The Devolopment of Mouth Nanospray for Black Cumin Essential Oil

(

Nigella

sativa

L.): Physical Properties, Stability and Antibacterial

Activity

Article

Milda Rahayu

, Septi Hariyani

, Uce Lestari*

Pharmacy Study Program, Faculty of Medicine and Health Sciences, Universitas Jambi, Telanaipura,

Jambi City, Indonesia

A

bstract

Halitosis is a common oral health problem that can reduce quality of life. This study aimed to evaluate

the physical properties, nanoparticle characteristics, and antibacterial activity of a mouth nano spray

containing black cumin essential oil (

Nigella

sativa

L.). Four formulations were prepared with different

essential oil concentrations: F1 (0.25%), F2 (0.5%), F3 (1.0%), and F4 (1.5%). Physical quality evaluation

included

organoleptic

properties,

pH,

homogeneity,

and

viscosity.

Nanoparticle

characterization

was

performed using a Particle Size Analyzer (PSA), while antibacterial activity against Streptococcus mutans

was assessed using the disc diffusion method, with chlorhexidine as the positive control and aquadest

as

the

negative

control.

All

formulations

exhibited

acceptable

physical

characteristics

as

clear

and

homogeneous liquids, with pH values ranging from 6.0 to 6.7, indicating suitability for oral application.

PSA analysis was conducted on formulation F2, which was selected as a representative formulation with

the best physical quality. The results showed a mean particle size of 42.7nm with a polydispersity index

of 0.6, indicating a relatively broad particle size distribution. The zeta potential value of −5.6mV suggested

low

electrostatic stability and a potential risk of particle aggregation, indicating the

need for

further

optimization. Antibacterial activity testing demonstrated that formulations F2, F3, and F4 exhibited strong

inhibitory effects, with inhibition zone diameters of 12.62 mm, 12.53 mm, and 12.32 mm, respectively,

exceeding that of the positive control (8.39mm).

Keyword

s

:

Halitosis,

m

outh

n

anospray, Nigella sativa L.,

n

anoemulsi

on

, Streptococcus mutans

*

Corresponding author

Email address:

ucelestari@unja.ac.id

(Uce Lestari)

DOI:

https://doi.org/10.22437/chp.v10i1.48881

Received

October 31

st

2025;

Accepted

February 22

nd

2026;

Available online

May 19

th

2026

(

https://creativecommons.org/licenses/by/4.0

)

94

M. Rahayu et al.,

Chempublish Journal, 10(1) 2026, 94-105

Graphical Abstract

Introduction

Oral health problems remain a major public

health

concern

in

Indonesia,

with

a

high

prevalence

reported

in

national

surveys.

According to the 2018 Basic Health Research

(Riskesdas),

57.6%

of

the

population

experienced

dental

and

oral

health

problems,

many

of

which

were

associated

with secondary conditions such as halitosis.

Halitosis,

or

oral

malodor,

is

often

underestimated

despite

its

significant

impact

on

self-confidence

and

social

interactions. This condition generally arises

from

microbial

activity

in

the

oral

cavity,

particularly

the

degradation

of

proteins

by

oral bacteria, resulting in the production of

volatile

sulfur

compounds

(VSCs)

and

organic

acids

that

cause

unpleasant

odors[1].

Among

oral

microorganisms,

Streptococcus mutans

plays an important role

in

the

development

of

oral

diseases,

including

dental

caries

and

plaque

formation.

Although

halitosis

is

multifactorial,

S.

mutans

contributes

indirectly

by

promoting

biofilm

formation

and

creating

an

acidic

environment

that

supports

the

growth

of

other

odor-

producing bacteria. In addition, its metabolic

activity leads to the accumulation of organic

acids

that

may

exacerbate

oral

malodor,

making

it

a

relevant

target

organism

in

antibacterial studies related to halitosis [1,2].

Various

strategies

have

been

developed

to

manage

halitosis,

including

the

use

of

synthetic

mouthwashes

containing

active

agents

such

as

chlorhexidine[3].

Although

chlorhexidine

is

effective

in

reducing

oral

bacterial

load,

its

long-term

use

has

been

associated

with

adverse

effects,

including

mucosal irritation, tooth discoloration, taste

disturbance,

and

disruption

of

the

normal

oral

microbiota.

