Ultrasound-Assisted Niosome Production for Nanomedicine

Niosomes are nonionic surfactant–based vesicular systems that have gained increasing attention as versatile carriers for bioactive compounds and pharmaceutical agents. Their ability to encapsulate both hydrophilic and lipophilic molecules, combined with favorable biocompatibility and stability, makes them attractive alternatives to liposomes. Ultrasonication plays a central role in the formation and optimization of niosomes, particularly in controlling vesicle size, lamellarity, and encapsulation efficiency.

Niosomes – Improved Formation and Encapsulation with Sonication

Niosomes are vesicular nanocarriers composed primarily of nonionic surfactants (e.g., Span®, Tween®) and cholesterol, which self-assemble into bilayered structures upon hydration. During conventional thin-film hydration, multilamellar vesicles are initially formed, typically exhibiting broad size distributions and limited reproducibility. Ultrasonication is therefore widely applied as a post-formation step to refine vesicle characteristics.
Sonication introduces high-energy acoustic cavitation, generating localized shear forces and microjets that fragment large multilamellar vesicles into smaller, more uniform unilamellar or oligolamellar structures. Multiple studies have demonstrated that probe-type sonication significantly reduces mean particle size into the nanoscale range (typically 150–300 nm) while lowering polydispersity indices below 0.3, indicating improved homogeneity.
Beyond size control, sonication enhances encapsulation efficiency (EE) by improving drug distribution within the bilayer or aqueous core. Lipophilic compounds such as simvastatin, artemisone, and curcumin preferentially partition into the surfactant bilayer, while hydrophilic drugs such as ceftizoxime localize in the aqueous compartments. Optimized sonication times (commonly 4–7 minutes) have been shown to yield EE values exceeding 75–95%, depending on surfactant composition and cholesterol ratio.

Niosomes: Applications in Pharma and Cosmetics

The pharmaceutical relevance of sonicated niosomes is well established across multiple therapeutic areas. In antimicrobial therapy, niosomal encapsulation markedly enhances the efficacy of antibiotics and natural antimicrobials against resistant pathogens. For example, coencapsulation of ceftizoxime and curcumin into niosomes resulted in more than a 64-fold reduction in minimum inhibitory concentrations against multidrug-resistant Staphylococcus aureus and Klebsiella pneumoniae, alongside sustained drug release over 72 hours.

In oncology, niosomes have been shown to improve the therapeutic index of poorly soluble anticancer agents. Artemisoneloaded niosomes exhibited significantly enhanced cytotoxicity toward melanoma cells while reducing toxicity toward normal keratinocytes, a benefit attributed to controlled release and vesiclemediated cellular uptake.

In cosmetic and dermatological applications, niosomes are particularly valuable for topical delivery. Encapsulation of Withania somnifera extracts into niosomes improved skin penetration, protected sensitive phytochemicals from degradation, and enabled controlled release into specific skin layers, supporting applications in antiaging and dermal therapy.

Collectively, these studies demonstrate that ultrasonically optimized niosomes enhance bioavailability, stability, and therapeutic performance across pharmaceutical and cosmetic domains.

Advantages of Probe-Type Sonicators over Ultrasonic Baths for Niosome Production

Although both probe-type and bath-type sonicators rely on acoustic cavitation, they are fundamentally different devices with markedly different performance capabilities. Ultrasonic baths are primarily designed for cleaning and degassing applications, whereas probe-type sonicators function as high-performance homogenizers and therefore offer decisive advantages for efficient and controlled niosome fabrication.
Probe sonicators deliver acoustic energy directly into the sample, resulting in significantly higher power density and more efficient cavitation. This leads to faster vesicle size reduction, improved reproducibility, and superior control over final particle characteristics.

Experimental comparisons indicate that probe sonication achieves smaller vesicle sizes and higher encapsulation efficiencies within minutes, whereas ultrasonic baths often require prolonged exposure and still yield broader size distributions. Furthermore, probe systems allow precise adjustment of amplitude, pulse cycles, and energy input, which is critical for scaling and process optimization.

Another key advantage is consistency. Probetype sonicators minimize batchtobatch variability, a crucial factor for pharmaceutical manufacturing and regulatory compliance. As demonstrated in multiple studies employing Hielscher ultrasonic processors, probe sonication reliably produces nanoscale niosomes with narrow polydispersity and high stability.

Exemplary Step-by-Step Instruction

The following generalized protocol synthesizes best practices reported across the cited studies:

1. Preparation of Organic Phase
   Dissolve the selected nonionic surfactant(s) (e.g., Span 60, Tween 60), cholesterol, and lipophilic drug or bioactive compound in a volatile organic solvent such as chloroform or a chloroform–methanol mixture.
2. Thin-Film Formation
   Remove the solvent under reduced pressure using a rotary evaporator at elevated temperature (≈60 °C) to form a uniform thin lipid film on the flask wall.
3. Hydration
   Hydrate the dried film with an aqueous phase (e.g., phosphate-buffered saline) containing hydrophilic drugs if applicable, under controlled temperature and stirring to produce multilamellar vesicles.
4. Sonication
   Subject the dispersion to probe-type ultrasonication (e.g., 50–200 W, pulsed mode) for 5–7 minutes while cooling to prevent overheating. This step reduces vesicle size and improves encapsulation.
5. Purification and Characterization
   Remove unencapsulated drug via centrifugation or ultrafiltration. Characterize size, polydispersity, zeta potential, and encapsulation efficiency using DLS, TEM, and spectroscopic methods.

This workflow has been successfully applied for antibiotics, anticancer agents, and phytochemicals, yielding stable nanoscale niosomes with high performance.

Get a Sonicator to Make Superior Niosomes!

Ultrasonication is a critical enabling technology for the efficient formation of niosomes and the high-performance encapsulation of drugs and bioactive compounds. Hielscher sonicators allow for superior control over vesicle size, uniformity, and encapsulation efficiency. Evidence from antimicrobial, anticancer, and topical delivery studies consistently demonstrates that ultrasonically optimized niosomes enhance bioavailability, therapeutic efficacy, and stability while reducing toxicity. As formulation science advances toward scalable and reproducible nanocarrier systems, ultrasonic niosome production represents a robust and industrially relevant platform for pharmaceutical and cosmetic applications.

The table below gives you an indication of the approximate processing capacity of our ultrasonicators:

Design, Manufacturing and Consulting – Quality Made in Germany

Hielscher ultrasonicators are well-known for their highest quality and design standards. Robustness and easy operation allow the smooth integration of our ultrasonicators into industrial facilities. Rough conditions and demanding environments are easily handled by Hielscher ultrasonicators.

Hielscher Ultrasonics is an ISO certified company and put special emphasis on high-performance ultrasonicators featuring state-of-the-art technology and user-friendliness. Of course, Hielscher ultrasonicators are CE compliant and meet the requirements of UL, CSA and RoHs.