Preparation of poly(l-lactide) microspheres of different crystalline morphology and effect of crystalline morphology on drug release rate

Izumikawa, Satoshi; Yoshioka, Sumie; Aso, Yukio; Takeda, Yasushi

doi:10.1016/0168-3659(91)90071-k

Cited by 118 publications

(70 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The results suggest that crystallinity of the microspheres decreased throughout the double-emulsion solvent extraction process after the formation of microspheres because the solvent evaporated rapidly in a short time, and the copolymer crystallized and had loose structure in the inner water phase. 16 The two peaks at 2θ=19.9° and 2θ=23.6° in the MAC microspheres were close to the peaks at 2θ=20.1° and 2θ=23.8° in BSA-loaded microspheres, which were also similar to the two peaks in the MAC. Therefore, no new peaks occurred among the three samples, suggesting that their basic crystal structure was not changed when the microspheres formed.…”

Section: Resultssupporting

confidence: 58%

Preparation and properties of BSA-loaded microspheres based on multi-(amino acid) copolymer for protein delivery

Chen

Zhang

et al. 2014

IJN

View full text Add to dashboard Cite

A multi-(amino acid) copolymer (MAC) based on ω-aminocaproic acid, γ-aminobutyric acid, L-alanine, L-lysine, L-glutamate, and hydroxyproline was synthetized, and MAC microspheres encapsulating bovine serum albumin (BSA) were prepared by a double-emulsion solvent extraction method. The experimental results show that various preparation parameters including surfactant ratio of Tween 80 to Span 80, surfactant concentration, benzyl alcohol in the external water phase, and polymer concentration had obvious effects on the particle size, morphology, and encapsulation efficiency of the BSA-loaded microspheres. The sizes of BSA-loaded microspheres ranged from 60.2 μm to 79.7 μm, showing different degrees of porous structure. The encapsulation efficiency of BSA-loaded microspheres also ranged from 38.8% to 50.8%. BSA release from microspheres showed the classic biphasic profile, which was governed by diffusion and polymer erosion. The initial burst release of BSA from microspheres at the first week followed by constant slow release for the next 7 weeks were observed. BSA-loaded microspheres could degrade gradually in phosphate buffered saline buffer with pH value maintained at around 7.1 during 8 weeks incubation, suggesting that microsphere degradation did not cause a dramatic pH drop in phosphate buffered saline buffer because no acidic degradation products were released from the microspheres. Therefore, the MAC microspheres might have great potential as carriers for protein delivery.

show abstract

Section: Resultssupporting

confidence: 58%

Preparation and properties of BSA-loaded microspheres based on multi-(amino acid) copolymer for protein delivery

Chen

Zhang

et al. 2014

IJN

View full text Add to dashboard Cite

show abstract

“…This observation thus suggests that the crystallinity affects the degradation rate and thus the drug-release kinetics. 40 In general, amorphous (non-crystalline) forms of the particles may present faster dissolution rates compared with crystalline forms. 40 Drug release is less rapid in amorphous nanoparticles than in crystalline particles.…”

mentioning

confidence: 99%

“…40 In general, amorphous (non-crystalline) forms of the particles may present faster dissolution rates compared with crystalline forms. 40 Drug release is less rapid in amorphous nanoparticles than in crystalline particles. Lack of crystallinity suggests better drug dispersion and increased drug-matrix interactions, leading to the conclusion that if slow-release kinetic is required, reduced crystallinity is favored, 39 as was achieved in our study.…”

mentioning

confidence: 99%

Preparation, characterization, and optimization of primaquine-loaded solid lipid nanoparticles

