Reference number  
DRS 392-4: 2018  
© RSB 2018  
 
 
 RWANDA 
STANDARD  DRS  
392-4 
 
First edition  
2018 -mm-dd 
 
Skin applied  mosquito repellents — 
Specification  — 
Part 4: 
Bathing soap s 
  DRS 392-4: 2018  
©RSB 2018 - All rights reserved                  ii 
 In order to match with technological development and to keep continuous progress in industries, 
standards are subject to periodic review. Users shall ascertain that they are in possession of the latest 
edition  
 
 
 
 
 
 
  
 
© RSB 2018  
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized 
in any form or by any means, electronic or mechanical, including photocopying and microfilm, without 
prior written permission from R SB. 
Requests for permission to reproduce this document should be addressed to : 
Rwanda Standards  Board  
P.O Box 7099 Kigali -Rwanda  
KK 15 Rd, 49  
Tel. +250 788303492  
Toll Free: 3250  
E-mail: info@rsb.gov.rw  
Website: www.rsb.gov.rw  
ePortal: www.portal.rsb.gov.rw  DRS 392-4: 2018  
iii                ©RSB 2018 - All rights reserved  
 Contents  Page 
Foreword  ................................ ................................ ................................ ................................ ...................  iv 
1 Scope  ................................ ................................ ................................ ................................ .............  1 
2 Normative references  ................................ ................................ ................................ ...................  1 
3 Terms and definitions  ................................ ................................ ................................ ..................  1 
4 Requirements  ................................ ................................ ................................ ................................  3 
4.1 General  ................................ ................................ ................................ ................................ ..........  3 
4.2 Active ingredi ents ................................ ................................ ................................ ........................  3 
4.2.1  Natural repellents  ................................ ................................ ................................ .........................  3 
4.2.2  Synthetic repellents  ................................ ................................ ................................ .....................  4 
4.3 Specific requirements  ................................ ................................ ................................ ..................  4 
4.4 Biological efficacy  ................................ ................................ ................................ ........................  5 
5 Packaging and la belling ................................ ................................ ................................ ...............  5 
5.1 Packaging  ................................ ................................ ................................ ................................ ...... 5 
5.2 Labeling  ................................ ................................ ................................ ................................ .........  5 
6 Sampling  ................................ ................................ ................................ ................................ ....... 6 
Annex  A (normative)  Determination of DEET content  ................................ ................................ ..........  7 
A.1 General  ................................ ................................ ................................ ................................ ..........  7 
A.2 Apparatus  ................................ ................................ ................................ ................................ ...... 7 
A.3 Preparation of calibration curve  ................................ ................................ ................................ . 7 
A.4 Procedure  ................................ ................................ ................................ ................................ ...... 7 
A.5 Calculation  ................................ ................................ ................................ ................................ .... 8 
 DRS 392-4: 2018  
©RSB 2018 - All rights reserved                  iv 
 Foreword  
Rwanda Standard s are prepared  by Technical Committees and approved by R wanda Standards Board (RSB) 
Board  of Directors in  accordance with the procedures of RSB, in compliance with Annex 3 of the WTO/TBT 
agreement on the preparation, adoption and application of standards.  
The main task o f technical committees is to prepare national standards.  Final Draft Rwanda S tandards adopted 
by Technical committ ees are ratified  by me mbers of RSB Board of Director s for publication and gazettment as 
Rwanda Standards.  
DRS 392-4 was prepared by Technical Committee RSB/TC 015, Pharmaceutical Products . 
DRS 392 consists of the following parts, under the general title Skin applied mosquito repellent  — Specification : 
 Part 1: Lotion s, cream s, gels and ointment s 
 Part 2: Spray s and roll -ons 
Part 3: Wipes  
Part 4: Bathing Soaps  
Part 5: Bracelets , wristbands  and patches  
Committee membership  
The following organizations were represented on the Technical Committee on Pharmaceutical products 
(RSB/TC 015) in the preparation of this standard.  
National Industrial Research and Development Agency (NIRDA)  
National Pharmacy Council (NPC)  
University of Rwanda/College of Sciences and Technology (UR/CST)  
Pharmacie NOVA  
Rwanda Development Board (RDB)  
AGROPY LTD  
IKIREZI NATURAL PRODUCTS  
HORIZON/SOPYRWA  DRS 392-4: 2018  
v                ©RSB 2018 - All rights reserved  
 Rwanda Social Securit y Board (RSSB)  
Pharmavie  
University of Rwanda/College of Medicine and Health Sciences (UR/CMHS)  
Rwanda Biomedical Center/ Malaria and Other Parasitic Diseases Division  (RBC/MOPDD)  
Society for Family Health  (SFH) – Rwanda  
Rwanda Biomedical Center/Medical Pr ocurement and Production Division (RBC/MPPD)  
INES - RUHENGERI  
Rwanda  Standards Board  (RSB) – Secretariat  DRS 392-4: 2018  
©RSB 2018 - All rights reserved                  vi 
 Introduction  
Mosquito repellents are an effective complement to bed nets in the prevention of mosquito borne diseases, 
especially malaria.  
 
