FORMULATING 95
shares a similar, if not more acute, vulnerability to hydrolysis and radical-mediated degradation in liquid environments.
Retinoid preservation Retinol and its derivatives are highly susceptible to degradation by light, oxygen, and heat. Commercial liquid serums often show significant potency loss; one analysis revealed that retinol concentration in serum products decreased by 25–79% over 30 days of storage, particularly when exposed to light.8 Retinol consists of a ß-ionone ring and a
polyprenoid side chain with conjugated double bonds, making it a prime target for reactive oxygen species (ROS). In liquid formulations, water acts as a
plasticizer, increasing molecular mobility and allowing oxygen to diffuse rapidly to the retinol molecule, leading to faster degradation. Freeze- drying mitigates this by removing the solvent medium, thereby immobilizing the reactants.9
Formulation science: The ‘Lyophilized Bead’ format Beyond bulk powders, lyophilization enables the fabrication of precise, spherical unit doses known as ‘Lyophilized Beads’ or spheres. These are manufactured for example by dispensing liquid droplets into cryogenic fluids, e.g. liquid nitrogen, to flash-freeze them, followed by lyophilization. These beads are structurally robust yet
dissolve instantly due to their high surface area. They allow for the encapsulation of exact dosages of high-value actives, minimizing waste and ensuring consistency. Successful lyophilization of these beads
requires a robust support matrix, with mannitol playing a pivotal role as a structural architect. Unlike amorphous stabilizers, mannitol is a preferred bulking agent that readily crystallizes during the freezing phase. This crystallization creates a rigid, skeletal lattice that supports the cake, preventing macroscopic collapse and ensuring the physical integrity of the dried bead.10 Furthermore, mannitol is chemically inert and
non-hygroscopic, properties that contribute to the long-term stability of the formulation. In the context of cosmetic applications, it is particularly prized for its ability to dissolve instantaneously upon wetting, imparting a desirable cooling sensation to the skin.
Clinical evaluation of Retin+ beads To validate the theoretical advantages of lyophilized retinol in a relevant environment, a clinical study was conducted on Retin+ beads, which contain Hydroxypinacolone Retinoate (HPR) and retinol, which have been developed and manufactured by MedSkin Solutions Dr. Suwelack AG.
Study design and methodology The study was an open, prospective clinical study conducted over 12 weeks (84 days) with 34 female subjects, aged 34 to 65 years (mean age 53), presenting with signs of ageing including lack of firmness and radiance.
www.personalcaremagazine.com Day 0 Mean ■ Day 84 Mean ■ 1.000.000 100.000 10.000 1.000 100 10 1 0.20 0 Total area Count Figure 1: Skin roughness parameters at D0 and D84 (VISIA-CR) Day 0 Mean ■ Day 84 Mean ■ 0.8 0.7 0.6 -12% (S) 0.51 0.5 0.44 0.4 0.3 0.2 0.44 +24% (S) 0.33 0.27 (NS) 0.35 0.35 (NS) 0.47 (NS) 0.64 0.63 Score 0.19 88.869 vs D0 D84: -7.7% (S) 82.028.67 vs D0 D84: -6.3% (S) vs D0 D84: -5.0% (NS)
3.877.67
3.633.33
(Final Distension) Uf
(Recover Rate) Ua/Uf
(Elastic Rate) Ur/Ue
(Visco-elasticity) Uv/Ue
Figure 2: Biomechanical properties –results at D0 and D84 (Cutometer) After a wash-out period, subjects applied
the investigational product (Retin+ beads mixed with water) to the whole face. The application frequency was every three days for the first two weeks (D0–D13), increasing to every 2 days from D14 to D83. A standardized auxiliary moisturizer was applied twice daily, with no other cosmetic products or soaps allowed. Instrumental evaluations were performed at Day 0 (Baseline), Day 14, and Day 84 for skin radiance, which was analysed using VISIA-CR high-resolution photography and specific image analysis algorithms (QIMA Newtone) for parameters including L* (lightness), b* (yellowness), and gloss. Skin texture/roughness was analysed via VISIA-CR image analysis. Biomechanics (firmness) was measured using
a Cutometer™ MPA 580 to assess viscoelastic properties.
(Elastic Recover) Ur/Uf
Clinical results The results of the study demonstrated statistically significant improvements across multiple parameters of skin ageing, confirming the efficacy of the lyophilized retinol bead format.
Skin smoothing and texture Image analysis revealed a significant improvement in skin texture. By Day 84, there was a statistically significant favourable decrease in the total area (-8%) and Count (-6%) of roughness parameters compared to baseline (p<0.05) (Figure 1). This indicates a measurable smoothing effect,
likely attributable to the accelerated cell turnover promoted by the potent retinol delivered via the spheres. Further analysis using Haralick indicators (skin smoothness (contrast) and skin texture regularity (entropy)) confirmed this trend, showing a combined improvement in visual smoothness and texture regularity, with over 70% of subjects
March 2026 PERSONAL CARE MAGAZINE
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