Assessment of pharmacokinetics and tolerability of intranasal diazepam relative to rectal gel in healthy adults

1. Epilepsy Research (2014) 108, 1204—1211
journal homepage: www.elsevier.com/locate/epilepsyres
Assessment of pharmacokinetics and
tolerability of intranasal diazepam relative
to rectal gel in healthy adults
Herbert R. Henney IIIa
, Michael R. Sperlingb
,
Adrian L. Rabinowicza,∗
, Gary Breamc
, Enrique J. Carrazanaa
a
Acorda Therapeutics, Inc., 420 Saw Mill River Road, Ardsley, NY 10502, USA
b
Department of Neurology, Thomas Jefferson University, 901 Walnut Street, Suite 400,
Philadelphia, PA 19107, USA
c
Aerial BioPharma, LLC, 9001 Aerial Center Parkway, Suite 110, Morrisville, NC 27560, USA
Received 14 January 2014; received in revised form 21 March 2014; accepted 28 April 2014
Available online 13 May 2014
KEYWORDS
Diazepam;
Intranasal;
Pharmacokinetics;
Seizures;
Adults
Summary Diazepam rectal gel (RG) is currently the only approved rescue therapy for out-
patient management of seizure clusters in the United States. There is an unmet medical need
for an alternative rescue therapy for seizure clusters that is effective, and more convenient to
administer with a socially acceptable method of delivery. An intranasal diazepam formulation
has been developed, and this study evaluates the tolerability and bioavailability of diazepam
nasal spray (NS) relative to an equivalent dose of diazepam-RG in healthy adults. Twenty-
four healthy adults were enrolled in a phase 1, open-label, 3-period crossover study. Plasma
diazepam and metabolite concentrations were measured by serial sampling. Dose proportion-
ality for 5- and 20-mg intranasal doses and the bioavailability of 20 mg diazepam-NS relative to
20 mg diazepam-RG were assessed by maximum plasma concentration (Cmax) and systemic expo-
sure parameters (AUC0—∞ and AUC0—24). The mean Cmax values for 20 mg diazepam-NS and 20 mg
diazepam-RG were 378 ± 106 and 328 ± 152 ng/mL, achieved at 1.0 and 1.5 h, respectively. Sub-
jects administered intranasal and rectal gel formulations experienced nasal and rectal leakage,
respectively. Diazepam absorption following intranasal administration was consistent but 3 sub-
jects with diazepam-RG had low plasma drug levels at the earliest assessment of 5 min, due to
poor retention, and were excluded from analysis. Excluding them, the treatment ratios (20 mg
diazepam-NS:20 mg diazepam-RG) and 90% confidence intervals for diazepam Cmax and AUC0—24
were 0.98 (0.85—1.14) and 0.89 (0.80—0.98), respectively, suggesting that the bioavailability
was comparable between the two formulations. Dose proportionality was observed between
the lowest and highest dose-strengths of intranasal formulation. Both intranasal and rectal
∗ Corresponding author at: Clinical Development and Medical Affairs, Acorda Therapeutics, Inc., 420 Saw Mill River Road, Ardsley, NY
10502, USA. Tel.: +1 914 326 5138.
E-mail address: arabinowicz@acorda.com (A.L. Rabinowicz).
http://dx.doi.org/10.1016/j.eplepsyres.2014.04.007
0920-1211/© 2014 Published by Elsevier B.V.

2. Pharmacokinetics of intranasal diazepam 1205
treatments were well tolerated with mild to moderate adverse events. Results suggest that
a single-dose of 20 mg diazepam-NS is tolerable and comparable in bioavailability to that of
diazepam-RG. The intranasal formulation may provide caregivers and patients with a more
socially acceptable and convenient alternative rescue therapy in the acute treatment of seizure
clusters.
© 2014 Published by Elsevier B.V.
Introduction
Despite the availability of anti-epilepsy drugs (ASDs),
approximately a third of patients with epilepsy are treat-
ment resistant (Friedman and French, 2012) and seizure
clusters occur in some individuals with treatment-resistant
epilepsy (Sillanpää and Schmidt, 2008). Clusters, also
reported as acute repetitive seizures, are characterized by
multiple seizures occurring over a relatively brief period
of time (Cereghino, 2007). One operational definition of
seizure cluster is the occurrence of 3 or more seizures within
a 24 h period with return to baseline between events (Haut,
2006).
Seizure clusters commonly occur outside the hospital,
and benzodiazepines, particularly diazepam, are the first-
line therapy in the outpatient setting (Pellock, 2007; Chen
and Wasterlain, 2006; Holsti et al., 2007). A rectal gel
formulation of diazepam (diazepam-RG) is currently the
only FDA-approved rescue therapy for the out-of-hospital
management of patients with refractory epilepsy who are
on stable regimens of AEDs but require intermittent use
of diazepam to control bouts of increased seizure activ-
ity (Diazepam rectal gel prescribing information, 2005).