Insecticides are used either for killing or controlling harmful insects. The insecticides which are applied for 
repelling insects are termed as “Repellents". Mosquito is one of the most harmful insects for mankind. To 
destroy them, many preparations are av ailable on the market in various recipes like pest killer spray, soap, oil, 
powder, repellent etc. Out of these, mosquito repellent is the most popular as it has germicidal and 
disinfectant properties and is able to repel mosquitoes and is convenient to us e. 
 
The mosquito repellent is used for warding off mosquitoes which are the most harmful insect s. Nowadays, 
mosquito repellents are used for controlling mosquito es and are becoming most preferably than other mosquito 
destroyers gradually. With the rise in the standard of living, increasing urbanization and population, the demand 
of mosquito repellent mat is constantly increasing particularly in tropical places. It is a convenient method for 
protection against mosquito es, so it has a tremendous market potent ial. Thus , there is a very good scope for 
development of such units in the country . 
 
Skin applied mosquito repellents possess the potential to target residual transmission. Entomological evidence 
has shown that repellents provide personal protection agains t malaria.  Product examples that are c ommon ly 
used  include lotions, gels, creams, ointments among others . However, many more  types of skin applied 
repellent products are now developed  in various forms such as sprays and roll -on, wipes, soaps and bracelets , 
wristbands and patches . 
 DRS 392-4: 2018  
1                ©RSB 2018 - All rights reserved  
 Skin applied mosquito repellents  — Specification — Part 4: Bathing 
soaps  
1 Scope  
This Draft Rwanda S tandard prescribes the requirements, sampling and test methods for skin applied mosquito 
repellents formulated and prepared as bathing soaps  and meant to be applied directly to the skin. 
2 Normative references  
The following documents are referred to in the text in such a way that some or all of  their content constitutes 
requirements of this document.  For dated references, only the edition  cited applies. For undated references, the 
latest edition of the reference d document (including any amendments) applies.  
RS ISO 862, Surface active agents — Vocabulary  
RS EAS 877, Bathing bar — Specification  
RS EAS 377 (all parts), Cosmetics and cosmetic products  
CIPAC 760, Determination of picaridin  
CIPAC 667, Determination of ethyl butylacetamidopropionate  
RS ISO 685, Analysis of Soaps — Determination of total alkali content and total fatty matter content  
ISO 4315, Surface active agents — Determination of alkalinity — Titrimetric method  
RS ISO 456 , Surface -active agents — Determination of free caustic alkali  
RS EAS 814, Determination of biodegradability of surfactants — Test method  
RS 191, Refined pyrethrum concentrate ― Specification  
DRS 394 -1, Mosquito repellents ― Performance Test Guidelines ― Part 1: Skin applied repell ents 
RS ISO 24153, Random sampling and randomization procedures  
3 Terms and definitions  
For the purposes of this standard, the terms and definitions given in RS ISO 862 and the following apply.   
©RSB 2018 - All rights reserved                  2 
 3.1 
bathing soaps  
soap product in the form of a bar or cake containing fatty acids and/or synthetic surface active agents as active 
ingredients and which is used for bathing purposes in soft hard water  
3.2 
mosquito  
any of numerous arthropod animals of the class mosquito, having an adult stage characterized by three pairs 
of legs and a body segmented into head, thorax, and abdomen and usually having one or two pairs of wings.  
3.3 
mosquito repellent  
substance applied to skin, clothing, or other surfaces which discourages mosquito  (and arthropods  in general) 
from landing or climbing on that surface . 
3.4 
natural repellents/biopesticides  
repellents that contain natural, plant -based active ingredients  
3.5 
synthetic repellents  
conventional repellents containing synthetic  chemical  active ingriedients  and carrier  compounds  as approved 
by a com petent authority  
3.6 
DEET   
N,N-Diethyl -meta -toluamide  or diethyltoluamide  
3.7 
IR3535   
ethyl butylacetylaminopropionate  
3.8 DRS 392-4: 2018  
3                ©RSB 2018 - All rights reserved  
 Picaridin  
1-(1-methylpropoxycarbonyl) -2-(2-hydroxyethyl) piperidine or 2 -(2-hydroxyethyl) -1-piperidinecarboxylic acid 1 -
methylpropyl ester  
4 Requirements  
4.1 General  
4.1.1 The product shall be in the form of cakes or bars. The colour of the cake or bar shall generally be 
uniform . 
 
