Stability of cefmetazole-doxycycline mixtures in sodium chloride and dextrose injections

Transcription

1 Journal of Clinical Pharmacy and Therapeutics (1994) 19, Stability of cefmetazole-doxycycline mixtures in sodium chloride and dextrose injections A. D. King, J, T. Stewart and F. W. Warren Deparfmenf of Medicinal Chemistry, College of Pharmacy, The Universify of Georgia, Afhens, GA , U.S.A. SUMMARY This study involved the mixing of cefmetazole I and 2Gm with doxycycline 100 and 200mg, in sodium chloride and dextrose injections. The mixtures were stored either at ambient temperature for 96 h or at 4 C for 168 h followed by 8 h' at ambient temperature. HPLC assay of both cefmetazole and doxycydine levels were performed at prescribed sampling times. Cefmetazole in doxycycline 100 and mixtures, in sodium chloride injection was not stable up to 4 h, but cefmetazole in doxycycline 100 and 200 rng mixtures, in sodium chloride injection was stable for up to 24 h. The cefmetazole controls were stable for 72 h in sodium chloride injection. Cefmetazole I Gm with doxycycline, in dextrose injection was stable up to 72 h. The cefmetazole and doxycycline mixture in dextrose injection was stable for 96 h. Cefmetazole and doxycyline in dextrose injection was stable up to 96 h, but the cefmetazole- doxycyche mixture was only stable for 72 h. Cefmetazole controls in dextrose injection were stable for 24h. Doxycycline 100 and were stable with cefmetazole 1 and, in both sodium chloride and dextrose injections for 96 h at ambient temperature. Doxycycline control solutions were also stable for 96 h. Cefmetazole 1 and and doxycycline 100 and were generally stable in both sodium chloride and dextrose injections at 4 C for 168 h, and at ambient temperature for 8 h. A precipitate was observed at 48 h with the cefmetazole doxycycline mix in sodium chloride and at 8 h in dextrose injection. In both cases, removal Compondence: 1. T. Stewart. from 4 C storage followed by storage and re-assay at ambient temperature supported the re-dissolution of one or both medications. INTRODUCTION Cefoxitin, in combination with doxycycline, has been recommended by the United States Center for Disease Control and Prevention for pelvic inflammatory disease (I). Since cefmetazole has a longer half-life than cefoxitin and is therefore only administered twice daily, combinations of cefmetazole and doxycycline may also be effective in pelvic inflammatory disease. No information was available in the literature on the stability of this drug combination in 0.9% sodium chloride or 5% dextrose in water injections. In this study, 2 g cefmetazole vials and 100 and doxycycline vials were reconstituted with appropriate volumes of 0.9% sodium chloride, or 5% dextrose, in water injection. Aliquots of each vial were transferred to polyvinyl chloride bags and diluted to either 100 or 250 mi volume with the respective injection. Bags were stored either at ambient temperature (23 f IT) for 96 h or at 4 C for 168 h followed by 8 h at ambient temperature. During the refrigeration study, any bag in which the assay of cefmetazole or doxycycline at a sampling time was less than 90% of initial concentration was removed from the 4 C storage and assayed at ambient temperature for various time periods to determine if the stability of either drug had increased or decreased. MATERIALS AND METHODS Mafrnmak Cefmetazole (Lot 204) working standard and 2 g cefmetazole injection (Lot 25174) were supplied by the 317

