Abstract:
Background: Medicines in multidose containers (ex: liquid dosage forms) expose to the
environment due to repetitive opening and closing, accelerates the degradation of its quality,
leading to inappropriate consumption. Thus, it is crucial to follow the instructions including
storage depicted by healthcare professionals.
Objective: To evaluate the physiochemical and microbial stability of commercially available
analgesic syrups after keeping open for 0th, 15th, and 30th days
Methods: Five brands (A-E) of analgesic syrups (paracetamol/ibuprofen) were purchased from
community pharmacies in Karapitiya using simple random sampling method and they were
opened according to the frequency mentioned in British National Formulary (BNF). The
organoleptic properties (OP) were observed for color, odor, and appearance. The pH, viscosity,
density, and uniformity of mass of delivered doses were tested using a digital pH meter,
Brookfield viscometer, pycnometer, and provided measuring cup, respectively. Microbial
evaluation was performed by enumeration of bacteria by the spread plate method. All tests were
conducted for 0th, 15th, and 30th days after opening. The data were analysed using a one-way
ANOVA. Standard limits given in United States Pharmacopeia (USP) were considered.
Results: The OPs remain unchanged throughout the study period. Except for sample D, others
were within USP limits of pH. The density of all samples increased with time and was statistically
significant (p<0.05). Viscosity changes of A, C, and E samples were statistically insignificant
(p>0.01), while B and D were statistically significant (p<0.01). In uniformity of mass of delivered
doses, except sample E, there was at least one occasion where the BP limit (≤2 doses exceed
average weight±10%) was exceeded. Samples A and D were devoid of microorganisms on 0th day,
while sample C (50 CFU/mL) was within USP limits (<102 CFU/mL). Samples B and E (5×102
CFU/mL) exceeded the limit and on 15th day, all samples were exceeded USP limits. On 30th day,
all samples were exceeded USP limits but had less CFU/mL than on 15th day.
Conclusion: As per the frequency mentioned in BNF, repeated opening of syrup bottles affects
their physical and microbiological quality and stability.
