Microencapsulation Report

A request for proposal has been issued by an international food company seeking a partner to develop an encapsulated method of releasing scents from food and beverage packaging. From InnoCentive:

“The Seeker, a multi-national food and beverage leader, is looking for partners or supplies that may be able to provide a new method of controlling the release of aromas in food and beverage packaging applications. This Challenge requires research organizations and other potential development partners to make proposals to the Seeker. The award for the winning proposal will be the opportunity to engage with this company in a lucrative and valuable contract.”

From the San Antonio news briefs:

“UIW to collaborate on vaccine development

Texas A&M University Health Science Center’s Center for Microencapsulation and Drug Delivery is hosting three students and a science educator from the University of the Incarnate Word. These individuals are trainees, supported with National Institutes of Health American Recovery and Reinvestment Act funds for vaccine development training.

The small business grant recipient is NanoRelease Technologies, a TAMUHSC spin-off company. The NRT trainees are visiting the CMDD to learn about the newest “nano-methods” for vaccine and drug encapsulation.

The work is focused on innovative formulations and purification of unique proteins that may improve delivery and reduce costs for vaccines.

Applications of the technologies include many types of infectious disease vaccines. The ongoing work of NRT is focused on biodefense and diseases that can affect people and livestock, such as brucellosis.”

Materiology is a beautifully illustrated reference book of over 500 materials and their manufacturing processes aimed at architects, designers, and other creative and production-oriented types. Microencapsulation is given a brief treatment in this book, discussing its use in incorporating substances such as anti-microbials and pharmaceuticals into polymers and textiles. A great addition to any personal, institutional, or R&D library, you can buy Materiology on Amazon.

Retin-A Micro

A Dermatology Times article about new drug technologies for treating dermatologic diseases highlights microencapsulation’s use in medicines for treating skin problems. From the article:

“Microencapsulation represents another type of intelligent delivery system that has been used to create a number of new products. By controlling the release rate of such medications as tretinoin (Retina-A Micro, Ortho Dermatologics) or benzoyl peroxide (NeoBenz Micro, Skin Medica), this type of delivery system helps to reduce irritation. Encapsulation of these active ingredients also enables compatibility with another active ingredient applied to the same site, Dr. Fleischer notes.”

“Creating Acanya presented a multitude of challenges because the goals were to optimize the skin tolerability and bioavailability of the two active ingredients while assuring their compatibility and product stability, he adds.

Dr. Dow’s answer to these challenges was to use a microparticle dispersion of benzoyl peroxide, which would optimize deposition in the follicular infundibulum, and propylene glycol as a functional excipient, which (in a low concentration) would provide in situ solubilization of the benzoyl peroxide and targeted delivery to the pilosebaceous apparatus without causing irritation. “

General Mills has collaborated with Martek to produce a microencapsulated omega-3 fatty acid to be used as a food additive. From the press release:

“Developed by General Mills, this technology is anticipated to enhance Martek’s ability to produce high-quality, cost-effective DHA powders for certain food applications, particularly long-shelf life products and applications with sensory and formulation challenges. Under the terms of the agreement, Martek is granted a perpetual and generally exclusive license, with respect to third parties, to the General Mills technology for use with DHA and other polyunsaturated fatty acids. General Mills retains the right to this technology for its own use and exclusively for all uses within some of its core businesses.”

“DHA omega-3 is a long-chain omega-3 fatty acid that serves as a primary building block for the brain and the eyes and supports brain, eye and cardiovascular health throughout life. There is a large and growing body of scientific evidence demonstrating that people of all ages benefit from an adequate supply of DHA omega-3 in their diets. Scientific reviews highlight the importance of DHA omega-3 in proper brain and eye development and function, as well as its importance in cardiovascular health.”

This article on Alternet discusses the particular threat that microencapsulated pesticides pose to honeybees pollinators.  Honeybees, the pollinators of a majority of our agricultural crops, are currently facing a mass die-off due to a number of disputed factors.

In 1974, the U.S. Environmental Protection Agency licensed the nerve gas parathion trapped into nylon bubbles the size of pollen particles.

What makes this microencapsulated formulation more dangerous to bees than the technical material is the very technology of the “time release” microcapsule.

This acutely toxic insecticide, born of chemical warfare, would be on the surface of the flower for several days. The foraging bee, if alive after its visit to the beautiful white flowers of almonds, for example, laden with invisible spheres of asphyxiating gas, would be bringing back to its home pollen and nectar mixed with parathion.

