DRAFT UGANDA STANDARD  
  DUS 2129  
First E dition  
2019 -mm-dd 
 
 
 Reference number  
DUS 2129: 2019 
© UNBS 2019   
  
Medical u ltrasound gel  — Specification   
 DUS 2129 : 2019  
ii © UNBS 2019  – All rights reserved  
 Compliance with this standard does not, of itself confer immunity from legal obligations  
A Uganda Standard does not purport to include all necessary provisions of a contract. Users are 
responsible for its correct application  
© UNBS 2019  
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilised in any 
form or by any means, electronic or mechanical, including photocopying and microfilm, without prior written 
permission  from UNBS.  
Requests for permission to reproduce this document should be addressed to  
The Executive Director  
Uganda National Bureau of Standards  
P.O. Box 6329  
Kampala  
Uganda  
Tel: +256 41 4 333 2 50/1/2/3  
Fax: +256 41 4 286 123  
E-mail: info@unbs.go.ug  
Web: www.unbs.go.ug  DUS 2129 : 2019  
© UNBS 2019  – All rights reserved  iii 
 Foreword  
Uganda National Bureau of Standards (UNBS) is a parastatal under the Ministry of Trade , Industry and 
Cooperatives established under Cap 327 , of the Laws of Uganda , as amended .  UNBS is mandated to  co-
ordinate the elaboration of standards and is  
(a) a member of International Organisation for Standardisation (ISO) and  
(b) a contact point for the WHO/FAO Codex Alimentarius Commission on Food Standards, and  
(c) the National Enquiry Point on TBT  Agreement  of the  World Trade Organisation (WTO).  
The work of preparing Uganda Standards is carried out through Technical Committees. A Technical 
Committee is established to deliberate on standards in a given field or area and consists of key stakeholders 
including governm ent, academia, consumer groups, private sector and other interested parties.  
Draft Uganda Standards adopted by the Technical Committee are widely circulated to stakeholders and the 
general public for comments. The committee reviews the comments before rec ommending the draft standards 
for approval and declaration as Uganda Standards by the National Standards Council.  
The committee responsible for this document is Technical Committee UNBS /TC 14, Medical devices . DUS 2129 : 2019  
iv © UNBS 2019  – All rights reserved  
 Introduction  
Ultrasound gel or a coupling age nt utilizes a basic physics principle where sound waves tend to carry very well 
through an aqueous or watery medium. When applied to the surface of the patient’s skin, the ultrasound gel 
acts as a coupling medium and enhances the transmission of ultrasonic  sound waves from the skins surface 
to the head of the ultrasound transducer. Ultrasound gel serves as a lubricant and improves the acoustic 
transmission of sound waves to the create the image for the sonographer to examine on the monitor.  
 DRAFT UGANDA STANDARD  DUS  2129 : 2019  
 
© UNBS  2019  – All rights reserved  1 
 Medical u ltrasound gel  — Specification  
1 Scope   
The Draft Uganda standard specifies the requirements, sampling and methods of test of  medical  ultrasound 
gels.  
2 Normative references  
The following referenced documents referred to in the text in such a way that some or a ll of their content 
constitutes requirements of this document. For dated references, only the edition cited applies. For undated 
references, the latest edition of the referenced document (including any amendments) applies.  
FDUS EAS 847 -17, Cosmetic industr y — Analytical methods — Part 17: Determination of pH  
FDUS ISO 21149, Enumeration and detection of aerobic mesophilic bacteria  
ISO 21150, Cosmetics -- Microbiology -- Detection of Escherichia coli  
US 1847:2017, Standard Test Methods for Specific Gravity, A pparent, of Liquid Industrial Chemicals  
US ISO 3104:1994, Petroleum products - Transparent and opaque liquids - Determination of kinematic 
viscosity and calculation of dynamic viscosity  
US ISO 22718 , Cosmetics -- Microbiology -- Detection of Staphylococcu s aureus  
US ISO 2 2717, Cosmetics -- Microbiology -- Detection of Pseudomonas aeruginosa  
US ISO 10993 -1:2003, Biological evaluation of medical devices — Part 1: Evaluation and testing  
3 Terms and definitions  
For the purposes of this document, the following terms and definitions apply. ISO and IEC maintain 
terminological databases for use in standardization at the following addresses: — ISO Online browsing 
platform: available at http://www.iso.org/obp  
3.1  
medical ultrasound gel  
conductive medium that enable s air free bond  between the skin /mucus linings of cavities  and the probe or 
transducer , letting the waves transmit directly to the tissues beneath and to t he parts that need to be imaged.  
3.2  
bacteriostatic  
capable of inhibiting the growth or reproductio n of bacteria . DUS 2129: 2019  
2 © UNBS 2019  – All rights reserved  
 4 Requirements  
4.1 General requirements  
4.1.1 The product shall be a clear viscous gel , free from any foreign matter, sediments and air bubbles . 
4.1.2 The ultrasound gel shall be odourless, bacteriostatic  and non-irritating  when tested in ac cordance with 
US ISO 10993 -1 
4.1.3 The ultrasound gel shall  be free from formaldehyde,  soluble  in water, non -staining and shall not 
damage transducers .  
4.1.4 The sterile ultrasound gel shall be  tested in accordance with Annex A  
4.2 Specific requirements  
The ultrasound  gel shall conform to the requirements specified in Table1 when tested in accordance with the 
test methods prescribed therein.  
Table 1 — Specific requirements  for ultrasound gel  
Characteristic  Requirement  Test method  
pH(neat)  6.5-7.5 FDUS EAS 847-17: 
Density  at 23ºC, g/cm3 0.683 -1.283  US 1847  
Viscosity , Centipoise , min  10,000  US ISO 3104  
 