Previous studies have reported that home treatment with
diazepam-RG was associated with greater seizure control,
improved quality of life and fewer emergency room visits
(Kriel et al., 1991, 1999). Although diazepam-RG may alle-
viate the need for treatment in an acute care facility,
thereby reducing the time between seizure onset and medi-
cal intervention, rectal administration still requires delivery
by trained caregivers and can be technically difficult to
administer during a seizure. In addition, rectal adminis-
tration is inconvenient (Tatum, 2002) and can be socially
embarrassing due to lack of personal privacy (Bhattacharyya
et al., 2006). Hence, there is an unmet need for an alterna-
tive therapy that is both socially acceptable and convenient
to administer in an outpatient setting.
Intranasal delivery provides a convenient and socially
acceptable delivery route (Wilson et al., 2004; de Haan
et al., 2010; Holsti et al., 2010; Kyrkou et al., 2006). A
diazepam nasal spray formulation (diazepam-NS) has been
developed as an alternative to diazepam-RG to control
increased bouts of seizure activity in patients with epilepsy
who are on stable regimens of AEDs (Bream et al., 2013).
The intranasal diazepam formulation is a single-use device
with strengths based on the dosing schedule of the refer-
enced product, diazepam-RG. The device consists of two
intranasal sprays with each spray of approximately 100 ␮L
to be administered per nostril.
The objective of the study reported here was to deter-
mine the bioavailability of a single dose of diazepam-NS
formulation relative to diazepam-RG in healthy individuals
and to evaluate the pharmacokinetic (PK) linearity between
the minimum and maximum dose-strengths of the nasal
spray formulation in healthy adults. The study also
assessed the tolerability of diazepam-NS formulation in this
population.
Methods
Study design
This was a phase 1, single-center, open-label, single-dose,
3-period, randomized, crossover study with 14 days separat-
ing the dose administrations. Following a 28-day screening,
subjects who met the eligibility criteria received 1 of the
following treatments during each dosing period in a random-
ized order: a 5-mg dose as one 2.5-mg spray of 100 ␮L in
each nostril, a 20-mg dose as one 10-mg spray of 100 ␮L
in each nostril, or a single 20-mg dose of diazepam-RG.
Subjects were required to fast for 10 h prior to dosing and
to remain fasting for 2 h after administration. Diazepam-NS
was administered in a reclined position at approximately 45◦
with the subject’s head facing straight upward. No prepara-
tion such as blowing or clearing of the nose was performed
prior to dosing, and subjects were asked to refrain from
blowing their nose for 4 h after administration. Diazepam-RG
was administered in the lateral decubitus position without
preparation or bowel cleansing. Subjects were kept in the
dosing position for 30 min with no restriction in movement
thereafter.
This study was conducted in accordance with Good Clin-
ical Practice requirements described in the current version
of the International Conference on Harmonization guide-
lines and all applicable regulations, and compliant with the
ethical principles described in the current version of the
Declaration of Helsinki. Prior to study initiation, the proto-
col, informed consent form, and all other study documents
were reviewed and approved by an Institutional Review
Board. Written informed consent was obtained from all
subjects.
Study drugs
Two concentrations of intranasal formulations (2.5% and
10% diazepam for 5 mg and 20 mg doses, respectively)
were supplied to the study site as microemulsion by UPM
Pharmaceuticals (Baltimore, MD). To administer the drug,
a single-use Pfeiffer bi-dose (Aptar Pharma, Congers, NY)
nasal spray device was used, capable of two actuations
with one spray per nostril. The inactive ingredients of the
intranasal formulation included diethylene glycol monoethyl
ether, propylene glycol monocaprylate, methyl laurate,

3. 1206 H.R. Henney III et al.
N-methyl-2-pyrrolidone, ethanol, and sterile water. The
diazepam rectal gel formulation (Valeant Pharmaceuticals,
North America) was supplied by the study site and adminis-
tered per the instructions provided in the package insert.
Subjects
Men and women 18—50 years of age, inclusive, weighing
between 88 and 111 kg with general good health based on
medical history, physical examination, and screening assess-
ments were eligible. The weight range was chosen based on
the diazepam-RG dosing information so that each subject
would receive a 20-mg dose. Subjects with the following
criteria were excluded: pregnant or lactating, history of
allergy or hypersensitivity to diazepam, history of any ill-
ness that may affect the PK of diazepam, abnormal liver
function tests, drug or alcohol abuse, use of tobacco or nico-
tine products within 90 days prior to study entry, or use
of any medications other than vitamin supplements, hor-
monal birth control, or replacement therapy within 1 week
of randomization and throughout study participation.