4.1.2 The product shall  be formulated as mosquito repellent  and shall be essentially product which ha s 
active ingredient (s) added at a certain level.  
4.1.3 When applied to the skin, it shall not cause any harmful effect and shall provide the benefit of repelling 
mosquitoes . 
4.1.4 The product shall meet all the requirements prescribe d in RS EAS 877. 
4.1.5 All ingredients shall conform to the requirements of RS EAS 377 and shall be declared on the label 
following descending order in terms of quantity.  
4.2 Active ingredients  
4.2.1  Natural repellents  
4.2.1.1  Active ingredients used in natural repellents shall be natura l plant based compounds such as essential 
oils or any other  plant extract approved as mosquito repellents.  
4.2.1.2   
4.2.1.3  The manufacturer  shall provide adequate data on the repellence of such ingredients.  
4.2.1.4  The manufacturer  shall have adequate data justifying the proportion of ingredient(s) for which claims 
are made, used in the product.  
4.2.1.5  The essential oils and other plant extract used in natural repellents shall be, but not limited to:  
a) Cedarwood oil ; 
b) Tea tree oil ; 
c) Geranium oil ; 
d) Rosemary  oil;  
©RSB 2018 - All rights reserved                  4 
 e) Lemongrass oil ; 
f) Citronella oil ; 
g) Eucalyptus oil ;  
h) Cinnamon oil ; and  
i) Neem oil.  
4.1.2.6  The proportion of single or blended essential oil in natural repellent shall be set by the manufacturer in 
accordance with specific standard and records shall be availed.  
4.1.2.7  Pyrethrum extracts such as pyrethrin s shall be considered in natural repellents. The limits of pyrethrin s 
in natural repellents shall not be less than 0.5 % and the extract used shall meet the requirements of RS 191.  
4.2.2  Synthetic repellents  
4.2.2.1  Synthetic repellents shall contain synthetic chemical compounds  as active ingredient (s)  which are 
able to discourage mosquitoes and send them flying or crawling away.  
4.2.2.2  If a synthetic active ingredient  is blended with other active ingredient (s), either natural or synthetic, 
the proportion shall be set by the manufacturer based on scientific research and records shall be availed.  
4.2.2.3  Active ingredients and their content in synthetic repellents shall  meet the requirements prescribed in 
table 1.  
Table 1 – Active ingredients for bathing soap formulated as mosquito repellents  
S/N Ingredients  Limits (%, w/w)  Test methods  
i.  DEET , % w/w.  4 –50  Annex A  
ii.  Picaridin , % w/w 5 – 20  CIPAC 740  
iii.  IR3535 , % w/w 7.5 – 20.07  CIPAC 667  
4.2.2.4  Synthetic repellents and their active ingredients shall be approved and registered by competent 
authority.  
4.3 Specific requirements  
The product shall also comply with the specific quality requirements given in Table 2 when tested I accordance 
with the corresponding test method.  
Table 2 – Specific requirements  
S/N Parameters  Requirements  Test methods  
 Total fatty matter , % by mass, min.  50 RS ISO 685  
1 Total alkalinity (as NaOH) % by mass, 
max.  1.0 ISO 4315  DRS 392-4: 2018  
5                ©RSB 2018 - All rights reserved  
 2 Free caustic  alkali (as NaOH), % by 
mass, max.  0.05 RS ISO 456  
3 Lather, mL, min.  200 RS EAS 877  
 
 4 Mush (loss in mass due mushing on a wet 
surface), g/30cm2, max.  10 
5 Freedom from grittiness  To pass the test  
6 Biodegradability test  To pass test  RS EAS 814  
 
