HS code · 4-digit heading
HS Code 29.35 – Sulphonamides
What HS 29.35 covers
Heading 2935 specifically covers 'Sulphonamides' within Chapter 29, Section VI of the Harmonized System. This classification is dedicated to organic compounds characterized by the presence of a sulfonyl group (-SO2-) directly attached to a nitrogen atom, forming a sulfonamide functional group (-SO2NH2, -SO2NHR, or -SO2NR2). This heading encompasses a wide range of compounds, most famously the 'sulfa drugs' or sulfonamide antibiotics, which were among the first effective systemic antibacterial agents. However, its scope extends beyond antimicrobials to include other pharmacologically active compounds (e.g., diuretics, antidiabetics like sulfonylureas), as well as industrial chemicals used in dyes, plastics, and agrochemicals. It is crucial to distinguish these compounds from other sulfur-containing organic compounds (e.g., thiols, sulfoxides in 2930) or other nitrogen-function compounds (e.g., amines, amides in 2921-2929) by precisely identifying the sulfonamide functional group. The historical significance of sulfa drugs underscores their enduring importance in medicine, while their continued use as APIs and chemical intermediates makes accurate classification vital for pharmaceutical trade compliance, regulatory approvals, and managing global supply chains. This heading highlights a specific class of organic chemicals defined by a unique functional group, crucial for its diverse applications.
- Covers
- Sulfanilamide
- Sulfadiazine
- Sulfamethoxazole
- Sulfacetamide
- Sulfapyridine
- Glipizide
- Furosemide
- Acetazolamide
- Saccharin (certain forms)
- Tolbutamide
- Chlorpropamide
- Sulfathiazole
- Sulfamerazine
- Sulfamethizole
- Sulfisoxazole
- Sulfaguanidine
- Indapamide
- Hydrochlorothiazide
- Metolazone
- Chlorthalidone
- Sulfonylurea herbicides
- Examples
An Indian pharmaceutical company exports several tons of bulk Sulfamethoxazole API to a drug manufacturer in the USA for the production of combination antibiotics (e.g., trimethoprim-sulfamethoxazole), typically shipped in sealed drums via ocean freight. A Swiss chemical producer ships Furosemide, a diuretic, to Brazil for pharmaceutical formulation, transported in controlled conditions by air cargo. A Chinese chemical plant exports a specific sulphonamide intermediate to Germany for use in the synthesis of certain agrochemicals, usually in large quantities via container vessels.
Subheadings under 29.35 6
Codes often confused with 29.35
Common mistake. A common misclassification error for 2935 is confusing sulphonamides with other sulfur-containing organic compounds (2930) or general nitrogen-function compounds (2921-2929) if the specific sulphonamide functional group (-SO2N-) is not correctly identified. For example, a compound with a sulfoxide group (-SO-) attached to a carbon, but no nitrogen directly bonded to the sulfonyl, would fall under 2930, not 2935. Another significant mistake is classifying sulphonamides in dosage form (e.g., tablets, injections) under 2935, when they should be classified under Chapter 30 (Pharmaceutical products). Heading 2935 is strictly for chemically defined, unmixed sulphonamides, typically in bulk form.
Top exporters and importers of HS code 2935, 2025
In 2025, the largest exporter of HS code 2935 in UN Comtrade data was Switzerland, with 41% of world exports; the largest importer in UN Comtrade data was Slovenia, with 33% of world imports. Countries that did not report 2025 data are estimated from partner records, which can understate them.
Top exporters 2025 · share of world exports
- 1 Switzerland $3.4B 41% of world exports
- 2 Ireland $1.7B 20% of world exports
- 3 China $740M 8.8% of world exports
World total: $8.4B Reported figures on UN Comtrade ↗
Top importers 2025 · share of world imports
- 1 Slovenia $2.9B 33% of world imports
- 2 United States $1.5B 17% of world imports
- 3 Germany $723M 8.1% of world imports
World total: $9.0B Reported figures on UN Comtrade ↗
How these figures are built
109 countries reported 2025 trade to UN Comtrade in HS 2022, and their own totals are used. Countries that did not report are estimated from what other countries recorded trading with them. Those estimates miss trade with other non-reporting countries, so they can be low, and a non-reporting country can rank higher than shown or be missing from the list. World totals add both and leave out trade between two non-reporting countries. Figures are in current US dollars; reported imports are mostly valued CIF and exports FOB, and exports include re-exports. The UN Comtrade links show the underlying records; they can also list a few reporters left out here (regional groups and older HS editions).
