.001±0.19

Antibacterial activity

Staphylococcus epidermidis is one of the major bacterial strains found in acne lesions. The

antibacterial activity of the nanoemulsion formulation was measured in terms of zone of

inhibition against S. epidermidis. DMSO was used as a control and it did not show any

antibacterial activity. Nanoemulsion formulation (NE2) showed highest antibacterial activity

(29.75±1.25 mm) and tretinoin (as standard) showed good inhibition of S. epidermidis

(22.5±0.57 mm) at a concentration of 500 µg/ml.



Table 8: Comparison of antibacterial activity against S. epidermidis of formulation (F2) and

standard

Concentration of Tretinoin

(µg/ml)

Average Zone of Inhibition (mm)

Formulation Standard

250 26.25±1.5 21.25±0.95

500 29.75±1.25 22.5±0.57

CONCLUSION

Nanoemulsion is a promising transdermal drug delivery vehicle. Many research scientists have

formulated and studied nanoemulsion containing tretinoin for topical application. Concentrations

of various components of nanoemulsion formulation such as oil, surfactant and cosurfactant were

screened using the pseudoternary phase diagrams. The optimum formulation of the

nanoemulsion based gel consist of tretinoin (0.05%), capmul MCM C8 (13.64%), triton X-100/n-

butanol (31.82%, Smix=2:1), carbopol 934 (1.5%) and water. Drug release profile was studied for

nanoemulsion formulation and nanoemulsion based gel. Nanoemulsion based gel showed no

release within the experimental period of 8 hours, which indicates that drug was not absorbed

and did not reach into the systemic circulation. Antiacne activity of tretinoin nanoemulsion

formulation showed good inhibition of S. epidermidis as compared to tretinoin as a standard.

Drug retention was found to be highest for nanoemulsion formulation and lowest for marketed

preparation. The developed nanoemulsion based gel of tretinoin showed better retention of drug

as compared to controls and therefore has a great potential for topical delivery of drug.

Nevertheless, significant work still needs to be carried out to confirm these results and explore

the tolerance of the vehicles in healthy patients and those with acne infection.

ACKNOWLEDGEMENT

The authors are grateful to the Shalaks Pharmaceuticals Pvt. Ltd. (New Delhi) for providing the

gift sample of tretinoin. The authors are thankful to Abitec Corporation (United States) for

providing the gift sample of oils. The authors are also indebted to Gattefosse (Cedex, France) for

providing the samples of surfactants and cosurfactants. We also wish to thank Dr. Abha Doshi,

Principal of M.E.T. Institute of Pharmacy for reading the manuscript.



REFERENCES:

1. Bershad S, (2001), Developments in topical retinoid therapy for acne. Seminars in

Cutaneous Medicine and Surgery, 20, 154-161.

2. Thiboutot D, Gollnick H, Bettoli V, Dreno B, Kang S, Leyden JJ, Shalita AR, Lozada

VT, Berson D, Finlay A, Goh CL, Herane MI, Kaminsky A, Kubba R, Layton A,

Miyachi Y, Perez M, Martin JP, Ramos-E-Silva M, See JA, Shear N, Wolf J, (2009),

New insights into the management of acne: an update from the global alliance to improve

outcomes in acne group. J. Am. Acad. Dermatol., 60, S1-50.

3. Rigopoulos D, Ioannidis D, Kalogeromitros D, Katsambas AD, (2004), Comparison of

topical retinoids in the treatment of acne. Clin. Dermatol., 22, 408-411.

4. Lucek R, Colbum W, (1985), Clinical pharmacokinetics of the retinoids. Clinical

Pharmacokinetics, 10, 38-62.

5. Lehman P, John J, Franz T, (1990), Percutaneous absorption of retinoids: Influence of

vehicle, light exposure and dose. J. Invest. Dermatol., 91, 56-61.

