Biodegradability of a hot‐pressed poly(lactic acid) formulation with controlled release of LH‐RH agonist and its pharmacological influence on rat prostate

Asano, Maszharu; Yoshida, Masaru; Kaetsu, Isao; Imai, Kyoichi; Mashimo, Tooru; Yuasa, Hisako; Yamanaka, Hidetoshi; Suzuki, Kunihiro; Yamazaki, Iwoo

doi:10.1002/marc.1985.030060710

Cited by 52 publications

(14 citation statements)

References 5 publications

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“…Terephthaloyl chloride (2) (Janssen Chimika, 97%) and isophthaloyl chloride (3) (Fluka, > 98%) were purified by recrystallization from dry petroleum ether. A 90% aqueous solution of racemic DL-lactic acid (Fluka) was the starting material for the preparation of an oligolactide (4, M w = 1720 g/mol, M n = 1060 g/mol, M 2 /M n = 1.61) similar to [10]. Poly(bisphenol A terephthalate/isophthalate) (5, M w = 72,100 g/mol, M n = 18,440 g/mol, M w M n = 3.91) was prepared by solution interface polycondensation according to the literature [9].…”

Section: Experimental Materialsmentioning

confidence: 99%

Synthesis of hydrolytically degradable aromatic polyesters with lactide moieties

Haderlein¹,

Schmidt²,

Wendorff³

et al. 1997

Polym. Adv. Technol.

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A synthetic route to higher molecular weight processable polyesters with bisphenol A terephthalate/isophthalate moieties and lactide moieties which are of potential interest for tissue engineering is described. The combination of aliphatic and aromatic moieties is a promising concept for processable polyesters with potential sites for physiological degradation and improved mechanical properties. The molecular structure of the copolyesters prepared by melt condensation via an acid chloride route and incorporation of the lactide moieties by transesterification of an oligo dl‐lactide was confirmed by infrared, 1H and 13C nuclear magnetic resonance spectroscopy as well as gel permeation chromatography. The thermal and mechanical properties of copolyesters with different amounts of lactide moieties are reported and correlated with their composition. The reaction mechanism by transesterification was proved by a model reaction with a physical blend of the components and the hydrolytical behavior of the copolyesters under physiological conditions has been investigated. © 1997 John Wiley & Sons, Ltd.

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Section: Experimental Materialsmentioning

confidence: 99%

Synthesis of hydrolytically degradable aromatic polyesters with lactide moieties

Haderlein¹,

Schmidt²,

Wendorff³

et al. 1997

Polym. Adv. Technol.

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“…The controlled release systems are capable of being targeted to tissue site and to deliver the physiological active agents over a long period of time are of considerable interest, and the use of biodegradable polymers is required to serve as drug carriers [1][2][3][4][5][6][7][8][9][10][11]. Most of biodegradable materials involve either peptide (-CONH-) or ester bonds (-CO0-) in their main chain, so that they can be degraded by the action of enzymes.…”

Section: Introductionmentioning

confidence: 99%

A new biodegradable polydepsipeptide microsphere for application in drug delivery systems

Yoshida

Asano

Kumakura

et al. 1990

Colloid & Polymer Sci

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A sequential polydepsipeptide containing a tripeptide sequence L-alanyl-Lalanyl-~ethyl L-glutamyl and an a-hydmxy acid L-lactic acid, poly(Ala-Ala-Glu(OEt)-. Lac), was synthesized to prepare the microspherical particles by the solvent evaporation process. In this case, the solvents play the most important role for the preparation of polydepsipeptide microspheres and, as an example, when 200 mg of the polydepsipeptide dissolved in 10 ml of 98/2 % chloroform/dichloroacetic acid mixture was stirred at 400 rpm and 30 ~ the microspherical particles with mean diameter of 58 ~ were formed after pouring into 200 ml of 1% (w/v) poly(vinyl alcohol) solution. 17 ~-Estradiol was incorporated into the particles, and the resulting particles were found to contain 5 mg of drug per 25 mg of the particle. The in vivo release of drug from the micmspherical formulation was evaluated by measuring the pharmacological influence on rat prostate. It was found that the sufficient amount of drug, keeping the effective pharmacological influence, is supplied during the first 12-week period, followed by an incomplete supplying of drug intil the implant is perfectly degraded in vivo in the 25th week from the start of implantation.

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“…NMR spectrum of copolyester 5 b (CDCl 3 , 300 MHz)13 C NMR spectrum of copolyester 5 b (CDCl 3 , 75 MHz) pared to molecular weight values are typical for polymers with enhanced stiffness of the backbone.Isothermal pyrolysis of polyester 5 in bulk (M -63, corresponding to 5 b with respect to the ratio of lactide moieties to aromatic moieties but another batch) at 230 for 50 min in vacuum resulted in evaporation of a colorless solid which was identified as DL-lactide. The solid residue was identified as homopolyester 4 00).…”

mentioning

confidence: 99%

“…300 MHz) and13 C NMR spectra (75 MHz) recorded on a Bruker AC 300 and 400. Gel permeation chromatography (GPC) was performed with tetrahydrofuran (THF) as a solvent and UV/RI detection versus polystyrene standards.…”

mentioning

confidence: 99%

Synthesis and properties of liquid crystalline aromatic copolyesters with lactide moieties

Haderlein

Petersen

Schmidt

et al. 1999

Macromol. Chem. Phys.

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High molecular weight liquid crystalline copolyesters were obtained by copolycondensation of aromatic diols and diacyl chlorides with oligolactides. The molecular structure of these copolyesters was verified by NMR studies. The copolyesters form nematic melts, which can be frozen in into a nematic glass. Unexpectedly, a fibrillar structure was observed exclusively on the surface of solution cast films. In spite of a significant content of lactide moieties of the copolyesters their films and fibers are characterized by exceptional mechanical properties. Initial experiments indicated excellent biocompatibility based on cell seeding experiments and microscopic evidence.

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Biodegradability of a hot‐pressed poly(lactic acid) formulation with controlled release of LH‐RH agonist and its pharmacological influence on rat prostate

Cited by 52 publications

References 5 publications

Synthesis of hydrolytically degradable aromatic polyesters with lactide moieties

Synthesis of hydrolytically degradable aromatic polyesters with lactide moieties

A new biodegradable polydepsipeptide microsphere for application in drug delivery systems

Synthesis and properties of liquid crystalline aromatic copolyesters with lactide moieties

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