An appraisal of polymers of DES technology and their impact on drug release kinetics

Bioinspired chitosan based functionalization of biomedical implant surfaces for enhanced hemocompatibility, antioxidation and anticoagulation potential: an in silico and in vitro study

“…If we compare these results with commercially available implants, this degradation rate is comparable to Orsiro cardiac implant [Biotronik Germany] and Ultimaster cardiac implant [Terumo, Japan]. 36 Clinical studies have shown that the Orsiro implant system utilized PLA material as a drug carrier. This PLA material underwent a slow degradation, with approximately 6% degrading within the first 30 days.…”

“…Looking at the drug release patterns of commercially available drug eluting coronary stents, it was found that initial burst release of drug followed by a sustained drug release is necessary for appropriate healing of lesion at target site. 36 The reason is that when medical devices are implanted inside human body, these create a lesion at target side to open the blocked area; hence, creating a lesion at the site which invites a plethora of platelets and growth factors to heal the lesion and can trigger the coagulation cascade leading to the early thrombus formation and device failure. 92 If an anticoagulant is coated on the medical device, it will be able to suppress the early thrombus formation through burst release of drug and once critical window is passed, it will keep releasing the drug in sustained manner.…”

“…34,35 The selection of a suitable drug carrier is a critical step as it works synergistically with the drug to ensure effectiveness of functions of biomedical implants. Looking at commercial coronary implants, initial stents (cypher and taxus) had nondegradable polymeric drug carriers including polyethylene vinyl acetate 36 and poly(styrene-block-isobutylene-blockstyrene), 37 respectively. Aer recognizing the limitations of permanent polymers in rst generation of stents, researchers directed their focus towards biodegradable alternatives.…”

“…Amomg different polymer poly(lactic acid) (PLA) and its derivatives, particularly poly(lactic- co -glycolic acid) (PLGA), poly( l -lactic acid) (PLLA), and poly( d , l -lactic acid) (PDLLA), grabbed the attention due to their biocompatibility, flexibility and degradation properties. 36 These polymers are used in contemporary drug-eluting stents (DES) like orsiro and synergy, which currently dominate the market. A key challenge associated with stents which has PLA is a drug carrier is the discrepancy between degradation time of drug carrier (18–24 months) and the desired drug release window (4–12 months).…”