In vitro release of GnRH from superfused hypothalami of male rats during pubertal development

1984 ◽  
Vol 104 (4_Supplb) ◽  
pp. S67
Author(s):  
G. BRABANT ◽  
A. K. RAY ◽  
R. GRECH
Keyword(s):  
Pubertal Development ◽  
In Vitro Release ◽  
Male Rats ◽  
Vitro Release

Testosterone regulates the secretion of thyrotrophin-releasing hormone (TRH) and TRH precursor in the rat hypothalamic-pituitary axis

1990 ◽  
Vol 125 (2) ◽  
pp. 263-270 ◽  
Author(s):  
A. E. Pekary ◽  
M. Knoble ◽  
N. H. Garcia ◽  
S. Bhasin ◽  
J. M. Hershman
Keyword(s):  
In Vitro Release ◽  
Serum Levels ◽  
Male Rats ◽  
Testosterone Replacement ◽  
Male Rat ◽  
Posterior Pituitary ◽  
Thyrotrophin Releasing Hormone ◽  
Releasing Hormone ◽  
Vitro Release

ABSTRACT Orchidectomy has been reported to decrease concentrations of thyrotrophin (TSH) in the circulation of male rats without affecting serum levels of thyroid hormones. To understand the mechanism underlying this observation, we have measured the effect of gonadal status on the in-vitro release of TSH-releasing hormone (TRH) by male rat hypothalamic fragments. Because hormone release rates can be affected by changes in the post-translational processing of the hormonal precursors, we have also studied the corresponding changes in the concentrations of TRH and TRH-Gly, a TRH precursor peptide in hypothalamus and pituitary, by radioimmunoassay. We observed a significant decline in the in-vitro release of TRH from incubated hypothalami 1 week after castration, which was quantitatively reversed by testosterone replacement. Concentrations of TRH and TRH-Gly in the posterior pituitary, on the other hand, which derive from neurones of hypothalamic origin, increased significantly with castration and were returned to the normal range by testosterone replacement. We conclude that the primary effect of testosterone is the stimulation of hypothalamic TRH release, resulting in the depletion of TRH and TRH precursors from TRH-containing neurones which project into the median eminence and posterior pituitary. Journal of Endocrinology (1990) 125, 263–270

Characterization, Intestinal Absorption and Pharmacokinetics of Long-Circulating Nanoparticles Loaded with Panaxnotoginseng saponins

2013 ◽  
Vol 662 ◽  
pp. 227-232
Author(s):  
Guo Wei Zhao ◽  
Xu Long Chen ◽  
Xin Li Liang ◽  
Zheng Gen Liao ◽  
Chun Liu Wang ◽  
...  
Keyword(s):  
Zeta Potential ◽  
Oral Administration ◽  
Intestinal Absorption ◽  
In Vitro Release ◽  
Entrapment Efficiency ◽  
Male Rats ◽  
Scanning Calorimetry ◽  
Time Curve ◽  
Vitro Release

The aim of the present study was to increase bioavailability after oral administration. In this study, Panaxnotoginseng saponins (PNS) was entrapped within the long-circulating nanoparticles (LCNs) by the multiple emulsion method. The PNS-LCNs were characterized in terms of size, zeta potential, morphology, thermal properties, drug entrapment efficiency (EE), and in vitro release of the PNS. In addition, the intestinal absorption of PNS-LCNs in vitro was investigated. The pharmacokinetics of PNS-LCNs following oral administration was determined over 72 h in male rats. It was found that the mean particle size and zeta potential of the PNS-LCNs were 147±4.5nm and −44.7±1.5mV, respectively, and the entrapment efficiency (EE) was 53.93%±0.69%. differential scanning calorimetry (DSC) indicated that PNS has different states in PNS-LCNs and original PNS. The release pattern of the PNS-LCNs followed the Weibull model. The release parameters (T50, TD) were observed to be higher for PNS-LCNs compared with original PNS (p< 0.01) in vitro release. The intestinal absorption study indicated that the intestinal permeability coefficient (Papp) of PNS-LCNs was higher than original PNS’s. The pharmacokinetics of PNS-LCNs was studied after oral administration to male rats, PNS-LCNs provided greater area under the concentration-time curve (AUC), higher plasma concentration (Cmax), longer mean residence time (MRT) and median time to maximum drug concentration (Tmax). LCNs could be used for improving permeability and increased bioavailability after oral administration of PNS.

