Carbomer Hydrogels Enable Crosslinker-Free Microencapsulation for Enhanced Vitamin E Delivery
Đekić, Ljiljana, et al. Pharmaceutics 16.5 (2024): 628.
Challenge: Fabricate non-toxic, crosslinker-free formulations that can maintain the photostability of oxidation-sensitive α-tocopherol (Vitamin E) and deliver desired characteristics of application and release.
Solution: Integrated crosslinker-free chitosan/SLES microcapsules into carbomer hydrogel matrices (0.5-1.0% w/w).
Key Results:
· Microcapsule Integrity Preservation: Maintained structural stability with >95% of chitosan/SLES microcapsules remaining intact after incorporation, confirmed through light microscopy analysis.
· Enhanced Application Properties: Doubled spreadability coverage on skin-mimetic surfaces compared to conventional gels, with simultaneous 40% faster dispersion in artificial sweat medium.
· Controlled release kinetics: diffusion-controlled α-tocopherol release from optimal polymer mesh structure (R² > 0.98) with predictable 24 h release profiles.
· Biocompatibility: Eliminated toxic crosslinking agents such as formaldehyde and glutaraldehyde from the system while maintaining 70.2 ± 3.1% of encapsulation efficiency.
· Stability: Sustained key characteristics of a topical product such as the physiological pH (5.2-5.8) and pseudoplastic rheology (12,500 ± 300 cP, 28.4 Pa, 0.31).
Carbomer-Enhanced Formulation Accelerates Post-Cataract Recovery
Caretti, L., et al. Clinical Ophthalmology (2019): 1157-1163.
Challenge: Address the main complications after cataract surgery are unstable tear film (reduced breakup time), significant ocular discomfort (elevated OSDI scores), and corneal surface damage.
Solution: Developed carbomer-sodium hyaluronate-trehalose (CHT) eye drops leveraging Carbomer's bioadhesive properties for prolonged ocular surface retention, trehalose for cellular protection, and hyaluronate for lubrication.
Key Results:
· Tear Film Stability: 62% greater BUT improvement (P<0.001).
· Symptom Relief: 3x faster OSDI reduction at 7 days (P<0.001).
· Patient Satisfaction: Significantly higher comfort scores (P<0.001).
· Healing Support: Equivalent fluorescein staining reduction.
· Mechanistic Advantage: Carbomer is crucial to prolonged ocular surface residency due to mucoadhesion, synergy with trehalose's water-retention mechanism, and ocular barrier properties to prevent evaporation.
Conclusion: Carbomer-containing CHT preparation has benefits and tolerability in treating dry eye and post-cataract healing. In some metrics (BUT, OSDI), the novel formulation outperforms the standard of care sodium hyaluronate in treatment of ocular irritation and tear film alterations.
Optimization of Hand Sanitizer Formulation Using the Rheological Behavior of Carbomer in Hydroalcoholic Medium
Berardi, Alberto, et al. International Journal of Pharmaceutics 616 (2022): 121503.
Challenge: Making a safe alcohol sanitizer (>60% v/v alcohol) with clear gel using traditional thickeners, as polymers will precipitate in hydroalcoholic medium; Few guidelines on high alcohol solutions.
Investigation: Evaluated Carbomer 974 (C974) and Carbomer 980 (C980) in hydroalcoholic media (50-80% w/w ethanol/isopropanol), neutralized with triethanolamine (TEA) or aminomethyl propanol (AMP). Focus: solvation, transparency, Critical Alcohol Concentration (CAlC - precipitation threshold).
Key Findings:
· Carbomer 980 is superior for ≥50% w/w alcohol formulations, offering better solvation and stability than C974.
· AMP is the preferred neutralizer, enabling significantly higher alcohol content (higher CAlC) before precipitation vs. TEA.
· Isopropanol gels are most challenging: Their CAlC is closer to the 60% v/v disinfectant minimum, making C980 + AMP essential for stability.
· C980 + AMP maximizes tolerance, allowing stable gels up to 80% w/w alcohol.