Dissolution test for lamivudine tablets: optimization and statistical analysis

Development of a Novel Polymeric Nanocomposite Complex for Drugs with Low Bioavailability

Semi-synthetic biopolymer complex (SSBC) nanoparticles were investigated as a potential oral drug delivery system to enhance the bioavailability of a poorly water-soluble model drug acyclovir (ACV). The SSBCs were prepared from cross-linking of hydroxyl groups on hyaluronic acid (HA) with poly(acrylic acid) (PAA) resulting in ether linkages. Thereafter, conjugation of 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) onto HA-PAA was accomplished using a 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC)/N-hydroxysuccinimide (NHS)-promoted coupling reaction. Nanoparticle powders were prepared by spray drying of drug-loaded SSBC emulsions in a laboratory nano spray dryer. The prepared SSBC was characterized by Fourier transform infrared (FT-IR) spectroscopy, differential scanning calorimetry (DSC), ¹H nuclear magnetic resonance (NMR) imaging, and X-ray diffraction (XRD) spectroscopy. The average particle size was found to be 257.92 nm. An entrapment efficiency of 85% was achieved as ACV has enhanced affinity for the hydrophobic inner core of the complex. It was shown that SSBC improved the solubility of ACV by 30% and the ex vivo permeation by 10% compared to the conventional ACV formulation, consequentially enhancing its bioavailability. Overall, this study resulted in the successful preparation of a hybrid chemically conjugated SSBC which has great potential for enhanced oral absorption of ACV with possible tuneable ACV permeability and solubility, producing an "intelligent" nanoenabled drug delivery system.

Quality of antiretroviral and opportunistic infection medications dispensed from developing countries and Internet pharmacies

WHAT IS KNOWN AND OBJECTIVE

Generic manufacturers help decrease the cost of antiretroviral (ARV) and antimicrobial medications which are used to treat opportunistic infections (OIs) in developing countries. Concerns have been expressed about potential quality issues with such medications as a result of the identification of numerous counterfeit medications in developing countries. However, few studies have assessed the quality of these medications using the United States Pharmacopeia (USP) compendial standards. The goal of this study was to assess the quality of ARV and OI medications obtained from various sources, including South Africa, United States, China, Ethiopia, Thailand, Laos, Mexico, Nigeria and five Internet pharmacies.

METHODS

Zidovudine, lamivudine, efavirenz, nevirapine, isoniazid and sulfamethoxazole/trimethoprim tablets/capsules were obtained from eight countries and five Internet pharmacies. The tablets/capsules were separated into distinct samples, based on the drug's active ingredient, manufacturer and drug control number. Each distinct sample was analysed for drug content, dissolution, content uniformity and breaking force using USP 32-National Formulary 27 (USP 32-NF 27) compendial methods and compared to the USP standards.

RESULTS AND DISCUSSION

A total of 2027 tablets/capsules were obtained with 88 distinct samples identified. All samples met the USP 32-NF 27 standards for drug content with a range of 92.7-108.6%. Six of the 88 samples failed the dissolution test by 1.5-8.3% below the standard range. Ninety-eight per cent of all 88 samples met the USP criteria for content uniformity based on weight variation. One sample of isoniazid was found to have a low breaking force of 2.8 kiloponds. The results of this study show that there were no problems with the samples of ARV and OI medications tested for drug quality from the specified locations. As there are many studies and reports that discuss the poor quality of generic medications with only a few assessing drug quality, the implications of this study's results are to: (i) help better understand patient outcomes; (ii) help patients gain access to beneficial medications for HIV and OIs; and (iii) ensure an overall increase in access to medications where needed.

WHAT IS NEW AND CONCLUSION

This study is one of the largest to date concerning medication type and sample size for the assessment of ARV and OI medications using drug content as a measure of quality. The samples were obtained from more diverse geographical locations compared to previous studies and, for the first time, included Internet pharmacies. In addition to drug content, this study evaluated a more complete quality profile including dissolution, content uniformity and breaking force. This study showed that drug quality should be assessed consistently in order to better identify counterfeit medications compared to current assessments and that there should be uniform guidelines for how to assess quality.

Evaluation and comparison of in-vitro dissolution profiles for different brands of amoxicillin capsules

BACKGROUND

Amoxicillin is an oral semi-synthetic, β-lactam antibiotic used to treat bacterial infections caused by susceptible micro organisms. It is usually prepared in capsule, tablet and powder for oral suspension form. Solid dosage forms for oral administration pose bioavailability problems related to the absorption process The World Health Organization (WHO) has promoted the use of generic brands in order to make the cost of medicines affordable. Generic substitution could be considered when a generic copy of a reference drug contains identical amounts of the same active ingredient in the same dose formulation and route of administration. However, the presences of generic products those are not interchangeable with that of the innovator and/or with each others have been reported.

OBJECTIVES

To evaluate and compare the in-vitro dissolution profiles of different generic brands of amoxicillin capsules with the innovator that are available in Ethiopian market.

METHODS

Dissolution profiles for nine brands of amoxicillin capsules contained amoxicillin 500 mg which are available in Ethiopian market were determined using a method from the United States Pharmacopoeia (USP, 2009). The obtained dissolution profile data of the eight brands were evaluated and compared with the innovator brand (Amoxil™) using two different statistical methods: the fit factors (f1 & f2) and the dissolution efficiency (D.E.) model. Most generic brands of amoxicillin capsules (62.5% of the tested brands) are not interchangeable with the innovator brand.

RESULTS

The calculated f1 factor for Brand A and Brand G are 10.1 and 1.1 respectively. However, for the rest six brands the f1 factors are greater than 15. The f2 factor for Brand G is 74.1 and for Brand A is 48.5 which is near to 50. Similarly, the f2 factors for the six brands are less than 50 which support the result of the f1 factors for the dissimilarity of these brands with the innovator brand. The mean dissolution efficiencies as well as the 95% confidence intervals are within ±10% only for two brands, Brand F and Brand G.

CONCLUSIONS

Most generic brands of amoxicillin capsules (62.5%) are not interchangeable with the innovator brand (Amoxil™).

Biowaiver monographs for immediate release solid oral dosage forms: lamivudine

Literature data relevant to the decision to allow a waiver of in vivo bioequivalence (BE) testing for the approval of immediate release (IR) solid oral dosage forms containing lamivudine as the only active pharmaceutical ingredient were reviewed. The solubility and permeability data of lamivudine as well as its therapeutic index, its pharmacokinetic properties, data indicating excipient interactions, and reported BE/bioavailability (BA) studies were taken into consideration. Lamivudine is highly soluble, but its permeability characteristics are not well-defined. Reported BA values in adults ranged from 82% to 88%. Therefore, lamivudine is assigned to the biopharmaceutics classification system (BCS) class III, noting that its permeability characteristics are near the border of BCS class I. Lamivudine is not a narrow therapeutic index drug. Provided that (a) the test product contains only excipients present in lamivudine IR solid oral drug products approved in the International Conference on Harmonization or associated countries in usual amounts and (b) the test product as well as the comparator product fulfills the BCS dissolution criteria for very rapidly dissolving; a biowaiver can be recommended for new lamivudine multisource IR products and major post-approval changes of marketed drug products.