Drug assay
Blood sampling for the PK measurements of diazepam and
the desmethyl metabolite was performed pre-dose and at
the following times after each dose administration: 5, 10,
15, 30, and 45 min, and 1, 1.5, 2, 4, 6, 9, 12, 24, 48, 96,
144, 192, and 240 h. Plasma diazepam concentrations were
assayed using a validated liquid chromatography with tan-
dem mass spectrometry assay (LC—MS/MS; Tandem Labs,
Durham, NC). The assay had a lower limit of quantitation of
1 ng/mL and was validated for concentrations in the range
of 1—500 ng/mL based on the analysis of 0.2 mL of human
plasma. Based on the inter-run quality control data, the
precision and the accuracy of the assay for diazepam were
3—5.9% and 2.4—6.8%, respectively.
Pharmacokinetic analysis
Noncompartmental analyses (WinNolin®
Phoenix version 6.1,
Pharsight Corporation, Mountain View, CA) were used to
estimate the following PK parameters from plasma sam-
ples: maximum observed plasma concentration (Cmax); time
to maximum concentration (Tmax); area under the plasma
concentration—time curves for time 0—24 h post-dose
(AUC0—24), to time of last measurable plasma concentration
(AUClast), and extrapolated to infinity (AUC∞); elimination
half-life (t1/2); apparent systemic clearance (CL/F). Concen-
trations below the limit of quantification were assigned as 0
for computation of descriptive statistics and for construction
of mean concentration—time profiles.
The relative bioavailability of diazepam with respect
to 20 mg diazepam-NS (test product) and 20 mg diazepam-
RG (reference product) was evaluated by comparing the
Cmax, AUC0—24, AUClast, and AUC∞ using an analysis of
variance (ANOVA) model with sequence, subject within
sequence, treatment, and period as the classification vari-
ables using the original data and the natural logarithm of
the data. Confidence intervals (CIs) (90%) were constructed
for the treatment ratios (test to reference) using the
log-transformed data and the two 1-sided test procedure
to determine whether the CIs were within the 80—125%
acceptance range for the two formulations to be comparable
(Guidance for industry [FDA], 2014). The pharmacokinetic
linearity between the 5-mg and 20-mg dose strengths of
diazepam-NS formulation was assessed by comparing the
natural log-transformed and dose normalized Cmax, AUC0—24,
and AUC∞ and the calculated CL/F values.
Subjects were observed for visual signs of rectal or nasal
leakage at 5, 15, 30, 45, and 60 min after administration. For
rectal doses, volume of loss was estimated as none, ≤1 mL,
>1 to ≤3 mL, or >3—4 mL, and at the 45 and 60-min checks,
the maximum amount of leakage since the previous assess-
ment was noted. For intranasal doses, nasal leakage was
quantified as none or observed and included a description
of the amount of leakage; occurrence of sneezing and time
of events were also noted.
Tolerability
Safety and tolerability assessments included treatment-
emergent adverse events (TEAEs), clinical laboratory
evaluations, vital signs, pulse oximetry, physical examina-
tions, and electrocardiograms. The TEAEs were rated as
mild (transient, required no special treatment, and did not
interfere with subject’s daily activities), moderate (required
simple therapeutic measures, low degree of inconvenience,
and may have interfered with daily activities) or severe
(required systemic drug therapy or other treatment and
interrupted daily activities). Independent of the assessment
of TEAEs, a nasal and pharyngeal irritation or inflamma-
tion assessment tool was used to determine the proportion
of subjects with nasal and pharyngeal symptoms by treat-
ment at pre-dose and 30 min, 1, 8, and 24 h post-dose. The
nasal mucosa was inspected for the presence or absence
of redness, edema, congestion, runny nose, or for other
signs or symptoms. Similarly, the pharynx was assessed for
redness, edema, post-nasal drip, or for other signs or symp-
toms. Subjects were also asked to report any incident of
irritation or inflammation in between the evaluation time,
and the reported discomfort was rated as mild, moderate, or
severe.
To assess the level of alertness following diazepam treat-
ment, a 4-level categorical scale was used that rated
subjects by treatment and time point as being either alert,
drowsy, sleeping but arousable, or sleeping not arous-
able. The assessment of treatment-emergent suicidality, as
required by regulatory authorities for all central nervous sys-
tem compounds in development, was evaluated using the
Columbia-Suicide Severity Rating Scale (C-SSRS).
Results
A total of 24 subjects (20 men and 4 women; mean age 34
years, range 21—46 years; mean weight 96.4 ± 4.98 kg) were
screened and all met the eligibility criteria for study partici-
pation. All 24 subjects completed dosing periods 1 and 2 and
were included in the safety and PK analyses. Four subjects
were not dosed in period 3, 2 withdrew consent for reasons
unrelated to adverse events (AEs), and 2 were discontinued
for positive urine drug screens.

