One of the major causes of global morbidity remains infectious diseases [1] , specifically in low-resource countries where insufficient resources, inadequate infrastructure and poor access to health services impact disease outcomes [2] . Thus to allow access to medicines for all and at a bearable price, the Bamako initiative was adopted in 1987 by the African ministers of health during the 37^th session of the World Health Organization (WHO) in Mali [3] . Amoxicillin is part of the beta-lactam family [4] . Effective against a broad spectrum of bacteria and of low toxicity for mammalian cells [5] , the use of beta-lactams represents 65% of the total world market for antibiotics [6] . A counterfeit medicine is a medicine that is deliberately and fraudulently provided with a label that does not indicate its identity and/or its true source. It can be a specialty or a generic product, and among counterfeit products, there are some that contain the right ingredients or bad ingredients or even no active ingredient and there are others where the active ingredient is in insufficient quantity or whose packaging has been falsified [7] .

So far, more than 920 medical products have been reported as counterfeit, belonging to all main therapeutic classes and concerning brand-name drugs as well as generic drugs. The WHO estimates that 25% of drugs used in developing countries are counterfeit or substandard and that 5% of antibiotics sold worldwide are counterfeit [8] . Among the counterfeit medicines discovered, many cases have shown harmful health effects. In extreme cases, we can observe the aggravation of the pathologies treated [9] . Quality control is, therefore, necessary to provide populations with quality amoxicillin and limit the consequences of the use of poor-quality amoxicillin. It is in this perspective that this work falls under the general objective of which was to contribute to the evaluation of the quality of generic drugs based on amoxicillin available in Senegal.

In this work, we proposed to carry out the control of the generics of amoxicillin within the framework of the follow-up of the quality. We therefore took 42 samples including 10 tablets, 15 drinkable suspensions and 17 capsules from 4 wholesale distributors in Senegal.

The primary and secondary packaging carried all the mandatory information required by good manufacturing practice. Visual analysis of the powder for odor and color criteria gave a white, crystalline powder with a characteristic amoxicillin odor. All the drugs were compliant in terms of the appearance of the capsules, the color and the smell of the powder. The study of the organoleptic characteristics revealed no apparent sign of degradation. Diop A et al. who detected by the visual inspection test the problems related to the presence of physical damage (breakage, dirt, cracks, foreign particles) and the absence of the expiry date [11] .

Visual inspection corresponds to the requirements of good manufacturing practices for medicinal products. This seems to show that all the samples in our study went through the normal supply circuit because GUEYE found in Senegal that nearly 67% (n = 34) of the antibiotics in the illicit sector showed non-compliance regarding labeling with absence of manufacturer’s address and/or batch number [12] .

The determination of the average weight and the variations in weight carried out on the capsules and tablets showed that the samples collected presented variations in weight in accordance with the standards generally accepted by the pharmacopoeias, that is to say, ±7.5% for capsules with an average weight between 300 mg and more and ±5% of tablets with a weight > 250 mg [13] .

The mass uniformity of capsules and tablets is therefore in line with the standard. Thus, our study allows us to note the absence of significant variations in weight which could lead to variations in dosage (under or overdose). These results do not agree with those of Lilian C. Koech who found 13.6% failure [14] .

Dissolution is an element that affects the bioavailability of the drug. Thus, a capsule or tablet that does not meet dissolution standards will necessarily have low bioavailability even with a good dosage. The dissolution test of all the capsules in our sample was compliant with a rapid release of more than 80% in 60 min (86.8% to 108.8%) [10] . All amoxicillin samples released the expected amount of active ingredient (PA) over time and met USP tolerance limits [15] .

The term PA refers to a substance that has therapeutic properties. It is therefore the essential component of the drug because the presence of PA is essential for obtaining a therapeutic effect. In our study, all amoxicillin samples exhibited retention time consistent with that of reference amoxicillin. The identification therefore complies with the specifications of USP 36, which recommends a difference in retention time between the samples and their standards of ≤2% [16] .

The dosage of PA guarantees the safety of the drug because the difference between a drug and a poison is the dose [17] . We cannot therefore speak of drugs when there is an underdose, even less when we are faced with an overdose. The underdosage of antibiotics is a source of resistance phenomena that jeopardize the achievements of antibiotic therapy in our developing countries.

Amoxicillin capsules, tablets and oral suspensions were assayed using high performance liquid chromatography. This assay made it possible to determine the amoxicillin content in all the samples analyzed. This assay showed that the samples have amoxicillin levels which are normal because they belong to the compliance interval which is [90% to 120%]. This result is different from that of Sherryl G. Robertson who found that 15% (28/190) did not meet pharmacopoeial requirements [18] . On the other hand, the Ecumenical Pharmaceutical Network, which found in one of the studies that 83 of the 92 samples (90.21%) were in complete compliance with the requirements of the pharmacopoeia [19] .

Since amoxicillin is one of the most widely used essential drugs in Senegal and even throughout the world, it is therefore essential to carry out the various checks before and after marketing authorization, not only to check the quality but also to also the constancy of the quality of these drugs. All samples in our study are 100% compliant with European and American Pharmacopoeia standards (90% - 120%).

This work gives a fairly clear idea of the quality of amoxicillin with 100% compliance.

We can therefore say that the use of amoxicillin in the formal sector guarantees a therapeutic result.

However, during storage of amoxicillin, degradation products or substances related to amoxicillin may appear in the product. Other studies will therefore have to be oriented in the direction of stability as well as the dosage of degradation products.

It will also be necessary to undertake studies on other commonly used antibiotics in order to guarantee our populations quality antibiotic therapy and thus limit the progression of resistant germs.

The authors declare no conflicts of interest regarding the publication of this paper.

Bernadette, C.D., Tata, S.F., El Béchir, N.M., Mahamar, N., Abba, T.H., Madani, M., Blaise, D., Diéry, D., Yaranga, K.B. and Omar, S.S. (2023) Audit of the Physico-Chemical Quality of Amoxicillin Based Drugs Marketed in Senegal. American Journal of Analytical Chemistry, 14, 351-361. https://doi.org/10.4236/ajac.2023.149019