how to determine whether a drug is acidic or basic! If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below.. To be honest, sometimes it can be extremely difficult to choose which equation you should use depending on whether the solution is basic or acidic. But what I do know, is that when the pka is small..
Theoretically, weakly acidic drugs (eg, aspirin) are more readily absorbed from an acid medium (stomach) than are weakly basic drugs (eg, quinidine). However, whether a drug is acidic or basic, most absorption occurs in the small intestine because the surface area is larger and membranes are more permeable (see Oral Administration) No, you cannot say because the terminology is, unfortunately, used interchangeably. For example, phenol has a pKa around 10. That means it is weakly acidic. However, amine pKa's are frequently referred to as being around 9-11, when in fact those numbers are the pKa of the conjugate acid
If the acid dissociates to a large extent, i.e. high [ H X +] ions, then its K a will be high. When you convert a high K a to p K a, p K a will be low (just a mathematical relationship). Thus, high K a = low p K a = strong acid. High K b = low p K b = strong base The lower the pH, the more acidic the system, with 7 standing at neutral. If the pH is lower than your pKa, then your molecule will be protonated (it will have its hydrogen attached); you can think of the environment as more acidic, therefore, the proton on the drug will not be abstracted As a result, acidic drugs are most likely to be absorbed in the acidic areas of the proximal duodenum; whereas, basic drugs will be best absorbed in more alkaline areas of the distal ileum. In addition to a drug's ionization status, a drug is more likely to be absorbed if it contains lipophilic chemical groups, lacks bulky/oxygenated side.
the solution is very basic (high pH means it is a stronger base) therefore, there will be low H+ (since this is the acid portion, its obviously gonna be low if there is more base aka OH-) resulting.. Basic drugs get ionized in acidic medium (right shift of eq 2), thus this form is poorly absorbed. Aspirin, an acidic drug is unionized in acidic medium of stomach, so is easily absorbed. Basic Medium: The opposite is true in case of basic medium. Acidic drugs are poorly absorbed while the basic drugs are well absorbed drug behaves as an acid or a base in solution. Amines, for example, arebasic and havepKa values of approximately 9, while phenols are acidic andtypically havepKavalues of around 10.The only sure way to know whethe To put it even more simply: A substance will become more lipid soluble in a solution with a pH similar to its own pH. A weak acid is more lipid-soluble in an acidic solution A weak base is more lipid-soluble in an alkaline solution Theoretically, weakly acidic drugs (eg, aspirin) are more readily absorbed from an acid medium (stomach) than are weakly basic drugs (eg, quinidin). However, whether a drug is acidic or basic, much of the absorption can occur in the small intestine because the surface area is larger and membranes are more permeable. Last updated 11 November 201
600mg of benzyl penicillin sodium (salt of weak acid and strong base,pKa=2.76, mol.wt= 356.4)in 2ml of water for injection answer=8.34 100mg/ml chlorpheniraminemaleate (salt of weak base and weak acid,mol.wt=390.8) in water for injection (pKbof chlorpheniramine=5.0, pKaof maleic acid=1.9 The functional group helps to determine whether something is acid, low pH, or basic and has a high pH. An example of an acidic functional group is a carboxyl. The carboxyl functional group is acidic because it is a proton (H+) donator when in solution. The carboxyl group will then become COO- An example of a basic functional group is the amino. In case to study whether it is acidic or basic, most of the acidic compounds dissolves in basic aqueous solutions and vice versa. When I do the experiment to determine the molecular weight of.