2 318 A. D. King et al. B I L Retention time (min) Fig. 1. Sample HPLC chromatogram of cefmetazole assay in a cefmetazole-doxycycline mixture. (A) doxycydine, (B) cefmetazole, (0 acetaminophen (internal standard). For assay conditions, see Materials and Methods. Upjohn Company, Kalamazoo, MI. Doxycydine (Lot 9M QSC-06) working standard and (Lot A718D) and doxycyline vials (Lot 6x038) were furmshed by Pfizer, Inc., New York NY. Sodium chloride injection (0.9%) in 100d viaflex bags (Lot ZP026302) and 250d viaflex bags (Lot C071233) and 5% dextrose in water injection in 100 mi viaflex bags (Lot ZP026906) and 250ml viaflex bags (Lot C189077) were purchased from Baxter Healthcare Cop, Deerfield, IL. HPLC solvents and supplies were obtained through the University of Georgia Chemical Research Store. All other chemicals and solvents used in the study were of the highest grade commercially available. Retention time (min) Fig. 2. Sample HPLC chromatogram of doxycycline assay in a doxycydine-cefmetazole mixture. (A) cefmetazole, (B) doxycydine. For assay conditions, see Materials and Methods. Liquid chromntography systems Two HPLC systems consisting of a Waters Associates Pump (Model Sol), a Micromeritics Autosampler (Model 728) equipped with a 20pI loop, a Kratos variable wavelength ultraviolet detector (Model 75 7) set either at 254nm for cefmetazole or 280nm for doxycycline, and a Shimadzu Integrator (Model CR-3A) were used in the study. A Spherisorb ODS column (25 an x 4.6 mm i.d., Keystone Scientific) was utilized for the cefmetazole assay and a p-bondapak CIS column' (30 an x 3.9 mm i.d., Phenomenex) was employed for the doxycycline assay. The assay method for cefmetazole was supplied by The Upjohn Company (2). The mobile phase consisted of 9010 v/v 0.1 M aqueous sodium acetate/acetonitrile at a flow rate of 1.0 mvmin and utilized a peak height ratio of

3 Sta&ilify of cefmetawle-doxycycline mixtures 3 19 Table 1. Stability of and cefrnetazole with and without doxycydine in sodium chloride and dextrose injections stored at ambient temperature for 96 h Actual cefmetazole i.v. fluid initial conc. % Initial conc. remaining* Cehetazole DoxycycIine volume mg/ml conc. conc. (d)' (mean f SD)t 4h 8h 24h 48h 72h 96h I Gm I Gm s f f s f f I Gm I Gm D-I f f f f 'S is 0.9% sodium chloride injection, D is 5% dextrose in water injection. tmean f SD, based on n=4. *Mean of four determinations; SD 4 5.3% unless otherwise stated. 5Mean of two determinations. cefmetazoldacetaminophen (internal standard) to obtain a calibration curve. The elution time for cefmetazole was about 5.3 min. The assay method for doxycycline was the official USP XXII method for doxycycline hyclate (3). The mobile phase consisted of 55:45:3 v/vfv absolute methanolh-1 M aqueous monobasic sodium phospha teln,n-dime thyl-noctylamine (ph adjusted to 8.0) at a flow rate of 1-5 dmin. The elution time for doxycycline was about 4.6 min. daily and injected in duplicate before and after each set of samples to obtain a cefmetazole calibration curve. An accurately weighed quantity of 11.6 mg of doxycycline hyclate working standard was transferred to a 10ml volumetric flask and water was added to this volume to give a ha1 concentration of 1 mg/ml, expressed as the free base. This standard was prepared fresh daily and injected in triplicate before and after each set of samples. Preparation of cefmetazole and doxycycline standard solutions Accurately weighed quantities of 0.5, 1.0 and 1.5 mg of cefmetazole working standard were added to individual 25 ml volumetric flasks. One ml of water was added, followed by acetaminophen internal standard solution (20 mg/ml in water) to this volume to give ha1 cefmetazole concentrations of 20, 40 and 60 pg/ml. These standards were prepared fresh Preparation of cefmetazole-doxycycline admixtures The vials of cefmetazole and the 100 and vials of doxycycline were reconstituted with either 0.9% sodium chloride injection or 5% dextrose in water injection. Aliquots equivalent to I Gm cefmetazole and 100mg doxycycline, and cefmetazole and 200mg doxycycline, were transferred to 100 ml polyvinyl chloride bags containing either sodium chloride injection or dextrose in water

