Excipients used in nano-sized liposomes also offer opportunity, "The pharmaceutical industry has made overtures toward the
use of liposomes (or 60 nanometer-sized emulsion droplets) as delivery systems but has yet to accept them fully," reports
the BCC Research study. "That acceptance has been stalled, in part because of the lack of precise scientific data on the exact
role of lipid-based excipients (oleochemicals) and their influence on adsorption of the drug." The excipients are used to
stabilize the liposomes (1).
In addition, fatty acids, alcohols, esters, and ethers are being considered as excipients for nanoparticle matrices. "Minimal
amounts of excipients are being used in vivo nanoparticle formulations with similar or enhanced immunogenicity in comparison to that of alum," according to the BCC Research
study (1).
A case in point is the work of researchers at Novartis Vaccines and Diagnostics (Emeryville, CA), who developed a lyophilized nanoparticle formulation that suspends the small amount of excipients used
(sucrose and mannitol or dioctyl sodium sulfosuccinate with trehalose and mannitol) in polyvinyl alcohol. The formulation
also contains adsorbed protein antigen (1, 3).
Calcium phosphate is also being considered as a replacement for aluminum salts, an US Food and Drug Administration-approved adjuvant for vaccines. BioSante Pharmaceuticals (Lincolnshire, IL) uses the excipient in its "CaP" nanotechnology. The company has completed Phase I of a clinical trial
on the technology as a vaccine adjuvant and a delivery system. Preclinical results indicate that the CaP nanotechnology also
performs well when injected as a facial-line filler. BioSante plans to initiate clinical tests of the technology in 2008 (1).
References
1. "Excipients in Pharmaceuticals," Report No. PHM010E, BCC Research (Norwalk, CT, 2006).
2. P. Van Arnum, "BASF Advances Nanocoating for Ibuprofen Formulation," Pharm. Technol. 30 (6), 48 (2006).
3. K. O Hagan et al., "A Practical Approach to the Use of Nanoparticles for Vaccine Delivery, J. Pharm. Sci. 95 (12), 2738–2750 (2006).
For analysis and trends in the excipient market, see the article "Measuring Excipient-Market Growth" in the April 2008 issue of Pharmaceutical Technology.
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