Lewis acid/bases are seen in terms of electron pair donating (base) or accepting (acids) species. If your compound has for example a Nitrogen with only three bonds around it the molecule is. This is all Acid-Base balance means. ACIDIC - TOO MUCH ACID - Lower than 7.35 means that there is too much acid in your system. NORMAL - Just right! pH between 7.35 and 7.45 is perfect for homeostasis. ALKALINE - NOT ENOUGH ACID - It just means NOT acidic enough. pH higher than 7.45 is considered Alkaline
2) A basic drug with a pKa of 7.8 is a known teratogen. If given IV to a pregnant woman whose blood pH is 7.4, will this drug cross the placenta and effect the baby? See the example below: In this example, 72% of the drug is ionized which means 28% of the drug is unionized and will pass through the placenta to effect the baby. Basics on Ionizatio One of the critical properties of an aqueous extraction medium or drug product is its pH. This is especially true for aqueous parenteral drug products, which are generally formulations whose pH can range from somewhat acidic (pH 3 or lower) to somewhat basic (pH as high as 10) Drugs also have relatively poor access to pericardial fluid, bronchial secretions and fluid in the middle ear, thus making the treatment of infections in these regions difficult. B. Protein Binding Many drugs bind to plasma proteins. Weak acids and neutral drugs bind particularly to albumin, while basic drugs tend to bind to alpha-1-aci It is a correction factor that accounts for the acid/base of the drug in its salt form.  salt mg acid orbase mg S = b) When do you use a salt factor? Basically, one always uses a salt factor. In order to keep it simple, we assumed it to be 1 so far. However, you need to take it into consideration as soon as a salt factor (S<1) or a.
Start studying Acidic and Basic drug examples. Learn vocabulary, terms, and more with flashcards, games, and other study tools Anticancer drugs â€¢ Alkylating group is attached to a nucleic acid base â€¢ Cancer cells grow faster than normal cells and have a greater demand for nucleic acid bases â€¢ Drug is concentrated in cancer cells - Trojan horse tactic 1.3.1 Linking a biosynthetic building block 1.3 Drug targeting Non selective alkylating agent Toxic N Cl Cl H 3C. In the body, the ratio of the ionized and unionized forms depend on the pH of the medium. Acidic drugs are unionized in the acidic medium and basic drugs are unionized in the basic medium. Acidic drugs are better absorbed from the acidic compartment. 5. Physical Forms. Drugs may exist as solids, liquids or gases The purpose of this study was to determine the pH levels of 29 different samples of methamphetamine on the street market in Cape Town. The sample was dissolved in water and the pH of each sample determined. The pH levels varied from 3.02 to 7.03 with an average of 5.0. Seventy-two percent (21) of the samples had a pH level below the saliva critical pH point of 5.6 and therefore. Based on how strong the ion acts as an acid or base, it will produce varying pH levels. When water and salts react, there are many possibilities due to the varying structures of salts. A salt can be made of either a weak acid and strong base, strong acid and weak base, a strong acid and strong base, or a weak acid and weak base
Define what do we mean by acidic and basic drugs. Demonstrate how to calculate the % ionization of drugs. Outline the importance of drug dissociation in different body compartments. Explain the effect of drug chemical structure on ionization. Describe how to study the strength of acidity and basicit The shape of the acid/base titration curve would establish the pKa's of the acidic and basic extractables and the amount of the acidic or basic extractables. The reason that answer was maybe was that the titration would have to be performed with sufficient sensitivity that it could deal with what are usually relatively dilute extracts
Excretion of acid and ways to jeopardize the system. 1. A strong non-volatile acid HA dissociates to release H + and poses an immediate threat to plasma pH. 2. Bicarbonate buffers the H + and generates CO 2, which is expelled in the lungs and results in depletion of body HCO 3-.Non-bicarbonate buffers (collectively referred to as B) carry the H + until the kidneys excrete it Since it is a weakly acidic drug, let's apply the following formula. Substituting in the above equation, % ionized=[10 (4.6 - 8.6) / (10 (4.6 - 8.6) +1)]* 100 =1/1.01=0.99 %. Let's go with another example. Working Example 2. Calculate the fraction of drug in the ionized form at pH 7.7 of a tissue for a basic drug with pKa 8.7. Solution Timolol is formulated as the salt of Maleic acid. The salt form of this drug is a conjugate acid of a weak base and has ACIDIC character. Question #4: The functional groups that enhance solubility are those that can interact with water via H-bonding or dipole/dipole interactions. The secondary alcohol, the secondary amine, th Acid-base problems A. A pharmaceutical molecule with antifungal properties is only active when deprotonated and negatively charged (A-). The protonated state (HA) is inactive. If the pK a of this drug is 10.0, (a) calculate the ratio of protonated to deprotonated compound at physiological pH (7.4) The binding of basic drugs is unpredictably affected by CKD, with some basic drugs exhibiting a slightly decreased V D (including bepridil, clonidine, and propafenone), and some exhibiting an.
