Goserelin/PLGA solid dispersion used to prepare long-acting microspheres with reduced initial release and reduced fluctuation of drug serum concentration in vivo

THYROID STIMULATORS AND THYROID STIMULATION

Acta Endocrinologica ◽

10.1530/acta.0.0660558 ◽

1971 ◽

Vol 66 (3) ◽

pp. 558-576 ◽

Cited By ~ 15

Author(s):

Gerald Burke

Keyword(s):

Regulatory System ◽

Control Site ◽

Thyroid Cell ◽

Primary Control ◽

Physico Chemical ◽

Site Of Action ◽

Long Acting

ABSTRACT A long-acting thyroid stimulator (LATS), distinct from pituitary thyrotrophin (TSH), is found in the serum of some patients with Graves' disease. Despite the marked physico-chemical and immunologic differences between the two stimulators, both in vivo and in vitro studies indicate that LATS and TSH act on the same thyroidal site(s) and that such stimulation does not require penetration of the thyroid cell. Although resorption of colloid and secretion of thyroid hormone are early responses to both TSH and LATS, available evidence reveals no basic metabolic pathway which must be activated by these hormones in order for iodination reactions to occur. Cyclic 3′, 5′-AMP appears to mediate TSH and LATS effects on iodination reactions but the role of this compound in activating thyroidal intermediary metabolism is less clear. Based on the evidence reviewed herein, it is suggested that the primary site of action of thyroid stimulators is at the cell membrane and that beyond the(se) primary control site(s), there exists a multifaceted regulatory system for thyroid hormonogenesis and cell growth.

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Comparative Powder Characterization and In Vivo Evaluation of Solvent-Wetted and Kneaded L-Sulpiride-Loaded Solid Dispersion

10.26226/morressier.57d6b2b9d462b8028d88d9c2 ◽

2016 ◽

Author(s):

Dong Shik Kim

Keyword(s):

Solid Dispersion ◽

In Vivo Evaluation ◽

Powder Characterization

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Formulation and In Vivo Hypoglycemic Effect of Glipizide Solid Dispersion

Current Drug Delivery ◽

10.2174/156720112801323134 ◽

2012 ◽

Vol 9 (4) ◽

pp. 395-404 ◽

Cited By ~ 1

Author(s):

Gayatri C. Patel ◽

Khusman V. Asodaria ◽

Hetal P. Patel ◽

Dinesh R. Shah

Keyword(s):

Solid Dispersion ◽

Hypoglycemic Effect

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Long-Acting Risperidone Dual Control System: Preparation, Characterization and Evaluation In Vitro and In Vivo

Pharmaceutics ◽

10.3390/pharmaceutics13081210 ◽

2021 ◽

Vol 13 (8) ◽

pp. 1210

Author(s):

Xieguo Yan ◽

Shiqiang Wang ◽

Kaoxiang Sun

Keyword(s):

Drug Loading ◽

Entrapment Efficiency ◽

In Vitro Dissolution ◽

Dissolution Behavior ◽

In Vivo Evaluation ◽

Long Term Treatment ◽

Long Acting

Schizophrenia, a psychiatric disorder, requires long-term treatment; however, large fluctuations in blood drug concentration increase the risk of adverse reactions. We prepared a long-term risperidone (RIS) implantation system that can stabilize RIS release and established in-vitro and in-vivo evaluation systems. Cumulative release, drug loading, and entrapment efficiency were used as evaluation indicators to evaluate the effects of different pore formers, polymer ratios, porogen concentrations, and oil–water ratios on a RIS implant (RIS-IM). We also built a mathematical model to identify the optimized formulation by stepwise regression. We also assessed the crystalline changes, residual solvents, solubility and stability after sterilization, in-vivo polymer degradation, pharmacokinetics, and tissue inflammation in the case of the optimized formulation. The surface of the optimized RIS microspheres was small and hollow with 134.4 ± 3.5 µm particle size, 1.60 SPAN, 46.7% ± 2.3% implant drug loading, and 93.4% entrapment efficiency. The in-vitro dissolution behavior of RIS-IM had zero-order kinetics and stable blood concentration; no lag time was released for over three months. Furthermore, the RIS-IM was not only non-irritating to tissues but also had good biocompatibility and product stability. Long-acting RIS-IMs with microspheres and film coatings can provide a new avenue for treating schizophrenia.

