Clindamycin Phosphate

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Cat Number

API0232786

CAS Number

24729-96-2

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Product Detail Description Scientific Support Customer Q&A

CAS Number

24729-96-2

EINECS

246-433-0

Synonyms

Cleocin phosphate, Clindets, Cleocin T

Molecular Formula

C18H34ClN2O8PS

Molecular Weight

504.96

Smiles

CCC[C@@H]1C[C@H](N(C1)C)C(=O)N[C@@H]([C@@H]2[C@@H]([C@@H]([C@H]([C@H](O2)SC)OP(=O)(O)O)O)O)[C@H](C)Cl

Appearance

White to off-white powder

Melting Point

114℃

Boiling Point

159℃

General Description

Clindamycin phosphate is the water-soluble phosphate ester prodrug of clindamycin, a lincosamide antibacterial agent. As a prodrug, it requires in vivo hydrolysis to release the microbiologically active clindamycin base.

Mechanism of Action

Clindamycin exerts its bacteriostatic effects by reversibly binding to the 50S subunit of the bacterial ribosome, inhibiting peptidyl transferase and disrupting early protein chain elongation. This prevents bacterial protein synthesis, suppressing growth of susceptible organisms. The phosphate ester itself is inactive until hydrolyzed to clindamycin, which achieves approximately 92-94% plasma protein binding and wide tissue distribution.

Application

Clindamycin phosphate is indicated for serious infections caused by susceptible anaerobic bacteria, streptococci, staphylococci, and pneumococci, including respiratory tract, skin, intra-abdominal, gynecological, and bone and joint infections . It is also widely used topically for acne vulgaris management.

Stein Gold L, et al. evaluated the first triple-combination topical acne treatment—fixed-dose clindamycin phosphate 1.2%/benzoyl peroxide 3.1%/adapalene 0.15% (IDP-126) gel—in 741 participants with moderate-to-severe acne. At week 12, IDP-126 demonstrated superior efficacy to vehicle and to all three component dyad gels, with 52.5% achieving treatment success (defined as ≥2-grade reduction and clear or almost clear skin) compared to 8.1% with vehicle and 27.8–30.5% with the dyads. IDP-126 also produced significantly greater reductions in both inflammatory (mean reduction of 29.9 lesions) and noninflammatory (35.5 lesions) counts, corresponding to >70% reductions from baseline. The gel was well tolerated, with adverse events being mostly mild to moderate in severity.

Fig. 1 Participant disposition (Stein Gold L, et al., 2022)

References

Stein Gold L, et al. Efficacy and Safety of a Fixed-Dose Clindamycin Phosphate 1.2%, Benzoyl Peroxide 3.1%, and Adapalene 0.15% Gel for Moderate-to-Severe Acne: A Randomized Phase II Study of the First Triple-Combination Drug. Am J Clin Dermatol. 2022;23(1):93-104.

Is Clindamycin Phosphate susceptible to hydrolysis of the phosphate ester?

Yes, it can hydrolyze to clindamycin and free phosphate. Storage in a cool, dry place and protection from moisture are essential to minimize this degradation pathway.

Does Clindamycin Phosphate require refrigerated storage?

No, it is stable at controlled room temperature (15-30°C). However, in tropical climates, storage in an air-conditioned environment is recommended to prevent thermal degradation.

What is the stability of Clindamycin Phosphate in aqueous solutions for IV formulations?

It has good stability at pH 5.5-7.0.

How is the 7-epimer impurity controlled in Clindamycin Phosphate?

The 7-epimer is a key process-related impurity. We use a validated HPLC method to ensure it is controlled to very low levels, well below pharmacopoeial limits, during storage.