JapaneseJournal
Journal of Community
Community Pharmacy
No.1,9-16（2019）Japanese
Pharmacy Vol.7,Vol.7,No.1,
9-16 (2019)《 Original Article 》

Examination regarding the force required to push
Rx-OTC-switch tablets out of PTP
Rika Tanaka1,2, Masahiro Murakami1*, Megumi Yasuda1, Manabu Amano1

For packaged tablets,“press through packages”(PTP) are commonly used. Although
PTP have numerous merits, patients with finger hypofunction sometimes have difficultyin pushing out tablets or capsules. In this study, we examined the force required to pushloxoprofen sodium tablets/capsules, as an over-the-counter (OTC) drug, out of PTP toprovide useful information for selecting products appropriate for individual patients.
We measured the force required to push 4 OTC drugs out of PTP (push-out force),
weight, diameter, and thickness. Subjective assessment was conducted using 7 grades
after pushing the respective tablets or capsules out of PTP cut in the form of 2 tablets.
The maximum score on the subjective assessment was 4.7 points. The minimum pushout force was 68.1 N. The maximum weight was 301.1 mg. The maximum thickness was
4.1 mm. The diameter of all drugs was 9.1 mm.
Product E was evaluated as the easiest to push out based on the push-out force, weight,diameter, and thickness. However, no significant difference was noted among the drugs
in the subjective assessment. For self-medication with OTC drugs, a product should besuitably selected for each patient. For this purpose, data, such as those obtained in thepresent study, are essential.
Key words; push-out force, Rx-OTC-switch drugs, press through packages, self-medication
Received March 8, 2019; Accepted May 15, 2019
1． Introduction

strategies, the government has promoted theutilization of generic products and self-medication.

Currently, the increase in national health

For self-medication, over-the-counter (OTC) drugs

expenditures related to the rapidly aging society is

are used in many cases; therefore, it is necessary forof great concern in Japan. As management

pharmacists to provide sufficient information.

1 School of Pharmacy, Hyogo University of Health Sciences
2 HANSHIN Dispensing Pharmacy Co., Ltd.

*Corresponding author: Masahiro Murakami, 1-3-6 Minatojima, Chuo-ku, Kobe-shi, Hyogo, 650-8530, Japan
Tel: 81-(0)78-304-3176
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the force
requiredVol.7,
to pushRx-OTC-switch
Journal ofregarding
Community
Pharmacy
No.1,
9-16 (2019) tablets

In particular, for the sale of drugs requiringcorrelated with the subjective difficulty of pushingguidanceout the drug5,6).

orcategory-1

drugs,

information

provision by pharmacists is obligatory. However,In this study, we measured the push-out force,currently, information on OTC drugs for health careweight, diameter, and thickness of loxoprofen

professionals is insufficient, and their package

sodium tablets, which are commercially available asinserts, which can also be inspected by patients, area category-1 drug, and examined the results ofprimarily used. For this reason, several reports on

subjective assessment of the difficulty to push out

the dissolution behavior or collapsibility, whichtablets to provide useful information for selecting

influences pharmacokinetics, have been publishedproducts. Loxoprofen sodium is an antipyretic

as information necessary for promoting the proper

analgesic that has been used as a prescription drug1,2)

use of OTC drugs

for over 30 years, and it was approved as an OTC.

Press through packages (PTP), which are thedrug in 2011. Loxoprofen sodium was selected ascommonly used packages for drug tablets or

the target drug of the survey, because it is the mostcapsules, are advantageous for quality maintenancecommonly used antipyretic analgesic in Japan 7).

and portability, and the drug can be easily removed2.

by pressing. On the other hand, one previous study

Methods

reported that it was sometimes difficult for patientswith finger hypofunction to push tablets or capsules

1. Drugs to be investigated3)

out of PTP . The term “frail” has been proposed

Of the OTC drugs containing loxoprofen sodium

due to the rapid aging of society; therefore, thealone, distributed as of September 2018, four

provision of product information based on theseproducts available for purchase through somecircumstances may be useful for selecting products

distribution channels were selected as target drugsin accordance with individual patients.

(Table 1).

The force required to push the drug out of PTP
2. Measurement of the push-out force(push-out force) can be measured using a force
gauge, which is a device to evaluate the strength or

The push-out force was measured using an FGP-

durability of an object. According to a previous

5 digital force gauge (Nidec-Shimpo Corporation,4).

