DARU Journal of Pharmaceutical Sciences (2019) 27:673–681
https://doi.org/10.1007/s40199-019-00301-3
RESEARCH ARTICLE
Improved transdermal delivery of cetirizine hydrochloride using
polymeric microneedles
Muhammad Sohail Arshad 1 & Sana Hassan 1 & Amjad Hussain 2 & Nasir Abbas 2 & Israfil Kucuk 3 & Kazem Nazari 4 &
Radeyah Ali 4 & Suleman Ramzan 4 & Ali Alqahtani 4 & Eleftherios G. Andriotis 5 & Dimitris G. Fatouros 5 &
Ming-Wei Chang 6,7,8 & Zeeshan Ahmad 4
Received: 15 May 2019 / Accepted: 13 September 2019 / Published online: 19 October 2019
# Springer Nature Switzerland AG 2019
Abstract
Purpose The aim of this study was to design and characterize microneedle patch formulation containing cetirizine hydrochloride.
Methods Chitosan was co-formulated with cetirizine hydrochloride. Transdermal patches were prepared by casting this solution
to microneedle molds. Control patches were formulated by casting this solution to a plain cuvet of same area as mold but lacking
microneedles. An array of methods namely; differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and
scanning electron microscopy (SEM) were employed for the characterization of the films and the microneedles accordingly
whereas in vitro permeation studies were conducted across rat skin. Light microscopy was performed to assess any histological
changes upon microneedles application onto the rat skin.
Results The patches had a reproducible thickness (0.86 ± 0.06 mm) and folding endurance. Both the blank and drug loaded
patches had 100 microneedles each of 300 micrometre length. In addition, the microneedle patches were ascribed with a two-fold
increase in drug permeation across rat skin in the presence of microneedles as compared to the control formulations. Histological
examination confirms a minimal invasion of the skin conferred by the microneedles.
Conclusion The microneedle patches serve as an alternate route of drug administration in patients with nausea and swelling
difficulties.
Keywords Microneedles . Transdermal Drug delivery . Cetirizine Hydrochloride
Introduction
Transdermal drug delivery (TDD) refers to the administration
of drug across the skin in order to impact the adjacent tissues
or to approach the blood stream [1]. Transdermal drug delivery is advantageous as it offers; ease of application, affluent
* Zeeshan Ahmad
zeeshan.ahmad@dmu.ac.uk
1
Faculty of Pharmacy, Bahauddin Zakariya University,
Multan, Pakistan
2
College of Pharmacy, University of the Punjab Lahore,
Lahore, Pakistan
3
Faculty of Engineering and natural sciences, Bursa Technical
University, Bursa, Turkey
4
The Leicester School of Pharmacy, De Montfort University,
Leicester, UK
removal of dosage form, improved patient compliance (pain
free) and the ability to control the rate of drug release. The
‘hepatic first pass effect’ is also avoided and drug absorption is
not affected by factors such as pH, drug-food interaction, and
enzyme activity with this route of administration [2, 3].
Nevertheless, some disadvantages are linked to TDD system
5
Department of Pharmacy, Aristotle University of Thessaloniki,
Thessaloniki, Greece
6
Department of Biomedical Engineering, Key Laboratory of Ministry
of Education, Zhejiang University, Hangzhou 310027, People’s
Republic of China
7
Zhejiang Provincial Key Laboratory of Cardio-Cerebral Vascular
Detection Technology and Medicinal Effectiveness Appraisal,
Zhejiang University, Hangzhou 310027, People’s Republic of China
8
Nanotechnology and Integrated Bioengineering Centre, University
of Ulster, Jordanstown Campus, Newtownabbey, Northern
Ireland BT37 0QB, UK
DARU J Pharm Sci (2019) 27:673–681
674
(TDDS); the barrier function of skin restricts the entry of polar
hydrophilic drug substances, only potent lipophilic drugs are a
suitable candidate for this route of administration. Drug permeation is affected by various factors including the age of skin, site
of application and any pre-existing skin conditions [4].
In recent years, substantial progress has been made in the
field of transdermal drug delivery [4–6] which enables prompt
the systemic delivery of hydrophilic polar drug substance.
