Abstract: Absorption is characterized by evaluating the absorption rate constant ka from plasma concentration versus time data graphs. Most pharmacokinetic models assume first order kinetics for the oral absorption of the drug; however zero-order assumption can also occur...
The rate of change of drug in the body at any time is equal to the amount of drug absorbed and the amount of drug eliminated from the body at any time, regardless of whether the absorption is first-order or the second order.A plasma-level time curve showing drug absorption and elimination can be made.
Zero-order drug absorption from the dosing site into the plasma occurs when a zero-order controlled release delivery system is used. This model is analogous to that of administration of drug by intravenous infusion.
Normally absorption process in the body is assumed to follow first-order kinetics. This model applies to the drugs those are in solution form or rapidly dissolving dosage forms.
Absorption rate constant can be determined by the “METHOD OF RESIDUALS” by plotting the oral absorption data. In One-Compartment Model, by plotting amount of drug absorbed versus time or by plotting the amount of drug unabsorbed versus time;Using both plasma and urinary data. And also in Two-Compartment Model (loo-reigelman method),by plotting the amount of drug unabsorbed vs. time.
In few individuals, the absorption of drug after a single oral-dose does not start immediately, Due to some physiological factors as stomach-emptying time and intestinal motility, the time delay prior to the commencement of first-order absorption is the lag-time.
Using the method of residuals to estimate ka and kel, the terminal phase of the absorption curve is usually represented by kel whereas steeper slope is represented by ka .In few cases kel obtained from oral absorption does not agree with that obtained after I/v bolus. Apparently the ka and kel obtained by this method has been interchanged. This phenomenon is termed as “flip-flop” of ka and kel.
The plot of the fraction unabsorbed against t, using blood data, yields the slope-ka/2.303.If this graph gives a linear regression; hence the rate of drug absorption DGI/ Dt is a first-order process. Similarly a graph of this fraction of drug unabsorbed vs. time can be made using urinary data as well. And the slope of this curve represents the absorption-rate constant. From this method an accurate measurement of absorption-rate constant can be made.
In two-compartment method also, the amount of drug unabsorbed vs. time can be plotted and accurate ka-determination can be done but the limitation in this method is that the determination of ke is first made by giving the same drug I/vly. The drugs that can’t be given orally, their ka can’t be determined by this method.So determination of absorption rate constant is a very important measure when comparing the bioavailability of the drug in bioequivalence studies.

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Abstract: Pain “is a part of a rapid warning relay instruction of the motor neurons of the central nervous system to minimize detected physical harm.”
Analgesia simply means the absence of pain without losing consciousness.
Opioid peptides are found in the central nervous system mainly in limbic and brainstem areas associated with pain reception, and the certain areas of the spinal cord. Their distribution corresponds to “areas of the human brain where electrical stimulation can relieve pain.” these opioid peptides interact with certain opioid receptors in the brain and certain other areas and produce their effects whether desirable or undesirable.
These opioid receptors includes mu, delta, kappa, orl-1.all of the opioid drugs act on these receptors and either modulate or potentiate their actions. Morphine is the prototype among such drugs. By acting on mu-receptors more strongly and less strongly on the other receptors, morphine induces its effect as sedation, analgesia, euphoria, respiratory depression, cough suppressant, decreased get secretions etc..
Tolerance is a major problem with all of the opioids and the physical and psychological tolerance of these drugs along with euphoria are the major reasons of drug addiction. For the withdrawal syndrome and addiction, some longer acting drugs that have mild withdrawal effects may be used as methadone. The opioid antagonists may also be used for the acute opioid toxicity as Naltrexone.