. The solid powder is more readily mixed with solid filler and made into tablets The most common acids used to neutralize the amine group of the drug are hydrochloric acid and sulfuric acid (and occasionally phosphoric acid). Drugs that are neutralized wit Additional base is added until all the free acid is converted into the salt form and we are at the pH>pHmax portion of the graph. To calculate the total quantity of drug that will remain dissolved in solution at a selected pH, either of two equations can be used, depending on whether the product is to be in a pH region above or below the pH max
solution. Identify the salts as acidic, basic or neutral. 6. For each salt, ask students to write out the parent acid and base that could be used to prepare the salt (by neutralization), and identify each as a strong or weak acid or base. Predict whether each salt should be acidic, basic or neutral based on th Some drugs strengths are expressed in terms of units of activity according to some biologic assay. Common drugs for which units are used include penicillin, insulin, bacitracin, heparin, nystatin, polymixin, and vitamins A, D, and E. Metric equivalency to units varies, with each drug using a unit system of measurement having its ow Discussion of pH and pK a Values The Henderson-Hasselback equation is shown below. [ ] [ ] log HA A pH pKa âˆ’ = + Where [A-] is conjugate base and [HA] is conjugate acid This equation is often used to determine the proportion of conjugate base [A-] and of conjugate acid [HA] one must use to attain a particular pH value of a buffer
An acid-base extraction is a type of liquid-liquid extraction. It typically involves different solubility levels in water and an organic solvent. The organic solvent may be any carbon-based liqiuid that does not dissolve very well in water; common ones are ether, ethyl acetate, or dichloromethane You can also calculate concentration from pH and pK a, the latter being derived from the acid dissociation constant K a.The higher the K a for a particular acid, the stronger the acid it is. The pK a for any acid is the pH at which half of the acid has been ionized (that is, when half of the acidic protons have been offloaded into the solution) Everything You Ever Wanted to Know About pKa, But Were Afraid to Ask Chem 330 Handout Bronsted-Lowry definitions of acid and base: Acid: a substance that can donate a proton Base: a substance that can accept a proton Lewis definitions: An acid is a substance that accepts a pair of electrons. A base is a substance that donates a pair of electrons..
A neutral pH is 7.0. The higher the number, the more basic (alkaline) it is. The lower the number, the more acidic your urine is. The average urine sample tests at about 6.0. If your urine sample. Figure 12.2.3 Diagram Illustrating Drug Distribution between Intestine and Blood (Weak Acid) By comparison in the intestine, pH = 6.4. The calculated D value is (100+1)/ (10+1) = 9.2. From this example we could expect significant absorption of weak acids from the stomach compared with from the intestine. Remember however that the surface area. Most drugs, however, are weak acids or weak bases 2that partially ionise when dissolved in water. HA = acid (the drug molecule); H 2 O = base Aâˆ’ += conjugate base (the drug anion); H 3 O = conjugate acid B = base (the drug molecule); H 2 O = acid OHâˆ’ = conjugate base (the drug anion); BH+ = conjugate acid 1 See Pharmacokinetic processes. When a drug is placed in a suppository base it will displace an amount of base as a function of its density. A Density Displacement Factor (DDF) is used to determine how much base a drug will displace. DDF Definition: the weight of drug, in grams, that will displace 1 gram of base Â¡ Example: 0.5 g boric acid in cocoa butter, DDF = 1. These reactions dose the acid part of the chlorhydrate (hydrochloric acid, in this case) with a strong base, such as sodium methylate, in a non-aqueous medium in acetic anhydride. When the dosage relates to a base (a tertiary amine, a weak base), the titration reagent is perchloric acid (HClO 4, a strong acid) in a non-aqueous medium. In fact.
