Korsmeyer-Peppas was a simple model known as “Power law” describing drug release from a polymeric system. Korsmeyer-Peppas model (1) describe some release mechanisms simultaneously such as the diffusion of water into the matrix, swelling of the matrix and dissolution of the matrix [12].

Higuchi model is given by the equation: ft = Q = A√ where, Q is the amount of drug released in time t per unit area A, C is the drug initial concentration, Cs is the drug solubility in the matrix media and D is the diffusivity of the drug molecules (diffusion coefficient) in the matrix substance.

The fundamental principle for evaluation of the kinetics of drug release was offered by Noyes and Whitney in 1897 as the equation (10): dM/dt = KS (Cs с Ct) (1) where M, is the mass transferred with respect to time, t, by dissolution from the solid particle of instanta- neous surface, S, under the effect of the …

Korsmeyer’s-Peppa’s model  A simple relationship which described drug release from a polymeric system equation was derived by Korsmeyer-Peppa in 1983  To understand the mechanism of drug release and to compare the release profile differences among these matrix formulations ,the percent drug released time versus time …

The data obtained were fitted according to zero-order (Q = Q 0 + k × t), first-order (ln Q = ln Q 0 + k × t), and square root of time (Q = k × √ t) models, where Q (mg) denotes the cumulative amount of drug released at time t (h), Q 0 is the initial amount of drug at t = 0, and k is the release constant (Table 1).

Zero order release kinetics refers to the process of constant drug release from a drug delivery device such as oral osmotic tablet, transdermal system, matrix tablet with low soluble drugs and other delivery system. Constant release is defined in this context as the same amount of drug release per unit time.

Routes of Delivery Medications can be taken in a variety of ways—by swallowing, by inhalation, by absorption through the skin, or by intravenous injection. Each method has advantages and disadvantages, and not all methods can be used for every medication.

That’s why pharmaceutical companies create controlled-release drugs, medications whose active ingredient releases at a prespecified time. Three types of controlled-release medications include pulse-release, extended-release and delayed-release drugs.

In general, the MWCO should be sufficiently large to permit drug transport. The ease of set-up and sampling with the DM make it a very simple and straightforward technique to study drug release from a wide variety of nano-sized dosage forms like nanospheres, liposomes, emulsions, nanosuspensions, and so forth [53–55].

The in vitro release study is a critical test to assess the safety, efficacy, and quality of nanoparticle-based drug delivery systems, but there is no compendial or regulatory standard. The variety of testing methods makes direct comparison among different systems difficult.

In general, two major factors control drug release from swelling controlled matrix systems. [9,15] These include: (i) the rate of aqueous medium infiltration into the matrix, followed by a relaxation process (hydration, gelation, or swelling); and (ii) the rate of matrix erosion.

Drug release is a phenomenon controlled by diffusion or dissolution or both. Generally, diffusion-controlled drug release is predicted by Higuchi (1963) square root of time model. In certain cases there is a stage zero, which indicates delay in release of drug from microspheres.

Drug-release behavior is an important factor for polymer nanoparticle application, directly related to drug stability and therapeutic results, as well as formulation development. If the diffusion of the drug is faster than matrix degradation, the mechanism of drug release occurs mainly by diffusion.

Standard solution concentration/ theoretical sample concentration x standard active ingredient activity x (if there is a transforming factor) x theoretical drug amount value. This is your calibration value. And there is scale factor too.

However, quite often the strength of a drug is presented as a percentage, as described below:

1. % w/v = percentage weight of a substance by volume measured in grams in 100 millilitres.
2. % w/w = percentage weight of a substance by weight measured in grams in 100 grams.

Answer: First convert 1% solution to mg/cc. A 1% solution is the same as 1000 milligrams in 100 cc or 10mg/cc. Percent solutions all are 1000mg/100cc. For example a 2% = 20mg/cc, 5% = 50mg/cc, 5.5% = 55mg/cc, etc……

To accurately calculate the percentages:

1. Weigh all of your ingredients (column D in the example above).
2. Total the weight (cell D8 in the example).
3. Divide the weight of the individual ingredient by the total weight of all ingredients and multiply by 100 (formula example shown for beeswax in cell E2).

Professionals seldom measure their ingredients by volume (cups). They usually prefer measuring by weight, and there are many reasons for this. Baking is not like cooking where you can add a little extra of this ingredient or leave out that ingredient.

Write down all of the ingredients in a recipe. Determine the cost of each ingredient in total (whether it be a 10lb bag or not) List how many grams of each ingredient you have in a recipe. Divide the total cost of the ingredient by the grams of each ingredient.

How to convert a formula from ounces to percentages

1. Step 1 — Add up the common mass terms.
2. Step 2 — Convert masses to grams.
3. Step 3 — Convert volume measurements to masses (grams)
4. Step 4 — Find the total mass of the formula.
5. Step 5 — Figure out individual percentages.
6. Step 6 — Double check your figures.

Converting Percentages Into Grams Divide the percentage by 100, or equivalently, move the decimal place two spots to the left to do this. This means 25 percent is 0.25, 44 percent is 0.44 and 10 percent is 0.1. Using this same method, 8 percent is 0.08.

0.31 cup

12.5 percent

4 oz = 0.5 cup.