In vivo and in vitro release of ivermectin from poly(ortho ester) matrices. I. Crosslinked matrix prepared from ketene acetal end-capped prepolymer

Shih, Chung; Fix, Joseph A.; Seward, R.L.

doi:10.1016/0168-3659(93)90104-d

Cited by 15 publications

(3 citation statements)

References 9 publications

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“…A correlation of the amount of drug remaining in the device with the amount of residual polymer suggested that erosion was a major determinant in the release of ivermectin, as would be expected for a system where ivermectin is chemically bound to the polymer. On the basis of the data obtained, it was concluded that the crosslinked strands are capable of providing canine heartworm profi laxis for more than 6 months [14] . Unfortunately, it was not possible to develop devices that would erode in a predictable and reproducible fashion so that this system was never commercialized.…”

Section: Resultsmentioning

confidence: 97%

“…In this particular instance, the objective was to develop an ivermectin device capable of preventing heartworm infestation in dogs for at least 6 months [14] . Since ivermectin is not stable at 140 -155 ° C, extrusion of strands was not a viable method so that a device based on a crosslinked POE II was developed.…”

Section: Development Of Ivermectin Containing Strands To Prevent Hearmentioning

confidence: 99%

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Poly(Ortho Esters)

Heller¹

2011

Handbook of Biodegradable Polymers

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Section: Resultsmentioning

confidence: 97%

Section: Development Of Ivermectin Containing Strands To Prevent Hearmentioning

confidence: 99%

Poly(Ortho Esters)

Heller¹

2011

Handbook of Biodegradable Polymers

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“…This type of poly(ortho ester) was investigated as a drug delivery system for Ivermectin containing strands to prevent heartworm infestation in dogs using a cross-linked matrix containing a trivalent alcohol as cross-linker (Shih et al 1993 ) . The degradation behavior was not suf fi ciently predictable.…”

Section: Poly(ortho Ester)smentioning

confidence: 99%

Biodegradable Materials

Schroeter¹,

Wildemann²,

Lendlein³

2013

Regenerative Medicine

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The ability of polymers to be degraded in physiological environments makes them interesting candidates for various medical applications. Degradation and metabolisation or excretion of polymeric implants can avoid a second surgery for the removal of an implant. Biodegradable materials can serve as a temporary substitute of the extracellular matrix or as matrix in controlled drug release systems, which both can be utilized in Regenerative Therapies.This chapter gives an overview about polymeric materials established in clinical use such as polyesters, polyurethanes, polyanhydrides, or carbohydrates. It describes further their synthesis and exemplary applications such as surgical sutures. Finally the importance of a continuing development of novel materials for future applications is pointed out, since the number of potential applications in the medical fi eld is expanding rapidly.

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Quantification of free ketene acetals and determination of cure kinetics of poly(ortho ester)s by a facile deuterium labeling method

Shih¹,

Waldron²,

Deeken³

1994

J of Applied Polymer Sci

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SYNOPSISA facile method was developed to quantify unreacted ketene acetals during polymerization of poly(ortho ester)s. The method was based on isotopic (deuterium) labeling of the unreacted ketene acetal groups arising from the diketene acetal monomer, 3,9-diethylidene-2,4,8,10-tetraoxaspiro[5,5]undecane (DETOSU) . In deuterium oxide, free ketene acetals are hydrolyzed to an a-deuterated ester; ortho ester bonds are hydrolyzed to the nondeuterated analog. The relative abundance of the deuterated ester side chain can be quantified by gas chromatography-mass spectrometry (GC-MS) . In the current method, aliquots of a diketene acetal/polyol ( s ) reaction mixture were dissolved (crosslinked polymers swollen) in methylene chloride and excess D20. The diketene acetal/polyol ( s ) reaction mixture was hydrolyzed under mildly acidic conditions to yield pentaerythritol dipropionate ( PDP; hydrolysis product of DETOSU) . PDP was extracted into an organic phase, silylated, and analyzed by GC-MS. Fragments corresponding to the C2H5C~O+ ion (57 a.m.u.) and C2H4DCzO+ ion (58 a.m.u.) were monitored and the quantity of free ketene acetal groups were calculated from the peak areas of the chromatograms. The precision of the method was +0.1%. The accuracy, as compared to a parallel 'H-NMR study, was within 5%. This method permits determination of the cure end-point of a poly (ortho ester) polymerization reaction to within +0.25%. The curing kinetics agreed well with DSC branching/crosslinking measurements.

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In vivo and in vitro release of ivermectin from poly(ortho ester) matrices. I. Crosslinked matrix prepared from ketene acetal end-capped prepolymer

Cited by 15 publications

References 9 publications

Poly(Ortho Esters)

Poly(Ortho Esters)

Biodegradable Materials

Quantification of free ketene acetals and determination of cure kinetics of poly(ortho ester)s by a facile deuterium labeling method

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