4 320 A. D. King et al. Table 2. Stability of 100mg and 2OOmg doxycycline with and without cefmetazole in sodium chloride and dextrose injections stored at ambient temperature for 96 h Actual doxycycline i.v. fluid Doxycycline Cefmetazole volume initial conc. mg/ml % Conc. remaining* conc. conc. (d)* (mean f SD)t 4h 8h 24h 48h 72h 96h $100 s-100 s f f $ s f f f f ,793 f ,738 f is 0.9% sodium chloride injection, D is 5% dextrose in water injecl ion. tmean f SD, based on n=4. *Mean of four determinations; SD SZWO unless otherwise stated. 5Mean of two determinations. injection. Aliquots equivalent to I Gm cefmetazole and doxycydine. and cefmetazole and doxycydine, were transferred to 250 ml polyvinyl chloride bags containing either sodium chloride injection or dextrose in water injection. Control bags containing only 1 and cefmetazole and 100 and doxycydine were also prepared in each injection. The mixtures were stored at ambient temperature (23 f 1 C) for up to 96 h with an assay of cefmetazole and doxycycline content at 0,4,8,24,48,72 and 96 h. Similar mixtures were also prepared and stored at 4'C for 168 h, followed by ambient temperature for 8 h, with assay of cefmetazole and doxycycline content at 0.4, 8,24,48, 72, 96 and 168 h, and then at I, 2,4 and 8 h after removal from 4 C storage. Any bag in which there was less than 90% of the initial concentration of cefmetazole or doxycydine remaining at a particular sampling time was removed from the 4 C storage, stored at ambient temperature, and assayed at various tie periods to note if stability increased or deaeased. Preparation of analytical samples To measure the cefmetazole content in each fluid, a loml aliquot was withdrawn from each bag and diluted, to yield a cefmetazole concentration of about 1 mg/ml. A 1.0 ml sample was transferred to a 25 ml volumetric flask and the 20 mg/d acetaminophen solution (internal standard) added to the volume. Injections of 20 pl sample solution were introduced into the liquid chromatograph to assay for cefmetazole content. To measure doxycycline content in each fluid, undiluted aliquot was withdrawn from each bag and 20 pl samples injected directly into the liquid chromatograph to assay for doxycycline concentration. Calculation of cefmetawle and doxycyciine content in admlrtures Peak height ratios of cefmetazole/acetaminophen were calculated from the standard solutions, and linear regression analysis of the data gave the slope and correlation coefficient of the calibration curve.

5 Table 3. Stability of 1 and cefmetazole with and without doxycycline in sodium chloride and dextrose injections stored at 4 C for 168 h followed by ambient conditions for 8 h Actual cefmetazole 9/0 Initial conc. remaining* i.v. fluid initial conc. Cefmetazole Doxycycliie volume mg/ml conc. conc. (d)* (mean f SD)t 4h 8h 24h 48h 72h 96h 168h +ih +2h +4h +8h s f $ f $ S f v, 8.21 f lo a f f S is 0.9% sodium chloride injection, D is 5% dextrose in water injection. tmean f SD, based on n=4. *Mean of four determinations; SD I6-% unless otherwise stated. SMean of two determinations. 43 B 3 h 8 P R 3 I bj h, w

6 Table 4. Stability of 100 and 200 doxycycline with and without cefrnetazole in sodium chloride and dextrose injections stored at 4 C for 168 h followed by ambient conditions for 8 h A d dox~~dine % ~Ntial mnc. remaining* i.v. fluid initial conc. Doxycydine Cefinetazole volume mg/d conc. conc. (Id) (mean f SD)t 4h 8h 24h 48h 72h 96h 168h +ih +2h +4h +8h $100 SlOO f $250 S f f I Gm D-I f Na f f NV S is sodium chloride injection, D is 5% dextrose in water injection. tmean f SD, based on n=4. *Mean of four determinations; SD < 5.3% unless otherwise stated. Mean of two det&nations. IND indicates no data collected.