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Development of In Situ Self-Assembly Nanoparticles to Encapsulate Lopinavir and Ritonavir for Long-Acting Subcutaneous Injection

Pharmaceutics ◽

10.3390/pharmaceutics13060904 ◽

2021 ◽

Vol 13 (6) ◽

pp. 904

Author(s):

Irin Tanaudommongkon ◽

Asama Tanaudommongkon ◽

Xiaowei Dong

Keyword(s):

Sustained Release ◽

Trough Concentration ◽

Self Assembly ◽

Subcutaneous Injection ◽

Drug Loading ◽

Entrapment Efficiency ◽

Long Acting

Most antiretroviral medications for human immunodeficiency virus treatment and prevention require high levels of patient adherence, such that medications need to be administered daily without missing doses. Here, a long-acting subcutaneous injection of lopinavir (LPV) in combination with ritonavir (RTV) using in situ self-assembly nanoparticles (ISNPs) was developed to potentially overcome adherence barriers. The ISNP approach can improve the pharmacokinetic profiles of the drugs. The ISNPs were characterized in terms of particle size, drug entrapment efficiency, drug loading, in vitro release study, and in vivo pharmacokinetic study. LPV/RTV ISNPs were 167.8 nm in size, with a polydispersity index of less than 0.35. The entrapment efficiency was over 98% for both LPV and RTV, with drug loadings of 25% LPV and 6.3% RTV. A slow release rate of LPV was observed at about 20% on day 5, followed by a sustained release beyond 14 days. RTV released faster than LPV in the first 5 days and slower than LPV thereafter. LPV trough concentration remained above 160 ng/mL and RTV trough concentration was above 50 ng/mL after 6 days with one subcutaneous injection. Overall, the ISNP-based LPV/RTV injection showed sustained release profiles in both in vitro and in vivo studies.

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Poly(ethylene glycol)-b-poly(1,3-trimethylene carbonate) Amphiphilic Copolymers for Long-Acting Injectables: Synthesis, Non-Acylating Performance and In Vivo Degradation

Molecules ◽

10.3390/molecules26051438 ◽

2021 ◽

Vol 26 (5) ◽

pp. 1438

Author(s):

Silvio Curia ◽

Feifei Ng ◽

Marie-Emérentienne Cagnon ◽

Victor Nicoulin ◽

Adolfo Lopez-Noriega

Keyword(s):

Ethylene Glycol ◽

Ring Opening ◽

Gel Chromatography ◽

Amphiphilic Copolymers ◽

Trimethylene Carbonate ◽

Poly Ethylene Glycol ◽

Poly Ethylene ◽

Long Acting ◽

In Vivo Degradation

This article presents the evaluation of diblock and triblock poly(ethylene glycol)-b-poly(1,3-trimethylene carbonate) amphiphilic copolymers (PEG-PTMCs) as excipients for the formulation of long-acting injectables (LAIs). Copolymers were successfully synthesised through bulk ring-opening polymerisation. The concomitant formation of PTMC homopolymer could not be avoided irrespective of the catalyst amount, but the by-product could easily be removed by gel chromatography. Pure PEG-PTMCs undergo faster erosion in vivo than their corresponding homopolymer. Furthermore, these copolymers show outstanding stability compared to their polyester analogues when formulated with amine-containing reactive drugs, which makes them particularly suitable as LAIs for the sustained release of drugs susceptible to acylation.

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Effect of Long-Acting Thyroid Stimulator on Serum Concentration of Luteinizing Hormone in the Rat

Clinical Science ◽

10.1042/cs0480231 ◽

1975 ◽

Vol 48 (3) ◽

pp. 231-233

Author(s):

P. Dandona ◽

D. J. El Kabir ◽

F. Naftolin ◽

P. C. B. MacKinnon

Keyword(s):

Luteinizing Hormone ◽

Serum Concentration ◽

Pituitary Gland ◽

Immunoglobulin G ◽

Adrenocorticotrophic Hormone ◽

Serum Concentrations ◽

Serum Luteinizing Hormone ◽

Serum Lh ◽

Long Acting ◽

Dexamethasone Suppression

1. The effect of long-acting thyroid stimulator (LATS) on the serum luteinizing hormone (LH) levels of the rat in pro-oestrus has been studied. 2. The injection of three out of four LATS-containing immunoglobulin G fractions caused an increase in amounts of serum LH. 3. Adrenalectomy and dexamethasone suppression did not alter this response. 4. Injection of large doses of adrenocorticotrophic hormone did not produce any increase in serum concentrations of LH. 5. It is postulated that LATS may have a direct effect on the release of LH from the pituitary gland.

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