Quick Facts
| CAS Number | 21462-39-5 (HCl) / 24729-96-2 (Phosphate) |
|---|---|
| Molecular Formula | C18H33ClN2O5S · HCl (HCl) / C18H34ClN2O8PS (Phosphate) |
| Molecular Weight | 461.44 (HCl) / 504.96 (Phosphate) |
| Pharmacopoeia | BP/USP/CEP/EP/CVP |
| Packaging | 25 KG/DRUM |
Product Overview
Clindamycin was developed in 1966 by B.J. Magerlein and colleagues at The Upjohn Company (now Pfizer) as a semi-synthetic derivative of lincomycin — a natural product first isolated in 1962 from Streptomyces lincolnensis soil samples collected near Lincoln, Nebraska. The key innovation was the substitution of the 7-hydroxyl group of lincomycin with chlorine via a stereospecific chlorination, producing 7-deoxy,7-chloro-lincomycin. This single-atom change proved transformative: clindamycin demonstrated roughly four times the oral bioavailability of lincomycin and significantly enhanced activity against Bacteroides fragilis, the most clinically important anaerobic pathogen.
The 7-chloro substitution alters the molecule's lipophilicity, improving tissue penetration — particularly into bone, abscess cavities, and gingival tissue. This pharmacokinetic advantage makes clindamycin one of the few oral antibiotics with reliable bone and dental tissue concentrations. In veterinary medicine, it has become the first-line lincosamide for deep pyoderma, periodontitis, and osteomyelitis in companion animals. The phosphate ester prodrug form (clindamycin phosphate) was developed later to solve the injection-site pain associated with the HCl salt, providing a water-soluble, enzymatically activated formulation for intravenous and topical use.
Two salt forms serve complementary roles in pharmaceutical manufacturing. Clindamycin HCl is the form used in oral capsules and tablets — it provides reliable gastric absorption and can be formulated as 75 mg, 150 mg, and 300 mg doses. Clindamycin phosphate is the water-soluble prodrug used for injectable solutions (IV/IM), topical gels and lotions for acne treatment, and vaginal creams. The phosphate ester is pharmacologically inactive until endogenous phosphatases cleave the ester bond in vivo, releasing active clindamycin with a slower pharmacokinetic profile that supports once- or twice-daily dosing.
As of mid-2026, the global clindamycin API market is driven by sustained demand in companion animal medicine (particularly North America and Europe), dermatology (topical acne formulations), and dental surgery prophylaxis (for penicillin-allergic patients). China is a major producer of clindamycin API, with manufacturing concentrated in Zhejiang, Hebei, and Henan provinces. KingWish supplies GMP-certified clindamycin HCl and clindamycin phosphate meeting BP/USP/CEP/EP/CVP standards, supporting pharmaceutical manufacturers in regulated and emerging markets worldwide.
Quality Specifications
| Purity (HPLC) | ≥ 98.5% (anhydrous basis), per USP monograph |
|---|---|
| Clindamycin B (Lincomycin) | ≤ 1.0% — the key impurity from incomplete chlorination |
| Related Substances | Individual impurity ≤ 0.5%, total impurities ≤ 2.0% |
| Residual Solvents | Compliant with ICH Q3C; acetone ≤ 5,000 ppm, methylene chloride ≤ 600 ppm |
| Heavy Metals | ≤ 20 ppm |
| GMP Status | Manufactured under ICH Q7 GMP conditions |
Pharmaceutical Applications
Oral Formulations (HCl)
Capsules 75/150/300 mg for bacterial infections. Veterinary oral solutions for dogs and cats at 5.5–11 mg/kg q12h. Palatable liquid formulations for feline administration.
Injectable & Topical (Phosphate)
IV/IM solutions 150 mg/mL. Topical 1% gel/lotion for acne. Vaginal cream 2%. Dental bone grafting prophylaxis. Phosphate ester activated in vivo by phosphatases.
Therapeutic Areas
- Companion Animals: Deep pyoderma, abscesses, periodontitis, osteomyelitis, toxoplasmosis in dogs and cats
- Human Medicine: Anaerobic infections, dental prophylaxis, acne vulgaris, bacterial vaginosis
- Swine & Poultry: Combined with aminoglycosides for polymicrobial respiratory infections
Sourcing Clindamycin API: Key Checks
Documentation
Request batch-specific CoA with full HPLC chromatogram. Verify clindamycin B (lincomycin) content is within limits — this is the most critical impurity. For injectable-grade phosphate, confirm bacterial endotoxin testing and sterility data are included.
Red Flags
Elevated clindamycin B (>1.0%) indicates incomplete chlorination during synthesis. Unexplained pH shift in phosphate salt can signal degradation. Prices substantially below market average may indicate non-GMP material or rejected batches.
Packaging & Logistics
Standard: 25 KG/DRUM with double LDPE liner. HCl salt: store at controlled room temperature (15–25°C), protect from moisture. Phosphate salt: store at 2–8°C recommended for long-term stability. Standard lead time 4–8 weeks.
Market Context
Global clindamycin API market driven by sustained demand in companion animal medicine, dermatology, and dental applications. China accounts for a major share of global production. Clindamycin phosphate commands a premium over HCl due to more complex synthesis and purification. Market report