Study on in vitro release patterns of fentanyl-loaded PLGA microspheres

2003 ◽  
Vol 20 (5) ◽  
pp. 569-579 ◽  
Author(s):  
S.-A. Seo ◽  
G. Khang ◽  
J. M. Rhee ◽  
J. Kim ◽  
H. B. Lee
Keyword(s):  
In Vitro Release ◽  
Plga Microspheres ◽  
Vitro Release

Reliability of a Single β-Thromboglobulin Measurement in a Diabetic Population : Importance of PGE1 in Anticoagulant Mixture

1987 ◽  
Vol 57 (02) ◽  
pp. 201-204 ◽  
Author(s):  
P Y Scarabin ◽  
L Strain ◽  
C A Ludlam ◽  
J Jones ◽  
E M Kohner
Keyword(s):  
In Vitro Release ◽  
Mean Value ◽  
Reliable Estimate ◽  
Diabetic Patients ◽  
Single Measurement ◽  
Diabetic Population ◽  
The Difference ◽  
Vitro Release

SummaryDuring the collection of samples for plasma β-thromboglobulin (β-TG) determination, it is well established that artificially high values can be observed due to in-vitro release. To estimate the reliability of a single β-TG measurement, blood samples were collected simultaneously from both arms on two separate occasions in 56 diabetic patients selected for a clinical trial. From each arm, blood was taken into two tubes containing an anticoagulant mixture with (tube A) and without (tube B) PGE!. The overall mean value of B-TG in tube B was 1.14 times higher than in tube A (p <0.01). The markedly large between-arms variation accounted for the most part of within-subject variation in both tubes and was significantly greater in tube B than in tube A. Based on the difference between B-TG values from both arms, the number of subjects with artifically high B-TG values was significantly higher in tube B than in tube A on each occasion (overall rate: 28% and 14% respectively). Estimate of between-occasions variation showed that B-TG levels were relatively stable for each subject between two occasions in each tube. It is concluded that the use of PGEi decreases falsely high B-TG levels, but a single measurement of B-TG does not provide a reliable estimate of the true B-TG value in vivo.

Preparation and In-vitro Evaluation of Fe3O4 Encapsulated by Chitosan Loaded Capecitabine Nanoparticles for the Treatment of Breast Cancer

2016 ◽  
Vol 6 (3) ◽  
Author(s):  
Shanmuganathan S. ◽  
Nigma S. ◽  
Anbarasan B. ◽  
Harika B.
Keyword(s):  
Fe3o4 Nanoparticles ◽  
Polymer Concentration ◽  
In Vitro Release ◽  
Entrapment Efficiency ◽  
In Vitro Evaluation ◽  
Sem Image ◽  
Therapeutic Molecules ◽  
Dialysis Method ◽  
Vitro Release

Nanoparticulate Carriers which is biodegradable, biocompatible and bio adhesive have significant feasible applications for administration of therapeutic molecules. The present study was aimed to formulate and optimise Capecitabine loaded Chitosan-Fe3O4 Nanoparticles and to study the in-vitro evaluation by sigma dialysis method. Capecitabine loaded chitosan – Fe3O4 nanoparticles batches with different ratios of drug: polymer (1:1, 1:2, 1:3, 1:4, 1:5, 1:6) were prepared by ionic gelation method. Increase in polymer concentration increases the nanoparticle drug content. Entrapment efficiency was 60.12% with drug to polymer ratio F3 (1:3). In-vitro release was found to be 65.20% for 12 hrs. Capecitabine from chitosanFe3O4 nanoparticles SEM image reveals discrete spherical structure and particles with size range of 100-500nm. FTIR studies represent the functional groups present with no characteristics change in formulations. Samples stored at refrigerator conditions showed better stability compared with samples kept at other conditions during 8 weeks of storage.

Formulation and In-vitro Evaluation of Chewable Tablets of Montelukast Sodium

2015 ◽  
Vol 5 (3) ◽  
Author(s):  
Laxman Devkota ◽  
Bhupendra Poudel ◽  
Junu Silwal
Keyword(s):  
In Vitro Release ◽  
Magnesium Stearate ◽  
Physical Parameters ◽  
Artificial Sweetener ◽  
Leukotriene Receptor Antagonist ◽  
Montelukast Sodium ◽  
Chewable Tablets ◽  
Leukotriene Receptor ◽  
Vitro Release

The objective of the present study is to develop chewable tablets containing different pharmaceutical compositions with simple manufacturing procedures using different excipients. Mannitols, L-HPC 11, Aspartame, Crospovidone, Crospovidone, Aerosil, and Magnesium Stearate are used as excipients for effective formulation of anti-asthmatic drug Montelukast. Montelukast is a selective, orally acting leukotriene receptor antagonist that is used for the treatment of asthma and seasonal allergic rhinitis. Montelukast chewable tablets were prepared by Direct Compression methods using suitable excipients. The chewable tablets were better presented using artificial sweetener Aspartame as flavouring agent. A total of forteen formulations were prepared and the granules were evaluated for pre-compression parameters. The formulated tablets were evaluated for post-compression parameters .The results showed that all the physical parameters were within the acceptable limits. The in vitro release study of all the formulations showed good release. The study concludes that aforementioned excipients can be used to design chewable montelukast sodium tablets.

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