7 Stability of cefmefawldoxycycline mixfures 323 Table 5. Stability of cefmetazole and doxycycline with and without the other medication in sodium chloride injection stored at 4 C for 48 h followed by ambient conditions for 8 h Actual i.v. fluid initial conc. Cefmetazole Doxycycline volume mg/ml conc. conc. (ml)* (mean f SD) % Initial conc. remainingt h ah 24h 48h +ih +2h +4h +sh 2 Grn S-I00 18,79* S f S "' 100 rng S f 0.035tt NDS ND ND ND NDT ND ND ND 'S is 0.9% sodium chloride injection. tmean of four determinations; SD 54% unless otherwise stated. SCehetazole, mean of two determinations. 5ND indicates no data collected. TCehetazole, mean f SD based on n = 4. "Doxyqcline, mean of two determinations. I-tDoxycycline, mean f SD based on n=4. where R, is the peak height ratio cefmetazole/ acetaminophen in each sample, M is the mean through origin slope of the calibration curve, Ds is the sample dilution factor, if any, and P, is the purity of the cefmetazole working standard expressed as a fraction. Doxycydine (mg/ml)=- AS, x C,, x Pst; AS, where A, is the peak area of the sample, A,, is the mean peak area of the standard doxycycline preparation, C,, is the concentration of the reference standard in mg/ml, and P,t is the purity of the doxycydine hyclate working standard expressed as a fraction. RESULTS AND DISCUSSION 'The correlation coefficients of cefmetazole standard curves in sodium chioride and dextrose in water injections were greater than Intra-day slope precision for cefmetazole was 1.8% and 1.7% for sodium chloride and dextrose injections, respectively. Inter-day slope precision for cefmetazole was in the 619% range for both injections. For doxycycline, chromatographic criteria defined in the USPXXII monograph were met. The average number of plates was 3500, peak tailing factor was <2.0, and the reproducibility of replicate injections was in the % and % ranges for sodium chloride and dextrose injections, respectively. Sample HPLC chromatograms of each drug under their respective assay conditions are shown in Figs I and 2. There were no interferences in the assays for either drug by the other medication or its degradation products or ingredients contained in the sodium chloride or dextrose injections. This was ascertained by degrading each drug in each injection with IN hydrochloric acid and 1 N sodium hydroxide for 6 h at SOT followed by diode array detection in the respective HPLC systems for cefmetazole and doxycycline. Each drug was judged to be stable in the respective mixtures if the drug content remained greater than 90% of initial levels. The stability of the mixtures was also compared to that of control solutions containing only cefmetazole or doxycycline in the appropriate injection fluid. Physical compatibility was judged by visual observation of the mixtures at the time of preparation and at each sampling time. Table I contains stability data for 1 and 2Gm cefmetazole with 100 and 200mg doxycycline in mixtures prepared with sodium chloride and dextrose injections and stored at ambient temperature for 96 h in polyvinyl chloride bags. The data shows that cefmetazole was not stable up to 4 h and cefmetazole was stable only up to 24 h with either