4. Pharmacokinetics of intranasal diazepam 1207
-100
0
100
200
300
400
500
600
700
800
0 4 8 12 16 20 24
Meandiazepam(ng/mL)
Time (h)
5 mg diazepam-NS 20 mg diazepam-RG 20 mg diazepam-NS
-100
0
100
200
300
400
500
600
700
0 4 8 12 16 20 24
Meandiazepam(ng/mL)
Time (h)
5 mg diazepam-NS 20 mg diazepam-RG 20 mg diazepam-NS
A
B
Figure 1 Mean plasma diazepam concentration—time profile by treatment: (A) after excluding 3 diazepam-RG subjects with low
bioavailability, and (B) including all subjects.
Pharmacokinetics
Concentration—time profiles for 5-mg and 20-mg diazepam-
NS formulations showed that the Cmax of 96.3 ± 28 and
350 ± 103 were reached at a median Tmax of 1.0 h, whereas
for 20 mg diazepam-RG, the Cmax of 352 ± 93 ng/mL was
reached at 1.5 h after administration (Fig. 1). Assessment
for leakage at 5—60 min after administration of diazepam-
RG showed varying degree of leakage in 7 subjects (33%).
However, only 3 subjects (13%) experienced poor retention
at the earliest assessment of 5 min, with leakage varying
in estimated quantity from less than 1 mL to 3 mL. These
subjects had lower diazepam exposures with mean Cmax less
than 10% measured in those with good rectal gel retention.
Nasal leakage was noted in 15 subjects (65%) at various time
points from 5 to 60 min after dosing with 20 mg diazepam-
NS. Four subjects sneezed within 2—36 min of dosing and
3 had nasal leakage. However, regardless of nasal leakage
or sneezing, the absorption of diazepam was consistent,
as the coefficients of variation for Cmax and AUC0—24 with
20 mg diazepam-NS were 28% and 27%, respectively, com-
pared with 46% and 43% with rectal gel.
Table 1 describes the summary statistics of noncom-
partmental PK parameters by dosing. The mean ± SD Cmax
for 5-mg and 20-mg diazepam-NS and 20-mg diazepam-
RG groups were 108 ± 31, 378 ± 106, 328 ± 152 ng/mL,
respectively; AUC0—24 values were 823 ± 285, 2720 ± 738,
and 2660 ± 1146 ng h/mL, respectively. After excluding
those subjects with rectal diazepam leakage, the mean
Cmax and AUC0—24 values for 20 mg diazepam-RG were
comparable to 20 mg diazepam-NS (375 ± 97 ng/mL and
3015 ± 710 ng h/mL, respectively). The estimated mean t1/2
values for diazepam varied from 96 to 108 h with a range
from 43.8 to 243 h.
To evaluate the bioavailability of the 20-mg diazepam-
NS formulation relative to 20 mg diazepam-RG, treatment
ratios and 90% CIs of natural log-transformed PK param-
eters were compared. Comparative bioavailability data,
when including all subjects, indicated that the ratios of
Cmax and AUC0—24 for 20 mg diazepam-NS exceeded 100%

5. 1208 H.R. Henney III et al.
Table 1 Diazepam noncompartmental PK parameters by treatment.
Group N Cmax (ng/mL)
Mean (SD)
Tmax (h)
Median
AUC0—24 (ng h/mL)
Mean (SD)
5 mg diazepam-NS 22 108 (30.5) 1.0 823 (285)
20 mg diazepam-NS 23 378 (106) 1.0 2720 (738)
20 mg diazepam-RG 23 328 (152) 1.5 2660 (1146)
20 mg diazepam-RG (subpopulation) 20a
375 (96.8) 1.25 3015 (710)
a Excluding subjects with poor retention.
Table 2 Bioavailability analysis between 20 mg diazepam-NS and 20 mg diazepam-RG.
PK parameters Geometric meana
Ratio (%)b
(test/ref)
90% CI Power
20 mg diazepam-NS
(test) N = 23
20 mg diazepam-RG
(ref) N = 20
Lower Upper
Ln(Cmax) 361.143 366.801 98.45 85.30 113.64 0.8260
Ln(AUC0—24) 2631.576 2972.011 88.55 80.23 97.72 0.9790
Ln(AUClast) 9172.612 10,868.107 84.40 75.44 94.42 0.9482
Ln(AUC∞) 11,118.795 13,378.723 83.11 75.34 91.68 0.9796
Ln, natural logarithm.
a Geometric mean based on least-squares mean of ln-transformed parameter values.
b Ratio (%) = geometric mean (test)/geometric mean (ref).
and the 90% CIs were outside of the standard acceptance
range (Cmax: 145.16, 90% CI: 98.73—213.43; AUC0—24: 119.76,
90% CI: 88.77—161.58). This result is due to inclusion of
subjects with low diazepam exposure in the diazepam-RG
group that altered the distribution of the data and conse-
quently the ratios. When the 3 subjects with low diazepam
exposures following rectal administration were excluded
from the analysis, the ratios for Cmax and AUC0—24 were
within the 90% CI acceptance range, whereas for AUClast
and AUC∞, ratios were outside the lower end of the range
by 5% (Table 2). These results show that the bioavailability
of 20 mg diazepam administered intranasally is comparable
to an equivalent dose given rectally when the latter is not
compromised by leakage.