One such example includes microneedle based TDDS, designed to modify the barrier function by disrupting the layer
of skin in order to allow hydrophilic molecules to pass into the
blood stream. [7]. The length of needles should be of such size
that they penetrate through the dermis but prevent the stimulation of dermal nerves [8].
Microneedles utilized for drug delivery are fabricated from
metal, ceramics, polymers or silicon [9, 10]. A variety of techniques are used to fabricate microneedles. These include; a)
micromolding of template forming materials such as silicon,
polydimethylsiloxane, or ceramics [11] b) lithography at glass
transition of a material [12], c) twisted light with spin (metallic
microneedles) [13] d) droplet born air blowing method [14].
Transdermal drug delivery through Microneedles approach
is achieved by one of the following routines; a) applying blank
microneedle to the skin followed by the placement of a patch,
b) medicated polymeric patch with microneedle [15], or c) a
metallic microneedles coated with drug solutions [16]. This
approach is suitable for the systemic delivery of drug molecules having high weight and higher water solubility.
Cetirizine hydrochloride, an anti-histaminic drug used for
the treatment of hay fever, angioedema’s and urticarial problems and allergies [17] was used as model drug in this study.
With a partition coefficient value of 1.5, the drug is likely to
have a limited penetration through intact. Since, therapeutic
conditions often demand long time administration of cetirizine
this may result in non-compliance amongst the patients.
Microneedle based transdermal delivery approach may provide
an elevated level of drug without affecting the daily routine.
The aim of this study was to design polymeric microneedle
patches containing cetirizine and evaluate the effect of
microneedles on drug permeation. The patch formulation with
or without microneedles were prepared using chitosan and
sodium alginate and drug penetration studies were performed
using rat skin.
Fabrication of template mold
The fabrication of the silicone rubber template includes the
following steps: i) Preparation of the stainless steel
microneedle master mould by conventional machining
methods, including grinding, electro-discharge machining,
and electro-polishing ii) Preparation of silicone rubber Dow
Corning Sylgard 184 silicone:hardener 10:1 iii) Casting of the
mixed silicone liquid over the stainless steel microneedle master mould iv) Heating the silicone liquid to 80 oCfor 1 h and v)
de-mould the cured microneedle template from the master
mould [18].
Methods
Chitosan was dissolved in an acetic acid aqueous solution (1%
v/v) to produce polymeric solution 2% (w/v). This solution
was then dialyzed through a dialyzing tube (cut off size 14 k
Dalton) at temperature 37 ± 0.5°C against deionized water until its pH increased to 6. This solution was dried (at 37°C) by
placing in a water bath until the solution of chitosan was 10
percent by weight (i.e. 10% w/v) [19].
Neutralized chitosan solution (10% w/v) was casted onto
the pre-fabricated microneedle molds of polydimethylsiloxane containing 10 × 10 cavities each of 300 micrometer depth.
The molds were centrifuged at 3500 rpm for 1 minute to force
the chitosan solution into the cavities of the mold. Casting and
centrifugation cycle was repeated twice to ensure that mold is
properly filled with chitosan solution. The excess solution was
removed from the surface of mold and filled solution was
dried at room temperature (25 ± 2°C) for 24 hour [20].
For sodium alginate microneedles the polymer solution of
20% w/w with or without drug was casted centrifuged and
dried as described for chitosan microneedles [21, 22].
Transdermal patches of same dimensions were also prepared
by casting the equivalent volume of formulation solution(s) in
the mold without centrifugation.
The drug loading to the polymer matrix was achieved by
dissolving the specified amount of cetirizine HCl to the respective polymer solutions (Table 1). The drug concentrations
were maintained at such levels that phase separation was not
reached.
Materials
Characterization studies of microneedles
Cetirizine Hydrochloride was received as a gift from Tagma
Pharma Lahore Pakistan. Chitosan and sodium alginate were
purchased from Sigma Aldrich, Germany. Acetic acid,
Sodium hydrochloride, Hydrochloric Acid, were purchased
from Merck, Germany. Distilled water was obtained from an
in-house facility.
Evaluation of films: folding, and thickness
Prepared transdermal patches and microneedle patches were
tested for uniformity in thickness using Vernier’s caliper.
