Methylphenidate

Engineered Monoclonal Antibodies

Diagram of engineered monoclonal antibodies

Engineered monoclonal antibodies are a class of biological therapies that are designed to target specific antigens on the surface of cells. These antibodies are produced using recombinant DNA technologies and are used in the treatment of various diseases, including cancer, autoimmune disorders, and infectious diseases.

Structure and Function

Monoclonal antibodies are composed of two identical heavy chains and two identical light chains, forming a Y-shaped molecule. The tips of the "Y" contain the antigen-binding sites, which are highly specific to the target antigen. This specificity allows monoclonal antibodies to bind to their target with high affinity, blocking or modulating the function of the antigen.

Types of Engineered Monoclonal Antibodies

There are several types of engineered monoclonal antibodies, each designed for specific therapeutic purposes:

• Chimeric antibodies: These antibodies are composed of murine (mouse) variable regions and human constant regions. They are less immunogenic than fully murine antibodies.

• Humanized antibodies: These antibodies are mostly human, with only the antigen-binding sites derived from murine sources. This reduces the risk of immune reactions.

• Fully human antibodies: These are entirely human in origin, produced using transgenic mice or phage display technologies.

• Bispecific antibodies: These antibodies are engineered to bind two different antigens simultaneously, offering unique therapeutic mechanisms.

Applications in Medicine

Engineered monoclonal antibodies have revolutionized the treatment of many diseases:

• Cancer therapy: Monoclonal antibodies can target specific tumor antigens, leading to direct tumor cell killing or recruitment of immune cells to attack the tumor.

• Autoimmune diseases: By targeting specific components of the immune system, monoclonal antibodies can reduce inflammation and tissue damage in diseases such as rheumatoid arthritis and multiple sclerosis.

• Infectious diseases: Monoclonal antibodies can neutralize pathogens or their toxins, providing passive immunity or enhancing the host's immune response.

Production

The production of engineered monoclonal antibodies involves several steps:

1. Antigen identification: The target antigen is identified and characterized. 2. Hybridoma technology: B cells from immunized animals are fused with myeloma cells to create hybridomas that produce the desired antibody. 3. Recombinant DNA technology: Genes encoding the antibody are cloned and expressed in suitable host cells, such as Chinese hamster ovary cells. 4. Purification and formulation: The antibodies are purified and formulated for clinical use.

Challenges and Future Directions

While engineered monoclonal antibodies have shown great promise, there are challenges such as high production costs, potential for immune reactions, and the development of resistance. Ongoing research aims to improve antibody design, reduce immunogenicity, and enhance therapeutic efficacy.

Related Pages

• Monoclonal antibody therapy
• Biopharmaceutical
• Immunotherapy
• Hybridoma technology

Introduction

Methylphenidate is a central nervous system stimulant used for the therapy of attention deficit disorder and narcolepsy. 

Methylphenidate-stereoisomers_2D-skeletal

Liver safety

Methylphenidate has been linked to a low rate of serum aminotransferase elevations during therapy and to rare instances of acute, clinically apparent liver injury, generally after its intravenous abuse.

Mechanism of action

Methylphenidate (meth" il fen' i date) is a piperidine derivative that is structurally related to amphetamine which acts as a central nervous system (CNS) sympathomimetic stimulant, probably by causing release of norepinephrine at CNS nerve terminals promoting neurotransmission.  Methylphenidate may also affect dopaminergic neurotransmission.  Therapy with methylphenidate has been shown to increase cognitive abilities and improve psychological functioning and performance in children and adults with suspected attention deficit disorders.  It has a paradoxical calming action in children with hyperactivity.  Methylphenidate is also used in the therapy of narcolepsy. 

FDA approval information for Methylphenidate

Methylphenidate was initially approved for use in the United States in 1955 and its indications have been broadened to include children above the age of 6 and adolescents with attention deficit disorder.  Methylphenidate is available in multiple forms for oral administration including capsules, tablets, oral solutions and as extended release and long acting forms in concentrations varying from 2.5 to 54 mg in generic forms and under several brand names including Ritalin, Concerta and Metadate.  Transdermal formulations are also available. 

Dosage and administration for Methylphenidate

The usual dose in adults is 10 mg two or three times daily and average maintenance dosage is 40 to 60 mg daily.  The dosage in children varies by formulation.  Methylphenidate is a controlled substance (Schedule II) and has abuse potential. 

Side effects of Methylphenidate

Common side effects include headache, insomnia, irritability, palpitations, tachycardia, nasal stuffiness, decreased appetite, cough and rash.

The following are CNS stimulants

• Amphetamines (including ecstasy or methylenedioxymetamphetamine)
• Armodafinil
• Atomoxetine
• Cocaine
• Methylphenidate
• Modafinil

• Dailymed label info on Methylphenidate
• FDA Methylphenidate