3. Permeability of the drug through biological membranes. This depends on the extent of ionization of the drug. The pH of the solution can affect the extent of ionization of weakly acidic or weakly basic drugs. A Drug in the non-ionized form is more permeable than in its ionized form Frequently the base form of a drug is administered in an altered form such as an ester or salt for stability or other reasons such as taste or solubility. This altered form of the drug usually has a different molecular weight (MW), and at times it may be useful to determine the amount of the base form of the drug in the altered form In forced degradation, the drug reacted with the water at acidic and basic conditions. The concentration of the acid or base is selected according to the stability of the drug substance. Generally, 0.1 to 1.0 M HCl or H 2 SO 4 (Hydrochloric acid or Sulfuric acid) is used to create the acidic conditions and 0.1 to 1.0 M NaOH or KOH (Sodium.
Conjugate Acid-Base Pairs. Acids and bases exist as conjugate acid-base pairs.The term conjugate comes from the Latin stems meaning joined together and refers to things that are joined, particularly in pairs, such as Brnsted acids and bases.. Every time a Brnsted acid acts as an H +-ion donor, it forms a conjugate base.Imagine a generic acid, HA. When this acid donates an H + ion to water. Calculate the fitness value of molecular descriptors of each individual. Charifson, P. S. & Walters, W. P. Acidic and Basic Drugs in Medicinal Chemistry: A Perspective. J. Med some commonly asked questions and answers about how the drug list works with your prescription drug plan. Q. What is a Drug List? A. The Local Choice Key Advantage Drug List is a list of U.S. Food and Drug Administration (FDA)-approved brand-name and generic drugs that have been reviewed and recommended for your Plan A functional group is a group of atoms and bonds within a molecule. The functional group helps to determine whether something is acid, low pH, or basic and has a high pH. An example of an acidic functional group is a carboxyl. The carboxyl functional group is acidic because it is a proton (H+) donator when in solution. Click to see full answer
In order to calculate the amount of base to be added to the drug to provide the correct amount of drug in each suppository, the displacement value must be used - but note that a displacement value is used only when the drug is expressed as an actual quantity, e.g. x mg or y g. (Suppository and pessary moulds are produced in nominal sizes of 1. Example 1: Aspirin (acetylsalicylic acid) has a pK a of 3.5. (i) Calculate the ratio of ionized/unionized of the drug in the stomach where pH is 1. (ii) Calculate the ratio of ionized/unionized in the intestine where pH is 6. (iii)Based on these calculations- where is aspirin absorbed within the body? Aspirin is a commonly used drug 1. are organic dyes with either acid or basic character 2. are organic dyes that change their colour on acceptance or release of protons 3. are used for rapid determination of an endpoint in an acid-base titration 4. are used for the quantitative determination of a given acid or base content of a solution 5 Metabolic acidosis is the most serious acid-base disorder and is due to increased production of endogenous acids rather than the salicylate itself. Plasma salicylate levels rarely exceed a maximum of about 5 mmol/l and the decrement in the [HCO3] is significantly higher than this in these severe cases
Generally, a compound that is an acid or a base acts as an acid or a base only when it is dissolved in water. In a water-based solution, these compounds produce ions. Recall that an ion is a charged particle. For example, if a hydrogen atom, which consists of one proton and one electron, loses its electron, it becomes a hydrogen ion. The hydroge Acids and Bases. Your organic teachers are quite likely to ask you questions like identify the most acidic protons or the most basic site in a molecule.These facts can be important for determining where a molecule is likely to react when treated with a base or acid respectively The site-specific exposure conditions will determine what values you should use in the exposure dose equation. The U.S. Environmental Protection Agency's (EPA's) Exposure Factors Handbook (1997) is a good source for locating ranges and percentiles for various exposure information that may be relevant to the site being evaluated cyclobenzaprine GC/MS for basic drugs and metabolites 0.05-0.10 mg/L day of test dextromethorphan GC/MS for basic drugs and metabolites 0.05-0.10 mg/L 18.93% k=2, 95.45% diphenhydramine GC/MS for basic drugs and metabolites 0.05-0.10 mg/L 18.93% k=2, 95.45% ketamine GC/MS for basic drugs and metabolites 0.05-0.10 mg/L day of tes
