Thematic area of your work "Nanocomposites and nanomaterials")

Poly-lactic acid/silica composites as potential drug delivery system
Kozakevych R.B., Polyshchuk L.M., Tertykh V.A.
Chuiko Institute of Surface Chemistry of National Academy of Sciences of Ukraine, 17 General Naumov Str., 0316, Kyiv, Ukraine
E-mail: kozakevych@gmail.com

Controlled drug delivery strategies continue to be the most convenient and compliant means of patient treatment. Among the biopolymers used in medical and pharmaceuticals industries these days, polylactide (PLA) is considered as one of the best materials due to its biocompatibility, complete biodegradability and non-toxic nature of degradation products.
Immobilization of sodium diclofenac via impregnation from alcohol solution on poly-lactic acid/silica composites was carried out. Two types of carriers based on silica and biocompatible natural polymer have been synthesized by grafting ring-opening polymerization of L-lactide onto the surface of porous silica (Silochrome) and silica modified with 3-aminopropyltriethoxysilane (Silochrome‑NH2). The L‑lactide oligomer was grafted onto the surface of silica nanoparticles through condensation reaction of L-lactic acid in the presence of stannous octoate catalyst.
In vitro release studies of the prepared biocomposites were executed according to the requirements of the State Pharmacopoeia of Ukraine using the rotating basket method. The diclofenac concentrations in the release liquids were registered spectrophotometrically by measuring the increase in absorbance at 276 nm. The diclofenac release profiles from the composite carriers are presented in Fig.
	
Fig. Release of adsorbed diclofenac from composites Silochrome/PLA (1) and Silochrome-NH2/PLA (2)	
It was demonstrated that release of diclofenac from poly-lactic acid/silica composites can be controlled by means of application of the silica carriers with different surface chemistry.