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Powder Formulations (powder + formulations)
Selected AbstractsAnthrax vaccine powder formulations for nasal mucosal deliveryJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 1 2006Ge Jiang Abstract Anthrax remains a serious threat worldwide as a bioterror agent. A second-generation anthrax vaccine currently under clinical evaluation consists of a recombinant Protective Antigen (rPA) of Bacillus anthracis. We have previously demonstrated that complete protection against inhalational anthrax can be achieved in a rabbit model, by intranasal delivery of a powder rPA formulation. Here we describe the preformulation and formulation development of such powder formulations. The physical stability of rPA was studied in solution as a function of pH and temperature using circular dichroism (CD), and UV-visible absorption and fluorescence spectroscopies. Extensive aggregation of rPA was observed at physiological temperatures. An empirical phase diagram, constructed using a combination of CD and fluorescence data, suggests that rPA is most thermally stable within the pH range of 6,8. To identify potential stabilizers, a library of GRAS excipients was screened using an aggregation sensitive turbidity assay, CD, and fluorescence. Based on these stability profiles, spray freeze-dried (SFD) formulations were prepared at pH 7,8 using trehalose as stabilizer and a CpG-containing oligonucleotide adjuvant. SFD formulations displayed substantial improvement in storage stability over liquid formulations. In combination with noninvasive intranasal delivery, such powder formulations may offer an attractive approach for mass biodefense immunization. © 2005 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 95:80,96, 2006 [source] Stabilization of alum-adjuvanted vaccine dry powder formulations: Mechanism and applicationJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 2 2003Yuh-Fun Maa Abstract Studies were performed to elucidate the mechanism of alum gel coagulation upon freezing and drying and its relationship to vaccine potency loss and to develop a novel freeze-drying process for the production of stable alum-adjuvanted vaccine formulations suitable for conventional needle injection and epidermal powder immunization (EPI). The alum hydroxide-adjuvanted hepatitis-B surface antigen (Alum-HBsAg) and the alum phosphate-adjuvanted diphtheria and tetanus toxoids (Alum-DT) were dehydrated by freeze drying (FD), spray drying (SD), air drying (AD), or spray freeze drying (SFD). After drying by FD, SD, or AD, alum gels coagulated when examined by optical microscopy and particle size analysis. In addition, desorption of antigen molecules from the coagulated when examined by optical microscopy and particle size analysis. In addition, desorption of antigen molecules from the coagulated alum gel upon reconstitution appeared to be difficult, as indicated by attenuated band intensity on SDS-PAGE. In contrast, SFD alum gels turned a homogenous suspension upon reconstitution, suggesting minimal alum coagulation. In the mouse model, the in vivo immunogenicity of SFD Alum-HBsAg was preserved, whereas the FD Alum-HBsAg suffered significant immunogenicity loss. Grinding of coagulated FD Alum-HBsAg into smaller particles could partially recover the immunogenicity. In a guinea pig study using EPI, the SD Alum-DT formulation was not immunogenic, but the SFD Alum-DT formulations had a vaccine potency comparable to that of the untreated DT administered by I.M. injection. Overall, the relationship of coagulation of alum gel upon reconstitution and the loss of vaccine potency was established in this study. Alum gels became highly coagulated after dehydration by spray drying and traditional freeze-drying processes. However, freezing rate played a critical role in preserving the adjuvant effect of alum and fast freezing decreased the tendency of alum coagulation. Spraying the alum gel into liquid nitrogen represents the fastest freezing rate achievable and resulted in no discernible alum coagulation. Therefore, SFD presents a novel and effective drying process for alum-adjuvanted vaccine formulations and is particularly valuable for dry powder applications such as EPI. © 2003 Wiley-Liss, Inc. and the American Pharmaceutical Association J Pharm Sci 92:319,332, 2003 [source] Persistence and metabolism of imidacloprid in different soils of West BengalPEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 7 2001A Sarkar Abstract A laboratory experiment was performed to study the persistence of imidacloprid from two formulations (Confidor 200,g,litre,1 SL and Gaucho 700,g,kg,1 WS), and its metabolism in three different soils (Gangetic alluvial soil of Kalyani, lateritic soil of Jhargram and coastal alkaline soil of Canning) of West Bengal following application at 0.5,kg and 1.0,kg AI,ha,1. Dissipation of imidacloprid in soil followed first-order kinetics and DT50 values ranged from 28.7 to 47.8 days. The shortest half-lives (28.7 and 35.8 days) were observed in the lateritic soil of Jhargram for both liquid and powder formulations. The formation of two metabolites of imidacloprid, imidacloprid-urea and imidacloprid-olefin, was first detected on day 30 of degradation at 28,(±1),°C in all three soils. © 2001 Society of Chemical Industry [source] | ||||||||||