Dipyridamole‐Loaded Poly(<scp>L</scp>‐lactide) Single Crystals as Drug Delivery Systems

D’Ilario, L.; Francolini, Iolanda; Martinelli, Andrea; Piozzi, Antonella

doi:10.1002/marc.200700224

Cited by 32 publications

(36 citation statements)

References 11 publications

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“…In 1907, Young and Burke 2 established qualitatively that both a prolonged time and an increased temperature of overheating led to a decreased tendency to crystallize during subsequent cooling, based on a large number of melt crystallizations of p-nitrotoluene. In work that followed, these findings were corroborated by observations reported for melts of organic compounds [3][4][5] , metals 6 and polymers 7,8 .…”

Section: Introductionsupporting

confidence: 75%

“…A magnetic stirrer bar was added to each test tube, which was then promptly sealed to prevent solvent evaporation and contamination. The test tubes were then moved directly to a second thermostatic bath at a temperature corresponding to a slight undersaturation with respect to form I (52, 55 or 60 °C) for a controlled period of time (8,30 or >360 min). The temperature levels and time limits are marked with horizontal and vertical lines, respectively, in Figure 3.…”

Section: Cooling Crystallizationsmentioning

confidence: 99%

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Influence of Solution Thermal and Structural History on the Nucleation of m-Hydroxybenzoic Acid Polymorphs

Nordström

Svärd

Malmberg

et al. 2012

Crystal Growth & Design

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The influence of solution pre-treatment on primary nucleation of m-hydroxybenzoic acid has been investigated through 550 cooling crystallization experiments. The metastable zone width has been determined at constant cooling rate and the time and temperature of the preceding superheating step have been varied. m-Hydroxybenzoic acid has two polymorphs and the influence of the polymorph used to prepare the solutions has also been investigated. There is an overall tendency in the experiments for the solution to exhibit a larger metastable zone width if it is superheated for a longer time and at a higher temperature, but under the investigated conditions this tendency is not very strong. The results show that the metastable form II preferentially crystallizes in all experiments and in particular when the solution has been more strongly superheated for several hours. However, when the time and/or the temperature of superheating is reduced there is an increasing tendency to obtain the stable form I. This is most clearly found for solutions prepared by dissolving form I. When the solutions are prepared by dissolution of form II, this tendency is weaker in what appears to be a systematic way. It is hypothesized that, unless the solution is strongly superheated for several hours, it will contain for a significant period of time clusters of solute molecules which can retain some degree of structure from the dissolved crystal. This leads to "memory" effects in the solution which may influence subsequent nucleation. The work includes a comprehensive review of previous published work on the influence of thermal history on nucleation in solutions and melts.

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Section: Introductionsupporting

confidence: 75%

Section: Cooling Crystallizationsmentioning

confidence: 99%

Influence of Solution Thermal and Structural History on the Nucleation of m-Hydroxybenzoic Acid Polymorphs

Nordström

Svärd

Malmberg

et al. 2012

Crystal Growth & Design

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“…Scanning force microscopy (SFM) images of the surfaces of PEO crystals revealed oriented fibril-like growth with increasing annealing temperature [15]. Recently, polymer single crystals and highly ordered structures have been employed in distinct potential applications including programmable assembly of nanoparticles [16], mimicking the natural bone nanostructures [17], magnetically recyclable catalyst support [18][19][20][21][22], templates to synthesize nanoparticle clusters [23,24], substrates for anisotropic deposition of Au nanoparticles [25], utilizable in semiconductor microelectronics and solid-state [26,27], ultrathin film systems [28], delivery systems for human papilloma virus-associated tumors [29][30][31], nano/micromotors [32,33], and photovoltaic devices [34].…”

Section: Introductionmentioning

confidence: 99%

Fine fibrillar and rectangular/hexagonal ordered grains of poly(3-hexyl thiophene) and poly(ethylene glycol) developed by seeding technique

et al. 2016

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The fibrillar poly(3-hexyl thiophene) single crystals were prepared from dilute solutions of toluene, xylene, and anisole (0.01 wt%), and were investigated from the perspective of structural properties. Next, the rectangular and hexagonal poly(ethylene glycol) single crystals were developed from the dilute solutions and molten thin polymer films. The developing methodology used for all growth systems was self-seeding. The dimensions of fibrillar and rectangular/hexagonal single crystals ranged from several nanometers to some microns. Random single-co-crystals were also grown from dilute solution (0.018 wt% in amyl acetate) of crystalline-amorphous diblock copolymers and homopolymers. The small-angle X-ray scattering, grazing incidence wide-angle X-ray scattering, and atomic force microscopy analyses were employed to characterize prepared grained samples. The incident X-ray experiments demonstrated highly ordered and lamellar crystalline structures.