These

limitations

have

driven

interest

in

herbal-based

oral

care

products

as

safer

alternatives.

One

such

innovation is the formulation of black cumin

extract mouthwash in the form of a dip bag;

however,

this

preparation

still

faces

challenges

physical

stability,

uneven

distribution

of

active

compounds,

and the potential for tooth staining [4].

95

M. Rahayu et al.,

Chempublish Journal, 10(1) 2026, 94-105

Black

cumin

(

Nigella

sativa

L.)

has

been

widely

recognized

for

its

antibacterial

properties, primarily attributed to bioactive

constituents

such

as

thymoquinone,

thymohydroquinone,

and

thymol.

These

compounds

have

demonstrated

inhibitory

effects

against

various

pathogenic

microorganisms,

including

bacteria

associated

with

oral

infections[5]

.

Despite

this

potential,

conventional

herbal

formulations

often

suffer

from

limited

bioavailability

and

suboptimal

delivery

of

active

compounds

within

the

oral

cavity,

thereby

reducing

their

therapeutic

effectiveness [6].

Nanotechnology

offers

a

promising

approach to overcome these limitations by

enhancing

the

stability,

bioavailability,

and

penetration

of

active

compounds.

Nanoemulsion-based

delivery

systems

can

improve

the

uniform

distribution

of

hydrophobic essential oils and protect them

from degradation. In particular, nano spray

dosage

forms

provide

additional

advantages, including ease of use, improved

hygiene,

rapid

onset

of

action,

and

more

uniform

dispersion

of

nanosized

particles

across

the

oral

surfaces.

Compared

to

conventional

herbal

mouthwashes,

nano

spray

formulations

are

expected

to

offer

enhanced antibacterial efficacy with reduced

side effects [7].

However,

studies

focusing

on

the

formulation of black cumin essential oil nano

sprays

for

oral

health

applications,

particularly

for

halitosis

management,

remain limited. Therefore, this study aimed

to

formulate

and

evaluate

a

mouth

nano

spray containing black cumin essential oil by

assessing its physical characteristics (particle

size, pH, viscosity, and spray properties) and

antibacterial

activity

against

Streptococcus

mutans

.

The

findings

of

this

study

are

expected

to

provide

scientific

evidence

supporting

the

development

of

innovative,

safe,

and

effective

nano-based

herbal

oral

care

products,

as

well

as

to

contribute

to

further

research

in

the

fields

of

pharmaceutical

technology

and

public

health [8].

Materials and Methods

Materials

Black

cumin

essential

oil

(

Nigella

sativa

L.)

was

obtained

from

PT.

Kisbiokim

Medika

Laboratori, West Sumatra, Indonesia. Tween

80,

Virgin

Coconut

Oil

(VCO),

polyethylene

glycol 400 (PEG 400), potassium sorbate, and

peppermint oil were purchased from Kimia

Jaya

Abadi,

Semarang,

Indonesia.

Sterile

Aquadest

was

obtained

from

Onitsuka®,

Japan.

Paper

discs

were

used

for

antibacterial

testing.

Streptococcus

mutans

ATCC

25176

was

employed

as

the

test

microorganism,

and

Mueller–Hinton

Agar

(MHA)

medium

was

purchased

from

Himedia,

Jakarta,

Indonesia.

Chlorhexidine

0.1%

(Minosep®,

Minirock

Mandiri,

West

Java,

Indonesia)

was

used

as

the

positive

control.

Formula Mouth Nano Spray Essential Oil of

Black Cumin Seeds (Nigella sativa L.)

The

mouth

nano

spray

formulation

was

developed using black cumin seed essential

oil

(

Nigella

sativa

L.)

as

the

primary

antibacterial

active

compound.

A

nanoemulsion

delivery

system

was

employed

to

improve

the

formulation’s

physicochemical

stability,

solubility,

and

bioavailability. Tween 80 and PEG 400 were

utilized as the surfactant and co-surfactant,

respectively,

while

virgin

coconut

oil

(VCO)

served as the oil phase. Potassium sorbate

was

incorporated

as

a

preservative,

peppermint

oil

as

a

flavoring

agent,

and

distilled

water

(aquadest)

as

the

aqueous

solvent.