Abstract: This paper compared the performance of ultrafiltration (UF), ultracentrifugation (UC) and microdialysis (MD) for determining the entrapment efficiency (EE) of submicron emulsions (SE) loaded with a model drug, silybin (SB). Also, a novel way was created to evaluate the drug phase distribution of SE. The EE of SEI, SEII and SEIII with a range of particle sizes (109.8, 171.7 and 213.2 nm) and the drug phase distribution of SEII and SEIII were separately determined by the three methods. The EEs of SEI were 99.8%, 91.1%, 84.4% determined by MD, UF, UC, respectively, and the EEs of SEII and SEIII were 99.5%, 86.4%, 72.1% and 99.4%, 84.3%, 66.3%, separately. The accuracy of MD to determine EE of SE is much less than that of UF. Although UC is the fastest and most simple to use, its results are the least reliable. The sequence of the amount of drug in SE is as follows: O/W interface, aqueous phase and oil phase. Over 80% of SB was in the O/W interface of SEII and SEIII individually. The method created is reliable for quantifying the phase distribution of drug in submicron emulsions.

Authors: Xiaoliang Liu;  Yu Zhang;  Xing Tang; Hongyao Zhang

Source: Journal of Microencapsulation, Volume 26, Issue 2 March 2009, pages 180 – 186

Abstract: Mucosal immunization has been suggested to be the best option for preventing Mycobacterium tuberculosis infection. The purpose of this study was to develop albumin microspheres containing Mycobacterium tuberculosis antigens and to determine if oral administration of the microspheres can induce antigen-specific mucosal and systemic immune responses. Albumin microspheres containingMycobacterium tuberculosis dead cells and cell lysate were prepared. The physico-chemical characteristics of the formulations were determined and the microspheres were administered to animal models to evaluate the induction of immune responses to the antigens. The results showed that the particle sizes, zeta potential and dissolution pattern of the microspheres were ideal for oral delivery of vaccines. In vivo studies showed high production of antigen-specific antibody production in serum, nasal, salivary and faecal samples. From the results of the study, it can be concluded that oral administration of Mycobacterium tuberculosis microspheres was successful in inducing antigen-specific systemic and mucosal immune responses.

Authors: Kwame G. Yeboah; Martin J. D’souza

Source: Journal of Microencapsulation, Volume 26, Issue 2 March 2009, pages 166 – 179

Abstract: Polylactide (PLA) and polylactide-co-glycolide (PLGA) particles entrapping rotavirus (strain SA11) were formulated using a solvent evaporation technique. To minimize denaturation of viral antigen during the emulsification process, serum albumin was used as a stabilizer. Use of NaHCO₃ and sucrose during the primary emulsification step resulted in uniform stabilized particles entrapping rotavirus. Sonication during the primary emulsion and homogenization during the secondary emulsion process resulted in particles of sizes 2-8 ?m, whereas nanoparticles were formed when sonication was used during both primary and secondary emulsion processes. Scanning electron and atomic force microscopy showed uniform pores and roughness throughout the polymer particle surface. Single dose oral immunization with 20 ?g of antigen entrapped in PLA particles elicited improved and long-lasting IgA and IgG antibody titer in comparison to the soluble antigen. The study shows results illustrating the usefulness of polymeric microparticles as a potential oral delivery system for rotavirus vaccine.

Authors: Bismita Nayak;  Amulya K. Panda;  Pratima Ray; Alok R. Ray

Source: Journal of Microencapsulation, Volume 26, Issue 2 March 2009 , pages 154 – 165

Abstract: Microencapsulation of model drug, acetylsalicylic acid into bio-based polymer, alginate-pectin matrix has been undertaken in this work to characterize the microcapsules based on their composition. Different proportions of the alginate-pectin solutions prepared with drug were homogenized and atomized using nitrogen gas into 1.0 M calcium chloride solution to form sol-gel microcapsules. Drug loaded microcapsules were dried using microwave energy under vacuum at low temperature. Average particle size of the microcapsules was found to be 90 micron. Scanning electron microscopy graphs and Fourier Transform Infrared Spectroscopy analysis on the microcapsules confirm the presence of drug in the polymer matrix. X-ray diffraction pattern showed that the microstructure was more like an amorphous pattern. Drug release of the microcapsules was tested in three different pH levels of 1.2, 7.4 and 8.2. Slow and controlled release of drug was observed at all the pH levels. Increase in pectin increased the drug release and also the release was more in acidic pH (1.2) as 75.6% for alginate: pectin-20 : 80.

Authors: S. Jaya;  T. D. Durance; R. Wang

Source: Journal of Microencapsulation, Volume 26, Issue 2 March 2009, pages 143 – 153