4.3 Microbiological requirements  
Characteristic  Requirement  Test method  
Sterile  Non sterile  
Total Aerobic Mesophilic Bacteria , Cfu, Max zero 100 FDUS ISO 21149  
Escherichia Coli  Absent  Absent  ISO 21150  
Staphylococcus Aureus  Absent  Absent  US ISO 22718  
Pseudomonas Aeruginosa  Absent  Absent  US ISO 22717  
5 packaging  
The ultrasound gel shall be packaged in suitable containers to ensure stability and prevent contamination  of 
the product  during of transportation, handling and storage . 
6 Labelling  
The package shall be legibly and indelibly marked with the following information:  
a) manufacturer's name and physical address;  
b) product name as “ Medical u ltrasound ge l”; 
c) batch / lot number;  
d) list of ingredients;  DUS 2129 : 2019  
© UNBS 2019  – All rights reserved  3 
 e) net content of the material when packed;  
f) month and year of manufacture and expiry  
g) country of origin;  
h)  storage instructions;  and  
i) warning/ precautions . 
j) For the sterile, it shall be labelled “sterile”.  
8 Sampling  
Sampling shall be done in accordance with annex B DUS 2129: 2019  
4 © UNBS 2019  – All rights reserved  
 Annex  A 
(Normative)  
 
Sterility test  
A.1 Introduction  
The following culture media have been found to be suitable for the test for sterility.  Fluid thioglyc ollate 
medium is primarily intended for the culture of anaerobic bacteria; however, it will also detect aerobic bacteria. 
Soya -bean casein digest medium is suitable for the culture of both fungi and aerobic bacteria.  
A.2 Fluid thioglycollate medium  
L-Cysti ne                    0.5 g   
Agar                      0.75 g  
Sodium chloride                    2.5 g  
Glucose monohydrate/anhydrous               5.5 g/5.0 g  
Yeast extract (water -soluble)                 5.0 g  
Pancreatic digest of casein                  15.0 g 
Sodium thioglycollate or                  0.5 g  
Thioglycollic acid                    0.3 mL  
Resazurin sodium solution (1g/L of resazurin sodium), freshly prepared        1.0 mL  
Water R                      1000 mL  
pH after sterilisation 7.1 ± 0.2  
A.2.1 Mix the L -cystine, agar, sodium chloride, glucose, water -soluble yeast extract and pancreatic digest of 
casein with the water R and heat until solution is effected.  
A.2.2 Dissolve the sodium thioglycollate or thioglycollic acid in the solution and, if necess ary, add 1 M 
sodium hydroxide so that, after sterilisation, the solution will have a pH of 7.1 ± 0.2. If filtration is necessary, 
heat the solution again without boiling and filter while hot through moistened filter paper.  
A.2.3 Add the resazurin sodium  s olution, mix and place the medium in suitable vessels which provide a 
ratio of  surface to depth of medium such that not more than the upper half of the medium  has undergone a 
colour change indicative of oxygen uptake at the end of the  incubation period.  Sterilise using a validated 
process. If the medium is stored, store at a temperature between 2 °C and 25 °C in a sterile, airtight container.  
A.2.4 If more than the upper one -third of the medium has acquired a pink colour, the medium may be 
restored once  by heating the containers in a water -bath or in free - flowing steam until the pink colour 
disappears and cooling quickly, taking care to prevent the introduction of non -sterile air into the container. Do 
not use the medium for a longer storage period than  has been validated.Fluid thioglycollate medium is to be 
incubated at 30 -35 °C.  DUS 2129 : 2019  
© UNBS 2019  – All rights reserved  5 
 A.2.5 For products containing a mercurial preservative that cannot be tested by the membrane -filtration 
method, fluid thioglycollate medium incubated at 20 -25 °C may be used i nstead of soya -bean casein digest 
medium provided that it has been validated as described in growth promotion test.  
A.3 Alternative thioglycollate medium  
Where prescribed or justified and authorised, the following alternative thioglycollate medium may be  used. 
Prepare a mixture having the same composition as that of the fluid thioglycollate medium, but omitting the 
agar and the resazurin sodium solution, sterilise as directed above. The pH after sterilisation is 7.1 ± 0.2. Heat 
in a water -bath prior to us e and incubate at 30 -35 °C under anaerobic conditions.  
A.4 Soya -bean casein digest medium  
Pancreatic digest of casein                  17.0 g  
Papaic digest of soya -bean meal                3.0 g  
Sodium chloride                    5.0 g  
Dipotassium hydrogen phosphate                2.5 g  
Glucose monohydrate/anhydrous               2.5 g/2.3 g  
Water R                      1000 mL  
pH after sterilization  7.3 ± 0.2  
A.4.1 Dissolve the solids in water R, warming slightly to effect solution. Cool the solution to room 
temperature. Add 1 M sodium hydroxide, if necessary, so that after sterilisation the solution will have a pH of 
7.3 ± 0.2.  
A.4.2 Filter, if necessary, to clarify, distribute into suitable vessels and sterilise using a validated process. 
Store at a temperatu re between 2 °C and 25 °C in a sterile well -closed container, unless it is intended for 
immediate use. Do not use the medium for a longer storage period than has been validated. Soya -bean 
casein digest medium is to be incubated at 20 -25 °C.  
The media used  comply with the following tests, carried out before or in parallel with the test on the product to 
be examined.  
A.5 Sterility  
Incubate portions of the media for 14 days. No growth of micro -organisms occurs.  DUS 2129: 2019  
6 © UNBS 2019  – All rights reserved  
 Annex  B 
(Normative)  
 