Four

formulations

(F1–F4)

containing

different

concentrations

of

Nigella sativa

essential oil were prepared to

96

M. Rahayu et al.,

Chempublish Journal, 10(1) 2026, 94-105

evaluate

the

influence

of

essential

oil

concentration

on

the

physicochemical

characteristics

and

antibacterial

activity

of

the

mouth

nano

spray,

as

summarized

in

Table 1.

Preparation of Mouth Nanospray

The

formulation

of

the

Nigella

sativa

essential oil mouth nano spray was carried

out

using

a

nanoemulsion

technique.

All

equipment and materials were prepared in

advance,

and

each

component

was

accurately weighed and measured according

to

the

required

formulation.The

oil

phase

was

prepared

by

mixing

black

cumin

essential

oil

with

Virgin

Coconut

Oil

(VCO)

until a homogeneous mixture was obtained

(Mixture

1).

Separately,

Tween

80

(surfactant)

and

polyethylene

glycol

400

(PEG

400,

co-surfactant)

were

mixed

until

homogeneous

(Mixture

2).

Mixture

2

was

then gradually added to Mixture 1, followed

by

the

addition

of

peppermint

oil.

The

resulting

oil

phase

was

stirred

using

a

magnetic stirrer at 600 rpm and heated to 50

°C. This temperature was selected to reduce

interfacial

tension

and

viscosity,

thereby

facilitating emulsification without degrading

the essential oil components. The aqueous

phase was prepared by dissolving potassium

sorbate

(0.1

mg)

in

sterile

distilled

water,

followed by heating to 50 °C to match the oil

phase temperature and prevent premature

phase separation.

Table 1.

Formulation

of Mouth Nano Spray

Black Cumin Seed Essential Oil Preparation

Materials

Concentration (% v/v)

Function

FI

FII

FIII

FIV

Black

cumin

seed

essential

oil

(

Nigella sativa

L.)

0.25

0.5

1

1.5

Anti-bacterial

active ingredients

Tween 80

7

Surfactant

VCO

2

Oil phase

PEG 400

3

Co- surfactan

Potassium sorbate

0.1

Preservatives

Peppermint oil

0.25

Fresheners

Aquadest

ad 100ml

Solvent

The emulsification process was initiated by

gradually

adding

the

oil

phase

into

the

aqueous phase under continuous magnetic

stirring

at

800

rpm

to

ensure

uniform

dispersion. Distilled water was subsequently

added to obtain a final formulation volume

of

100

mL.

The

resulting

coarse

emulsion

was

further

homogenized

using

a

mechanical homogenizer at 10,000 rpm for

20–30

min,

followed

by

ultrasonication

for

60 min to reduce droplet size and promote

the

formation

of

a

stable

nanoemulsion

system.

The

process

yielded

a

clear

and

transparent

nano

spray

formulation,

indicating

successful

nanoemulsion

formation.

Physical Quality and Stability of Nano Spray

Physical

quality

and

stability

evaluations

were

conducted

to

assess

the

physical

integrity

of

the

mouth

nano

spray

and

to

detect any signs of phase separation during

the storage period [9]. All formulations were

stored

in

tightly

closed

containers

at

room

temperature (25 ± 2 °C) and protected from

direct light for four weeks [9].

97

M. Rahayu et al.,

Chempublish Journal, 10(1) 2026, 94-105

Organoleptic

Evaluation.

Organoleptic

properties,

including

appearance,

color,

odor, and taste, were evaluated by visual and

sensory

observation.

The

assessment

was

performed

weekly

for

four

weeks

by

observing

several

changes

in

clarity,

color

uniformity,

and

odor

intensity.

Taste

evaluation was conducted cautiously using a

small

amount

of

sample

to

assess

acceptability

and

the

absence

of

irritation

[10].

pH

Measurement.

The

pH

of

each

formulation

was

measured

using

a

calibrated

digital

pH

meter

at

room

temperature.

Measurements

were

conducted

weekly

for

four

weeks.

The

acceptable

pH

range

for

oral

preparations

was

set

between

6.0

and

7.0

to

ensure

compatibility

with

the

oral

cavity

and

to

minimize the risk of mucosal irritation [11].

Homogeneity

Test.

Homogeneity

was

evaluated

by

visual

inspection

of

the

formulation

spread

on

a

clean

glass

slide

under

adequate

lighting

conditions.

The

presence

or

absence

of

visible

coarse

particles,

sedimentation,

or

phase

separation

was

observed

at

weeks

0–4.

