A Pfizer-supported project in China has developed a sustained-release formulation of recombinant human growth hormone (rhGH). The researchers used microspheres to sustain the release of rhGH and thus create the possibility of less frequent administration.
“These results suggest that rhGH-PELA microspheres have the potential to be clinically effective and safe when administered only once every two months, a dose regimen for better patient acceptance and compliance,” the researchers wrote in the journal Molecular Pharmaceutics .
Pfizer provided the Beijing-based researchers with rhGH for use in the experiments. In rats the use of microspheres extended the release of rhGH for up to 56 days and showed better pharmacological efficacy than daily administration over six days.
“All these results strongly suggested that PELA microspheres, prepared by a combination of traditional and membrane emulsification methods, held great potential as a clinically effective and safe system for sustained delivery of rhGH,” the researchers wrote.
Meanwhile, researchers in South Korea have created siRNA/capsid nanocarrier complexes that show potential for tumour-specific targeting in vivo. The researchers have also increased the stability of siRNA during circulation around the body to extend the lifespan of the therapeutic after delivery.
“The enhanced longevity of siRNA in vivo could be explained by shielding effect derived from the capsid shell, where the encapsulated siRNAs are protected from nucleases in plasma,” the team of researchers wrote in Molecular Pharmaceutics .
By shielding the siRNA from nuclease attack the capsid nanocarriers could increase the longevity of the therapeutic. “Our siRNA delivery system provides an alternative approach to systemically deliver siRNA to the tumour sites as well as to enhance the stability of siRNA in vivo,” the researchers wrote.