A decision tree for rapid quality assurance and control of rifampicin-containing oral dosage forms for global distribution for tuberculosis treatment.

For centuries tuberculosis remained as a complex socioeconomic problem impeding human development. Directly observed treatment short-course and fixed dose combinations were implemented in tuberculosis therapy for maximum success of treatment. However, drug shortages primarily hindered the expansion of directly observed treatment short-course, which lead to development of the global tuberculosis drug facility. Since large geographical area is covered by the global tuberculosis drug facility for global drug supply for tuberculosis eradication programs, a rapid quality control and assurance has become necessary to ensure the quality and performance of supplied antituberculosis drugs. In this manuscript a decision tree is proposed for facilitating rapid quality control (in vitro and in vivo) of antituberculosis formulations procured by the global tuberculosis drug facility. This decision tree also predicted to be applicable at every stages of anti tuberculosis drug product development, especially in identification of poor quality products and monitoring batch-to-batch variability. Further, it provides opportunity for effective quality control in resource poor settings and the gained knowledge is anticipated to be applicable for development and evaluation of antimalarial and antiAIDS fixed dose combinations.

Dissolution testing of marketed rifampicin containing fixed dose combination formulations using a new discriminative media: a post marketing retrospective study.

Currently recommended compendial dissolution methods for quality control of orally administered solid dosage forms of rifampicin containing formulations are not found to be able to forecast the in vivo performance. A recently proposed dissolution method of 0.01 N HCl at 50 rpm using paddle apparatus for screening was found to be more appropriate and able to predict the in vivo performance of those formulations. The objective of this investigation was to validate the new method of dissolution testing for solid dosage forms of rifampicin containing formulations using a basket apparatus and to compare it with the frequently recommended pharmacopeial method. In the present study the newly proposed dissolution condition (0.01 N HCl) was validated using six formulations of two, three and four drug combinations from two different manufacturers by basket method and compared with the widely recommended compendial medium. In this investigation, the appropriateness of the proposed methodology was confirmed by the dissolution results of the two FDC formulations (a two-drug and a four-drug combinations) that had previously passed the bioequivalence tests. It was found that the recommended dissolution medium of 0.01 N HCl can be used for screening of rifampicin containing formulations using both paddle and basket dissolution apparatus at 50 rpm and 100 rpm, respectively.

Quality control of anti-tuberculosis FDC formulations in the global market: part II-accelerated stability studies.

OBJECTIVE: To determine the quality and performance of rifampicin (RMP) containing fixed-dose combination (FDC) formulations of anti-tuberculosis drugs sourced from the international market with respect to physical, chemical and dissolution properties after storage at accelerated stability conditions (40 degrees C/75% relative humidity) and to identify appropriate storage specifications. METHODS: Formulations across different companies and combinations were subjected to 6-month accelerated stability testing in packaging conditions recommended by the manufacturer. Various pharmacopeial and nonpharmacopeial tests for tablets were performed for 3- and 6-month samples. RESULTS: All the formulations were found to be stable, where extent of dissolution was within +/- 10% of that of the initial value, and all formulations passed the pharmacopeial limits for assay and content uniformity of 90-110% and +/- 15% of average drug content, respectively. CONCLUSIONS: Good quality RMP-containing FDCs that remain stable after 6-month accelerated stability testing are available in the marketplace.

Establishment of a reference formulation for bioequivalence assessment of rifampicin-containing FDCs: an essential step towards improving tuberculosis treatment.