Omwoyo¹,

Ogutu²,

Oloo³

et al. 2014

IJN

View full text Add to dashboard Cite

Primaquine (PQ) is one of the most widely used antimalarial drugs and is the only available drug that combats the relapsing form of malaria. PQ use in higher doses is limited by severe tissue toxicity including hematological- and gastrointestinal-related side effects. Nanoformulation of drugs in an appropriate drug carrier system has been extensively studied and shown to have the potential to improve bioavailability, thereby enhancing activity, reducing dose frequency, and subsequently reducing toxicity. The aim of this work was to design, synthesize, and characterize PQ-loaded solid lipid nanoparticles (SLNs) (PQ-SLNs) as a potential drug-delivery system. SLNs were prepared by a modified solvent emulsification evaporation method based on a water-in-oil-in-water (w/o/w) double emulsion. The mean particle size, zeta potential, drug loading, and encapsulation efficiency of the PQ-SLNs were 236 nm, +23 mV, 14%, and 75%, respectively. The zeta potential of the SLNs changed dramatically, from −6.54 mV to +23.0 mV, by binding positively charged chitosan as surface modifier. A spherical morphology of PQ-SLNs was seen by scanning electron microscope. In vitro, release profile depicted a steady drug release over 72 hours. Differential scanning calorimeter thermograms demonstrated presence of drug in drug-loaded nanoparticles along with disappearance of decomposition exotherms, suggesting increased physical stability of drug in prepared formulations. Negligible changes in characteristic peaks of drug in Fourier transform infrared spectra indicated absence of any interaction among the various components entrapped in the nanoparticle formulation. The nanoformulated PQ was 20% more effective as compared with conventional oral dose when tested in Plasmodium berghei -infected Swiss albino mice. This study demonstrated an efficient method of forming a nanomedicine delivery system for antimalarial drugs.

show abstract

“…The peak at 1662 cm −1 appears shifted to 1669 cm −1 , which could be attributed to a weak hydrogen bonding (22). The band intensity increases with the Prg content in membranes.…”

Section: Ftir Spectroscopymentioning

confidence: 90%

“…The controlled release of progesterone can maintain the proper level of drug used in insemination protocols, allowing ovulation synchronization. There are several studies that incorporate progesterone in different polymeric matrices with this purpose (17)(18)(19)(20)(21)(22).…”

Section: Introductionmentioning

confidence: 99%

Modeling of Progesterone Release from Poly(3-Hydroxybutyrate) (PHB) Membranes

et al. 2015

View full text Add to dashboard Cite

Abstract. Poly(3-hydroxybutyrate) (PHB) biodegradable polymeric membranes were evaluated as platform for progesterone (Prg)-controlled release. In the design of new drug delivery systems, it is important to understand the mass transport mechanism involved, as well as predict the process kinetics. Drug release experiments were conducted and the experimental results were evaluated using engineering approaches that were extrapolated to the pharmaceutical field by our research group. Membranes were loaded with different Prg concentrations and characterized by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and Fourier transform infrared spectroscopy (FTIR). SEM images showed that membranes have a dense structure before and after the progesterone addition. DSC and FTIR allowed determining the influence of the therapeutic agent in the membrane properties. The in vitro experiments were performed using two different techniques: (A) returning the sample to the receptor solution (constant volume of the delivery medium) and (B) extracting total volume of the receptor solution. In this work, we present a simple and accurate Blumped^second-order kinetic model. This lumped model considers the different mass transport steps involved in drug release systems. The model fits very well the experimental data using any of the two experimental procedures, in the range 0≤t≤∞ or 0≤M t ≤M ∞ . The drug release analysis using our proposed approaches is relevant for establishing in vitro--in vivo correlations in future tests in animals.

show abstract

Preparation of poly(l-lactide) microspheres of different crystalline morphology and effect of crystalline morphology on drug release rate

Cited by 118 publications

References 9 publications

Preparation and properties of BSA-loaded microspheres based on multi-(amino acid) copolymer for protein delivery

Preparation and properties of BSA-loaded microspheres based on multi-(amino acid) copolymer for protein delivery

Preparation, characterization, and optimization of primaquine-loaded solid lipid nanoparticles

Modeling of Progesterone Release from Poly(3-Hydroxybutyrate) (PHB) Membranes

Contact Info

Product

Resources

About