Moreover, the dosage forms were tested for integrity after
folding.
DARU J Pharm Sci (2019) 27:673–681
Table 1
675
Composition of different formulations
Formulation
Blank MN
Drug loaded MN
Drug loaded Patch
Blank MN
Drug loaded MN
Drug loaded Patch
Sodium Alginate (% w/v)
Chitosan (% w/v)
Polymer to Drug ratio
20
-
20
1:5
20
1:5
10
-
10
1:4
10
1:4
Scanning electron microscopy test of microneedle
formulations
The morphology of microneedle patches were examined for
needle size, shape and other physical attributes using scanning
electron microscope (SEM) (Oxford Instruments, UK). The
specimens were sputter coated with gold solution to obtain a
clear image of the object.
Differential scanning calorimetry
This technique was used to record enthalpic change in the
constituent polymer(s), cetirizine hydrochloride and the prepared microneedle following increase in its temperature. Each
of these materials were heated to 300°C at 10°C. min−1 using a
DSC equipment previously calibrated at same rate up to
450°C for temperature and heat flow using Nickel and Zinc
at standard materials [21, 23] .
Thermogravimetry analysis
Thermogravimetric analysis (TGA) records weight loss in the
samples following increase in temperature. The samples including chitosan, sodium alginate, cetirizine Hydrochloride
and prepared microneedles were heated from 25°C to 350°C
at a heating rate of 10°C.min−1 and weight loss was recorded
to evaluate physical stability of the materials [24, 25].
FTIR
Fourier transform infra-red (FTIR) spectroscopic analysis records the vibration of different functional groups in the samples following interactions with light radiation over a specific
wavelength range (400-4000 cm−1) [26, 27].
Table 2 Evaluation of
microneedle thickness and
folding
In vitro delivery of cetirizine drug across rat skin
from sodium alginate microneedles and patch
of sodium alginate
The study was performed after an approval of protocol from
departmental Animal Ethical Committee BZU (49/PEC dated
2-1-2018). Rats weighting 150 ± 25 g were used as experimental animals for this study. The animals were kept at ambient
temperature and provided with a free access to food and water.
The animals were euthanized by injecting higher doses of anesthetic ketamine (100 mg/kg IP) followed by decapitation.
Drug permeation through the rat skin was investigated by
using modified Franz cell, comprising of donor and acceptor
compartments having a permeation area of 1 cm2. Briefly, the
acceptor compartment was filled with freshly prepared
Phosphate buffer solution (pH 7.4) and its temperature was
maintained at 37°C by circulating water in the jacket of acceptor chamber in order to simulate the physiologic conditions. An excised rat skin (1 cm2), previously defatted by
dipping in hot water followed by teasing the dermis from
epidermis, and hydrated in phosphate buffer (pH 5.6) in order
to establish equilibrium with the dilution medium was
clamped carefully between the donor and recipient chambers.
Transdermal patch formulations (plain and microneedle
patches) were applied to rat skin and the solution in recipient
compartment was stirred at 600 rpm in order to ensure a
prompt mass transfer following permeation. Aliquots of
1 mL were removed from the recipient compartment at
predetermined time intervals over a time period of 8 h and
same volume of buffer solution (blank) was replaced in order
to maintain the sink conditions. Drug contents of each sample
were then measured by spectrophotometric method [28, 29].
Briefly, a stock solution of cetirizine hydrochloride 1% w/v
was prepared using buffer solution by dissolving 1.0 ± 0.002 g
in volumetric flask 100 ± 0.01 ml. this solution was sonicated
Evaluation test
Chitosan microneedle
Sodium alginate microneedle
Folding endurance
Thickness of microneedle patch
Width of the microneedle patch
Appearance of microneedle film
Polymer solution color
120
9.1 ± 4.33 mm
0.86 ± 0.06 mm
Smooth surface appearance
Transparent light yellowish
74
9.1 ± 6.77 mm
0.81 ± 0.07 mm
Rough surface appearance
Transparent light brownish
DARU J Pharm Sci (2019) 27:673–681
676
Fig. 1 Photographic images of
microneedle patches prepared
from chitosan.
for 5 min to ensure complete dissolution of drug. A working
standard (100 μg.ml−1) was then prepared by diluting the
stock solution (1:100). Different Dilutions with drug concentration 5-100 μg.ml−1 were prepared and absorption was recorded at 244 nm using UV visible spectrophotometer (Perkin
elmer, USA). Light Absorption was plotted as a function of
concentration and fitted with linear regression equation. This
equation was then used to determine the drug concentration
from unknown samples [30, 31]. Diffusion of cetirizine from
polymeric microneedles and patch was recorded through rat
skin using modified Franz cell [19, 29].