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Abstract: MET (mesenchymal-epithelial transition factor) is a proto-oncogene that encodes a protein MET, also known as c-Met or hepatocyte growth factor receptor (HGFR). MET is a membrane receptor that is essential for embryonic development and wound healing. Hepatocyte growth factor (HGF) is the only known ligand of the MET receptor. MET is normally expressed by cells of epithelial origin, while expression of HGF is restricted to cells of mesenchymal origin. Upon HGF stimulation, MET induces several biological responses that collectively give rise to a program known as invasive growth. Abnormal MET activation in cancer correlates with poor prognosis, where aberrantly active MET triggers tumor growth, formation of new blood vessels (angiogenesis) that supply the tumor with nutrients, and cancer spread to other organs (metastasis). MET is deregulated in many types of human malignancies, including cancers of kidney, liver, stomach, breast, and brain. Normally, only stem cells and progenitor cells express MET, which allows these cells to grow invasively in order to generate new tissues in an embryo or regenerate damaged tissues in an adult. However, cancer stem cells are thought to hijack the ability of normal stem cells to express MET, and thus become the cause of cancer persistence and spread to other sites in the body.

The proto-oncogene MET product is the hepatocyte growth factor receptor and encodes tyrosine-kinase activity. The primary single chain precursor protein is post-translationally cleaved to produce the alpha and beta subunits, which are disulfide linked to form the mature receptor.
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Abstract: Multiple personality disorder, or MPD, is a mental disturbance classified as one of the dissociative disorders in the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV). It has been renamed dissociative identity disorder (DID).MPD or DID is defined as a condition in which “two or more distinct identities or personality states” exist.
       MPD is an incredibly creative defense mechanism to protect the host from the trauma of the past and the present. Full blown DID or poly- fragmented DID (more than 100 personalities) is characteristically a result of severe, and prolonged occurrences of physical, sexual, or emotional abuse occurring before the age of 12 (and often before the age of 5). The female to male ratio for DID is about 9:1, but the reasons for the gender imbalance are unclear.
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Abstract: Factor Xa is a zymogen of factor Xa, a serine protease, which occupies a pivotal position in the coagulation cascade. Factor Xa is found at the convergent point of extrinsic and intrinsic pathway leading to coagulation.  Factor Xa and factor Va combine on the phospholipid membranes to form the “prothrombinase complex”, which activates prothrombin to thrombin. Thrombin cleaves fibrinogen to fibrin resulting in clot formation [1]. Factor Xa consist of two chains – a heavy chain and a light chain. These two are linked by a single disulfide bond. The light chain contains the N-terminal GLA (γ-carboxyglutamic acid) domain as well as two EGF (epidermal growth factor) domains. The GLA domain contains 11 γ-carboxyglutamic acid residues which are responsible for binding to the negatively charged phospholipids in the presence of calcium ions. The EGF domains provide the binding site for EPR-1 ( Effector cell protease receptor). The heavy chain contains trypsin-like serine protease domain. The organization of this domain is similar in coagulation enzymes like factor VIIa, factor Xa and protein C [2].  Factor Xa deficiency was first reported in 1950s in two families, Prower and Stuart; and as a result, factor Xa is also known as “Stuart” and “Stuart and Prower” factor [3].
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Abstract: Copper catalyzed alkyne-azide cycloaddition (CuAAC) is one of the most reliable click reaction that has enabled the practical and efficient preparation of 1,4-disubstituted 1,2,3 triazoles from a wide range of substituted alkynes and azides which cannot be typically attained by the traditional Huisgen thermal cycloaddition reaction[1].The reaction defined as “click reaction” requires benign reaction conditions, simple work up and purification procedure and can still rapidly creates molecular diversity through the use of reactive modular building blocks [2].  
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Abstract: A well designed controlled drug delivery system can overcome some of the problems of conventional therapy and enhance the therapeutic efficacy of a given drug. To obtain maximum therapeutic efficacy, it becomes necessary to deliver the agent to the target
tissue in the optimal amount in the right period of time there by causing little toxicity and minimal side effects.
There are various approaches in delivering a therapeutic substance to the target site in a sustained controlled release fashion.One such approach is using microspheres as carriers for drugs. Microspheres are characteristically free flowing powders consisting of protiens or synthetic polymers which are biodegradable in nature and ideally having a particle size less than 200 μm.
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Abstract: Cancer is the second leading cause of death worldwide, following heart diseases. World Health Organization has estimated 12 million deaths worldwide due to cancer in 2030 [1]. According to the American Cancer Society, about 1.5 million new cancer cases and more than 500,000 deaths are expected to occur due to cancer in USA alone in 2009 [2]. Although progress has been steadily made in cancer research to reduce mortality and improve survival, cancer still accounts for nearly 1 in every 4 deaths in the USA [2]. There are many different types of cancer, but all share a common feature – rapid and uncontrolled cell proliferation. Emergence of new tumors is associated with mutations or abnormalities in expression of various cell cycle regulators like cyclins and cyclin-dependent kinases (Cdk) [3]. Therefore, targeting Cdk/cyclin complexes represent a promising therapeutic approach in oncology.
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Abstract: Chiral building blocks are fundamental for the synthesis of biologically active compounds such as pharmaceuticals, agrochemicals, flavors and fragrances.  Asymmetric saturation of alkenes, ketones, and imines by hydrogen or organic hydrogen donors provides an ideal access to chiral alkanes, alcohols, and amines respectively. A small amount of chiral catalyst repeatedly delivers hydrogen atoms to one of the enantiofaces of substrates, producing large amounts of optically active compounds. This chirality multiplication is achieved largely in a homogeneous phase with chiral molecular catalysts consisting of a metallic element and an optically active organic compound(s) [1].
A great number of transition metal complexes have been prepared and used as homogeneous catalysts. These include titanium, zirconium and lanthanide based catalysts. Also present are iridium, rhodium and ruthenium complexes [6-9]. 
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Abstract: An ideal chemical reaction should be simple to perform, give maximum yields, utilize readily available starting materials, be a one-pot reaction and be environmentally friendly [1]. No reaction comes close to achieving this ideality; however, multicomponent reactions are best positioned to achieve this. By definition, multicomponent reactions are those reactions whereby more than two reactants combine in a sequential manner to give highly selective products that retain majority of the atoms of the starting material [2]. This makes multicomponent reactions (MCRs) highly convergent reactions, with high atom efficiency, good bond forming capabilities and higher yields in comparison to a similar multistep reaction. Click Here To Read Entire Abstract.

