Biowaivers are recommended for immediate-release solid oral dosage forms using dissolution testing as a surrogate for in vivo bioequivalence studies. Several guidance are currently available (the World Health Organization (WHO), the US FDA, and the EMEA) where the conditions are described. In this study, definitions, criteria, and methodologies according to the WHO have been applied. The dissolution performances of immediate-release metronidazole, zidovudine, and amoxicillin products purchased in South African and Indian markets were compared to the relevant comparator pharmaceutical product (CPP)/reference product. The dissolution performances were studied using US Pharmacopeia (USP) apparatus 2 (paddle) set at 75 rpm in each of three dissolution media (pH1.2, 4.5, and 6.8). Concentrations of metronidazole, zidovudine, and amoxicillin in each dissolution media were determined by HPLC. Of the 11 metronidazole products tested, only 8 could be considered as very rapidly dissolving products as defined by the WHO, whereas 2 of those products could be considered as rapidly dissolving products but did not comply with the f 2 acceptance criteria in pH 6.8. All 11 zidovudine products were very rapidly dissolving, whereas in the case of the 14 amoxicillin products tested, none of those products met any of the WHO criteria. This study indicates that not all generic products containing the same biopharmaceutics classification system (BCS) I drug and in similar strength and dosage form are necessarily in vitro equivalent. Hence, there is a need for ongoing market surveillance to determine whether marketed generic products containing BCS I drugs meet the release requirements to confirm their in vitro bioequivalence to the respective reference product.

-Purpose. Sceletium plant species have been reported to contain psychoactive alkaloids, specifically belonging to mesembrine-type alkaloids. Sceletium is presently marketed through health shops and on the internet as dried plant powder and as pharmaceutical dosage forms and purported to be useful in the treatment of psychological disorders. However, there are no validated analytical methods and reference standards of the relevant alkaloids are not commercially available for use in the analysis and quality control of Sceletium products and dosage forms. Hence, the objective of this research was to isolate and characterize appropriate analytical markers for use in the assay and as well as markers for fingerprinting by high performance liquid chromatography (HPLC). Methods. The separation of the relevant alkaloids was carried out on a C18 column and detected at a UV wavelength of 228nm. The method was validated and used to assay the mesembrine-type alkaloids namely Δ 7 mesembrenone, mesembranol, mesembrenone, mesembrine and epimesembranol. Results. The calibration curves were found to be linear over the entire concentration range of 400-60,000 ng/ml with correlation coefficients >0.99. The accuracies of the relevant alkaloids were found to be between 94.8 and 103.6% with an inter-day relative standard deviation (RSD) of less than 2.8%. The precision studies showed inter-day RSD's of less than 3%. The recoveries were all within the range of 95 and 105% (RSD<4.5%) and the limits of quantitation (LOQ) and detection (LOD) were found to be 100 and 200 ng/ml respectively using the respective S/N ratios of 3 and 10. Conclusions. An HPLC method for the quantitative analysis of Δ 7 mesembrenone, mesembranol, mesembrenone, mesembrine and epimesembranol in Sceletium plant material has been developed and validated. This assay method can be applied for the quality control of Sceletium plant material which is used as an African Traditional Medicine for the treatment of psychological disorders. _______________________________________________________________________________________

Complementary medicines containing the succulent herb Sceletium are being sold without information regarding their phytochemical contents, which is essential for the quality control of medicines. Furthermore, several different Sceletium species exist and little has been reported on the alkaloidal identities and contents of the various species. We therefore conducted phytochemical investigations on six selected Sceletium specimens, identified on the basis of their venation pattern as either 'emarcidum' or 'tortuosum' type. The tortuosum type consisted of S. tortuosum, S. expansum and S. strictum, whereas the emarcidum type consisted of S. emarcidum, S. exalatum and S. rigidum. Analysis was conducted by high-performance liquid chromatography with UV and alkaloids were identified by online mass spectroscopy. S. tortuosum and S. expansum samples contained mesembrine together with mesembrenone, mesembranol and epimesembranol, although the latter two alkaloids were present in low concentrations in S. expansum. S. strictum contained mesembrenone, mesembrine and either 4'-O-demethylmesembrenone or 4'-O-demethylmesembrenol. The emarcidum type specimens showed a complete absence of the major alkaloid mesembrine, as well as the other alkaloids usually associated with these species. In only one of the species of the emarcidum typeS. exalatum-two peaks corresponded to either 4'-O-demethylmesembrenone or O-methyljoubertiamine and either 4'-O-demethylmesembrenol or N-demethylmesembrenol, respectively. This study clearly indicates that not all Sceletium species contain the mesembrine-type alkaloids usually associated with Sceletium. It is thus important to identify the correct Sceletium species to ensure correct alkaloidal content for the manufacture and quality control of products containing this plant material.

Acyclovir, indicated in the treatment of herpes labialis ("cold sores"), is formulated as semisolid topical dosage forms and marketed in numerous countries. Since the formulations of the various acyclovir products may differ from country to country, this study was undertaken to compare the in vitro release of acyclovir from various generic cream products available on the South African and Indian markets using the respective brand/innovator product as the reference product. The in vitro studies were carried out using vertical diffusion cells with a diffusional surface area of 1.767 cm(2) and various commercially available membranes. Normal saline was used as receptor fluid and the temperature maintained at 32 ± 0.5°C. The in vitro release comparisons were based on the recommendations described in the US Food and Drug Administration Draft Guidance for acyclovir ointment and the SUPAC-SS Guidance for non-sterile semisolid dosage forms. The release rates (slope) of the test (T) and the relevant reference product (R) were monitored and compared. The comparative release of acyclovir from the various generic formulations compared with the reference product was found to be within the limits of 75-133.33% with a 90% confidence interval. These experiments indicate that the generic acyclovir cream formulations exhibited release rates that were comparable to the innovator product and could be considered to be bioequivalent.