Pharma 101 /Product Types
From a simple aspirin tablet to a living CAR-T cell — every therapy type carries its own manufacturing complexity, regulatory pathway, and risk profile. Here's the full landscape, with real-world examples.
Why therapy type matters
A small-molecule painkiller goes through the Center for Drug Evaluation and Research (CDER). A monoclonal antibody may go through CDER or the Center for Biologics (CBER). A pacemaker with a drug coating sits at the Office of Combination Products — which then assigns a lead center. And a diagnostic AI algorithm lands at the Center for Devices and Radiological Health (CDRH).
Get the therapy type right and you know the rules. Get it wrong and you're filing to the wrong center, under the wrong regulations, with the wrong data package.
Small molecule
Defined structure, reproducible synthesis, and decades of regulatory precedent. Still the majority of approved medicines — delivered via many different routes.
Oral solid dosage
The most common dosage form in the world. OSD products include compressed tablets, hard and soft-gel capsules, granules, and oral powders. Manufactured at massive scale, with critical quality attributes centred on dissolution rate, content uniformity, and stability.
Bioavailability is the central challenge — the drug must survive the GI tract, dissolve at the right rate, and be absorbed. Modified-release technologies (extended-release, enteric coating) and salt/polymorph selection add significant formulation complexity.
Sterile parenteral
Intravenous bags, vials, ampoules, prefilled syringes, and auto-injectors. Because they bypass every natural barrier the body has, they must be sterile, particulate-free, and pyrogen-free — zero tolerance for contamination.
Manufacturing takes place in classified cleanrooms under aseptic processing or via terminal sterilisation. EU GMP Annex 1 (2022 revision) and 21 CFR 211.113 set the bar. Media fill runs must demonstrate zero microbial growth across thousands of units.
Topical & transdermal
Creams, ointments, gels, foams, lotions, and transdermal drug delivery systems (TDDS — patches). Topical products act locally at the site of application (skin, eye, mucosa). Transdermal patches are engineered to cross the skin barrier and deliver drug systemically — avoiding first-pass hepatic metabolism and providing controlled, sustained release.
Skin permeation is the defining challenge: only small, lipophilic molecules cross intact skin readily. Permeation enhancers, microneedle arrays, and iontophoresis technologies are extending the range of deliverable molecules. Quality attributes focus on drug content, release rate, and adhesive performance.
Inhalation
Metered-dose inhalers (MDIs), dry powder inhalers (DPIs), soft mist inhalers, and nebulisers deliver drug directly to the lung — enabling local effects (asthma, COPD, cystic fibrosis) or systemic absorption via the vast alveolar surface area.
The device is inseparable from the drug: aerodynamic particle size distribution (APSD) determines whether particles reach the lower airways or deposit in the throat. Most inhaled products are combination products (drug + device), regulated primarily as drugs by CDER but subject to device performance standards. Propellant choice, actuator design, and patient technique all affect dose delivery.
Biologic & nucleic acid
Proteins, antibodies, and nucleic acids produced in cells or chemically synthesised to engage RNA and DNA directly. The manufacturing process is the product — any change can alter the molecule.
Biologic drug
Monoclonal antibodies (mAbs), fusion proteins, cytokines, hormones, enzymes, and vaccines. Produced in CHO cells, E. coli, yeast, or other expression systems. Post-translational modifications — glycosylation patterns, disulfide bonds — affect potency and safety. A manufacturing change that seems minor can require a full comparability study before the product can be released.
Advanced therapy
CAR-T cells, stem cell therapies, viral vectors (AAV, lentivirus), CRISPR-based gene editing, and in vivo gene correction. Living or nucleic-acid-based — cannot be terminally sterilised, often have very short shelf lives, and autologous therapies (patient's own cells) are manufactured one-patient-at-a-time. In Europe, regulated as Advanced Therapy Medicinal Products (ATMPs).
Oligonucleotide & RNA
Short synthetic strands of nucleic acid that interact directly with RNA targets in the cell. Small interfering RNA (siRNA) silences a specific gene by degrading its messenger RNA. Antisense oligonucleotides (ASOs) modulate splicing or block translation. mRNA therapeutics instruct cells to produce a target protein — as in COVID-19 vaccines and emerging cancer immunotherapies.
Unlike gene therapy, these don't permanently alter DNA. siRNA and ASOs are chemically synthesised and regulated as drugs via NDA. mRNA therapeutics follow a different path: because mRNA is manufactured using biological processes and acts more like a biologic, they are typically approved via BLA (as with Comirnaty). Delivery to target tissues — especially the liver — is the central challenge, typically solved with LNP formulations (see below).
Device & digital
Regulated by CDRH, not CDER or CBER. Risk-classified by the harm they can cause if they fail.
Medical device
Implants, surgical instruments, in-vitro diagnostics (IVDs), imaging systems, infusion pumps, and continuous glucose monitors. A medical device achieves its purpose through physical or mechanical means, not pharmacological action.
FDA classifies devices into three risk tiers. Class I (bandages) — general controls only. Class II (glucose meters) — 510(k) clearance by demonstrating substantial equivalence to a predicate device. Class III (pacemakers, implantable defibrillators) — full Pre-Market Approval (PMA) with clinical evidence.
