FORMULATION AND EVALUATION OF METRONIDAZOLE AND ERYTHROMYCIN GEL BY DENNIS MWANGI KIBE U29/2013/2010 SUPERVISED BY ;PROF F.N KAMAU

INTRODUCTION Metronidazole is used in topical preparations for management of rosacea,acne vulgaris and fungating wounds. Erythromycin as a topical agent is mainly used mainly in combination with benzoyl peroxide and also in combination with tretinoin for the treatment of bacterial infections such as severe acne and also acne vulgaris

JUSTIFICATION Metronidazole topical formulation has positive effects on skin conditions rosacea and acne vulgaris. Topical erythromycin also has palliative and curative effects on severe acne and rosacea. A combination of the two would therefore produce a synergistic or augmenting effect to the benefit of the patient

OBJECTIVES To formulate a medicated gel containing both erythromycin and metronidazole To evaluate the content of metronidazole and erythromycin in the gel using a suitable method

METHODOLOGY FORMULATION The ingredients(%w/w) guar gum(5),metronidazole(1),erythromycin(2),benzyl alcohol(1),glycerine(1) and water(qs). Erythromcin base was extracted by hydrolyzing erythromycin ethyl succinate using 0.1M sodium carbonate for a period of 24 hrs,washed and dried for 7 days in a dessicator, purified by rehydrolysis,washed and dried again for 7 days Thin layer chromatography done to ascertain purity

FORMULATION CONT; Metronidazole base was extracted from finely ground tablets,dissolved in dilute HCL, filtration done to remove excipients,dilute NaOH was added to precipitape the base. The base was washed and dried in an oven at 40 degrees celsius for about 3 days Melting point determination done to ascertain purity( degrees celsius)

EVALUATION METHOD 1 HPLC method RP(4.6mmX25mm,5µm L7 packing);mobile phase 0.001M monobasic potassium phosphate pH4 and absolute methanol(35:65%v/v). Flow rate 0.8ml/min. Detection 254nm for metronidazole,215nm for erythromycin(90-125%)

RESULTS AND DISCUSSION 1 Only metronidazole was detected through this method. No peak obtained at 215 nm. The percentage label claim was %(complied to BP 2002 specifications) AREA UNDER THE PEAK SAMPLE ASAMPLE BSAMPLE CSTANDARD AVERAGE

METHOD 2( EVALUATION OF ERYTHROMYCIN ) HPLC RP(4.6mm x25mm with 5µm L7 packing) column; mobile phase acetonitrile- 0.2M K2PHO4-Water(35;5;60 v/v/v). Detection wavelength 215 nm flow rate 0.8ml/min

RESULTS AND DISCUSSION 2 No peak obtained. Dr. chepkwony obtained a peak using the same method. No Xterra column available,also due weak chromphore of erythromycin

METHOD 3(evaluation of erythromycin) Microbiological method; agar diffusion method. It lacks precision and has low sensitivity. Tryptone soya agar inoculated with Bacillus subtilis was the medium. 24 Hrs incubation, temperature ;37 degrees Celsius.

RESULTS AND DISCUSSION 3 Table showing zones of inhibition ZONES OF INHIBITION (mm) STANDARD HIGH9(µH) STANDARD LOW(µl) SAMPLE HIGH(SH) SAMPLE LOW AVERAGE

RESULTS CONT;

RESULTS AND DISCUSSION CONT; The zones of inhibition of sample solutions clearer and larger than the standard solutions This can be explained since metronidazole has relatively low activity against Bacillus subtilis The percentage label claim was %,much higher about 3 times the expected value.( % USP 2002) Synergistic or augmenting activity of metronidazole to erythromycin

CONCLUSION Possible formulation of a gel containing erythromycin and metronidazole Metronidazole content was accurately determined by HPLC % Erythromycin content not accurately determined due to effect of metronidazole

RECOMMEDATIONS A suitable method to be developed for accurate evaluation of the contents. Further development of the microbiological assay to take into account their individual activity Studies on synergistic activity and stability tests. Manufacture of a gel containing both metronidazole and erythromycin

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