SETTING: Selection of a reference product for bioequivalence studies of rifampicin (RMP) in prequalifying fixed-dose combinations (FDC) for worldwide distribution through the WHO is critical. OBJECTIVE: To investigate the feasibility of establishing FDC formulations as reference products for bioequivalence studies of RMP in prequalification programmes. DESIGN: A biostudy was conducted as an open, two-period randomised cross-over trial. Two three-drug FDCs containing RMP, isoniazid and ethambutol hydrochloride were administered to a group of 22 volunteers with a wash-out period of 1 week. Plasma samples were collected and analysed for the concentration of RMP and desacetyl-RMP, a major active metabolite of RMP, up to 24 h. Pharmacokinetic parameters of RMP were calculated: Cmax, AUC0-24, Tmax, kel and absorption efficiencies. RESULTS: No significant difference was observed between the administered formulations with respect to the major pharmacokinetic parameters Cmax, Tmax and AUC0-24 when evaluated by parametric (two-way ANOVA) and non-parametric (Hauschke's analysis) statistical analysis. The concentration of RMP falls within the reported acceptable therapeutic range. CONCLUSION: FDCs can be developed as a reference product for bioequivalence studies.

Plasma pooling: utility in expediting bioequivalence assessment of rifampicin-containing fixed-dose combinations.

To improve the rapidity of the registration process of rifampicin (RMP) containing fixed-dose combination (FDC) formulations, a plasma pooling methodology was used to increase the throughput of bioanalysis of plasma samples from bioequivalence trials of FDCs. Plasma samples of a biostudy were analysed for RMP using traditional analysis methods as well as a plasma pooling method (volunteer and time pooling). Both methods produced similar results, with less than 15% variability in both volunteer and time pooling. The plasma pooling method for bioanalysis was validated. Further studies are required to identify and reduce the percentage variability.

Quality control of anti-tuberculosis fixed-dose combination formulations in the global market: an in vitro study.

OBJECTIVE: To determine the quality, and especially the dissolution properties of rifampicin, of fixed-dose combination (FDC) formulations of anti-tuberculosis agents manufactured by major market holders in the anti-tuberculosis sector and supplied for use in national tuberculosis control programmes. METHODS: Dissolution studies were performed for four formulations supplied by four different manufacturers in four dissolution media (0.1N and 0.01N HCl, phosphate buffer [PB] and 20% vegetable oil in PB), at four different agitation rates using USP apparatus II. The formulations were subjected to 4-week accelerated stability studies (40 degrees C / 75% RH) and evaluated for physical, chemical and dissolution stability. RESULTS: The formulations tested complied with pharmacopeial quality control (QC) tests. The extent of rifampicin release was independent of dissolution medium; however, a slight decrease in the dissolution rate was observed in two products. More than 75% of drug was released in 45 min at all agitation intensities except 30 rpm, and 20% oil in the medium reflected fed state. Formulations were stable in the packaging conditions recommended by the manufacturer for at least 4 weeks. CONCLUSIONS: The formulations tested passed the QC tests and were found to be stable. A decrease in the rate, although not the extent, of dissolution necessitated multiple point dissolution in gastric and intestinal pH conditions to ensure consistency in in vivo bioavailability.

Fixed dose combinations for tuberculosis: Lessons learned from clinical, formulation and regulatory perspective.

Worldwide, tuberculosis (TB) remains one of the most important communicable diseases in terms of morbidity and mortality. Its control requires multi-drug therapy for at least six months, which could lead to patient non-compliance, failure of therapy and ultimately resulting in the emergence of drug resistance. Fixed dose combinations (FDCs) in TB therapy reduce the number of tablets to be consumed and thereby increase patient compliance with recommended treatment regimens. Thus, FDCs play a significant role in preventing the emergence of drug resistance and successful treatment. However, the quality of FDCs with respect to variable bioavailability and their registration requirements are major hurdles to their implementation in national TB control programs. It is anticipated that a large global market for FDCs will encourage large-scale production and increased competition, which in turn will result in FDCs at affordable prices. The Global Drug Facility (GDF), established by the World Health Organization (WHO), aims to ensure universal uninterrupted access to quality TB drugs for implementation of directly observed treatment short-course (DOTS) in resource-poor countries. In this program, four FDCs were accepted as the drugs of first choice because of their obvious advantages in controlling TB. This demands the necessity of addressing quality and registration requirements of FDCs systematically. In light of this current knowledge on anti-TB FDCs, their dosage, combinations, available clinical studies and the experiences with TB therapy has been discussed in this article, which should serve as lessons for selection of appropriate FDCs for other diseases such as malaria and AIDS.