Drug requirements

The approval of a new drug requires preclinical and chnical studies and takes an average of 10 years to complete. The preclinical and chnical trials have to prove the safety and efficacy of every new medicine. 

Cytochrome P450 2D6 Extremely high activity in about 2% of Caucasian populations and completely deficient activity in about 7%. Inefficiency in ultrarapid metabolizers and extremely heavy effects in poor metabolizers for more than 50 drugs. A few drugs requiring bioactivation by CYP have low efficacy in poor metabolizers (example codein is activated to morphine via CYP2D6). 

Does the drug require refrigeration If so, does the refrigerator work ... 

A drug must be kept in the container in which it was dispensed or purchased. Some drugs require special containers, such as light-resistant (brown) botdes to prevent deterioration that may occur on exposure to light. 

A few antineoplastic drugs require treatment measures before administration. An example of preadiniiiistration treatment is hydration of the patient witii 1 to 2 liters of IV fluid infused before administration of cisplatin (Platinol) or administration of an antiemetic before the adiniiiistration of mechbretiiamine These measures are ordered by the primary health care provider and, in some instances, may vary slightly from the manufacturer s recommendations. 

Analytical methods and specifications must be established and validated so as to define and control the quality and purity of the raw materials, intermediates and the finished product. For many standard chemical raw materials, the development of specifications will not be necessary as they are already published in US and European pharmacopoeia (for example, standards for water, organic solvents and various excipients). The ultimate objective of these activities is to be able to manufacture the drugs required for clinical trials in accordance with good manufacturing practice (GMP). 

When 50% of the reeeptors are oeeupied [R] and [DR], free and oeeupied receptors, must be equal and cancel out so that K = D, the concentration of drug required to bind to 50% of the receptors. Thus the lower the concentration of drug required to achieve this occupancy, the greater its affinity. Unfortunately its affinity does not necessarily reflect its potency in producing an effect. 

ICso is defined as the concentration of drug required to inhibit cell growth by 50% compared to a control. The IC50 values were calculated from the graphs obtained from the in vitro cytotoxicity assays and are the average of three independent experiments, each performed in triplicate. 

In order to determine the potential correlation between any of these variables and affinity for the PCP/sigma receptor, we determined the concentration of these drugs required to displace specific binding of 3H-PCP to rat cortical membranes (Johnson and Snell 1985). In other experiments, we determined the effect of... 

The identification of a drug requires optimization of the balance among multiple properties, among them potency/efficacy, pharmacokinetics (PK), safety, and intellectual property. As a consequence, these are also the factors that are important to... 

Essentially all antipsychotic medications pass through the placenta. The use of these drugs requires critical attention to the timing of the exposure, the dose and duration of use, and fetal susceptibility. When possible, discontinuing antipsychotics for the first trimester is the safest option, as weeks 6 to 10 are the most vulnerable period for organ formation. 

Lithium and other mood-stabilizing drugs require baseline and routine laboratory monitoring to help determine medical appropriateness for initiation of therapy and monitoring of potential adverse effects. Guidelines for such monitoring are outlined in Table 36-6. 

Many drugs require a certain pH range to maintain product stability. As discussed previously, drug solubility may also be strongly dependent on the pH of the solution. An important aid to the formulator is the information contained in a graph of the solubility profile of the drug as a function of pH (Fig. 2). The... 

The answers are 31-b, 32-a, 33-d (Katzung, pp 4—7.) The absorption, distribution, and elimination of drugs require that they cross various cellular membranes The descriptions that are given in the question define the various transport mechanisms. The most common method by which ionic compounds of low molecular weight (100 to 200) enter cells is via membrane channels. The degree to which such filtration occurs varies from cell type to cell type because their pore sizes differ. 

Earlier studies demanded calculation of an LD50 value (i.e. the quantity of the drug required to cause death of 50 per cent of the test animals). Such studies required large quantities of animals, were expensive, and attracted much attention from animal welfare groups. Its physiological relevance to humans was often also questioned. Nowadays, in most world regions, calculation of the approximate lethal dose is sufficient. 

Ribavirin may be considered for bronchiolitis caused by respiratory syncytial virus in a subset of patients (those with underlying pulmonary or cardiac disease or with severe acute infection). Use of the drug requires special equipment (small-particle aerosol generator) and specifically trained personnel for administration via oxygen hood or mist tent. 

Quantifying drug requirements not possible, except high risk areas or predictable circumstances (terrorism, for example)... 

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