Acute Kidney Injury in COVID-19.

COVID-19 is mainly considered a respiratory illness, but since SARS-CoV-2 uses the angiotensin converting enzyme 2 receptor (ACE2) to enter human cells, the kidney is also a target of the viral infection. Acute kidney injury (AKI) is the most alarming condition in COVID-19 patients. Recent studies have confirmed the direct entry of SARS-CoV-2 into the renal cells, namely podocytes and proximal tubular cells, but this is not the only pathomechanism of kidney damage. Hypovolemia, cytokine storm and collapsing glomerulopathy also play an important role. An increasing number of papers suggest a strong association between AKI development and higher mortality in COVID-19 patients, hence our interest in the matter. Although knowledge about the role of kidneys in SARS-CoV-2 infection is changing dynamically and is yet to be fully investigated, we present an insight into the possible pathomechanisms of AKI in COVID-19, its clinical features, risk factors, impact on hospitalization and possible ways for its management via renal replacement therapy.

Dosage form development, in vitro release kinetics, and in vitro-in vivo correlation for leuprolide released from an implantable multi-reservoir array.

PURPOSE: Implanted multi-reservoir arrays improve dosing control relative to osmotic pumps or polymer depots. The limited reservoir volume requires concentrated formulations. This report describes the development of a stable solid phase formulation of leuprolide acetate for chronic in vivo delivery from a multi-reservoir microchip and examines the correlation between in vitro release kinetics and serum pharmacokinetics. MATERIALS AND METHODS: Concentrated formulations (>10% w/v) were prepared using small volume processing methods. Drug yield, release kinetics, and formulation stability were evaluated in vitro by HPLC. The correlation between in vitro and in vivo kinetic data was determined for a solid formulation by direct comparison of data sets and using absorption kinetics calculated from the Wagner-Nelson equation. RESULTS: High yield and the control of release kinetics by altering peptide formulation or reservoir geometry were demonstrated. Lyophilized leuprolide in a soluble solid matrix exhibited reproducible release kinetics and was stable (>95% leuprolide monomer) after 6 months at 37 degrees C. A strong correlation was found between in vitro release kinetics and in vivo absorption by direct comparison of data sets and using the Wagner-Nelson absorption (slopes of 1.01 and 0.91; R(2) 0.99). CONCLUSIONS: Reproducible releases of a stable solid leuprolide formulation from a multi-reservoir microchip were achieved in vitro. Chronic pulsatile release was subsequently performed in vivo. Comparison of in vitro and in vivo data reveals that pharmacokinetics were controlled by the rate of release from the device.

Chronic, programmed polypeptide delivery from an implanted, multireservoir microchip device.

Implanted drug delivery systems are being increasingly used to realize the therapeutic potential of peptides and proteins. Here we describe the controlled pulsatile release of the polypeptide leuprolide from microchip implants over 6 months in dogs. Each microchip contains an array of discrete reservoirs from which dose delivery can be controlled by telemetry.