Kyoto). It was expressed in Newtons (N). The

Furthermore, several studies reported that the push-digital force gauge was attached to an FGS-50E

out force, drug weight, diameter, and thickness were

special electric vertical force-gauge stand (Nidec-study, the strength differs among products

Table 1

List of Products

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Journal of regarding
Community
Vol.7,
No.1,
9-16（2019）tablets
TanakaJapaneseet al.；Examination
thePharmacy
force required
to pushRx-OTC-switch

Shimpo Corporation, Kyoto), and an instrument for
fixing PTP was installed at the stand base (Fig. 1).
PTP were set on the instrument, and the digitalforce gauge was lowered at a velocity of 50 mm/min.
The maximum force added until the aluminum sheetof the PTP was broken was taken as the push-outforce. Ten measurements/product were conducted,
and the mean was calculated. It was previously
reported that there is a negative correlation between
the force required to push tablets out of PTP
measured using a digital force gauge at a velocity of50 mm/min and the subjectively assessed difficultyin pushing out tablets5). Therefore, in this study, thepush-out force was also measured at a velocity of 50Figure 1mm/min.
3. Measurement of weight, diameter, and thickness

Instrument used to measure
the push-out force

A: Tablet in PTP,
B: A tablet was enclosed/fixed.

The weight of each product was measured usinga GH-300 direct-reading balance (A&D Company,The subjective assessment of difficulty to pushLtd., Tokyo). Six measurements/product wereout tablets was performed using the following

conducted, and the mean was calculated. Theprocedures: the subjects pushed each tablet out ofdiameter and thickness of each product were

PTP cut into 2-tablet units, and then evaluated themeasured using a digital Vernier caliper (A&Ddifficulty using 7 grades: “very easy”, “easy”,

Company, Ltd., Tokyo). Six measurements/product“slightly easy”, “not either”, “slightly difficult”,

were conducted, and the mean was calculated.

“difficult”, and “very difficult”. Scoring was carriedout regarding the response “very easy” as 7.

4. Subjective assessment of the difficulty to pushout tablets/capsules

5. Statistical analysis

The subjects were adult volunteers aged ≥20

Finger function was analyzed using the Student’syears. We excluded those who were unable to pusht-test. The results of the subjective assessment weretablets/capsules out of PTP due to disease-related

analyzed using the Steel-Dwass method and Mann-finger hypofunction. As background factors, aninterview regarding age, sex, and handedness was

Whitney U test. The correlation between fingerconducted.

fingerfunction and the subjective assessment wasfunction, the grip strength and pinching strength

examined using Spearman’s rank correlation(finger-tip pinching, finger-pulp pinching, andcoefficient test. The correlations between the push-finger-side pinching) were measured 3 times, andout force, weight, diameter, or thickness and thethe mean was calculated.

subjective

Subsequently,

toevaluate

assessment

wereanalyzed

using

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et al.；Examination
the force
requiredVol.7,
to pushRx-OTC-switch
Journal ofregarding
Community
Pharmacy
No.1,
9-16 (2019) tablets

Pearson’s correlation coefficient test. For analysis,

3. Push-out force, weight, diameter, and thickness

Statcel 3 software (The Publisher OMS Ltd., Tokyo)

The maximum push-out force was 74.5 Nwas used. A p-value of 0.05 was considered(Product Y). The minimum push-out force was 68.1

significant.

N (Product E). The weight of Product E was thehighest (301.1 mg), and that of Product K was thelowest (250.9 mg). The diameter of all products was

6. Ethical considerations
Prior to this study, its content was sufficiently

9.1 mm. The thickness of Product Y was the highest

explained to the subjects using an explanatory(4.1 mm), and those of Products L and K were thedocument, and written informed consent waslowest (3.3 mm) (Fig. 2).

received from those who consented to participate in
4. Subjective assessment

this study. The protocol of this study was approved

The subjective assessment score for Product E

by the President of Hyogo University of Health

was the highest (4.7 points), and that for Product L

Sciences (Approval No.: 17020).

was the lowest (4.2 points). Regarding sex, the3.

subjective assessment scores for all products wereResults

lower by females. Regarding age, the scores for allproducts were higher by those aged ≥75 years.

1. Subject background
The mean age of the subjects was 66.8±17.4

Furthermore, there was a significant difference inyears. They consisted of 39 (68.4%) aged <75 years

the score for Product K between the two age groups

and 18 (31.6%) aged ≥75 years. There were 19(P = 0.0012) (Fig. 3).

males (33.3%) and 38 females (66.7%). Fifty-threesubjects (93.0%) were right-handed and 4 (7.0%)

5.