A

formulation

was

considered

homogeneous

if

no

visible

particles

or

separation

were

detected throughout the observation period.

Viscosity

Test

.

Viscosity

was

determined

using

an

Ostwald

viscometer

following

a

standard procedure. A volume of 5 mL of the

formulation

was

introduced

into

the

viscometer and allowed to equilibrate at 25

± 1 °C. The flow time between the upper and

lower calibration marks was recorded using

a

stopwatch,

and

viscosity

values

were

calculated by comparison with aquadest as

the reference liquid.

Characterization

of

Mouth

Nano

Spray

Nanoparticles

The

nanoparticle

characteristics

of

the

mouth

nano

spray

containing

black

cumin

(

Nigella sativa

L.) essential oil were evaluated

using

a

Particle

Size

Analyzer

(PSA).

This

analysis

was

conducted

to

determine

the

principal physicochemical parameters of the

nanoemulsion

system,

including

mean

particle size, polydispersity index (PDI), and

zeta

potential.

These

parameters

are

essential

for

assessing

particle

size

uniformity, dispersion homogeneity, and the

colloidal

stability

of

the

developed

nano

spray formulation.

The mean particle size provides information

regarding the nanoscale dimensions of the

dispersed

droplets,

while

the

PDI

value

indicates

the

width

of

particle

size

distribution

and

the

degree

of

system

homogeneity.

In

addition,

zeta

potential

analysis

was

performed

to

evaluate

the

electrostatic stability of the nanoemulsion by

measuring

the

surface

charge

of

the

particles.

Higher

absolute

zeta

potential

values

generally

indicate

greater

repulsive

forces

between

particles,

contributing

to

improved

colloidal

stability

and

reduced

aggregation tendency.

Formulations

selected

for

PSA

characterization were based on preliminary

physical

evaluation,

including

clarity,

homogeneity, absence of phase separation,

and overall physical stability during storage.

The

selected

formulation

was

considered

the

most

representative

system

for

describing

the

nanoparticle

characteristics

of

the

developed

mouth

nano

spray

preparation.

Particle

Size

Test.

Particle

size

measurements

were

carried

out

using

a

Particle Size Analyzer (PSA) with the Dynamic

Light

Scattering

(DLS)

principle.

The

mouth

nanospray

sample

was

first

diluted

using

distilled water as a dispersion medium until

a

suitable

concentration

was

obtained

for

98

M. Rahayu et al.,

Chempublish Journal, 10(1) 2026, 94-105

measurement,

to

prevent

multiple

scattering. A total of

±1

mL

of

sample

was

placed

into

a

clean

cuvette

that

had

been

cleaned beforehand to avoid contamination.

Measurements

were

carried

out

at

a

controlled temperature of 25 °C with three

repetition

to

ensure

the

accuracy

and

reproducibility

of

the

results.

The

average

particle

size

obtained

was

used

to

confirm

the formation of the nanoparticle system.

Polydispersity

Index

(PDI).

Polydispersity

index

(PDI)

testing

was

performed

using

a

PSA instrument with the DLS principle under

the same measurement conditions. The PDI

value

is

used

to

evaluate

the

particle

size

distribution and the level of homogeneity of

the nanoparticle system. Scientifically, a PDI

value

<0.3

indicates

a

narrow

particle

size

distribution

and

a

relatively

homogeneous

system, while a PDI value between 0.3–0.6 is

still

acceptable

for

pharmaceutical

nanoparticle

systems

but

indicates

a

broader

size

distribution.

A

high

PDI

value

indicates

the

presence

of

particle

size

irregularities

and

the

potential

for

aggregation in the system.

Zeta

Potential

Test

.

Zeta

potential

measurements

were

performed

using

a

Particle Size Analyzer (PSA) by taking ±1 mL

of

sample

that

had

been

diluted

using

the

appropriate

medium.

The

sample

was

placed in a special cuvette for zeta potential

measurement, then analyzed at 25 °C

with

three

repeated

measurements.

The

zeta

potential value is used as an indicator of the

colloidal

stability

of

nanoparticles.

In

general,

nanoparticle

systems

with

zeta

potential values greater than +30 mV or less

than

−30

mV

are

considered

to

have

good

electrostatic stability due to the presence of

repulsive

forces

between

particles

that

are

strong enough to prevent aggregation. Zeta

potential

values

close

to

zero

indicate

low

stability and a tendency for particle clumping

[12].

