What pH is aspirin most stable?

between about 2 and 3
To interpret these, the minimum points on the graphs are the areas of best stability, for example, a pH between about 2 and 3 is the most stable for aspirin and as the pH goes above pH 8 the hydrolysis is more rapid and the drug is less stable.

What is the pH of acetylsalicylic acid?

Aspirin (acetylsalicylic acid) has a pKa of 2.97 Calculate the percentage of aspirin (acetylsalicylic acid) available for absorption in the stomach (pH = 2.0) and in the duodenum at (pH = 4.5).

Is acetylsalicylic acid stable?

The stability of acetylsalicylic acid in such solutions was tested at room temperature, in a 12h period. The study also demonstrated that acetonitrile and 1,4-dioxane turned out to be the most stable solvents, and an above 80% of initial concentration of acetylsalicylic acid was found in this case.

How does aspirin affect pH?

The aspirin causes blood pH to drop, and in response hyperventilation kicks in to raise the pH. An influx of an acid such as aspirin, or of a large dose of an alkaline substance like baking soda, can affect blood pH, but the effect is temporary due to the blood’s rapid buffering action.

What is the pH of maximum stability?

The pH-rate profile was studied over the pH range of 2.0–12.0 with a maximum stability at pH 3.0–5.0.

Does pH affect hydrolysis?

Hydrolysis was shown to be almost completely hindered at solution pH≥4 at curing temperatures≤105 °C and at pH≥5 at curing temperatures≤150 °C, whereas cross-linking still occurred to some extent at pH≤6.5 and drying temperatures as low as 70 °C.

What is the side effect of acetylsalicylic acid?

The most common side effects of Bayer Aspirin include: upset stomach, heartburn, drowsiness, and.

What’s the pH of antacid?

Stomach acid has a pH value of 1 and an antacid tablet has a pH of 10. When they are mixed together, the pH is closer to 7, which is neutral.

Is aspirin stable in water?

Of the various solvent systems studied, aspirin was found most stable in water-polyethylene glycol (4:1, v/v),which provides an excellent medium for preparation of intravenous dosage forms. Phosphate buffer showed significant catalysis of aspirin hydrolysis.

How does temperature affect aspirin?

As the temperature is increased from −20 °C to 25 °C to 70 °C, the breakage propensity increases and then decreases. The increase in the breakage propensity of Aspirin with increasing temperature is reflected in the values of C1/ρl which increases, corresponding to an increase in H/Kc2.

Why is aspirin considered a weak acid?

Science Concepts: Aspirin is a weak acid and it tends to ionize (give up a H atom) in an aqueous medium at high pH. In a low pH environment like the stomach (pH =2), aspirin is predominantly unionized and crosses membranes into the blood vessels readily.

Where does aspirin get absorbed?

Aspirins absorption is pH sensitive at the level of the small intestine. Absorption is higher through the small intestine than the stomach for the same pH range. At pH 3.5 or 6.5, aspirin’s intestinal absorption is greater than the gastric absorption of the compound.

What is the pH of acetylsalicic acid?

Acetylsalicylic acid is a weak acid and the pKa valuehas variously been reported as 3.49,83.5,5,14and3.6.15Therefore, the solubility of ASA is pH depen-dent, increasing with increasing pH above the pKa.10

Which is the main degradation product of acetylsalicylic acid?

In addition, quantitative, as well as qualitative analysis was performed during one assay. The stability of acetylsalicylic acid in such solutions was tested at room temperature, in a 12h period. In the work, in all cases, only one main degradation product, salicylic acid, was found.

How does hydrolysis affect the stability of aspirin?

Also, drug decomposition may yield toxic by-products that are harmful to the patient. Hydrolysis of the drug entity can be a major factor in the instability of solutions. Aspirin, for example, undergoes hydrolysis with the resultant degradation products being salicylic acid and acetic acid.

How does acetylsalicylic acid pass through the stomach?

The non-ionized acetylsalicylic acid passes through the stomach lining by passive diffusion. Ideal absorption of salicylate in the stomach occurs in the pH range of 2.15 – 4.10. Intestinal absorption of acetylsalicylic acid occurs at a much faster rate.