Oral Capsules and Tablets
Oral solids are the default format because they carry the most active per dose and patients accept them.
Routes of Delivery
The route decides the barrier, the dose ceiling and the regulatory category before the formulation does. An active that works by injection may be unusable orally, and a format that is a supplement in one market is a drug in another. This section compares seven routes and what multi-layer encapsulation can change on each.
What each route page covers
Every route page sets out the same variables: the physical barrier (gut wall, mucosa, stratum corneum), realistic dose volume or mass, residence time, enzymatic and pH environment, typical bioavailability for small molecules and peptides, approved reference products, and the regulatory category that format usually falls into. Each page then explains where encapsulation helps (protection, dispersion, residence, release profile) and where it does not. Use the pages side by side when a partner is choosing between formats for the same active.
The seven routes
Oral capsules and tablets carry the highest dose and consumer acceptance but face acid, enzymes and first-pass metabolism. Oral liquids and shots add stability and taste problems. Sublingual and buccal formats bypass first pass for small, potent molecules. Intranasal delivery offers fast absorption and partial brain access in microliter volumes. Transdermal and topical routes are limited by the 500 Da barrier. Injectable ampoules are drug products requiring sterile manufacture. Veterinary delivery covers feed, water and species-specific constraints.
How to choose
Start from the molecule: molecular weight, logP, solubility, potency and stability. A potent small molecule suits sublingual or transdermal routes; a high-dose hydrophilic nutrient suits oral solids; a peptide usually requires injection unless a research program justifies an oral or nasal attempt. The Formulation Finder tool applies this logic, and the Delivery Challenges library explains each barrier in depth. Where two routes are viable, the regulatory category and the commercial channel usually decide between them.
Key facts
- Drugs are classified by solubility and intestinal permeability into four Biopharmaceutics Classification System classes (Amidon et al. 1995, Pharm Res 12:413)
- Poor oral absorption is more likely when a molecule exceeds 500 Da, has logP above 5, or has more than 5 hydrogen bond donors or 10 acceptors (Lipinski et al. 1997, Adv Drug Deliv Rev 23:3)
- Oral semaglutide, co-formulated with the absorption enhancer SNAC, has oral bioavailability of about 0.4 to 1% (FDA label, Rybelsus 2019)
How our delivery technology applies
Across routes, encapsulation changes four things: protection of the payload from its environment, dispersion of poorly soluble actives, residence time at an absorption surface through mucoadhesive layers, and release rate through layer number and thickness. It does not change the intrinsic size or charge of a molecule. Each route page states which of the four levers applies and what data would confirm it.
Not sure which route fits your active? Use the Formulation Finder or request a feasibility call.
Oral Liquids and Shots
In a liquid, the problem is shelf life before it is absorption.
Sublingual and Buccal Delivery
Sublingual and buccal routes send drug straight into systemic circulation, bypassing the gut and the liver on first pass.
Intranasal Delivery
The nose absorbs fast and avoids first-pass metabolism, and a fraction of a nasal dose can reach the brain along olfactory and trigeminal nerves.
Transdermal and Topical Delivery
Skin is built to keep molecules out.
Injectable Ampoules and Parenteral Formats
Injection is the reference route for peptides and proteins because it bypasses every absorption barrier.
Veterinary Delivery
Animals add three constraints human formulation rarely faces: species-specific metabolism, dosing through feed or water to groups, and palatability that decides whether the dose is eaten.
Related reading
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