To determine whether linearity exists between the lowest
and highest dose-strengths of diazepam intranasal formu-
lation, dose-normalized PK parameters of 5-mg and 20-mg
doses were compared (Table 3). Due to the observed long
half-life of diazepam, which ranged from 43.8 to 243 h across
subjects and treatments, a carry-over of residual plasma
diazepam was observed when a 20-mg dose of intranasal for-
mulation or rectal gel preceded a 5-mg dose, especially in
those subjects with diazepam half-life greater than 80 h. As
higher pre-dose diazepam concentrations would impact the
Cmax and AUC values, the analysis utilized corrected concen-
trations by subtracting residual diazepam using the average
terminal-phase rate constant for each subject. Comparison
of dose-normalized PK parameters showed that the treat-
ment ratios and the respective 90% CIs were within the
standard acceptance range, thus demonstrating that the 5-
mg and 20-mg strengths were dose-proportional.
To address the potential impact of the route of adminis-
tration on the metabolism of diazepam, the PK parameters
of desmethyl diazepam obtained from dosing period 1
were compared for all 3 treatments. The results indi-
cated that the metabolite concentrations accumulated
very slowly over time after dosing with 20 mg diazepam-
NS and rectal gel treatments with nearly superimposable
concentration—time profiles (Fig. 2). The highest mean
plasma metabolite concentrations for 5 mg and 20 mg
diazepam-NS and diazepam-RG were 9.9 ± 3.1 ng/mL at
144 h and 37.3 ± 13 and 35.5 ± 14.5 ng/mL at 96 h, respec-
tively, indicating that the metabolite Cmax values were about
10% of those of diazepam following each treatment, regard-
less of route of administration and dose.
Tolerability
All subjects reported at least 1 TEAE (Table 4). All these
events were considered mild or moderate in severity and
resolved without treatment. There were no serious AEs or
severe TEAEs. There were no clinically significant changes
in vital signs, respiratory function, or electrocardiograms in
any of the treatment groups. Increased lacrimation was the
most commonly reported TEAE by 78—82% of the subjects
treated with 5-mg and 20-mg diazepam-NS doses, reflect-
ing the local effects of intranasal administration. This TEAE,
which occurred almost immediately after dosing, was mild
and was of short duration; 47% were resolved within 5 min
after administration, 92% were resolved within 45 min, and
all were resolved within 3 h of onset. Other TEAEs that
were related to local effects of intranasal administration
were nasal symptoms reported in 9% to 44% in each of
the 2 diazepam-NS groups compared with 4% for diazepam-
RG. These included rhinorrhea, nasal inflammation, nasal
congestion, nasal discomfort, nasal edema, paranasal sinus
hypersecretion, dysgeusia, and sneezing. Pharyngeal TEAEs

6. Pharmacokinetics of intranasal diazepam 1209
Table 3 Dose-proportionality analysis between minimum and maximum dose-strengths of diazepam intranasal formulations.
Dependent variable Geometric meana
Ratio (%)b
(20 mg/5 mg) 90% CI Power
20 mg 5 mg Lower Upper
Ln(Cmax/dose) 17.9529 19.6278 91.47 82.02 102.01 0.9569
Ln(AUC0—24/dose) 143.5121 137.3799 94.25 87.70 101.29 0.9991
Ln(AUC∞/dose) 539.8293 556.9134 96.93 88.74 105.89 0.9918
Ln(CL/F) 1.8524 1.7956 103.16 94.44 112.69 0.9918
a Geometric mean based on least-squares mean of ln-transformed parameter values.
b Ratio (%) = geometric mean (20 mg)/geometric mean (5 mg).
-5
0
5
10
15
20
25
30
35
40
45
0 4 8 12 16 20 24
Meandesmethyldiazepam(ng/mL)
Time (h)
5 mg diazepam-NS 20 mg diazepam-RG 20 mg diazepam-NS
Figure 2 Mean desmethyl diazepam concentration—time profiles for dosing period 1 after excluding data from 3 diazepam-RG
subjects with low bioavailability.
Table 4 TEAEs reported by ≥5% of subjects in any treatment group.
