## 1 Introduction  
Nanoparticles (NPs) based drug delivery systems have considerable potential for treatment of many human diseases. The important technological advantages of nanoparticles used as drug carriers (nanocontainers) are high stability, high carrier capacity, feasibility of encapsulation both--hydrophilic or hydrophobic substances, and feasibility of variable routes of administration, including oral application and inhalation. NPs can also be designed to allow controlled (sustained) drug release from the matrix. These properties of NPs enable improvement of drug bioavailability and reduction of the dosing frequency, as well as to fulfill targeted and controlled administration, and may resolve the problem of nonadherence to prescribed therapy, which is one of the major obstacles in the control of epidemics. A variety of nanoparticulate-based drug delivery systems have been developed: liposomes, dendrimers, \(\beta\)-cyclodextrintrin, various emulsions, and nanospheres [1; 2; 3; 4]. Liposomes and emulsions of liposomes are less popular because of their short shelf life, limited drug capacity, aggressive conditions used for their preparation and problems in sterilization [5]. More promising for drug delivery are nanospheres [4] referred to as nanoparticles (NPs) below. Various degradable and non-degradable polymers of both natural and synthetic origin such as albumin [6, 7], acrylic polymers [8, 9, 10], polystyrene [11], polycyanoacrylates [12], poly(epsilon-caprolactone) [13, 14], poly(lactic acid) [15, 16], to name a few, were used in nanodrug formulations. One can say without exaggeration that preference should be given to NPs made of biodegradable polymers which will be cleared from the body after the fulfillment of their function. The most promising are synthetic biodegradable polymers with low immunogenicity such as poly(caprolactone), poly(lactic acid) and poly(lactic-co-glycolic acid), etc. These polyester class of biomaterials, however, produce acidic products (glycolic and lactic acids with pKa 3.83 and 3.86, accordingly) during degradation that are considered to be toxic and induce undesired phenotype modulation in cells [17]. Besides, polyesters showed lower affinity to living tissues (due to the lack of hydrophilic CO-NH bonds in the backbones) [18] that can decrease the bioavailability of the NPs prepared from this type of polymers. Hence, better candidates for medical and pharmacological applications are biodegradable polymers containing peptide-like CO-NH links in the backbones that increase polymer-tissue affinity and, therefore, particles designed from these polymers are expected to have improved bioavailability. At the same time polyesters show reasonable rate of biodegradation as compared with other hetero-chain polymers such as polyamides, polyurethane and polyureas--The polymers which contain desirable CO-NH links but biodegradable much slowly. Therefore, more promising look hybrids of polyesters with these hetero-chain polymers--Poly(ester amide) (PEAs), poly(ester urethane)s (PEURs), and poly(ester urea)s (PEUs), which combine useful properties of \"parent polymers\"--Polyesters and CO-NH links containing polymers such as polyamides, polyurethane, and polyureas. Especially attractive are the polymers composed of physiological building blocks--Naturally occurring \(\alpha\)-amino acids and other non-toxic building blocks such as fatty diols and dicarboxylic acids, amino-acid-based biodegradable (AABB) polymers [17, 19, 20, 21, 22, 23, 24, 25, 26, 27]. The AABB polymers showed better biocompatibility compared to polyesters [17, 23, 24, 25] along with wider range of material properties and look more promising for sophisticated biomedical applications [17, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30], including the construction of the biodegradable particulates promising as drug delivery containers. The AABB PEAs were successfully used for constructing nanobiocomposites containing bacteriophages along with other medications which showed a high wound healing potential [31, 32].