Bioequivalence Study of Clindamycin Phosphate Injection (Clinott-P(cid:31)) in Thai Healthy Volunteers
Amorn Leelarasamee MD*, Wallapa Tatong PhD**, Narat Kasattut MS***, Tatta Sriboonruang BSc***, Duangchit Panomvana Na Ayudhya PhD***
Affiliation : * Department of Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University ** Department of Pharmaceutical Chemistry, Faculty of Pharmaceutical Sciences, Chulalongkorn University *** Department of Pharmacy, Faculty of Pharmaceutical Sciences, Chulalongkorn University
Background and
Objective : Generic clindamycin given intramuscularly, should have identical active
ingredient(s), strength, and demonstrable bioequivalence to those of original product. The aim of this inves-
tigation was to compare the bioavailability of a single, intramuscular injection, of 2 ml. of 300 mg. of a generic
clindamycin (Clinott-P(cid:31)) and the original preparation (Dalacin C(cid:31)).
Materials and Methods : A randomized, double-blinded, crossover study was conducted. Twenty-four healthy
males were recruited at Siriraj Hospital and randomized to receive a single intramuscular injection of either
Clinott-P(cid:31) or Dalacin C(cid:31). Treatment was followed by a two-week washout period. Blood samples were collected
at 0, 0.5, 1, 1.5, 2, 2.5, 3, 4, 6, 8, 10, 12 and 24 hours after the injection. Plasma samples were analysed
for clindamycin by a validated HPLC method at the Faculty of Pharmaceutical Sciences, Chulalongkorn
University.
Results : Twenty-four volunteers enrolled in and completed the study. They exhibited an average height of
167.92 cm (SD = 5.82), weight of 60.10 kg (SD = 7.36), body mass index of 21.27 (SD = 1.73) and normal
blood chemistries. The Cmax of Clinott-P(cid:31) was 3.94225 µg/ml at Tmax 1.75 hours and of Dalacin C(cid:31), 3.6847 µg/
ml at Tmax 2.09 hours. The AUC0-24 of Clinott-P(cid:31) was 16.32 + 6.13 µg.hr/ml and Dalacin C(cid:31) was 17.24 + 7.46
µg.hr/ml. Ninety percent confidence intervals of the mean ratios (test/reference) of log transformed of Cmax
(93.07-123.43%), AUC(0-24) (82.58-112.31%) and AUC(0-inf) (81.54-110.06%) were all within the standard
range (80-125 %) for bioequivalence study. Tenderness after injection around the deltoid area was assessed
blindly and was found to be slight (visual basic score < 5) and presented for one or two days after the
injection.
Conclusion : The two brands of clindamycin exhibit comparable pharmacokinetic parameters and volunteers
exhibited slight and tolerable tenderness at the injection site.
Keywords : Clindamycin phosphate, Bioequivalence study
