Polymers Blending as Release Modulating Tool in Drug Delivery

Abstract

Different polymeric materials have been used as drug delivery vehicles for decades. Natural, semisynthetic, and synthetic polymers each have their own specific characteristics and, due to the physicochemical limitations of each polymer, tuning the release rate and targeting the active ingredient to a specific organ or site of action is a complicated task for pharmaceutical scientists. In this regard, polymer blending has been considered as an attractive approach to fabricate novel and unique drug delivery systems with modified physical and/or chemical characteristics. There are three major polymer blending approaches that are used for drug delivery purposes: physical mixtures, core-shell model, and block copolymer model. Each of these types of polymer blends could significantly affect the loading capacities and the kinetics of drug release from the relevant formulations. Drug release from these blended polymers can be tuned through the changes in temperature and pH of the environment, and physiochemical properties of the target organs. Furthermore, the possible molecular interactions among polymers and drug molecules can significantly affect the drug release profile from these blended polymeric micro- and nanocarriers. In this review, first of all, different types of polymers and their various applications in biomedical sciences have been discussed and smart or stimuli responsive polymers are introduced and categorized based on their nature. Then, the purpose of polymer blending in drug delivery systems has been discussed. Different types of polymer blends including physical mixtures, core-shell polymeric carriers, and block copolymers have been summarized with focus on the effect of polymer blending on encapsulated drug release profiles. Finally, the consequence of each blending approach on drug release profile and kinetics of drug release have been mentioned in tabular format.

Electrochemically produced local pH changes stimulating (bio)molecule release from pH-switchable electrode-immobilized avidin–biotin systems

“…Many different systems have been researched for the controlled release based on a broad variety of the stimulating input signals (light irradiation, 10 change of temperature 11 or pH values, 12 applications of magnetic field 13 or electric potential, 14 additions of (bio)chemical substances, 15 etc.). Systems for the controlled release based on natural or artificial signal-degradable polymers 1,16 or on electrostatic attractionrepulsion at interfaces 17 have been represented with many studied examples. However, these systems have very low specificity for the loaded and then released substances.…”

Injectable Thermosensitive Hydrogels for a Sustained Release of Iron Nanochelators

“…To evaluate the thermosensitivity of prepared hydrogels, rheological properties such as loss modulus, storage modulus, and viscosity were measured over a temperature ramp from 4 to 40 °C ( Figure 2 ). Since the high content of drugs in thermosensitive hydrogels generally suppresses their thermo‐gelling property, [ 20 ] each corresponding hydrogel without DFO‐NPs (HA; 7%, F127; 30%, and HA/F127; 7/30%) were also tested to confirm the effect of DFO‐NPs on gelation. HA and DFO‐NP/HA showed no significant change in rheological properties as the temperature ramped up (Figure 2a,b ), and the storage and loss moduli stayed below 1000 Pa.…”

Single and Multiple Stimuli-Responsive Polymer Particles for Controlled Drug Delivery

“…Biocompatibility and biodegradability are two other factors that make polymers so favorable [2]. Many polymers have been extensively used in the field of drug delivery [3,4]. The most commonly used biodegradable polymers are poly(lacticco-glycolic) acid (PLGA) and poly (ε-caprolactone) (PCL).…”

“…The most commonly used biodegradable polymers are poly(lacticco-glycolic) acid (PLGA) and poly (ε-caprolactone) (PCL). Whereas the most common non-biodegradable polymers are poly (methyl methacrylate) and polyacrylate [4].…”