ThePharmaFacts

     TETRACYCLINE All are obtained from Actinomycetes species  T hey are bitter solids & their hydrochlorides soluble in water Derivatives of Octahedro Napthacene (having 4 annulated six- membered rings together) Amphoteric compounds (having both acid & base properties)   General Information:      General Structure:      SAR of Tetracyclines:       1.Modification at C1 & C3:         -  Keto-enol tautomerism of ring A in C1  &  C3 is common feature to all biologically active tetracyclines, blocking this system by forming derivatives  like A–C = O  at C1 and C3 results in loss of antibacterial activity          - Function of C1 & C3 is essential for activity       2. Modification at C2 position:          - Antibacterial activity depends on the carboxamide (CONH 2 ) moiety.   ...

Cephalosporins Derived from a fungus Acremonium which word is previously known as Cephalosporium Discovered in 1945 by Brotzu He observed that the culture produced substances which were effective against Salmonella typhi (an agent causing typhoid) General Information:     General Structure:                SAR Of Cephalosporins:      1.  7-Acylamino substituents: -      Acylation of the amino group generally increases potency against gram  positive bacteria, but decrease in gram-negative potency. -     High antibacterial activity is observed only when the new acyl groups are derived from carboxylic acids for gram-positive bacteria. -    Substituents on the aromatic ring that increases lipophilicity provide higher gram-positive activity and generally lower gram-negative activity. -    Phenyl ring in the side-chain can be replaced wi...

              Local Anesthetics : (LA)      - These agents prevent generation and conduction of nerve impulses at the site of application or injection    - This leads to loss of sensation which is reversible    - Also causes absence of pain sensation at specific location without loss of consciousness hence also known as "Local Analgesics"         Routes of Administration :     i) Topical Anaesthesia (Surface)    ii) Intravenous (IV) - Either for regional nerve block or for large region block    iii) Spinal Anaesthesia (Within spinal theca)         Mechanism of Action of LA :    i) Generation and propagation of nerve impulses at the site of action on cell membrane are blocked    ii) Blocking of Na/K ATPase enzyme leads to Na & K ions influx & outflux restriction respectively therefore membrane stabilization   ...

                Patients all over world are facing tremendous health care hazards that are caused by the Severe Acute Respiratory Distress Syndrome Coronavirus 2 (SARS-CoV-2) pandemic. Remdesivir {First described in 2016} is the first approved treatment for severe coronavirus disease 2019 (COVID-19). It is a " Novel Nucleoside Analog " with a broad antiviral activity spectrum among RNA viruses, including Ebolavirus (EBOV) and Respiratory Pathogens like the Middle East Respiratory Syndrome Coronavirus (MERS-CoV), SARS-CoV, and SARS-CoV-2. In vivo, Remdesivir showed therapeutic as well as prophylactic effects in animal models of EBOV, MERS-CoV, SARS-CoV, and SARS-CoV-2 infection. However, the substance failed to some extent in a clinical trial on ebola virus disease (EVD), where it was inferior to investigational monoclonal antibodies in an interim analysis. As there was no placebo control in this study, no conclusions on its efficacy in EVD can be ...

Regulation of Secretion:     -Thyroid hormone secretion is controlled by Anterior Pituitary gland via thyrotropin or TSH.    -TSH is stimulated by TRH which is secreted from Hypothalamus.    -Somatostatin from Hypothalamus, T3 & T4 inhibits Anterior Pituitary gland directly from releasing TSH while only T3 & T4 inhibits Hypothalamus to release TRH.    -The action of TRH on Pituitary Gland & TSH on Thyroid gland is mediated by enhanced cAMP synthesis.    -Higher concentration of TSH acts via IP3/DAG Pathway & Mediate intracellular calcium pathway in thyroid cell. Mechanism of Action:    -Thyroid hormones bind to ligand-binding domain of thyroid hormone receptor (TR) & and it heterodimerizes with retinoid X receptor (RXR).    -Then it undergoes conformational changes releasing 'corepressor' & binding with 'coactivator'.    -This induces gene transcription followed by Production of ...