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“…19 Briefly, PLLA was purified and crystallized from 0.25% (w/v) p-xylene solution at a T c of 90°C according to the procedure described by Iwata and Doi. 22 At the end of crystallization, the single crystals were collected by centrifugation and repeatedly washed first with cold p-xylene and then with ethanol, in which they were finally suspended.…”

Section: Preparation Of Plla Sc and Surface Aminolysis Reactionmentioning

confidence: 99%

“…17,18 This investigation explores the use of pristine and surface amino-functionalized lamellar poly(l-lactide) single crystals (PLLA sc and APLLA sc , respectively), possessing a two-dimensional microsized, one-dimensional nanosized lamellar morphology, as a delivery system for an Escherichia coli-expressed HPV16-E7. 19,20 The chemical and physicochemical properties of PLLA sc and APLLA sc were analyzed. The polymer lamellae were adsorbed with the E7 tumor antigen.…”

Section: Introductionmentioning

confidence: 99%

Amino-functionalized poly(L-lactide) lamellar single crystals as a valuable substrate for delivery of HPV16-E7 tumor antigen in vaccine development

Bonito¹,

Petrone²,

Casini³

et al. 2015

IJN

Self Cite

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Background Poly( l -lactide) (PLLA) is a biodegradable polymer currently used in many biomedical applications, including the production of resorbable surgical devices, porous scaffolds for tissue engineering, nanoparticles and microparticles for the controlled release of drugs or antigens. The surfaces of lamellar PLLA single crystals (PLLA sc ) were provided with amino groups by reaction with a multifunctional amine and used to adsorb an Escherichia coli -produced human papillomavirus (HPV)16-E7 protein to evaluate its possible use in antigen delivery for vaccine development. Methods PLLA single crystals were made to react with tetraethylenepentamine to obtain amino-functionalized PLLA single crystals (APLLA sc ). Pristine and amino-functionalized PLLA sc showed a two-dimensional microsized and one-dimensional nanosized lamellar morphology, with a lateral dimension of about 15–20 μm, a thickness of about 12 nm, and a surface specific area of about 130 m 2 /g. Both particles were characterized and loaded with HPV16-E7 before being administered to C57BL/6 mice for immunogenicity studies. The E7-specific humoral-mediated and cell-mediated immune response as well as tumor protective immunity were analyzed in mice challenged with TC-1 cancer cells. Results Pristine and amino-functionalized PLLA sc adsorbed similar amounts of E7 protein, but in protein-release experiments E7-PLLA sc released a higher amount of protein than E7-APLLA sc . When the complexes were dried for observation by scanning electron microscopy, both samples showed a compact layer, but E7-APLLA sc showed greater roughness than E7-PLLA sc . Immunization experiments in mice showed that E7-APLLA sc induced a stronger E7-specific immune response when compared with E7-PLLA sc . Immunoglobulin G isotyping and interferon gamma analysis suggested a mixed Th1/Th2 immune response in both E7-PLLA sc -immunized and E7-APLLA sc -immunized mice. However, only the mice receiving E7-APLLA sc were fully protected from TC-1 tumor growth after three doses of vaccine. Conclusion Our results show that APLLA single crystals improve the immunogenicity of HPV16-E7 and indicate that E7-APLLA sc could be used for development of an HPV16 therapeutic vaccine against HPV16-related tumors.

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Dipyridamole‐Loaded Poly(L‐lactide) Single Crystals as Drug Delivery Systems

Cited by 32 publications

References 11 publications

Influence of Solution Thermal and Structural History on the Nucleation of m-Hydroxybenzoic Acid Polymorphs

Influence of Solution Thermal and Structural History on the Nucleation of m-Hydroxybenzoic Acid Polymorphs

Fine fibrillar and rectangular/hexagonal ordered grains of poly(3-hexyl thiophene) and poly(ethylene glycol) developed by seeding technique

Amino-functionalized poly(L-lactide) lamellar single crystals as a valuable substrate for delivery of HPV16-E7 tumor antigen in vaccine development

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