Histological studies
After piercing with microneedle patches, the excised skin tissues were fixed in ethanol 70% w/v for 72 h and sliced with
microtome [32]. The sliced tissues were examined under a
light microscope for the integrity of the rat epidermis.
Fig. 2 Scanning electron micrographs of (left) chitosan and (Right) sodium alginate-based microneedle films; (Top) blank polymer microneedles
(bottom) cetirizine loaded polymeric microneedle patch films
DARU J Pharm Sci (2019) 27:673–681
677
150
microneedles. The results point to significant care to prevent needle side folding [33].
Optical microscopic images of the microneedle films depict
the needle projections being smaller than fingerprints in the
background (Fig. 1). Inclusion of cetirizine in the patches did
not affect the shape of the microneedles.
Cetirizine
Alg Powder
Microneedle
120
Endo Up
90
60
Scanning electron microscopy test of microneedle
formulations
30
0
-30
0
100
200
300
Temperature C
80
Cetirizine
Chitosan
Microneedle
Endo Up
60
40
20
Scanning electron microscopic studies were performed to get
an insight on the microneedle patches morphology. The
microneedle patch appeared as a smooth film with evenly
distributed microneedle projections (N = 100). Each of the
needles had a four cornered base with a facet width of 100
micrometers which narrows to a fine tip over a length of 300
microns (Fig. 2). A closer look at the patches with broken
microneedles revealed a hollow tube-like structure of the chitosan needles while the alginate counterparts were filled [29,
34]. It is noteworthy to state that the results from optical microscopy of freshly prepared drug loaded microneedles
patches of both polymers depict an acceptable morphology.
However, following transportation to other facility for SEM,
these patches undergo mechanical stress which result in occasional damage to the microstructures.
Differential scanning calorimetry
0
0
100
200
300
Temperature C
Fig. 3 DSC thermograms of (Top) cetirizine HCl, sodium alginate
powder and microneedle patches containing sodium alginate and
cetirizine HCl, (Bottom) cetirizine HCl, Chitosan powder and
microneedle patches containing chitosan and cetirizine HCl
Results and discussion
Evaluation of films: folding, and thickness
Chitosan and sodium alginate microneedles thickness was observed 9.1 ± 4.3 mm. The folding endurance of microneedle
patches were observed through the flat side as well as needles
side of the film. Folding endurance for chitosan the flat side
exceed 120 while the sodium alginate counterpart it was 75
folding before being damaged (Table 2). Chitosan
microneedles were more flexible as compared to the sodium
alginate microneedles. The results suggest an acceptable operational performance of the patches.
The needle side folding of film caused significant
damage to the needles following 10-15 folding damaged
in both sodium alginate microneedles and chitosan
DSC thermograms of cetirizine demonstrate a sharp endothermic peak at 220°C with heat of fusion ∆H 161.29 J.g−1. These
results confirm the crystalline nature of the drug. The thermograms of sodium alginate showed endothermic peak at 100°C
which manifest the dehydration from the polymer while an
exothermic peak at 240-60°C was observed due to pyrolysis
reaction [35, 36] (Fig. 3 top). A broadened endothermic peak
with relatively lower intensity recorded at ~195°C indicates
the melting of cetirizine HCl. A tailing effect in this endothermic peak suggests that melting of cetirizine HCl is coupled
with another thermal event possibly the decomposition of accompanying polymer.
