Monitoring forced degradation of drugs using silica coated AgNPs with surface-enhanced Raman scattering.

Potential degradation products (DPs), even in small concentrations, can cause changes in pharmacological and toxicological properties of a drug with a significant impact on product quality and safety. Thus, their stability and understanding of possible degradation mechanisms have a significant importance. Although liquid chromatography is the conventional technique used for forced degradation studies with excellent accuracy and reproducibility, the main disadvantages of the technique are being expensive and time-consuming.

Chromatographic Determination of Thermodynamic Acid Dissociation Constants of Tetracycline Antibiotics and Their Epimers.

The presented study describes the development of reversed-phase liquid chromatography method using a core-shell particle column with a pentafluorophenyl stationary phase for the dissociation constant (pKa) determination of the tetracycline group antibiotics (tetracycline, oxytetracycline, chlortetracycline) and their epimers (4-epitetracycline, 4-epioxytetracycline, 4-epichlortetracycline). The pH values were measured in the acetonitrile (ACN)-water binary mixtures, used as mobile phases, instead of in water and take into account the effect of the activity coefficients. Thermodynamic acid dissociation constant (pKa1) values of studied antibiotics and their epimers were calculated using retention factor (k) at different mobile phase pH values in studied binary mixtures with ACN percentages of 20, 25, 30 and 35% (v/v).

Terra Firma-Forme Dermatosis Misdiagnosed as Nevoid Acanthosis Nigricans.

Terra firma-forme dermatosis (TFFD) is a clinical condition characterized by brown-gray, velvety, pigmented patches or plaques, resembling dirt on the skin. Nevoid acanthosis nigricans (NAN) is a rare and recently described form of acanthosis nigricans occurring during childhood or early adulthood. Herein we describe a patient with TFFD, initially misdiagnosed as NAN.

An Extraordinary Manifestation of Nodular Cystic Fat Necrosis.

Nodular cystic fat necrosis (NCFN) is characterized by mobile subcutaneous nodules composed of necrotic adipocytes encapsulated by fibrous tissue. The classical presentation of NCFN is solitary or multiple, up to 40, discrete nodules scattered usually on the extremities or trunk. Here, the authors present an elderly woman who developed an unusual and striking clinical picture of NCFN, two months after a fall.

Sirolimus-Induced Diffuse Alveolar Hemorrhage: A Case Report.

Sirolimus is a mammalian target of the rapamycin, a protein kinase, which is responsible for inhibition of T cell and B cell proliferation. Sirolimus has side effects on lugs, and may cause cryptogenic organizing pneumonia, diffuse alveolar hemorrhage, lymphocytic pneumonitis, hypersensitivity pneumonitis, desquamative interstitial pneumonia, and pulmonary alveolar proteinosis. Diagnosis is based on the combination of clinical, radiological, histological, and pathological investigation.