Acid base properties of organic compounds are essentially the same as inorganic acid (mineral acid) properties and inorganic base properties. All organic acids and organic bases are weak acids and weak bases, however, while there are both strong and weak inorganic acids and bases. Strong acids exhibit the properties of acids (e.g. low pH, hydrogen ions in solution, and corrosiveness) more. 6. 6 g of azelaic acid is added to 24 g of cream base to produce AzelexÂ® cream. What is the concentration of this product? _____ 7. HytoneÂ® contains 500 mg of hydrocortisone powder with 19.5 g of emollient base. What is the percentage strength of HytoneÂ®? _____ 8. How much boric acid is contained in 30 g of a 10% boric acid ointment? _____ 9 Elimination of Weak Acid and Weak Base Drugs As a drug passes through the renal tubules, it will be either reabsorbed or eliminated in the urine. Which path it takes depends on the pKa of the drug and the pH of the urine. pKa is used to describe the strength of acids (the lower the pKa, the stronger the acid) The pH controller would then pace the acid metering pump at an appropriate rate to bring the pH back down into range. One of the biggest advantages to a system of this basic design is that it is simple and capable of handling relatively high flows In addition, milk is slightly more acidic than plasma (pH of milk is approximately 7.2 and plasma is 7.4) allowing weakly basic drugs to transfer more readily into breast milk and become trapped secondary to ionisation. Milk composition varies within and between feeds and this may also affect transfer of drugs into breast milk
In such cases, called first-order elimination (or kinetics), the metabolism rate of the drug is a constant fraction of the drug remaining in the body (ie, the drug has a specific half-life). For example, if 500 mg is present in the body at time zero, after metabolism, 250 mg may be present at 1 hour and 125 mg at 2 hours (illustrating a half. hydroxybutyric acid (GHB), lysergic acid diethylamide (LSD), marijuana, and methaqualone. Schedule II â€¢ The drug or other substance has a high potential for abuse. â€¢ The drug or other substance has a currently accepted medical use in treatment in the United States or a currently accepted medical use with severe restrictions Determine if students can apply the concepts learned from the example with aspirin, a weak acid, to a drug that is a weak base, such as cocaine. The students should be able to hypothesize how the results would have differed if they had performed the experiment with cocaine To summarize, whenever you need to determine the more acidic proton, visualize (or better draw) the conjugate bases and determine which one is the more stable base on the ARIO factors. Practice. 1. Determine if the blue- or red-colored proton is more acidic in each of the following compounds: Check your answers
o Best if more reactive (i.e. more anionic or more basic) â€¢ Leaving Group: o Same as SN2 o best if more stable (i.e. can support negative charge well) o Examples: TsO- (very good) > I- > Br- > Cl- > F- (poor) o However, tertiary or allylic ROH or ROR' can be reactive under strongly acidic conditions to replace OH or OR â€¢ Solvent Repeat with the anion. If all answers are no, it is neutral. Or if one is acidic and one is basic. Example: CH3CO2NH4 CH3CO2- -->ANION cannot remove H+ (attached to C), not acidic Can add H to form HCH3COO OR CH3CO2H (formic acid) weak acid, therefore basic NH4+-->CATION Can remove H+, to form NH3, a weak base, acidic Overview of Acid-Base Balance. An important property of blood is its degree of acidity or alkalinity. The acidity or alkalinity of any solution, including blood, is indicated on the pH scale. The pH scale, ranges from 0 (strongly acidic) to 14 (strongly basic or alkaline). A pH of 7.0, in the middle of this scale, is neutral An acid-base indicator is used to indicate the endpoint of the reaction. These indicators change the color of the solution at the endpoint. In modern labs instead of indicators, pH meters are used to detect the endpoint. 5 Types of Acid Base Titration. Acid-base titration can be done in both aqueous and nonaqueous media. A. Aqueous acid base.