In Vitro Antibacterial Activity

The antibacterial activity of the mouth nano

spray formulations was evaluated using the

disc

diffusion

method

according

to

the

Clinical

and

Laboratory

Standards

Institute

(CLSI) M07-A9 guidelines

[13]

.

Streptococcus

mutans

ATCC

25176

was

employed

as

the

test microorganism due to its important role

in

oral

pathogenicity

and

halitosis-

associated conditions.

Mueller–Hinton

Agar

(MHA)

medium

was

prepared by dissolving 38 g of MHA powder

in

1000

mL

of

distilled

water,

followed

by

heating

until

completely

dissolved.

The

prepared

medium

was

sterilized

in

an

autoclave at 121 °C under 1–2 atm pressure

for

15

min

After

sterilization,

the

medium

was cooled to approximately 40–45 °C and

aseptically poured into sterile Petri dishes.

The

bacterial

culture

was

rejuvenated

on

MHA plates and incubated at 37 °C for 24 h.

A

standardized

bacterial

suspension

was

then

prepared

by

transferring

2–3

well-

isolated

colonies

into

sterile

0.9%

NaCl

solution. The turbidity of the suspension was

adjusted

to

match

the

0.5

McFarland

standard,

corresponding

to

approximately

1.5

×

10⁸

CFU/mL

[14]

,

to

ensure

uniform

bacterial

inoculum

density

during

antibacterial testing.

The

agar

surface

was

inoculated

evenly

using

a sterile

cotton

swab

and

allowed

to

dry

for

3–5

min.

Sterile

paper

discs

(6

mm

diameter)

were

impregnated

with

20

µL

of

each

mouth

nano

spray

formulation

and

placed

on

the

agar

surface.

Chlorhexidine

0.1% (Minosep®) and sterile distilled water

were used as positive and negative controls,

respectively.

All

tests

were

performed

in

triplicate [15]. The plates were incubated at

37 °C for 24 hours, after which the diameters

of inhibition zones were measured using a

digital caliper and expressed in millimeters

99

M. Rahayu et al.,

Chempublish Journal, 10(1) 2026, 94-105

as mean ± standard deviation (SD). Statistical

analysis

was

performed

using

one-way

ANOVA followed by a post hoc test, with a

significance level set at

p

< 0.05.

Result and Discussion

Physical Properties of the Nano Spray

Organoleptics.

Organoleptic

tests

are

carried

out

to

assess

the

physical

characteristics

of

the

preparation including

appearance,

color,

aroma,

and

taste.

The

results

of

observations

show

that

the

F1

0.5%

formula

is

liquid,

clear

in

color,

transparent,

and

has

a

minty

taste

and

aroma.

At

F2

1%

it

is

liquid,

clear

in

color,

transparent, has a minty taste and aroma; F3

1.5%

is

liquid,

white

in

color,

has

a

minty

flavor

and

aroma.

While

F4

1.5%

is

liquid,

slightly brownish white (the typical color of

black

cumin

seed

essential

oil)

due

to

the

highest concentration of essential oils used

in

the

formulation,

has

a

minty

flavor

and

aroma. The formulas that are in accordance

with

the

characteristics

of

mouth

spray

preparations

are

F1

and

F2

(Table

2).

In

terms of color, F1 and F2, show good clarity

and

appear

transparent,

indicating

that

there is no precipitation or color change that

can

reduce

the

physical

stability

of

the

product. While F3 and F4 show that there is

an

effect

of

the

concentration

of

active

ingredients

on

the

physical

appearance

of

the prepared produced. In terms of aroma,

the entire formula shows a distinctive mint

smell that gives a fresh sensation. This is due

to

the

volatile

content

of

essential

oils

or

mint

flavors.

The

difference

in

aroma

intensity in each formula can be affected by

variations in the concentration of additives

(e.g.

flavoring

agent

)

used.

Meanwhile,

in

terms of taste, all formulas show a distinctive

mint taste. The fresh taste produced is one

of

the

important

factors

in

increasing

acceptability.

Differences

in

flavor

intensity

between

formulas

are

possible

due

to

differences

in

concentration

flavoring

agent

as

well

as

the

interaction

of

active

ingredients with additives.

Table 2.

