Article Figures & Data
Figures
- Fig. 1.
Biodegradable pasty polymers may be injected through a syringe. These injectable polymers have the potential to be incorporated with drugs and used as site-specific drug-eluting implants.
- Fig. 2.
Preparation of polymers from secondary alcohols on castor oil or 12-hydroxystearic acid. The cyclic monomers used were Ɛ-caprolactone, trimethylene carbonate, or a 6:1 molar ratio of D,L-lactide and glycolide.
- Fig. 3.
Fourier-transform infrared spectroscopy spectra of pasty polymers confirmed polymerization. Characteristic C=O bands between 1746 and 1723 cm−1 were observed for polymers, as well as the disappearance of the characteristic hydroxyl bands in CO and HS.
- Fig. 4.
Viscosity was measured at varying shear rates. Polymers with the highest molecular weight were the most viscous. Any further increase in molecular weight resulted in solid polymers.
- Fig. 5.
Hydrolytic degradation of pasty polymer in each series I–VI was determined in phosphate buffer (pH 7.4) at 37°C. Weight loss was determined by drying the sample at each time point to determine the weight of the polymer.
Tables
- TABLE 1
Six series of polymers were synthesized, each with its own fatty acid: polymer pair
Initiator Polymer Series Indentification CO PCL I CO PTMC II CO PLGA III HS PCL IV HS PTMC V HS PLGA VI - TABLE 2
Molecular weight and fatty acid:polymer ratios of all polymers within series I–VI (Table 1)
Entry Seriesa Initiator:Polymerb Mwc Mnb Viscosityd Flow Behaviore w/w kDa kDa Pa·s 1 I 71:29 3.0 1.3 0.13 Newtonian 2 I 60:40 5.0 1.6 25 Pseudoplastic 3 I 41:59 6.1 2.3 81 Pseudoplastic 4 I 30:70 8.2 3.1 1.1 × 104 Pseudoplastic 5 II 80:20 2.7 1.2 1.2 Newtonian 6 II 68:32 3.1 1.4 1.6 Newtonian 7 II 56:44 3.8 1.7 2.8 Newtonian 8 II 44:56 4.4 2.1 7.4 Newtonian 9 II 23:77 7.2 4.0 63 Newtonian 10 III 92:8 1.9 1.0 0.92 Newtonian 11 III 69:31 2.6 2.3 2.8 Newtonian 12 IV 60:40 3.2 0.50 17 Pseudoplastic 13 IV 50:50 3.5 0.61 33 Pseudoplastic 14 IV 41:59 4.2 0.74 2.5 × 102 Pseudoplastic 15 V 46:54 3.2 0.65 3.0 Newtonian 16 V 24:76 5.8 1.3 35 Newtonian 17 VI 66:34 2.1 0.46 27 Newtonian 18 VI 56:44 2.2 0.53 5.7 Newtonian 19 VI 43:57 2.7 0.70 27 Newtonian GPC, gel permeation chromatography; Mn, number average molecular weight; Mw, weight average molecular weight.
↵a Series number according to the data in Table 1.
↵b The relative amounts (w/w) of fatty acid initiator and polymer as well as the true polymer Mn values were calculated from relative 1H NMR peaks of either component.
↵c Mw was estimated by GPC relative to polystyrene standards and is reported in kilodaltons.
↵d Viscosity at shear rate 0.1 second−1.
↵e Flow behavior from shear rate 0.1–100 second−1.
Data Supplement
- Supplemental Figures -
Figures S1-S19.
- Supplemental Figures -
In this issue
Pasty Biodegradable Polyesters and Polycarbonates
