Abstract: This invention relates to a pharmaceutical composition made of a clindamycin salt complexed with strongly acidic non-spherical resin particles, wherein predominantly all of the resin particles are less than 75 microns in diameter, to form clindamycin-resin complex, wherein in the clindamycin-resin complex provides for immediate release of the clindamycin in a target environment and at least one non-ionic excipient. In one embodiment, the inventive subject matter is an oral liquid pharmaceutical formulation made of a complex of clindamycin hydrochloride, a fractionated resin and excipients to stabilize the complex. The pharmaceutical formulation remains stable in deionized water until the dosage form reaches an ion-rich environment (stomach or intestine), there which the active ingredient clindamycin hydrochloride is released.