logo belmatech

Hormone releasing Implantable Devices
For laboratory animals

New implants for sustained release
œstrogen, progesterone, and testosterone

Our implants have been developed by a team of researchers from Liège University, Belgium, with a total of several dozen years of experience in endocrinology, reproductive biology, and hormone-dependent cancers. These researchers founded our company, Belma Technologies, to produce and distribute these devices.

The advanced technology used in Belma implants ensures levels of performance well beyond those of the matrix pellets that have been on the market for decades: constancy of the daily doses released throughout the treatment period and very small inter-implant variations in the doses released.

Implants Belma

Comparison of daily doses released by
Belma implants (blue) and matrix pellets (red) over time

The small inter-individual variations of the Belma implants, which are shown clearly in the opposite graph, ensure more homogeneous experimental results (see graph below) and thus have a decisive potential advantage for the experimenter, namely, the possibility of using a smaller number of animals per protocol for a level of statistical significance identical to that achieved with animals treated with matrix pellets.

Fig 1: The plots correspond to the means ± SD.

Schema Tumeur

Comparative scatter
of experimental results
using Belma implants versus matrix pellets

Fig 2: Melanoma B16K1 tumor weight at sacrifice. Ovariectomized mice (OVX) were treated with Matrix pellets (0.01mg/60 days) or with Belma implants (ME2/60 days).(1) (2)

Nos Implants

Our implants

  • Innovative technology derived from the implants used in human medicine: a cylindrical polymer reservoir surrounded by a membrane ensuring very constant release over time
  • E2, P4, or T released for 1, 2, or 3 months.
  • Devices developed to release daily doses that will produce physiological plasma concentrations in mice and rats (see Tables 1 and 2).
  • Two E2 implants available: The first one (E2) makes it possible to achieve pre-ovulatory plasma concentrations and is used mainly in hormone-dependent cancer animal models to support tumour cell growth. The second one (E2 Light) makes it possible to deliver pro-oestrous doses and is designed for gynaecological models (e.g., endometriosis).

Fig 3: Cross-section of a placebo implant (coloured membrane).

Table 1 :
Plasma concentrations, normal values

  Rat  Mouse
E2 (pg/ml)  2,4 – 145,4  2,4 – 145,4
P4 (ng/ml) 1,2 – 18,4 1,2 – 18,4
T (ng/ml) 0,66 – 5,4 1,7 – 14,4

Table 2 :
Plasma concentrations, values with Belma implants

  Rat  Mouse
Belma E2 (pg/ml) 52 - 108 41,2 - 105,6
Belma E2L (pg/ml)   35,2 - 72,0
Belma P4 (ng/ml) 5,3 – 11,2 3,0 - 5,9
Belma T (ng/ml) 0,9 - 3,7 2,9 - 7,5

Our experienced team is at your disposal to answer your questions and queries regarding the use of our implants and the long-term hormone treatment of laboratory animals.


  1. Pequeux, C. et al. Stromal estrogen receptor-alpha promotes tumor growth by normalizing an increased angiogenesis. Cancer Res 72, 3010–3019 (2012).
  2. Gérard C. et al. Accurate Control of 17β-Estradiol Long-Term Release Increases Reliability and Reproducibility of Preclinical Animal Studies. J Mammary Gland Biol Neoplasia. 2017 Mar;22(1):1-11.

Contact us

by Email :
> Form

by phone: +32 (0)4 366 05 00