In-vivo biodegradation of extruded lipid implants in rabbits

Implants as Sustained Release Delivery Devices for Vaccine Antigens

“…In addition, granuloma formation or increased vascularization may occur. Fibrous capsule formation was also reported by Sax et al for implants prepared from a mixture of high and low melting point lipids (Sax et al 2012b ). Cardamone et al observed some local foreign body responses to their implant, however, the authors concluded that this response may be benefi cial for vaccination (Cardamone et al 1997 ).…”

“…This results in the observation of a decrease in drug release; a constant drug release profi le can therefore not be achieved using these systems. Also, the time required for biodegradation depends heavily on the choice of lipid and the manufacturing technique (Schwab et al 2009 ;Sax et al 2012b ). Sax et al for example, observed that surprisingly, implants prepared by twin screw extrusion from a mixture of a high melting lipid (D118), a low melting lipid (H12 or E85), and a pore-forming agent (PEG 6000) showed biodegradability when tested in vivo in a rabbit model for over 6 months (Sax et al 2012b ).…”

“…Also, the time required for biodegradation depends heavily on the choice of lipid and the manufacturing technique (Schwab et al 2009 ;Sax et al 2012b ). Sax et al for example, observed that surprisingly, implants prepared by twin screw extrusion from a mixture of a high melting lipid (D118), a low melting lipid (H12 or E85), and a pore-forming agent (PEG 6000) showed biodegradability when tested in vivo in a rabbit model for over 6 months (Sax et al 2012b ). Compressed implants of D118 however stayed intact for more than 4 weeks (Schwab et al 2008 ) and no macroscopic encapsulation was visible after surgical removal.…”

Composites of fatty acids and ceramic powders are versatile biomaterials for personalized implants and controlled release of pharmaceuticals

“…It may be possible to formulate similar lipid/ceramic matrices with other solid lipids found naturally in the human body. Implantable matrices based on cholesterol, phospholipids and triglycerides have been extensively and successfully explored for sustained release of pharmaceuticals [32][33][34], but as far as we know not for structurally loaded or larger implants. These studies with pharmaceutical release devices support our findings that solid lipid implants are biocompatible and further indicate that the resorption rates and drug release rates can be controlled by varying the lipid composition.…”

Fasudil Loaded PLGA Microspheres as Potential Intravitreal Depot Formulation for Glaucoma Therapy

“…Moreover, spray-drying the microspheres in a nonaqueous system or the manufacture of microspheres using microfluidics could significantly improve the encapsulation efficiency [46]. A completely different approach could be the covalent attachment of fasudil to polyacid poly(L-glutamic acid) based layer-by-layer thin films [75]; or the use of lipid based implants manufactured by compression or extrusion [76,77]. Alternatively, a more lipophilic and potent ROCK inhibitor such as netarsudil could be used, which would be more easily encapsulated into lipophilic polymers such as PLGA and achieve similar efficacy with a lower dose.…”