Organoleptic data of Nano Spray

Formula

Organoleptics

Appearance

Color

Aroma

Taste

F1

Liquid

Clear

Mint

F2

Liquid

Transparent

Mint

F3

Liquid

White

Mint

F4

Liquid

Brownish White

Mint

Overall,

the

organoleptic

evaluation

demonstrated that all formulations fulfilled

the essential quality requirements for mouth

spray preparations, including a liquid dosage

form,

clear

appearance,

fresh

aroma,

and

mint flavor. Differences among formulations

were

primarily observed in the

intensity of

aroma and taste, which were influenced by

the

concentration

of

black

cumin

essential

oil incorporated into the formulation. These

sensory

variations

may

serve

as

important

considerations

in

determining

the

formulation

with

the

highest

consumer

acceptability and overall preference [16].

pH of Nano Spray

The pH evaluation was conducted to ensure

that

the

mouth

nano

spray

formulations

were within the acceptable pH range for safe

oral application (Table 3). An ideal pH range

for

oral

spray

preparations

generally

falls

between 5.0 and 7.0, as this range minimizes

the risk of irritation to the oral mucosa while

100

M. Rahayu et al.,

Chempublish Journal, 10(1) 2026, 94-105

maintaining

the

stability

of

active

compounds, particularly black cumin (

Nigella

sativa

L.) essential oil.

The

results

demonstrated

that

all

formulations exhibited pH values within the

acceptable range of 5.0–7.0, indicating their

suitability

for

application

in

the

oral

cavity.

None

of

the

formulations

were

excessively

acidic

or

alkaline,

thereby

reducing

the

potential

risk

of

irritation,

discomfort,

or

damage to oral tissues during use. Overall,

all

formulations

showed

good

pH

stability,

suggesting that the developed mouth nano

spray

possesses

favorable

physicochemical

characteristics

for

oral

administration

and

may

effectively

contribute

to

halitosis

management

without

causing

adverse

effects on the oral mucosa.

Table 3.

pH Test Results

Formula

pH value

Acceptable

Range

F1

6.0

5.0-7.0

F2

6.0

5.0-7.0

F3

6.0

5.0-7.0

F4

6.0

5.0-7.0

Homogeneity of Nano Spray

On the homogeneity test of the preparation,

it

was

obtained

that

all

formulations

(F1

0.25%;

F2

0.5%;

F3

1%;

F4

1.5%)

shows

a

homogeneous result. This indicates that all

materials used can be mixed evenly with a

liquid,

transparent,

and

clear

form.

Homogeneous

nano

spray

mouths

are

important

because

they

are

able

to

distribute

the

active

substances

evenly,

thereby

supporting

the

stability

of

the

preparation while increasing the comfort of

use and clinical effectiveness in overcoming

halitosis.

Table 4.

Homogenity result

Formula

Result

F1

Homogeneous

F2

Homogeneous

F3

Homogeneous

F4

Homogeneous

The main objective of homogeneity testing is

to

ensure

that

each

component

of

the

ingredients in the preparation is thoroughly

mixed

without

any

phase

separation

or

accumulated particles. Based on the results

shown in Table 4, no particles were found to

clump on the glass of the object, so it can be

concluded

that

the

preparation

meets

the

homogeneity

requirements

with

an

even

arrangement and is free of particle clumps.

Viscosity of Nano Spray

Based on the viscosity test results, the four

oral

nano

spray

formulations

showed

a

decrease in viscosity after storage (Table 5).

The F1 formulation decreased from 1.76 cP

to 1.07 cP, F2 from 1.55 cP to 0.87 cP, F3 from

1.53

cP

to

0.82

cP,

and F4

from

1.76 cP

to

1.20

cP.

This

decrease

indicates

the

possibility

of

physical

or

chemical

changes

occurring

in

the

dosage

form,

such

as

degradation of thickening agents, changes in

solution

structure,

or

interactions

between

formulation components during storage.

Table 5.

Viscosity Test Results

Formula

Viscosity Value

(cP)

Standard

Before

After

F1

1.76

1.07

1.0

F2

1.55

0.87

1.0

F3

1.53

0.82

1.0

F4

1.76

1.20

1.0

Among the four formulations, F4 showed the

smallest decrease in viscosity, thus showing

better

physical

stability

compared

to

other

formulations. However, the overall viscosity

value

after

storage

is

still

within

the

appropriate

range

for

solution-based

oral

sprays, namely around 0.8 to 1.2 cP, thus still

101

M.H. Pasaribu et al.,

Chempublish Journal, 10(1) 2026, 1-20

supporting

the

spray

characteristics

and

comfort of use.