Abstract: Hypertension is a major risk factor for cardiovascular diseases. It is estimated that one billion people in the entire world are affected by high blood pressure [1]. Moreover, the condition is complicated by multiple pathways present in the body which act to maintain blood pressure. Current agents directed toward the reduction of blood pressure are less than satisfactory for patients to reach therapeutic goals (<30% of the patients actually achieve treatment goals). Thus, there is still an ever-growing need for new classes of antihypertensive drugs with novel mechanisms that can help in mediating the blood pressure [2].
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Abstract: Today many people complain about extra fat deposits and overweight. 
While exercise and dieting may be useful for losing unwanted weight and fat, some fat deposits may not respond to efforts at weight loss. Applying liposuction techniques may be an option in these situations. Liposuction is not a low-effort alternative to exercise and diet. It is a form of body contouring with significant attendant risks and is not a weight loss method. The amount of fat removed varies by doctor, method, and patient, but the average amount is typically less than 10 pounds (5 kg).
There are several factors that limit the amount of fat that can be safely removed in one session. Ultimately, the operating physician and the patient make the decision. There are negative aspects to removing too much fat. Unusual "lumpiness" and/or "dents" in the skin can be seen in those patients "over-suctioned". The more fat removed the higher the surgical risk.
Reports of people removing 50 pounds (22.7 kg) of fat are exaggerated. However, the contouring possible with liposuction may cause the appearance of weight loss to be greater than the actual amount of fat removed. The procedure may be performed under general or local ("tumescent") anesthesia. The safety of the technique relates not only to the amount of tissue removed, but to the choice of anesthetic and the patient's overall health. It is ideal for the patient to be as fit as possible before the procedure and to have given up smoking for several months.

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Abstract:
The skin is the most superficial part of the body. The signs of ageing are most visible in the skin. Although, ageing skin is not a threat to a person, it can have a detrimental effect on the psychology of a person. A look into the causes of skin ageing, the available treatments and preventive measures for this inevitable change is important to help both the already aged, as well as, the youth.

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