Stability of Oxytocin Preparations in Malawi and Rwanda: Stabilizing Effect of Chlorobutanol

Designing Formulation Strategies for Enhanced Stability of Therapeutic Peptides in Aqueous Solutions: A Review

Over the past few decades, there has been a tremendous increase in the utilization of therapeutic peptides. Therapeutic peptides are usually administered via the parenteral route, requiring an aqueous formulation. Unfortunately, peptides are often unstable in aqueous solutions, affecting stability and bioactivity. Although a stable and dry formulation for reconstitution might be designed, from a pharmaco-economic and practical convenience point of view, a peptide formulation in an aqueous liquid form is preferred. Designing formulation strategies that optimize peptide stability may improve bioavailability and increase therapeutic efficacy. This literature review provides an overview of various degradation pathways and formulation strategies to stabilize therapeutic peptides in aqueous solutions. First, we introduce the major peptide stability issues in liquid formulations and the degradation mechanisms. Then, we present a variety of known strategies to inhibit or slow down peptide degradation. Overall, the most practical approaches to peptide stabilization are pH optimization and selecting the appropriate type of buffer. Other practical strategies to reduce peptide degradation rates in solution are the application of co-solvency, air exclusion, viscosity enhancement, PEGylation, and using polyol excipients.

In Vivo Evaluation of the Oral Toxicity of the Chlorobutanol

Chlorobutanol (CB) is used as a preservative in cosmetics and has antibacterial activity. This study investigated the single- and repeated-dose 28-day oral toxicity of a CB solvent in Sprague Dawley (SD) rats. For the single-dose oral toxicity study, a dose of 62.5, 125, or 250 mg per kg of body weight (mg/kg b.w.) of CB was given once orally via gavage. For the repeated-dose 28-day toxicity study, the high dose was set as 100 mg/kg b.w./day, and the middle, middle-low, and low doses were set to 50, 25, and 12.5 mg/kg b.w./day, respectively. Body weight was not significantly changed in the repeated-dose toxicity study. Relative liver and kidney weights were significantly increased in both sexes of the 100 mg/kg b.w./day treatment group. However, there were histopathological changes in liver and kidney for females and males, respectively. These data suggested that the approximate lethal dose (ALD) of CB was over 250 mg/kg b.w./day in the single-dose study, and the no adverse effect level (NOAEL) for CB was over 50 and 12.5 mg/kg b.w./day for female and male rats in the repeated-dose toxicity study.

Identification of Substandard and Falsified Medicines: Influence of Different Tolerance Limits and Use of Authenticity Inquiries

Substandard and falsified medicines have severe public health and socioeconomic effects, especially in low- and middle-income countries. The WHO has emphasized the need for reliable estimates of the prevalence of such medicines to efficiently respond to this problem. In the present study, we used 601 medicine samples collected in Cameroon, the DR Congo, and Malawi to assess the rates of substandard and falsified medicines based on different criteria. Based on the specifications of the U.S. Pharmacopoeia for the amount of the active pharmaceutical ingredients, the rate of out-of-specification medicines was 9.3%. By contrast, this rate ranged from 3.3% up to 35.0% if the tolerance limits of other pharmacopoeias or recently published medicine quality studies were used. This shows an urgent need for harmonization. Principal methods to assess the rate of falsified medicines are packaging analysis, chemical analysis, and authenticity inquiries. In the present study, we carried out an authenticity inquiry for the aforementioned medicine samples, contacting 126 manufacturers and 42 distributors. Response rates were higher for samples stated to be manufactured in Asia (52.4%) or Europe (53.8%) than for samples manufactured in Africa (27.4%; P < 0.001). One sample had been identified as falsified by packaging analysis by the local researchers and two additional ones by chemical analysis. Notably, seven additional falsified samples were identified by the authenticity inquiries. The total rate of falsified medicines resulted as 1.7%. Considerations are discussed for assessing the rates of "substandard" and "falsified" medicines in future medicine quality studies.

Quality of oxytocin and misoprostol in health facilities of Rwanda

Sustainable Development Goal 3.1 calls for a reduction of the maternal mortality ratio to less than 70 per 100,000 live births by 2030. The most important cause of maternal mortality is post-partum haemorrhage (PPH). Oxytocin injections and misoprostol tablets are medicines of first choice for the management of PPH in low- and middle-income countries (LMICs). Unfortunately, both substances are chemically unstable, and previous studies have revealed serious quality problems of these medicines in LMICs. The present study is the first report on their quality in Rwanda. From 40 randomly selected health facilities (hospitals, health centers, retail pharmacies and private clinics) in different parts of Rwanda, as well as from six wholesalers and government stores, oxytocin injections and misoprostol tablets were collected. Oxytocin storage temperatures in the health facilities were monitored for six months using temperature data loggers, and found to correctly follow the storage requirements stated by the manufacturers (2–8°C, or room temperature) with few minor deviations. Oxytocin injections (57 samples, representing seven batches of four brands) were tested for their oxytocin content and pH value according to the United States Pharmacopeia. Twenty-four samples from three European manufacturers passed all tests. However, all nine samples of one batch of a Chinese manufacturer showed an excessive content of oxytocin (range 117.2–121.5% of the declared amount). Another batch of the same manufacturer showed extreme variations of the concentration of the preservative benzyl alcohol. Misoprostol tablets (25 samples, representing ten batches of six brands) were tested for content and dissolution according to the International Pharmacopoeia. Fifteen samples passed, but all 10 samples of two brands from India failed with extreme deviations, containing only 42.5–48.7% of the stated amount of misoprostol. In conclusion, oxytocin quality in Rwanda was better than reported from other African countries. However, two extremely substandard brands of misoprostol tablets were found. The Rwandan authorities reacted quickly and efficiently, and recalled these substandard medicines from the market. For oxytocin and misoprostol, with their well-known problems of quality and stability, procurement should possibly be restricted to medicines which are WHO-prequalified or which have been manufactured in countries with stringent regulatory authorities.