Medicines informal market in Congo, Burundi and Angola: counterfeit and sub-standard antimalarials.
BACKGROUND
The presence of counterfeits and sub-standards in African medicines market is a dramatic problem that causes many deaths each year. The increase of the phenomenon of pharmaceutical counterfeiting is due to the rise of the illegal market and to the impossibility to purchase branded high cost medicines.


METHODS
In this paper the results of a quality control on antimalarial tablet samples purchased in the informal market in Congo, Burundi and Angola are reported. The quality control consisted in the assay of active substance by means of validated liquid chromatographic methods, uniformity of mass determination, disintegration and dissolution tests. Moreover, a general evaluation on label and packaging characteristics was performed.


RESULTS
The results obtained on thirty antimalarial tablet samples containing chloroquine, quinine, mefloquine, sulphadoxine and pyrimethamine showed the presence of different kinds of problems: a general problem concerning the packaging (loose tablets, packaging without Producer name, Producer Country and sometimes without expiration date); low content of active substance (in one sample); different, non-declared, active substance (in one sample); sub-standard technological properties and very low dissolution profiles (in about 50% of samples). This last property could affect the bioavailability and bioequivalence in comparison with branded products and could be related to the use of different excipients in formulation or bad storage conditions.


CONCLUSIONS
This paper evidences that the most common quality problem in the analysed samples appears to be the low dissolution profile. Here it is remarked that the presence of the right active substance in the right quantity is not a sufficient condition for a good quality drug. Dissolution test is not less important in a quality control and often evidences in vitro possible differences in therapeutic efficacy among drugs with the same active content. Dissolution profile can be dramatically affected by the choice of excipients in the oral solid formulation and, in many cases, is out of specifications due to the absence of formulation studies by producers of developing countries.
Gaudiano
Maria Cristina
MC
Dipartimento del Farmaco, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Roma, Italy. mariacristina.gaudiano@iss.it
Di Maggio
Anna
A
Cocchieri
Emilia
E
Antoniella
Eleonora
E
Bertocchi
Paola
P
Alimonti
Stefano
S
Valvo
Luisa
L
D000810:Angola; D000962:Antimalarials / Q000737:chemistry / Q000592:standards* / Q000600:supply & distribution*; D002063:Burundi; D002845:Chromatography; D003223:Congo; D004348:Drug Labeling / Q000592:standards; D004349:Drug Packaging / Q000592:standards; D006801:Humans; D011786:Quality Control; D012995:Solubility; D013607:Tablets / Q000737:chemistry / Q000592:standards / Q000600:supply & distribution
D000962:Antimalarials; D013607:Tablets