TEAE (preferred term) Diazepam-NS Diazepam-RG
5 mg (N = 22) N (%) 20 mg (N = 23) N (%) 20 mg (N = 23) N (%)
Subjects with one or more TEAE 21 (96) 23 (100) 17 (74)
Lacrimation increased 18 (82) 18 (78) 0
Somnolence 5 (23) 12 (52) 14 (61)
Rhinorrhea 7 (32) 10 (44) 1 (4)
Nasal inflammation 2 (9) 9 (39) 1 (4)
Dizziness 1 (5) 4 (17) 5 (22)
Nasal congestion 4 (18) 4 (17) 0
Nasal discomfort 4 (18) 2 (9) 0
Paranasal sinus hypersecretion 0 4 (17) 0
Dysgeusia 1 (5) 2 (9) 0
Fatigue 1 (5) 0 3 (13)
Feeling abnormal 0 1 (4) 2 (9)
Nasal edema 0 3 (13) 0
Sneezing 2 (9) 2 (9) 0
Euphoric mood 0 0 2 (9)
Eye irritation 2 (9) 0 0

7. 1210 H.R. Henney III et al.
such as dry throat (4.5%) and throat irritation (4.5%) were
less common and were reported only in the diazepam-NS
dose groups. Systemic TEAEs such as somnolence and dizzi-
ness were dose-related and were reported by the 5-mg and
20-mg diazepam-NS and diazepam-RG groups: 23%, 52%, and
61% for somnolence and 5%, 17%, and 22% for dizziness,
respectively.
The nasal and pharyngeal assessments indicated that
the incidence of nasal symptoms were dose-related to the
intranasal doses, as 32% treated with 5 mg diazepam-NS
and 48% with 20 mg diazepam-NS experienced symptoms
of nasal redness, congestion, or runny nose. The symp-
toms peaked at 30—60 min after administration of intranasal
doses and returned to baseline levels by 8 h. Nasal discom-
fort, described as mild, was less common and occurred in 4
subjects during the 24 h observation period. Pharyngeal signs
or symptoms were also less common and were not reported
by more than 9% in either of the diazepam-NS groups.
Alertness evaluation indicated that decrease in alertness
was dose-related and that by 24 h after administration all
subjects were alert. There were no indications of treatment-
emergent suicidal ideation or behaviors, as evaluated by
C-SSRS.
Discussion
The results of this study showed that nasally administered
diazepam was well tolerated with mild local effects resolved
without treatment, and that the rate and extent of absorp-
tion of diazepam from the 20-mg intranasal formulation is
comparable to that of 20 mg of the rectal gel. This study
also demonstrated that the lowest and highest strengths of
the intranasal diazepam formulation are dose proportional
when assessed using the dose-normalized PK parameters.
Large inter-patient variability in diazepam PK is well
known. A study (Ivaturi et al., 2013) that compared the
bioavailability of two investigational diazepam intranasal
formulations with rectal gel in healthy adults showed that
the Cmax values and systemic exposure were comparable.
Although the nasal formulations were rapidly absorbed in
their study (median Tmax: 0.75 h) with 70—90% bioavailabil-
ity relative to rectal gel, the authors noted considerable
variability between subjects in Cmax and exposure, possibly
related to incomplete nasal dosing in some subjects (Ivaturi
et al., 2013). The same study also discussed variability in
PK following diazepam-RG administration. On the basis of
a pooled analysis of healthy subjects, the study indicated
that the between-subject PK variability in those treated
with diazepam-RG was substantial and ranged from 30% to
70% (Ivaturi et al., 2013). The variability in the absorp-
tion of diazepam when administered as rectal gel has been
attributed to rectal contents as well as to leakage (Lamson
et al., 2011). Although in the current study rectal leakage
of diazepam was observed in 7 of the 23 (30%) subjects,
leakage at the earliest assessment of 5 min was noted in 3
subjects (13%). Notably, the diazepam exposure in these 3
subjects was substantially low due to poor retention with
levels less than 10% of the systemic exposure measured in
other subjects from the diazepam-RG group (mean Cmax:
375 ± 97 ng/mL). Nasal leakage was noted in 15 subjects up
to 1 h after dosing with the 20-mg nasal formulation and 3 of
these subjects sneezed within 36 min of dosing. Regardless
of nasal leakage or sneezing, the diazepam exposure in these
subjects was comparable to the diazepam-RG group subjects
who did not experience low drug exposure due to early rectal
leakage; this suggests that nasal leakage or sneezing fol-
lowing intranasal formulation may not have resulted in drug
loss.
