Clarification of the internal structure and factors of poor dissolution of substandard roxithromycin tablets by near-infrared chemical imaging.

The spread of substandard and falsified medicines has become a global problem, especially in low- and middle-income countries (LMICs). Previously, we found that some tablets containing the same active ingredient had large differences in their dissolution even though their contents were comparable. In this study, we investigated the poor dissolution of roxithromycin tablets using near-infrared chemical imaging (NIR-CI) to visualize the internal tablet structure. Roxithromycin tablets collected in LMICs and the pioneer product Rulid® as a reference were cut to a flat surface for analysis. NIR spectral data were normalized, and a principal component analysis was performed to create a tablet internal structure image. For Rulid®, the differences between the spectra with high and low scores were small, and well-defined aggregation of ingredients was not observed. However, large differences in the scores were found for roxithromycin tablets manufactured in some LMICs, and non-uniformity of ingredient distribution and aggregation were observed. Additionally, some pharmaceutical excipients, such as starch or magnesium stearate, were found in certain aggregates by comparing NIR spectra. The NIR-CI results showed some excipients existed as large aggregates, which indicated that the ingredients were not evenly mixed in the roxithromycin tablet, and this contributed to its poor dissolution.

A Cross-Sectional Investigation of the Quality of Selected Medicines for Noncommunicable Diseases in Private Community Drug Outlets in Cambodia during 2011-2013.

Although the issue of substandard and falsified medicines is quite well known, most research has focused on medicines used to treat communicable diseases, and relatively little research has been carried out on the quality of medicines for noncommunicable diseases (NCDs). This study was designed to assess the quality of seven widely used medicines for NCDs in Cambodia during 2011-2013. Medicines were collected from private community drug outlets in Phnom Penh (urban area), by stratified random sampling and in Battambang, Kandal, Kampong Speu, and Takeo (rural areas) by convenience sampling. Samples were subsequently analyzed by visual inspection, authenticity investigation, and pharmacopoeial analysis by high-performance liquid chromatography. Various discrepancies were observed in visual inspection of packages and medicines. Of 372 tablet/capsule samples from 64 manufacturers in 16 countries, the manufacturers confirmed 107 (28.8%) as authentic; the authenticity of other samples could not be verified. Three hundred sixty-four (97.8%) samples were registered in Cambodia. Among all samples, 23.4% (95% CI 19.2-28.0) were noncompliant in one or more of the quality tests: 12.9% (95% CI 9.7-16.7) contained an amount of active pharmaceutical ingredient outside the permitted range, including some showing extreme deviations, 14% (95% CI 10.6-17.9) failed because of content variation, and 10.8% (95% CI 7.8-14.4) failed to meet pharmacopoeial reference ranges in dissolution tests. Pharmaceutical quality appeared to be unrelated to storage conditions. Although no sample was obviously falsified, there is a high prevalence of substandard medicines for NCDs in Cambodia, indicating the need for focused regulatory action, including collaborative initiatives with manufacturers.

A Cross-Sectional Investigation for Verification of Globalization of Falsified Medicines in Cambodia, Indicated by Tablets of Sildenafil Citrate.

Medicine falsification is a global issue. Viagra, an erectile dysfunction therapeutic (EDT) medicine consisting primarily of sildenafil citrate, is the most commonly falsified medicine worldwide. Recently falsified EDTs have been reported multiple times in developing countries. The globalization of falsified EDTs has become a concern. In the present study, we selected sildenafil citrate tablets as an indicator and examined samples from a developing country, Cambodia, to investigate the availability of falsified sildenafil tablets in Cambodia and verify the current globalization status of falsified medicines from the standpoint of a developing country. Six samples of the originator Viagra, and 68 samples of generic sildenafil products were purchased from private drug outlets and wholesalers in Phnom Penh, Svay Rieng, and Battambang. The samples' manufacturers were contacted to authenticate the samples. The quantities and dissolution rates of active ingredients were measured by a high-performance liquid chromatography system with photodiode array. Five generic samples were strongly suspected to be falsified medicines because of their extremely low quality; however, there was little distribution and no falsified medicine alleged to be produced by the originator of Viagra, which charges high prices. That finding indicates that falsification reflects local economic circumstances.

Quality of omeprazole purchased via the Internet and personally imported into Japan: comparison with products sampled in other Asian countries.

OBJECTIVE: To evaluate the quality of omeprazole personally imported into Japan via the Internet and to compare the quality of these samples with previously collected samples from two other Asian countries. METHODS: The samples were evaluated by observation, authenticity investigation and pharmacopoeial quality analysis. Quality comparison of some selected samples was carried out by dissolution profiling, Raman spectroscopy and principle component analysis (PCA). RESULTS: Observation of the Internet sites and samples revealed some discrepancies including the delivery of a wrong sample and the selling of omeprazole without a prescription, although it is a prescription medicine. Among the 28 samples analysed, all passed the identification test, 26 (93%) passed the quantity and content uniformity tests and all passed the dissolution test. Dissolution profiling confirmed that all the personally imported omeprazole samples remained intact in the acid medium. On the other hand, six samples from two of the same manufacturers, previously collected during surveys in Cambodia and Myanmar, frequently showed premature omeprazole release in acid. Raman spectroscopy and PCA showed significant variation between omeprazole formulations in personally imported samples and the samples from Cambodia and Myanmar. CONCLUSIONS: Our results indicate that the pharmaceutical quality of omeprazole purchased through the Internet was sufficient, as determined by pharmacopeial tests. However, omeprazole formulations distributed in different market segments by the same manufacturers were of diverse quality. Measures are needed to ensure consistent quality of products and to prevent entry of substandard products into the legitimate supply chain.

Erroneous formulation of delayed-release omeprazole capsules: alert for importing countries.

BACKGROUND: Poor drug quality is a matter of serious concern, especially in countries where drug regulation and law enforcement are constrained by limited resources. This study was carried out to investigate the cause of quality failure of omeprazole in Cambodia in 2010 and Myanmar in 2014. METHODS: We conducted pharmacopoeial quantity, content uniformity and dissolution tests of 156 samples of omeprazole capsules collected in Cambodia in 2010 and Myanmar in 2014. High failure rates were found, especially in dissolution testing, and detailed investigation of several unacceptable samples was carried out by means of in-vitro dissolution profiling, scanning electron microscopy (SEM) and X-ray computed tomography (X-ray CT) to identify the cause of failure. RESULTS: Dissolution profiling with and without the acid stage showed that acid caused premature omeprazole release, indicating that the enteric coating of the omeprazole granules was ineffective. SEM examination of two failed samples revealed cracked and broken granules mixed with apparently intact omeprazole granules in the capsule. X-ray CT examination indicated that some granules of failed samples completely lacked enteric coating, and others had incomplete and non-uniform enteric coating or malformation. CONCLUSIONS: Omeprazole capsules collected in Myanmar and Cambodia showed high failure rates in pharmacopoeial tests, especially dissolution tests. Some samples were found to have ineffective or absent enteric coating of the granules, resulting in premature dissolution and degradation in acidic conditions. This is a potentially serious public health issue that needs to be addressed by regulatory authorities in Cambodia and Myanmar, possibly through a collaborative initiative with manufacturers.