4.4 Biological efficacy  
When tested in accordance with DRS 394 -1, the product shall have repelled 100 % of the mosquitoes from 
landing or climbing on that surface, within  protection time indicated by the manufacturer.  
5 Packaging and label ling 
5.1 Packaging  
The product shall be pack aged in a suitable, well -closed container, to protect the integrity of the product.  
5.2 Labeling  
The container shall be labeled legibly and indelibly with the following information:  
a) name of the product ; 
b) manufacturer’s name and physical add ress;  
NOTE  The name, physical address of the distributor/supplier and trade mark may be added as required.  
c) active ingredient content ; 
d) batch or code number;  
e) net weight;  
f) country of origin;  
g) instructions for use ; 
h) date of manufacture and best before date ; 
i) safety precaution ; 
j) special population  whose exposure is prohibited (out of reach of children  and pregnant women) ; and   
©RSB 2018 - All rights reserved                  6 
 k) storage condition s. 
6 Sampling  
Random samples of the product shall be drawn for test in accordance with RS ISO 24153 from the market, 
factor y or anywhere else . DRS 392-4: 2018  
7                ©RSB 2018 - All rights reserved  
 Annex  A 
(normative)  
 
Determination of DEET content  
A.1 General  
The sample is dissolved in carbon disulfide and the difference in absorbance at 14.18 µm and at 14.48 µm is 
determined. The quantity of meta -isomer is obtained from this value by means  of a calibration curve prepared 
by the use of a reference standard.  
A.2 Apparatus  
A.2.1  Double -beam infrared spectrophotometer. Perkin -Elmer model 21 or equivalent.  
A.2.2  Two equivalent infrared absorption cells, with sodium chloride windows and a path length  of 
approximately 0.4 mm.  
A.3 Preparation of calibration curve  
A.3.1  Weigh (to the nearest 0.1 mg) into four volumetric flasks sufficient amounts of the reference DEET 
standard of known  purity to give concentrations of approximately 20, 40, 60 and 80 g/L when dissolved in carbon 
disulfide.  
A.3.2  Fill the reference cell with carbon disulfide and the sample cell with each of the standard solutions in 
turn, and record the spectra. The spect rum may be scanned rapidly, except for the region 12 – 15 µm, where a 
normal speed should be used. Carry out a blank measurement with carbon disulfide to correct for any inequality 
in the paired cells and to determine whether a cell correction is required.  
A.3.3  Measure the absorbance at 14.18 µm and at 14.48 µm and calculate the difference between these 
value s, ΔA, for each of the solutions. Plot the values of ΔA against the concentration (g/l) of the meta -isomer.  
 
A.3.4  If a cell correction is required, t he value of ΔA is determined from the formula:  
 
  ΔA = [A 14.18 – A14.48]ref. - [A14.48]blank 
 
  where, 
 ref. = determination with reference standard  
blank = determination on CS 2 blank  
 
A.4 Procedure  
Weigh (to the nearest 0.1 mg) about 0.5 g of the sample, transfer quantitatively to a 10 mL volumetric flask, 
and make up to the mark with carbon disulfide. Measure the infrared absorption at 14.18 μm and 14.48 μm 
using the same conditions as described in section A.3. Determine the con centration of meta -isomer by  
©RSB 2018 - All rights reserved                  8 
 comparing this value with the calibration curve. A standard sample should be run each day to check the 
calibration of the instrument.  
A.5 Calculation  
DEET content (g/kg) =𝐶1 𝑥 𝑃 
𝐶2 
where,  
 C1 = concentration (g/L) of standard DEET found from calibration curve  
 C2 = concentration (g/L) of sample taken  
   P = purity (g/kg) of the reference standard.  
  DRS 392-4: 2018  
9                ©RSB 2018 - All rights reserved  
 Bibliography  
[1] USPC/USP Pharmacopeial Forum 2009 (Vol. 35 (3),  Topical and Transdermal Drug P roducts  
[2] Manual on development and use of FAO and WHO specifications for pesticides, November 2010, 2nd 
Edition  
[3] Product Performance Test Guidelines. OPPTS 810.3700: Insect Repellents to be applied to human 
Skin 
 
 DRS 392-4: 2018  
ICS 65.100  
 
 
©RSB 2018 - All right s reserved