Uncoated Implants

Clark et al. (1993) prepared complexes of aromatic aldehydes and PST in an effort to produce stable compositions capable of prolonged release. Various compositions were prepared with 1% (w/w) 2-hydroxy-3-methoxybenzaldehyde, 4-hydroxy-3-methoxybenzaldehyde, or 4-methoxy-benzaldehyde and 99% PST. The isolated complexes were pressed into implants that were injected subcutaneously behind the ear in swine. Table III reports the data obtained during the 21-day study. Pigs treated with a 

Performance of Pigs Treated with Complexed PST-Containing Implants  

PST treatment Average daily gain (kg) Percent, increase over control FIG ratio Percent change fiom control 

Raman and Gray (1994) layered PST, glycerin, and a wax and surfactant blend onto nonpareil seeds in three passes using a fluid-bed coater. These were then compressed into tablets. The in vitro dissolution results indicated some delayed release. 

Sivaramakrishnan (1991) prepared wax and wax/water-insoluble surfactant slabs of the zinc salt of PST/L-arginine (1 1 ratio). The wax and surfactant were melt blended, PST was added, and the mixture was homogenized and quickly cooled. Slabs of bees wax (100%) or a 9010 

---

Chitosan coatings are capable of supporting and enhancing osseointegration similarly to calcium-phosphate-coated and uncoated implants... 

PDMS engineering animals receiving coated implants significantly lower compared to that of uncoated implants, neurite extension of rat pheochromocytoma cells was clearly greater on PVA/PAA IPN films than on PDMS substrates ... 

GBCH-polymers were the first synthetic materials that displayed relatively high thromboresistance. For instance, poly(methyl methacrylate) grafts, having been coated with GBCH and implanted in dog s vena cava, were patent for 14 days, while uncoated PMMA grafts were totally covered with thrombin within the first 2 hours44). 

When a similar plasma polymerization coating was applied on the surface of a memory-expandable stainless steel stent, whose bare surface has notoriously poor blood compatibility, and implanted in a pig without using any drug to suppress blood coagulation, all five coated samples stayed patent, whereas uncoated stents with drug showed partial to total closure [7]. Such a clear-cut result, i.e., 5 out of 5 patency, has been scarcely seen in any animal experiments, which again seems to indicate the superior biocompatibility of imperturbable surfaces created with LCVD coatings. 

Figure 2.4 Formation of a connective tissue capsule separating an uncoated Ti6AI4V surface (right) from the surrounding bone (left) after implantation into the femoral condyle of adult dogs for 6 months (Itiravivong et al., 2003).

To counteract the high corrosion rate of Mg alloy implants electrochemically deposited coatings of fluorine-doped hydroxyapatite (FHAp) and brushite (DCPD) were developed by Bakhsheshi-Rad et al. (2014). As shown in Table 5.2 potentiodynamic polarisation measurements of uncoated and coated Mg-Ca alloys subjected to electrochemical corrosion in Kokubo s SBF (Table 7.8) confirmed the corrosion-resistant nature of the coatings. The anodic polarisation curve of the uncoated specimen shows a breakdown immediately after the... 

---