What is the difference between Type A and Type B pharmaceutical gelatin?

Beyond Biopharma · Pharmaceutical Gelatin FAQ

Short answer: Type A pharmaceutical gelatin is made by an acid process, typically from porcine (pig) skin, and its isoelectric point is higher, around pH 7–9. Type B pharmaceutical gelatin is made by an alkali (lime) process, typically from bovine hide or bone, and its isoelectric point is lower, around pH 4.7–5.4. Because the isoelectric point controls how the protein carries electrical charge at the pH of a formulation, the two types behave differently in charged systems such as hard-shell formation and coating baths, even though their Bloom and viscosity windows can overlap. Neither type is inherently firmer or better; the right choice depends on the source preferred and the pH and charge behaviour the application needs.

The two letters describe two processes

In pharmaceutical (as in food) gelatin, the letters A and B are industry shorthand for how the collagen raw material was prepared before hot-water extraction. Type A means an acid process. The raw material is swollen in dilute acid and then hot-water extracted, a relatively fast route that suits pig skin well. Type B means an alkali or lime process. The material is held in a lime or alkaline bath, often for several weeks, before extraction — a slower route that suits the dense, well-mineralised collagen of bovine hide and bone. The two routes were developed for different raw materials, and they leave different chemical traces on the gelatin, most visibly in the isoelectric point.

Head-to-head comparison

Why the isoelectric point matters more than the letter

At the level of a finished pharmaceutical, the most consequential difference is the isoelectric point (pI), because that single value decides how the gelatin is charged at the pH of the material around it. Type A, with a pI around pH 7–9, is near-neutral or positively charged in most pharma-process waters. Type B, with a pI around pH 4.7–5.4, already carries a net negative charge in neutral and even mildly acidic systems. Charge affects how gelatin interacts with other charged species in a bath, how it adsorbs onto surfaces, and how stable a coating or film remains. In hard-capsule shell production, plate coating and film casting, formulators often have a working preference for one type based on their equipment, their water quality and the rest of the formula.

What does not differ between the two types

A common assumption is that the letter sets gel firmness. It does not. Two pharmaceutical gelatins labelled Type A and Type B with the same measured Bloom value set gels of nearly the same firmness and melt in the same thermo-reversible way. The Bloom number on the certificate of analysis (COA), not the A or B designation, carries that information. Likewise clarity, odour and reactivity are properties of the individual refined grade and its source, not of the type label alone.

Choosing between them in a pharma context

• When bovine material is required or preferred (for example to satisfy religious or market expectations), Type B is the natural fit because Type B is the route usually applied to bovine hide and bone.
• When a porcine source or a quicker, acid route is wanted, Type A is typically used for pig skin.
• When the deciding factor is charge behaviour at the formulation pH, confirm the isoelectric point on the COA and test the selected gelatin in your actual bath rather than relying on the letter.

There is no absolute quality ranking: Type A and Type B both appear throughout pharmaceutical and medical applications, and suppliers routinely offer both. The reliable next step is to compare the full COA of candidate lots, not just the type. For a broader overview of pharmaceutical gelatin grades, see the pharmaceutical gelatin FAQ.