Evaluating the effects of crystallinity in new biocompatible polyester nanocarriers on drug release behavior

Figures & data

Table 1 Intrinsic viscosity [η], average molecular weight (M_n), and thermal properties of the prepared polyesters

	[η] (dL/g)	Mn (Da)	Tm (°C)	Tg (°C)	Tcc (°C)	ΔHm (J/g)
PPAd	0.57	14,000	43.3	−58.8	−1.1	48.1
PPGlu	0.58	14,000	45.9	−45.0	−	46.0
PPPim	0.70	19,000	44.9	−56.9	−29.6	53.7
PPAz	0.84	25,000	57.1	−46.7	−	65.7

Abbreviations: PPAz, poly(propylene azelate); PPPim, poly(propylene pimalate); PPGlu, poly(propylene glutarate); PPAd, poly(propylene adipate).

Figure 1 Differential scanning calorimetry thermograms of the studied aliphatic polyesters. (A) First scan of polyesters as received and kept at room temperature for 2 months, and (B) a second scan of polyesters after quenching.

Abbreviations: PPAz, poly(propylene azelate); PPPim, poly(propylene pimalate); PPGlu, poly(propylene glutarate); PPAd, poly(propylene adipate).

Figure 2 Wide angle X-ray diffraction patterns of the studied aliphatic polyesters.

Abbreviations: PPAz, poly(propylene azelate); PPPim, poly(propylene pimalate); PPGlu, poly(propylene glutarate); PPAd, poly(propylene adipate).

Table 2 Diffraction angles 2θ for poly(propylene alkanedicarboxylate) crystals

Polyester	Diffraction angle 2θ (degrees)							Degree of crystallinity (%)
PPAz		19.90	22.36	23.98				29.8
PPPim		19.64	21.45	23.09	25.06	26.43	28.67	43.9
PPGlu		20.04	24.70	28.07	30.00	39.62	44.72	55.4
PPAd	18.71	19.90	20.80	22.09	24.14	26.65		67.5

Abbreviations: PPAz, poly(propylene azelate); PPPim, poly(propylene pimalate); PPGlu, poly(propylene glutarate); PPAd, poly(propylene adipate).

Figure 3 Human umbilical vein endothelial cell viability after incubation for 24 hours with different polymers and different polymer concentrations.

Abbreviations: PPAz, poly(propylene azelate); PPPim, poly(propylene pimalate); PPGlu, poly(propylene glutarate); PPAd, poly(propylene adipate); PLA, polylactic acid.

Table 3 Nanoparticle yield, drug loading content, and entrapment efficiency of the polyesters

Polyester	Nanoparticle yield (%)	Drug loading content (%)	Entrapment efficiency (%)	Particle size (nm)
PPAz	36 ± 6	19 ± 4	57 ± 7	228 ± 14
PPPim	28 ± 10	18 ± 3	52 ± 5	192 ± 12
PPGlu	30 ± 12	23 ± 4	61 ± 7	164 ± 12
PPAd	31 ± 8	16 ± 3	49 ± 5	175 ± 15

Note: all measurements were performed in triplicate.

Abbreviations: PPAz, poly(propylene azelate); PPPim, poly(propylene pimalate); PPGlu, poly(propylene glutarate); PPAd, poly(propylene adipate).

Figure 4 Particle size distribution of ropinirole HCl-loaded nanoparticles.

Abbreviations: PPAz, poly(propylene azelate); PPPim, poly(propylene pimalate); PPGlu, poly(propylene glutarate); PPAd, poly(propylene adipate).

Figure 5 Scanning electron micrographs of ropinirole HCl-loaded nanoparticles with the studied polyesters. (A) PPAz; (B) PPPim.

Abbreviations: PPAz, poly(propylene azelate); PPPim, poly(propylene pimalate).

Figure 6 Wide angle X-ray diffraction patterns for ropinirole HCl and ropinirole HCl-loaded nanoparticles.

Abbreviations: PPAz, poly(propylene azelate); PPPim, poly(propylene pimalate); PPGlu, poly(propylene glutarate); PPAd, poly(propylene adipate).

Figure 7 Release profiles for ropinirole HCl from polyester nanoparticles.

Abbreviations: PPAz, poly(propylene azelate); PPPim, poly(propylene pimalate); PPGlu, poly(propylene glutarate); PPAd, poly(propylene adipate). 20