Correlations

betweenthepush-out

were left-handed. Regarding current drugs, 38

force/weight/diameter/thickness

andsubjective(66.7%) selected “present” and 19 (33.3%) selectedassessment
The relationship with the subjective assessment“absent”.

was examined, revealing a negative correlation withthe push-out force (r = - 0.404, P = 0.595). A

2. Finger function
The mean grip strength was 28.4 ± 10.5 kg. The

positive correlation was noted with the weight (r =mean finger-tip pinching strength was 9.7 ± 3.8 kg.

0.658, P = 0.341). There was no correlation with theThe mean finger-pulp pinching strength was 10.9 ±diameter (r = - 0.107, P = 0.893). A strong positive

3.7 kg. The mean finger-side pinching strength wascorrelation was noted with the thickness (r = 0.836,

13.7 ± 4.8 kg. The values of all grip and pinchingP = 0.164).

strength items for males were higher than those for

4. Discussion

females, demonstrating significant sex differences.
Furthermore, only the mean finger-tip pinchingstrength was higher among subjects aged ≥75 years

There are several commercially available OTC(Table 2).

drug s containing the same component, as1312★Vol7No1_日本地域薬局薬学会誌_本文.indd 12

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Journal of regarding
Community
Vol.7,No.1,
9-16（2019）tablets
TanakaJapaneseet al.；ExaminationthePharmacy
force required
to pushRx-OTC-switch

represented

byoralpreparations

containingthat it became easier to push out tablets or capsules

loxoprofen sodium. In this study, we measured thewith an increase in the tablet weight, diameter, orweight, diameter, and thickness of loxoprofen

thickness5). Furthermore, another study reported

sodium preparations, in addition to the force

that the push-out force decreased with an increase

required to push tablets out of PTP, and examinedin the tablet thickness4). This study demonstrated

their correlations with the subjectively assessed

correlationsdifficulty to push them out in order to provide usefulweight/thickness

information for selecting products appropriate forsuggesting the usefulness of the results as data on

individual patients.

the difficulty to push tablets or capsules out of PTP.

Regarding the difficulty to push tablets orandthepush-out

subjective

force/

assessment,

Age- or sex-related differences in finger function
were previously reported8)

capsules out of PTP, previous studies noted acorrelation between the push-out force measured

In this study, there were also significant6)

using a force gauge and sensory assessment , andTable 2

betweendifferences in the grip strength and pinching

Finger Function

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the force
requiredVol.7,
to pushRx-OTC-switch
Journal ofregarding
Community
Pharmacy
No.1,
9-16 (2019) tablets

strength between males and females (Table 2).

significant differences in the subjective assessment

On the other hand, when comparing theresults between the two age groups, there
were no significant differences in any
parameter of finger function. An age-based
comparison of the subjective assessment
revealed a significantly higher score for
Product K in subjects aged ≥75 years.
Although no significant difference was noted
for other products, the scores tended to behigher in subjects aged ≥75 years. This canbe explained by the higher mean value ofpinching strength, critical for pushing tablets
out, in subjects aged ≥75 years than those
aged <75 years.

score among the products (Fig. 3). Takeshita et al.6)
reported that an approximately 10-N difference inpush-out force can be felt by humans. The largest
difference in the push-out force was 6.4 N,
precluding subjective recognition (Fig. 2A).
The present study demonstrated that Product E ismost easily pushed out in consideration of the pushout force from PTP, and the weight, diameter, andthickness of the tablet. However, there was no
significant difference in the subjective assessment,suggesting that the difference in push-out force ishardly noticed. In the present study, neither
hardness nor feeling of PTP were evaluated. Thesefactors may have influenced the subjectiveassessment. In addition, the push-out force

The push-out force, diameter, and thickness ofnecessary for PTP may affect drug compliance.

Product K were the same as those of Product L. Inaddition, the weights were comparable between theTo support self-medication with OTC drugs, it isproducts, with a difference of only 10.5 mg.

important to select products meeting patients’ needs.

However, a significant difference was observed

To achieve this, information, such as the results of

only for Product K, suggesting the involvement of

this study, may be necessary, in addition tothe hardness of the PTP sheet. Details remain

information from package inserts, which bothunknown, because the hardness of the PTP sheet

pharmacists and patients can inspect.

was not measured in the study.
Conflicts of Interest

Tablets measuring ≥10 mm in diameter are
visually recognized as large9). Therefore, this may

The authors have no conflict of interest to report.

contribute to the impression of difficulty. However,
all of the tablets were likely easily ingested because

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JapaneseJournal
Journal of Community
Community Pharmacy
No.1,9-16（2019）JapanesePharmacy Vol.7,Vol.7,
No.1,
9-16 (2019)

Figure 2

Measurement of the push-out force, weight, diameter, and thickness
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push
Rx-OTC-switch
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