6. Montassier P, Duchene D, Poelman MC, (1997), Inclusion complexes of Tretinoin with

cyclodextrins. Int. J. Pharm., 153, 199-209.

7. Sinico C, Manconi M, Peppi M, Lai F, (2005), Liposomes as carriers for dermal delivery

of tretinoin: In vitro evaluation of drug permeation and vesicle-skin interaction. J.

Control. Release, 103, 123-136.

8. Tabbakhian M, Sharifian A, Shatalebi MA, (2008), Preparation and in vitro

characterization of tretinoin containing microspheres suited for dermatological

preparations. Res. Pharm. Sci., 3, 31-40.

9. Khanna S, Katare OP, Drabu S, (2010), Lecithinized microemulsions for topical delivery

of tretinoin. International Journal of Drug Development and Research, 2, 711-719.

10. Patel RP, Patel KP, Modi KA, Pathak, CJ, (2011), Novel anti-acne drug delivery system

of tretinoin. Int. Res. J. Pharm., 1, 65-71.

11. Allec J, Chatelus A, Wagner N, (1997), Skin distribution and pharmaceutical aspects of

adapalene gel. J. Am. Acad. Dermatol., 36, S119-125.

12. Pathak P, Nagarsenker M, (2009), Formulation and evaluation of lidocaine lipid

nanosystems for dermal delivery. AAPS PharmSciTech, 10, 985-992.



13. Shakeel F, Ramadan W, Gargum HM, Singh R, (2010), Preparation and in vivo

evaluation of indomethacin loaded true nanoemulsions. Sci. Pharm., 78, 47-56.

14. Russel WB, Saville DA, Schowalter WR, (1991), Colloidal Dispersions. J. Disper. Sci.

Technol., 12, 381-382.

15. Manson TG, Graves SM, Wilking JN, Lin MY, (2006), Extreme emulsification:

Formation and structure of nanoemulsions. J. Phys. Condens. Matter, 9, 193-199.

16. Schramm LL, (2005), Emulsions, foams and suspensions: Fundamentals and

applications. Germany, Wiley-VCH. 4-5.

17. Ugelstadt J, El-Aassar MS, Vanderhoff JW, (1973), Emulsion polymerization- Initiation

of polymerization in monomer droplets. J. Polym. Sci., 11, 503-513.

18. Shinoda K, Kunieda H, (1983), Phase properties of emulsions: PIT and HLB, in: Schuster

D (Ed.) Encyclopedia of emulsion Technology. Marcel Dekker, New York.

19. Divsalar A, Saboury AA, Nabiuni M, Zare Z, Kefayati ME, Seyedarabi A, (2012),

Characterization and side effect analysis of a newly designed nanoemulsion targeting

human serum albumin for drug delivery. Colloid Surf. B, 98, 80-84.

20. Anton N, Benoit JP, Saulnier P, (2008), Design and production of nanoparticles

formulated from nanoemulsion templates-A review. J. Control Release, 128, 185-199.

21. Sharma N, Bansal M, Visht S, Sharma PK, Kulkarni GT, (2010), Nanoemulsion: A new

concept of delivery system. Chron. Young Sci., 1, 2-4.

22. Ruth HS, Attwood D, Ktistis G, Taylor C, (1995), Phase studies and particle size analysis

of oil-in-water phospholipid microemulsions. Int. J. Pharm., 116, 253-261.

23. Chudasama A, Patel V, Nivsarkar M, Vasu K, Shishoo C, (2011), Investigation of

microemulsion system for transdermal delivery of itraconazole. J. Adv. Pharm. Technol.

Res., 2, 30-38.

24. Marsalek R, (2012), Zeta potential- Applications. International Conference on

Environment and Industrial Innovation, 35, 15-19.

Documents

NANOEMULSION SYSTEM FOR TOPICAL DELIVERY OF TRETINOIN. RPA1516193015.pdf · gelling. Nanoemulsion based gel was evaluated for pH and drug content. The pH of the gel was determined