Digital health
Software that performs a medical function independently of any hardware device. AI-powered diagnostic imaging tools, clinical decision-support algorithms, and digital therapeutics (DTx) can all qualify as SaMD.
The FDA's Digital Health Center of Excellence leads oversight. IEC 62304 governs software development lifecycles. AI/ML-based SaMD faces a unique challenge: the algorithm can change its own behaviour through learning. FDA addresses this through the Predetermined Change Control Plan (PCCP), letting developers define which algorithm updates are pre-approved without a new submission.
Combination, hybrid & platform
When a product crosses therapy-type boundaries, regulatory complexity multiplies. The FDA's Office of Combination Products determines which center takes the lead — based on the product's primary mode of action.
Bioconjugate
An antibody (biologic) chemically linked to a cytotoxic small-molecule payload via a cleavable or non-cleavable linker. The antibody targets cancer cells; the payload kills them. ADCs inherit the manufacturing complexity of both worlds: biologic upstream (cell culture, purification) plus highly potent small-molecule (HPAPI containment, conjugation chemistry).
Drug-to-antibody ratio (DAR) and linker stability are the critical quality attributes. An ADC with too-high DAR aggregates and becomes toxic; too-low DAR loses efficacy. Regulated as biologics (BLA) by FDA CDER.
Combination product
Products that combine a drug, biologic, and/or device into a single entity or co-packaged kit — drug-eluting stents, prefilled syringes, auto-injectors, metered-dose inhalers, vaginal rings with hormones, and intravaginal/intrauterine drug-releasing devices.
The FDA's Office of Combination Products (OCP) issues a Request for Designation (RFD) to assign a lead center based on primary mode of action. The product must satisfy both drug and device regulations — a drug-eluting stent needs both a PMA and evidence that the drug coating is safe and effective.
Radiopharmaceutical
A targeting molecule (small molecule, peptide, or antibody) linked to a radioactive isotope. Used for both imaging (PET/SPECT diagnostics) and therapy (radioligand therapy, or RLT — delivering a lethal radiation dose directly to tumour cells). The theranostic approach uses a diagnostic isotope to confirm the target is expressed, then switches to a therapeutic isotope to treat.
Manufacturing requires dedicated radiation-controlled facilities with specialised containment. Short half-lives (hours to days) mean production and shipping timelines are extremely tight. Regulated as drugs by FDA CDER, with additional oversight from the Nuclear Regulatory Commission (NRC) for radioactive materials.
Delivery platform
Lipid nanoparticles (LNPs), liposomes, and albumin-bound nanoparticles (nab-drugs) are not a therapy class but a delivery platform — the vehicle that carries another payload to its target. They matter enough to list separately because they fundamentally change what can be delivered: nucleic acids like mRNA and siRNA cannot cross cell membranes on their own and depend entirely on LNPs to reach the cytoplasm.
LNP composition (ionisable lipid, PEG-lipid, cholesterol, helper lipid) determines tissue targeting and endosomal escape efficiency. mRNA-LNP formulations are now the dominant platform for RNA therapeutics and vaccines. Nab-paclitaxel (Abraxane) demonstrated that albumin-bound nanoparticles can improve the tolerability of cytotoxics without a Cremophor carrier.
At a glance
| Therapy type | FDA center | Approval path | Mfg complexity | Key differentiator |
|---|---|---|---|---|
| Oral Solid Dosage | CDER | NDA / ANDA | Bioavailability & dissolution control | |
| Sterile Injectable | CDER | NDA | Sterility assurance, aseptic processing | |
| Topical & Transdermal | CDER | NDA / ANDA | Skin permeation rate and adhesive performance | |
| Inhalation | CDER (drug-led) | NDA | Particle size distribution dictates lung deposition | |
| Biologics | CDER / CBER | BLA | Process is product — comparability for any change | |
| Cell & Gene | CBER | BLA | Living product; autologous = 1 patient = 1 batch | |
| siRNA / ASO / mRNA | CDER | NDA (siRNA/ASO) / BLA (mRNA) | Delivery to target cell; nucleic acid stability | |
| Medical Device | CDRH | 510(k) / PMA | Risk class drives pathway; design controls critical | |
| SaMD | CDRH | 510(k) / De Novo | Algorithm updates may require new submission | |
| ADC | CDER | BLA | Biologic + HPAPI handling + conjugation chemistry | |
| Drug-Device Combo | OCP assigns lead | Depends on PMOA | Must satisfy two regulatory frameworks simultaneously | |
| Radioligand Therapy | CDER + NRC | NDA / BLA | Radioactive containment; short half-life logistics | |
| LNP / Nanoparticle | CDER (payload-led) | NDA / BLA | Particle size, PdI, encapsulation efficiency, endosomal escape |
PMOA = Primary Mode of Action | HPAPI = Highly Potent Active Pharmaceutical Ingredient | PdI = Polydispersity Index | Complexity rating is relative and indicative only.
Keep going
Sources & further reading
The pathway depends on the product's intended use, composition, claims, and market. These official starting points support the regulatory examples used in this guide.
Recognized technical references used throughout include ICH Quality Guidelines ↗ and ISO 13485 ↗.
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