Sampling  
B.1 General requirements of sampling  
In drawing, preparing, storing and handling samples, the following prec autions and directions shall be 
observed.  
B.1.1 Samples shall be taken in a protected place not exposed to damp a ir, dust or Soot.  
B.1 2 The sampling instrument shall be clean and dry.  
B 1.3 The samples, the material being sampled, the sampling instrument and the containers for samples 
shall be protected from adventitious contamination.  
B.1.4 The samples shall be placed in clean and dry glass containers. The sample containers shall be of a 
size such that they are almost completely filled by the sample.  
B.1.5 Each container shall be sealed air -tight after filling and marked with full details of sampling, batch or 
code number, name of manufacturer, and other important particulars of the consignment.  
B.1.6 The samples shall be stored in such a. manner that the temperature of the material does not vary 
unduly from the normal temperature and they are protected from lig ht.  
B.1.7 Sampling shall be done by a person agreed to between the purchaser and the supplier, and in the 
presence of the purchaser or his representative and the supplier or his representatives.  
B.2 Sampling of packages  
B.2.1 General - The sampling proc edure for packages shall consist essentially in selecting and drawing, a 
sufficient number of unit packs.  
B2.2 Lot - In a single consignment, all the packages containing medical ultrasound gel of the same type 
and form, representing the same batch of manu facture, shall constitute a lot. If the consignment consists of 
packages containing medical  ultrasound gel of different types or forms or batches of manufacture, then the 
packages containing products of the same type, form and batch of manufacture shall be  grouped together; 
each group shall constitute a separate lot.  
B.2.3  Scale of Sampling -For ascertaining the conformity of a lot to the requirements prescribed in the 
specifications for individual medical ultrasound gel  and toilet goods, tests shall be c arried out on each lot 
separately. The number (n) of packages to be selected for drawing the samples shall depend on the size (N) 
of the lot in accordance with Table B.1. 
Table B.1 — Scale of sampling for packages  
No. of packages in the lot(N)  No. of packa ges to be selected,(n)  
 
Upto 3  Each container  
4 to 50  3 
51 to 150  4 
151 to 300  5 
301 to 500  6 
501 and above  7 DUS 2129 : 2019  
© UNBS 2019  – All rights reserved  7 
 B.2.4 The packages shall be selected at random and to ensure randomness of selection, random number 
tables shall be used. In case such tab les are not available, the following procedure may be adopted: ‘Starting 
from any package, count all the packages in one order as 1,2,3 . . . . . . . . . up to r and so on, where r is the 
integral part of N/n.  Every rth package thus counted shall be withd rawn to give a sample for purposes of test  DUS 2129: 2019  
8 © UNBS 2019  – All rights reserved  
 Bibliography  
[1] British Pharmacopoeia , 2015   
[2] Food and Drug Administration  Center for Devices and Radiological Health  DUS 2129: 2019  
© UNBS  2019  – All rights reserved  9 
 Certification marking  
Products that conform to Uganda standards may be marked with Uganda  National Bureau of Standards 
(UNBS) Certification Mark shown in the figure below.  
The use of the UNBS Certification Mark is governed by the Standards Act, and the Regulations made 
thereunder. This mark can be used only by those licensed under the certifi cation mark scheme operated by 
the Uganda National Bureau of Standards and in conjunction with the relevant Uganda Standard. The 
presence of this mark on a product or in relation to a product is an assurance that the goods comply with the 
requirements of t hat standard under a system of supervision, control and testing in accordance with the 
certification mark scheme of the Uganda National Bureau of Standards. UNBS marked products are 
continually checked by UNBS for conformity to that standard.  
Further part iculars of the terms and conditions of licensing may be obtained from the Director, Uganda 
National Bureau of Standards.  
 
 DUS 2129: 2019    
 
ICS 11.120.01  
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