8 324 A. D. King et al. Table 6. Stability of cefmetazole and doxycycline with and without the other medication in dextrose injection stored at 4'C for 8 h, followed by ambient conditions for 88 h i.v. fluid Actual initial conc. % Initial conc. rernainingt Cefmetazole Doxycydie volume rng/ml conc. conc. (ml)' (mean f SD) 4h 8h +16h +40h +64h +88h 17.65$ I00 mg D-ZOO f ,6 D-I ofi ND" 2 Grn f 0.006e 'D is 5% dextrose in water injection. tmean of f9ur determinations; SD 56.3% unless otherwise stated. SCefmetazole, mean of two determinations. SCefmetazole, mean f SD based on n=4. moxycycline, mean of two determinations. "ND indicates no data collected. HDoxycydine, mean f SD based on n= or doxycycline in sodium chloride injection. The respective control solutions of cefrnetazolc were stable for 72 h. Cefmetazole with doxycycline 100mg was stable up to 72 h in dextrose injection. The cefmetazole- doxycycline mixture in dextrose injection was stable up to 96 h. The cefmetazole I Gm-doxycycline in dextrose injection was stable up to 96 h, but the cefmetazole 2Gm-doxycydine 200mg mixture was only stable up to 72 h. Both cefmetazole control solutions were only stable up to 24 h. The doxycycline data shown in Table 2 indicates that 100 and doxycydine were stable with 1 and 2Gm cefmetazole in sodium chloride and dextrose injections for up to 96 h at ambient temperature. The respective control solutions were also stable up to 96 h. Table 3 contains stability data for 1 and cefmetazole with 100 and 200mg doxycycline in mixtures prepared with sodium chloride and dextrose injections and stored at 4 C for 168 h followed by ambient temperature for 8 h. Cefmetazole was shown to be stable in these mixtures for the entire study period. Similar data was also obtained for doxycydine, as shown in Table 4. However, during the 4 C-168 h study, a visual inspection of the cefmetazole- doxycydine mixtures in sodium chloride and dextrose injections indicated that a precipitate was observed at 48 h following preparation in sodium chloride injection and at 8 h for the dextrose mixture. In the cefmetazole- doxycycline mixture in sodium chloride injection, assay of both medications indicated approximately 90% of initial levels. In the dextrose injection, levels of cefmetazole were above 90%, while doxycycline concentrations were clearly less than 90%. The bags were immediately removed from the 4 C storage and stored at ambient temperature, with subsequent re-assay of cefmetazole and doxycycline levels at various time periods. The data in Table 5 indicated that cefmetazole and doxycycline levels in sodium chloride injection increased upon storage at ambient temperature, thus implying a redissolution of both medications at ambient temperature. The data in Table 6 indicated that doxycycline levels in the dextrose mixtures also increased upon removal from storage at 4 C and storing at ambient temperature. Why this phenomenon was not observed with similar mixtures in this study stored under identical conditions was not clear. CONCLUSION Cefmetazole with doxycycline 100 and mixtures in sodium chloride injection at ambient temperature was not stable up to 4 h. Cefmetazole with doxycycline 100 and mixtures in sodium chloride injection was stable up to 24 h. The respective cefmetazole control solutions in sodium

9 Stubihfy of cefmetazo/e-doxycyche mixtures 325 chloride injection were stable up to 72 h. Cefmetazole with doxycycline in dextrose injection was stable up to 72 h. The cefmetazole and doxycycline mixture in dextrose injection was stable up to 96 h. The cefmetazole I Gm and doxycycline in dextrose injection was stable up to 96 h, but the cefmetazole- doxycycline mixture was only stable up to 72 h. The cefmetazole control solutions in dextrose injection were only stable up to 24 h. Doxycycline 100 and were stable with cefmetazole 1 and in sodium chloride and dextrose injections for up to 96 h at ambient temperature. The doxycycline control solutions were also stable up to 96 h. Cefmetazole 1 and and doxycycline 100 and were generally stable in sodium chloride and dextrose injections stored at 4 C for 168 h followed by ambient temperature for 8 h. The cefmetazole -doxycycline mixture in both sodium chloride and dextrose injections showed a precipitate at 48 h in sodium chloride and after 8 h in dextrose. Subsequent storage and re-assay at ambient temperature showed that levels of cefme tazole and doxycycline increased, thus indicating a possible redissolution of both medications. ACKNOWLEDGEMENT The authors thank The Upjohn Company for financial support. REFERENCES CDC. (1989) Pelvic Inflammatory Disease1 989 CDC Guidelines, Morbidity, Mortality Weekly Report, 3 8 ISuppl. 81, pp Centers for Disease Control and Prevention, Atlanta, G h Bothwell WM, Bombardt PA (1985) Reversed Phmc Liquid Chromatographic Method for U-72, 797A in Solutions, Internal Memo to D. L. Teegarden. The Upjohn Company, Kalamazoo, MI, December. (1990) Doxycydine monograph, The United States Phamacopeia, 22nd Revision, National Formula y, 17th revision, p U.S. Pharmacopeial Convention, Rockville, MD.