The thermogram of chitosan showed a broad endothermic peak with onset temperature ~80°C relating to release
of water while an exothermic peak at ~300°C manifests
decomposition of amine (GlcN) units of the polymer
(Fig. 3 bottom) [37]. These thermal events i.e. dehydration
and decomposition were recorded at lower onset temperatures 70 and 250°C respectively, in microneedle patches
prepared from chitosan and cetirizine. This reflects a plasticizing effect of the cetirizine HCl. Moreover, the thermogram of drug loaded chitosan based microneedle patches
films did not show melting peak of the cetirizine HCl suggesting a non-crystalline form of the drug.
DARU J Pharm Sci (2019) 27:673–681
678
a
b
CeƟrizine
Sodium Alginate
Microneedle
120
CeƟrizine
Chitosan
Microneedle
120
100
% Wt loss
100
% Wt loss
Fig. 4 TGA of A) Sodium
Alginate, cetirizine and cetirizine
loaded sodium alginate-based
microneedle patch and B)
Chitosan, cetirizine and cetirizine
loaded chitosan based
microneedle patch. Part C & D
show first derivative of sodium
alginate and chitosan
thermograms, respectively.
80
60
40
20
80
60
40
20
0
0
0
200
400
600
0
200
Temperature °C
d
CeƟrizine
Sodium Alginate
Microneedle
dW/dt
dW/dt
c
-1.4
-1.2
-1
-0.8
-0.6
-0.4
-0.2
0
0.2
0
200
600
400
600
CeƟrizine
-1.4
-1.2
-1
-0.8
-0.6
-0.4
-0.2
0
0.2
Chitosan
Microneedle
0
200
Temperature °C
400
600
Temperature °C
a
100
ceƟrizine
90
TransmiƩance AU
80
70
Sodium Alginate
60
50
40
30
Microneedle
20
10
0
1000
2000
Wave numbers
3000
4000
cm-1
b
100
ceƟrizine
90
80
TransmiƩance AU
Fig. 5 FTIR spectra of A)
Sodium Alginate, cetirizine and
cetirizine loaded sodium alginate
based microneedle patch and B)
Chitosan, cetirizine and cetirizine
loaded chitosan based
microneedle patch.
400
Temperature °C
70
Chitosan
60
50
40
30
Microneedle
20
10
0
1000
2000
3000
Wave numbers cm-1
4000
DARU J Pharm Sci (2019) 27:673–681
Fig. 6 Cumulative amount of
drug permeated through rat skin
A) Chitosan films B) Sodium
Alginate films
679
a
CM
CP
1000
CummulaƟve amount
permeated (μg.cm-1)
CummulaƟve amount
permeated (μg.cm-1)
1200
800
600
400
200
0
SP
1000
800
600
400
200
0
0
200
400
Time (Min)
Thermo-gravimetric analysis
The gravimetric analysis of cetirizine revealed no weight loss
in cetirizine up to 200°C which reflects thermal stability of the
drug. At temperatures above 220°C there is a step like decrease in mass suggesting its degradation (Fig. 4).
TG thermograms of sodium alginate showed weight loss of
13, 33 and 20% over the temperature ranges of 100-200, 200266 and 266-600°C, respectively. Similarly, the weight changes in sodium alginate films containing cetirizine with the
MN
b
SM
1200
ED
a
Dermis
600
0
200
400
600
Time (Min)
temperature were triphasic; around 7% weight loss recorded
over a temperature range of 120-200°C, approximately 30%
over 200-280°C and another 15% weight loss over a temperature range 300-550°C (Fig. 4A). The first stage of weight loss
is linked to the removal of water from the samples while the
second phase account for combustion of carbon in the polymer followed by further decay of material at high temperature.
Weight changes recorded from TGA of chitosan read; approximately 10% loss over 50-127°C (Phase I), 35% loss between 220-330°C (Phase II), followed by 20% weight loss
upto 600°C (Phase III). The results from thermogravimetric
analysis of cetirizine HCl loaded patches mimic those found
with the polymer except with a slower gradient of phase I and
early onset of Phase II.
First derivative of % weight loss described changes in the
gradients of sample weight with the temperature. The composite films of sodium alginate showed lower gravimetric gradient than the individual components where it was noted otherwise for chitosan counterpart (Fig. 4C &D).
BV
FTIR
CT
At 10x
b
MN
CT
At 10x
Fig. 7 Microscopic images of the excised skin pierced with sodium
alginate microneedle patch.