Rectal administration of medications is generally viewed
as inconvenient and socially embarrassing. However, a sur-
vey of adult patients with resistant epilepsy indicated that
the majority (93%) would prefer a rectal medication that
could be used outside the hospital than to be transported to
the emergency room (Tatum, 2002). Despite indicating this
preference, nearly 50% of those surveyed were of the view
that the use of rectal medication is equally embarrassing to
having a seizure, suggesting that embarrassment is a barrier
to the use of rectal medication for seizure clusters. These
findings highlight the need for an alternative rescue medica-
tion in the treatment of seizure clusters. In this regard, the
key attributes of a rescue medication for seizure clusters
would be the time to reach the plasma diazepam concen-
tration to exert anticonvulsant effect and to sustain the
exposure levels for sufficient duration to maintain seizure
control. A number of earlier studies have attempted to
establish an association between the anticonvulsant effect
of diazepam and its PK. In a study by Milligan et al. (1981),
rectal administration of diazepam was highly effective in
terminating absence status as evidenced by reduction of
spike-wave activity in the electroencephalogram. Notably,
the authors stated that the therapeutic effect of diazepam
was observed at serum levels below 150 ng/mL. In their
subsequent studies, Milligan et al. showed a significant
reduction in spike frequency (Milligan et al., 1982) and
recurrent seizures (Milligan et al., 1984) when patients
were treated with rectal diazepam suppositories com-
pared with placebo, which corresponded to mean serum
diazepam levels of 210 ± 125 ng/mL and 190 ± 73 ng/mL,
respectively. However, no correlation was found between
serum diazepam concentration and anticonvulsant effect.
Despite the lack of consensus on plasma diazepam concen-
tration required for anticonvulsant effect, Dreifuss et al. in
the original report of diazepam-RG designed their study to
maintain diazepam concentrations at 150—300 ng/mL based
on data from intravenous administration (Dreifuss et al.,
1998).
In the current study, the median Tmax for 20 mg diazepam-
NS was 1 h with comparable Cmax and systemic exposure to
that of 20 mg diazepam-RG. These findings suggest that a
single-dose of 20 mg diazepam-NS could potentially provide
adequate seizure control for those patients experiencing
increased seizure activity and may thereby alleviate the
need for costly emergency medical care. Considering that
the purpose of this study was to assess the relative bioavail-
ability of diazepam-NS formulation in the acute treatment
of seizures, such as in seizure cluster, Cmax and AUC0—24
estimates were considered clinically more relevant than
exposures derived using AUC∞. With the use of bioequiv-
alence methodologies as measured by Cmax and AUC0—24,
the bioavailability of 20 mg diazepam-NS was found to be
comparable to 20 mg diazepam-RG. Although the estimated
equivalence for AUClast and AUC∞ were similar, the lower
tails of the respective CIs fell outside the accepted range

8. Pharmacokinetics of intranasal diazepam 1211
by 5%. However, these differences should not be consid-
ered as clinically important, as these exposure estimates do
not affect the Cmax and Tmax that are necessary for seizure
control.
A limitation of the present study was that it was carried
out in a controlled, adult population without epilepsy, which
did not include elderly or pediatric individuals. Bioavailabil-
ity may vary in these populations.
In conclusion, all tested doses and formulations of
diazepam in this study were well tolerated with expected
safety profiles. Although mild to moderate local TEAEs
were reported with the intranasal formulation, they did
not affect the use of the product nor did they impact
the overall diazepam exposure. Based on the PK profile
and bioavailability, the 20-mg diazepam-NS formulation
was pharmacokinetically comparable to 20 mg diazepam-
RG, suggesting that the intranasal formulation may provide
caregivers and patients with a more socially acceptable and
more convenient alternative to rectal gel in the acute treat-
ment of seizure clusters.
Funding
This study was funded by Neuronex, Inc., a wholly owned
subsidiary of Acorda Therapeutics, Inc.
Conflict of interest
H.R.H was an employee of Acorda Therapeutics, Inc., with
stock options at the time of the study. A.L.R. and E.J.C. are
employees of Acorda Therapeutics, Inc., with stock options.
M.R.S. is a consultant for Acorda Therapeutics, Inc., and
electroCore Medical. G.B. was an employee of Neuronex,
Inc., a wholly owned subsidiary of Acorda Therapeutics, Inc.,
at the time of the study.
Acknowledgments
Authors thank Bagi Ravishankar, PhD, David Squillacote, MD,
and Risa Torkin, PhD, for their assistance in manuscript
development. Editorial assistance was provided by Infusion
Communications and funded by Acorda Therapeutics, Inc.
References
Bhattacharyya, M., Kalra, V., Gulati, S., 2006. Intranasal midazolam
vs rectal diazepam in acute childhood seizures. Pediatr. Neurol.
34, 355—359.
Bream, G., Leibowitz, M.T., Wargin, W., Abernathy, K., Ward,
D., 2013. Assessment of pharmacokinetic linearity and relative
bioavailability of a nasal diazepam formulation compared with
diazepam rectal gel in healthy adult subjects. In: Presented at
the 65th Annual Meeting of the American Academy of Neurology,
March 16—23, 2013, San Diego, CA.
Cereghino, J.J., 2007. Identification and treatment of acute repeti-
tive seizures in children and adults. Curr. Treat. Options Neurol.
9, 249—255.
