Preparation of redispersible dry emulsion using Eudragit E100 as both solid carrier and unique emulsifier

Development of spray‐ and freeze‐dried high‐concentration sesamol emulsions and antioxidant evaluation in fibroblasts and UV‐exposed rat skin slices

“…With respect Figure 1 and Table 2 show that HPMC-containing SEOH dry or reconstituted emulsions generally yielded larger droplet size than when SC was used as the excipient, whereas SPAN values were similar. This typical effect of HMPC, a widely used emulsifying agent in the preparation of o/w emulsions, has been reported in many formulations and attributed to the presence of a small lipophilic group in HMPC, which can lead to stronger repulsions between emulsion droplets than when other emulsifiers such as polyvinyl alcohol or polyoxyethylene sorbitan are used [Cui et al, 2007;Ahmed and Aboul-Enein, 2007]. Unlike HPMC, amphiphilic casein derivatives contain non-polar residues able to adsorb at hydrophobic surfaces thus giving low steady-state interfacial tensions [Dickinson, 1999].…”

“…The width of the droplet size distribution was expressed by the SPAN value of Eq. 3 [Pedersen et al, 1998;Cui et al, 2007] The antioxidant effect of emulsions was first evaluated by their ability to reduce the stable free radicals GAL [Papadimitriou et al, 2006] or DPPH [Kourounakis et al, 1999;Molyneux, 2004] at room temperature and the results compared to those of SEOH, Trolox, s and CTR emulsions. In the GAL test, solutions of test compounds in nheptane were incubated in the presence of the radical (1.2 mM) and X-band (9.79 GHz) ESR spectra were timely recorded at 211C (Bruker ESP 300; Karlsruhe, Germany) in 50-mL glass capillaries (Hirschmann Lab., Eberstadt, Germany) sealed at both ends by Critoseal ; time constant, 20.48 ms; modulation amplitude, 0.497 G; scan rate, 2.38 G/s for a sweep width of 100 G. The ESR signals were quantitated by double integration of the simulated GAL spectra (with hyperfine coupling constants: a H1 5 5.64 G and a H2 (4 H) 5 1.26 G) using Winsim software [Dulling, 1994].…”

“…In this latter process, water is ultimately removed by rotary evaporation [Porter et al, 1996], freeze-drying (FD) or spraydrying (SD) [Lladser et al, 1968;BergenstÅ hl, 1996, 2007;Molina and Cadorniga, 1995;Ahmed and Aboul-Einein, 2007], yielding lower particle sizes in the range of 0.3-3 mm [Pedersen et al, 1998;Christensen et al, 2001;Ahmed and Aboul-Enein, 2007]. In dry emulsions, addition of o/w-emulsion ingredients such as sodium caseinate (SC) or hydroxypropyl methylcellulose (HPMC) results in a decrease of interfacial tension that facilitates the emulsification [Pedersen et al, 1998;Cui et al, 2007] and provides spherical but not agglomerated powder particles [Fäldt and BergenstÅ hl, 1996]. The association of HPMC with dextrin, sucrose, colloidal SiO 2 , a-lactose monohydrate, or CaHPO 4 in dry emulsion preparations obtained after SD [Christensen et al, 2001[Christensen et al, , 2002Hansen et al, 2005] or of SC with maltodextrine and/or lactose [Pedersen et al, 1998] resulted in improved physical stabilities of the dry emulsions.…”

“…In recent years, dry forms of emulsions have been developed as improved formulations for pharmaceuticals [Takeuchi et al, 1991;Vyas et al, 1992;Sastre et al, 2004;Harris et al, 2004;Steckel and Brandes, 2004;Hansen et al, 2005;Jang et al, 2006;Cui et al, 2007]. They are based on lipids from which an oil-inwater (o/w) emulsion easily reconstitutes upon aqueous dilution [Farah et al, 1987] or after in vivo adminis-tration [Takeuchi et al, 1991, Jang et al, 2006Ahmed and Aboul-Einein, 2007].…”

Pairwise Polymer Blends for Oral Drug Delivery

“…Five commercially available polymers commonly utilized in drug delivery formulations were selected for the study, along with one newly synthesized cellulose ω‐carboxyalkanoate (CAAdP) that has recently shown substantial promise in ASD formulations (Figure ) . The synthetic polymers E100 and PVP as well as cellulose‐based HPMC are excipients frequently used for ASDs, for example, of the antiviral drug ritonavir . More recently, new commercial ASDs containing HPMCAS have been developed, whereas CMCAB has also shown substantial promise in ASD and other formulations .…”