The FTIR spectrum of cetirizine showed the peak at
1457 cm −1 due to vibrations of C-Cl, a sharp peak at
1740 cm−1 is attributed to the stretching of the C=O group
of the COOH, stretching vibration NH manifest a spectral
peak at 2384, a broad peak at 3200-3600 cm−1 arises from
dimer O-H stretching vibrations of COOH.
The Sodium Alginate spectrum showed peaks at 1596,
1409 and 1024 cm−1 due to stretching vibration of aromatic
C-C bonds, carboxylate group and carbonyl group respectively (Fig. 5A). The FTIR spectrum of chitosan manifest peaks at
1023,1320, 1581, 3349 cm−1 due to the vibration of carbonyl,
hydroxyl (O-H), N-H of amine, and OH functional groups,
respectively (Fig. 5B). Following film formulation, the position of these peaks was slightly shifted to higher wavelengths
suggesting a loose packing of these groups which require low
energy for these vibrations. One may question that the spectra
of composite films were influenced by the polymer counterpart, a justification to this observation is that the polymer
components are ≤80% of the formulation. No additional peak
DARU J Pharm Sci (2019) 27:673–681
680
was recorded in the FTIR spectrum of transdermal patches
implying that there wasn’t a chemical reaction between the
polymer and drug.
Ex vivo delivery of cetirizine
The time profile of cetirizine permeation across rat skin is
measured by Franz diffusion cell using spectrophotometric
method. Spectrophotometric absorption data follows a linear
regression function (y = mx + b) over a concentration range
10-60 μg.ml−1. Correlation coefficient R2 value 0.998 confirms that the model equation could be used to describe the
data.
For chitosan patch formulation a steady state was observed
at 200 min while the microneedle counterpart depicts a plateau
at significantly higher concentration i.e. 450 min (Fig. 6A).
The steady state concentration from sodium alginate patch and
microneedle patch was 749 and 973 μg/cm2.hr, respectively
(Fig. 6B). It is reasonable to describe that microneedle based
patch of chitosan and sodium alginate has ~45 and 25% higher
drug concentration as compared to control (plain polymer
patch formulation), after 6 h of application.
Histological examination of the excised skin
Histological examination of the skin samples previously administered with microneedle patch revealed the presence of
epidermis (ED) with discontinuation, intact dermis deeper inside blood vessels (BV) and skeletal muscles connective tissue
(CT) Fig. 7A. Furthermore, the presence of additional channels in the proximity of the outer surface of excised skin evidence a breakdown in the physiologic barrier by the
microneedles. Other features of the skin tissue such as intact
connective tissue signifies that microneedle induced only a
controlled perturbation in the top layer of skin Fig. 7B.
Histological examination confirms a minimal invasion of the
skin conferred by the microneedles which provides channels
for the transfer of drug substance across the skin.
Conclusion
Microneedles composed of chitosan and sodium alginate with
drug to polymer ratios 1:4 and 1:5, respectively prepared
using molding and casting technique were evaluated for integrity and permeation enhancement of entrapped drug. Both the
chitosan as well as sodium alginate-based patches had sufficient plasticity and folding endurance implying their application for the transdermal drug delivery. Furthermore, the results
of DSC and FTIR studies revealed that none of these materials
show chemical incompatibility with drug. Therefore, these
natural biodegradable polymeric materials are suitable for formulation development. Since molded polymeric films retain
the needle morphology on drying, one can presume their penetration through stratum corneum provide a facilitated path for
the drug substances.
The results of permeation studies confirm that polymeric
microneedle films significantly improve the transdermal permeation of cetirizine as compared the control i.e. polymeric
films without microneedles. Efficient permeation profile refers to successful formulation development with promising
therapeutic outcomes.
Acknowledgements The authors acknowledge the financial support provided by Higher Education Commision of Pakistan under National
Research Program for Universities (NRPU) vide No: 7401/Punjab/
NRPU/R&D/HEC/2017.
Authors’ contributions All authors contributed to the preparation of the
manuscript and the study (i.e. through various streams be it planning,
experiments, analysis of data, data preparation etc).
Compliance with ethical standards
Conflict of Interest The authors have no conflict of interests.
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