Sustained activity and release of leuprolide acetate from an in situ forming polymeric implant

Ravivarapu, Harish B.; Moyer, Katie; Dunn, Richard L.

doi:10.1007/bf02830516

Cited by 38 publications

(38 citation statements)

References 14 publications

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“…All of the following methods were previously validated for dogs (Ravivarapu et al 2000;Gallelli et al 2010;Cabrera Blatter et al 2011;Ithurralde et al 2013).…”

Section: Animalsmentioning

confidence: 99%

Plasma ACTH, α-MSH and cortisol variations in the dog during the oestrous cycle in different photoperiods

Gallelli¹,

Monachesi²,

Miceli³

et al. 2015

Vet. Med. - Czech

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ABSTRACT:The hypothalamic-pituitary-adrenal axis (HPA) is a complex system regulated by multiple factors. Sexual dimorphism of this axis has been described in different species under physiological conditions and it has been proposed that sexual hormones could have an effect on it. There are only a few reports about sex-linked variations in HPA axis hormones in the dog. Thus, studying the impact of sexual hormones on the HPA axis would broaden the knowledge about its function in this species. Therefore, the objective of this study was to determine whether there are variations in HPA plasma hormones (ACTH, alfa-melanocyte-stimulating hormone [α-MSH] and cortisol) according to the sex and photoperiod (positive or negative photoperiod were considered when the duration of the light hours of the day was more than 12 or less than 12, respectively) under basal conditions (like anoestrus) and throughout the oestrous cycle in the female dog. The population under study consisted of 11 intact female and 14 intact male dogs. Under basal conditions neither ACTH nor α-MSH concentrations showed differences between sexes and different photoperiods. Cortisol showed greater values in the negative photoperiod than in the positive, both in females and males (P = 0.03 and P = 0.015, respectively). Throughout the oestrous cycle, all the studied hormones showed variations (P < 0.0001). The greatest concentrations of ACTH were observed at proestrus, while α-MSH and cortisol showed their greatest concentrations at oestrus. The three hormones decreased in diestrus. ACTH and cortisol concentrations were higher in the negative photoperiod (P = 0.04 and P < 0.0001, respectively), while α-MSH concentrations were higher in the positive photoperiod (P = 0.012). In the group of females oestradiol and progesterone correlated with ACTH (r = 0.75, P < 0.0001; r = 0.34, P < 0.01, respectively), α-MSH (r = 0.49, P < 0.0001; r = 0.52, P < 0.0001, respectively) and cortisol (r = 0.33, P < 0.01; r = 0.5, P < 0.0001, respectively). These results show that in females, HPA axis hormones vary during the oestrous cycle in relation to oestradiol and progesterone fluctuations. The ACTH, α-MSH and cortisol concentrations also showed differences between photoperiods in females, but only cortisol did so in males. These findings suggest that sexual hormones could have an effect on the HPA axis. Further research needs to be done to fully understand this interaction and the mechanisms involved.

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“…All of the following methods were previously validated for dogs (Ravivarapu et al 2000;Gallelli et al 2010;Cabrera Blatter et al 2011;Ithurralde et al 2013).…”

Section: Animalsmentioning

confidence: 99%

Plasma ACTH, α-MSH and cortisol variations in the dog during the oestrous cycle in different photoperiods

Gallelli¹,

Monachesi²,

Miceli³

et al. 2015

Vet. Med. - Czech

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“…The implant formulation consisted of 45% w/w 75/25 poly(DL-lactide-co-glycolide) (PLG) polymer having an intrinsic viscosity of 0.20 dl/g dissolved in N-methyl-2-pyrrolidone (NMP) and containing 6% w/w leuprolide in the polymer solution. This formulation was designed to release the drug for a period of 3-4 mo after subcutaneous injection (Ravivarapu et al, 2000).…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Remotely Delivered Leuprolide Acetate as a Contraceptive Agent in Female Elk (Cervus Elaphus Nelsoni)

Baker

Wild

Hussain

et al. 2005

Journal of Wildlife Diseases

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Practical application of fertility control technology in free-ranging wild ungulates often requires remote delivery of the contraceptive agent. The objective of this investigation was to evaluate the potential of remote delivery of leuprolide acetate for suppressing fertility in female elk (Cervus elaphus nelsoni). Fifteen captive adult female elk were randomly allocated to one of three experimental groups. Six elk were injected intramuscularly with a dart containing leuprolide, and the remaining nine elk received the same formulation without leuprolide. We determined pregnancy rates, suppression of luteinizing hormone (LH) and progesterone concentrations, and reversibility of treatments during 1 August 2002 to 3 September 2003. Leuprolide formulation caused a decrease in concentrations of LH and progesterone, temporary suppression of ovulation and steroidogenesis, and effective contraception (100%) for one breeding season. These results extend the practical application of this contraceptive agent to include dart delivery, where in the absence of such technology, wild elk must first be captured and restrained before treatment.

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“…N-methyl pyrrolidone is a relatively nontoxic solvent commonly used for solubilization, 20 transdermal drug delivery, 21 and in situ gel formulation. 22 A specific amount (5 mg) of buprenorphine HCl was added to the polymer solution and mixed thoroughly for 60 seconds using a vibrating mixer (Vibra Model 231, Fisher Scientific, Pittsburgh, PA). The resultant drug/polymer solution was transformed into a gel by injecting it into a Spectra-Por dialysis bag containing 1.5 mL of the dissolution medium (Figure 1).…”

Section: Preparation Of In Situ Gelmentioning

confidence: 99%

In vitro dissolution method for evaluation of buprenorphine in situ gel formulation: A technical note

2007

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Sustained activity and release of leuprolide acetate from an in situ forming polymeric implant

Cited by 38 publications

References 14 publications

Plasma ACTH, α-MSH and cortisol variations in the dog during the oestrous cycle in different photoperiods

Plasma ACTH, α-MSH and cortisol variations in the dog during the oestrous cycle in different photoperiods

Evaluation of Remotely Delivered Leuprolide Acetate as a Contraceptive Agent in Female Elk (Cervus Elaphus Nelsoni)

In vitro dissolution method for evaluation of buprenorphine in situ gel formulation: A technical note

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