Investigation Particle Size of Nano Spray

The

particle

characteristics

test

for

the

Mouth Nano Spray preparation was carried

out

on

a

formula

that

was

considered

the

best and was physically stable and had good

inhibitory power. The formula chosen is F2

which has a concentration of 0.5%. The tests

carried

out

were

PSA

test,

Polydispersity

index test and Zeta potential test

(Table 7).

In

this study, nanoemulsion testing was carried

out using

a Particle Size Analyzer

(PSA). Based

on

the

measurement

results,

the

black

cumin

seed

essential

oil

nanoemulsion

preparation

has

a

particle

size

at

the

nanometer

scale

with

a

good

polydispersibility index value. The test data

obtained

a

particle

size

of

42.7

nm

with

a

polydispersity index value of 0.6. The particle

size is in accordance with the nanoemulsion

criteria, which is in the range of 1–100 nm.

The

obtained

polydispersity

index

(PDI)

value

of

0.6

indicates

a

relatively

broad

particle size distribution; however, this value

remains

within

the

acceptable

range

for

nanoemulsion

systems,

suggesting

moderate homogeneity while indicating the

need

for

further

formulation

optimization

[17].

Table 7.

PSA (

Particle Size Analyzer

) Test Results

Formula

Uji PSA

Droplet Size

PdI

(Polydispersity Index

)

Potential Zeta

F2

42.7 nm

0.6

-5.6 μV

Standard

1-100 nm

<0.7

> 30 μV

However,

the

potential

zeta

value

of

black

cumin

seed

essential

oil

nanoemulsion

preparations

was

recorded

lower

than

the

stability

standard,

which

was

–5.6

μV.

The

relatively

low

zeta

potential

value

suggests

limited

electrostatic

stabilization;

however,

physical stability of the system may also be

supported by steric stabilization provided by

the nonionic surfactant Tween 80 present in

the formulation. The range of potential zeta

values

can

be

used

as

an

indicator

of

the

stability

of

the

stockpile

during

storage.

A

potential

zeta

value

of

more

than

30

mV

indicates

that

the

preparation

has

good

electrostatic stability. If it is in the range of 5–

15 mV, it indicates limited flocculation, while

in the range of 3–5 mV, it indicates maximum

flocculation[18].

The

low

value

of

this

potential

zeta

reduces

the

repulsive

force

between

particles,

making

it

easier

for

particles

to

flocculate.

This

flocculation

condition can trigger the separation of the oil

phase and the water phase which ultimately

affects

the

stability

of

the

nanoemulsion

[19].

Antibacterial Activity against Streptococcus

mutans

The

antibacterial

activity

of

the

formulated

mouth

nano

spray

was

evaluated

against

Streptococcus

mutans

,

a

primary

bacterium

associated with dental caries, using the agar

diffusion method. This assay was conducted

to

determine

the

inhibitory

effect

of

each

formulation

by

measuring

the

diameter

of

the

inhibition

zone

formed

around

the

sample.

The

detailed

inhibition

zone

diameters

and

their

corresponding

activity

categories are presented in the Table 8.

Table 8.

Inhibition Zone Diameter Result

102

M.H. Pasaribu et al.,

Chempublish Journal, 10(1) 2026, 1-20

Formula

Diameter of

the barrier

zone (mm)

The Devolopment of Mouth Nanospray for Black Cumin Essential Oil ( Nigella sativa L.): Physical Properties, Stability and Antibacterial Activity

Milda Rahayu , Septi Hariyani , Uce Lestari*

Pharmacy Study Program, Faculty of Medicine and Health Sciences, Universitas Jambi, Telanaipura, Jambi City, Indonesia

A bstract

Introduction

The Devolopment of Mouth Nanospray for Black Cumin Essential Oil

(

Nigella

sativa

L.): Physical Properties, Stability and Antibacterial

Activity

Milda Rahayu

, Septi Hariyani

, Uce Lestari*

Pharmacy Study Program, Faculty of Medicine and Health Sciences, Universitas Jambi, Telanaipura,

Jambi City, Indonesia

A

bstract