Chen, J.W., Wasterlain, C.G., 2006. Status epilepticus: pathophysi-
ology and management in adults. Lancet Neurol. 5, 246—256.
de Haan, G.J., van der Geest, P., Doelman, G., Bertram, E., Edel-
broek, P., 2010. A comparison of midazolam nasal spray and
diazepam rectal solution for the residential treatment of seizure
exacerbations. Epilepsia 51, 478—482.
2005. DIASTAT® AcuDialTM (diazepam rectal gel) [prescribing infor-
mation]. Valeant Pharmaceuticals North America, LLC, Durham,
NC.
Dreifuss, F.E., Rosman, N.P., Cloyd, J.C., Pellock, J.M., Kuzniecky,
R.I., Lo, W.D., Matsuo, F., Sharp, G.B., Conry, J.A., Bergen,
D.C., Bell, W.E., 1998. A comparison of rectal diazepam gel
and placebo for acute repetitive seizures. N. Engl. J. Med. 338,
1869—1875.
Friedman, D., French, J.A., 2012. Clinical trials for therapeutic
assessment of antiepileptic drugs in the 21st century: obstacles
and solutions. Lancet Neurol. 11, 827—834.
2014. Guidance for industry: bioavailability and bioequivalence
studies for orally administered drug products-general consider-
ations, http://www.fda.gov/cder/guidance/index.htm
Haut, S.R., 2006. Seizure clustering. Epilepsy Behav. 8, 50—55.
Holsti, M., Dudley, N., Schunk, J., Adelgais, K., Greenberg, R.,
Olsen, C., Healy, A., Firth, S., Filloux, F., 2010. Intranasal mida-
zolam vs rectal diazepam for the home treatment of acute
seizures in pediatric patients with epilepsy. Arch. Pediatr. Ado-
lesc. Med. 164, 747—753.
Holsti, M., Sill, B.L., Firth, S.D., Filloux, F.M., Joyce, S.M., Fur-
nival, R.A., 2007. Prehospital intranasal midazolam for the
treatment of pediatric seizures. Pediatr. Emerg. Care 23, 148—
153.
Ivaturi, V., Kriel, R., Brundage, R., Loewen, G., Mansbach, H.,
Cloyd, J., 2013. Bioavailability of intranasal vs. rectal diazepam.
Epilepsy Res. 103, 254—261.
Kriel, R.L., Cloyd, J.C., Hadsall, R.S., Carlson, A.M., Floren, K.L.,
Jones-Saete, C.M., 1991. Home use of rectal diazepam for clus-
ter and prolonged seizures: efficacy, adverse reactions, quality
of life, and cost analysis. Pediatr. Neurol. 7, 13—17.
Kriel, R.L., Cloyd, J.C., Pellock, J.M., Mitchell, W.G., Cereghino,
J.J., Rosman, N.P., 1999. Rectal diazepam gel for treatment
of acute repetitive seizures. The North American Diastat Study
Group. Pediatr. Neurol. 20, 282—288.
Kyrkou, M., Harbord, M., Kyrkou, N., Kay, D., Coulthard, K., 2006.
Community use of intranasal midazolam for managing prolonged
seizures. J. Intellect. Dev. Disabil. 31, 131—138.
Lamson, M.J., Sitki-Green, D., Wannarka, G.L., Mesa, M., Andrews,
P., Pellock, J., 2011. Pharmacokinetics of diazepam admin-
istered intramuscularly by autoinjector versus rectal gel in
healthy subjects: a phase I, randomized, open-label, single-
dose, crossover, single-centre study. Clin. Drug Investig. 31,
585—597.
Milligan, N., Dhillon, S., Richens, A., Oxley, J., 1981. Rectal
diazepam in the treatment of absence status: a pharma-
codynamic study. J. Neurol. Neurosurg. Psychiatry 44, 914—
917.
Milligan, N., Dhillon, S., Oxley, J., Richens, A., 1982. Absorption of
diazepam from the rectum and its effect on interictal spikes in
the EEG. Epilepsia 23, 323—331.
Milligan, N., Dhillon, S., Griffiths, A., Oxley, J., Richens, A., 1984.
A clinical trial of single dose rectal and oral administration
of diazepam for the prevention of serial seizures in adult
epileptic patients. J. Neurol. Neurosurg. Psychiatry 47, 235—
240.
Pellock, J.M., 2007. Overview: definitions and classifications of
seizure emergencies. Child Neurol. 22, 9S—13S.
Sillanpää, M., Schmidt, D., 2008. Seizure clustering during drug
treatment affects seizure outcome and mortality of childhood-
onset epilepsy. Brain 131 (Pt 4), 938—944.
Tatum, W.O., 2002. Adult patient perceptions of emergency rec-
tal medications for refractory seizures. Epilepsy Behav. 3, 535—
538.
Wilson, M.T., Macleod, S., O’Regan, M.E., 2004. Nasal/buccal mida-
zolam use in the community. Arch. Dis. Child. 89, 50—51.