Source: UN Comtrade (United Nations Statistics Division), 2025 annual data.
Questions about HS 29.35
What is HS code 2935?
HS code 2935 is a 4-digit heading in the Harmonized System that covers: Sulphonamides. Heading 2935 specifically covers 'Sulphonamides' within Chapter 29, Section VI of the Harmonized System. This classification is dedicated to organic compounds characterized by the presence of a sulfonyl group (-SO2-) directly attached to a nitrogen atom, forming a sulfonamide functional group (-SO2NH2, -SO2NHR, or -SO2NR2). This heading encompasses a wide range of compounds, most famously the 'sulfa drugs' or sulfonamide antibiotics, which were among the first effective systemic antibacterial agents. However, its scope extends beyond antimicrobials to include other pharmacologically active compounds (e.g., diuretics, antidiabetics like sulfonylureas), as well as industrial chemicals used in dyes, plastics, and agrochemicals. It is crucial to distinguish these compounds from other sulfur-containing organic compounds (e.g., thiols, sulfoxides in 2930) or other nitrogen-function compounds (e.g., amines, amides in 2921-2929) by precisely identifying the sulfonamide functional group. The historical significance of sulfa drugs underscores their enduring importance in medicine, while their continued use as APIs and chemical intermediates makes accurate classification vital for pharmaceutical trade compliance, regulatory approvals, and managing global supply chains. This heading highlights a specific class of organic chemicals defined by a unique functional group, crucial for its diverse applications.
What products fall under HS code 2935?
Sulfanilamide, Sulfadiazine, Sulfamethoxazole, Sulfacetamide, Sulfapyridine, Glipizide, Furosemide, Acetazolamide, Saccharin (certain forms), Tolbutamide, Chlorpropamide, Sulfathiazole, Sulfamerazine, Sulfamethizole, Sulfisoxazole, Sulfaguanidine, Indapamide, Hydrochlorothiazide, Metolazone, Chlorthalidone, Sulfonylurea herbicides
What are common misclassifications for HS code 2935?
A common misclassification error for 2935 is confusing sulphonamides with other sulfur-containing organic compounds (2930) or general nitrogen-function compounds (2921-2929) if the specific sulphonamide functional group (-SO2N-) is not correctly identified. For example, a compound with a sulfoxide group (-SO-) attached to a carbon, but no nitrogen directly bonded to the sulfonyl, would fall under 2930, not 2935. Another significant mistake is classifying sulphonamides in dosage form (e.g., tablets, injections) under 2935, when they should be classified under Chapter 30 (Pharmaceutical products). Heading 2935 is strictly for chemically defined, unmixed sulphonamides, typically in bulk form.
Which countries are the top exporters of goods under HS code 2935?
In 2025, the top exporters of HS code 2935 in UN Comtrade data were Switzerland ($3.4B, 41% of world exports), Ireland ($1.7B) and China ($740M). World exports came to about $8.4B, adding countries' reported figures and partner-based estimates for those that did not report (UN Comtrade data). Countries that did not report 2025 data are estimated from partner records, which can understate them.
Which countries are the top importers of goods under HS code 2935?
In 2025, the top importers of HS code 2935 in UN Comtrade data were Slovenia ($2.9B, 33% of world imports), the United States ($1.5B) and Germany ($723M). World imports came to about $9.0B, adding countries' reported figures and partner-based estimates for those that did not report (UN Comtrade data). Countries that did not report 2025 data are estimated from partner records, which can understate them.
How is HS code 2935 structured?
HS code 2935 is a 4-digit heading under Chapter 29 of the Harmonized System. The first 2 digits (29) identify the chapter, and digits 3-4 (35) specify the heading. This code contains multiple 6-digit subheadings for precise product classification.