Comparison of the physicochemical properties and in vivo bioavailability of generic and innovator artemether-lumefantrin tablets in Kumasi, Ghana

Context: Malarial remains a leading course of death in developing countries. Current treatment protocol involves the use of artemisinin-based combination therapy. In endemic areas, cost of treatment is a concern hence generic prescription is on the high. It is therefore necessary to investigate how equivalent or otherwise the generics are to the innovator brand Coatem®. Aims: To compare the physicochemical properties and in vivo bioavailability of a locally manufactured generic artemether-lumefantrine tablet formulation and that of the innovator brand sold on the Kumasi market, Ghana. Methods: The most used locally manufactured generic and the innovator brands were sampled from retail pharmacies. The samples were confirmed by colorimetry. Pharmaceutical equivalence of the brands was determined using compendial tests. In vivo bioavailability study on the two brands was done using a two-period, single dose, cross-over design involving 20 healthy rabbits. Pharmacokinetic parameters (AUC0-72, AUC0-∞, and Cmax) for both brands derived from the study were analysed statistically. Results: Both the generic and innovator brands passed the physicochemical tests. The artemether component of both brands complied with the pharmacopoeia specification for dissolution testing while the lumefantrine did not. Average bioequivalence was demonstrated per the FDA criterion with the geometric mean ratios and corresponding 90% confidence intervals falling within the acceptable limits of 0.80 – 1.25. Conclusions: Based on the similarity demonstrated between the two brands, evidence have been shown to support substitutability of the often-expensive innovator brand with the affordable locally produced brand

Detection, quantification, and investigation of the red blood cell partitioning of cryptolepine hydrochloride

Context: The fight against malaria is limited by the development of resistance of Plasmodium to medication. This has led to an urgent search for alternative medicinal agents. Aims: To determine the affinity of cryptolepine for the red blood cell. Methods: HPLC method for the identification and quantification of cryptolepine was developed. Lipid solubility for both quinine (control) and cryptolepine was determined. Partitioning and repartitioning of cryptolepine into RBCs were studied. Time, concentration, temperature and pH were varied to see their effect on the partitioning of cryptolepine. Plasma protein binding was determined by the red blood cell partitioning method. Results: An accurate, precise and robust HPLC method for cryptolepine hydrochloride was developed. Cryptolepine and quinine had lipophilicity of 0.91 ± 0.02 and 1.52 ± 0.27, respectively. The highest partitioning values of 2.02 ± 0.08 for cryptolepine and 0.93 ± 0.02 for quinine were obtained at 40 minutes. Concentration-dependent protein binding was observed for both compounds with cryptolepine having 0.43 and 0.38 for quinine. Partitioning was also found to be temperature dependent with the highest partitioning obtained at 370C for cryptolepine (1.56 ± 0.04) and quinine (0.78 ± 0.01). Partitioning of cryptolepine and quinine were inversely related to pH with R2 values of 0.94 and 0.96, respectively. P-values between partitioning and repartitioning for cryptolepine and quinine were 0.04 and 0.05, respectively. Conclusions: Partitioning was found to be time, temperature, concentration and pH dependent. Partitioning was irreversible for cryptolepine and reversible for quinine. Protein binding in both cases was moderate

Chemical Composition and In Vitro Evaluation of the Mosquito (Anopheles) Repellent Property of Neem (Azadirachta indica) Seed Oil

As one of the killer diseases in the world, malaria contributes to child mortality and global death annually. As a result, many reactive mechanisms have evolved to control and repel mosquitoes. The use of synthetic mosquito repellents with N,N-Diethyl-meta-toluamide (DEET) is one of the popular interventions despite its dermatological limitations such as skin irritations. Ethnobotanical reviews have identified that the adoption of natural repellents promises high repellence on mosquitoes with minimal side effects compared with synthetic ones. However, this has received little attention in modern pharmaceutical literature. This research is focused on the formulation of a natural mosquito repellent from the oil extracted from Azadirachta indica (A. Juss). The oil cream was formulated in concentrations of 10% v/w, 12.5% v/w, 15% v/w, 17.5% v/w, and 20% v/w using an in vitro evaluation approach. Pharmacopoeia characteristics of the cream such as pH, viscosity, spreadability, and organoleptic properties were carried out to verify acidity, permeation, and flow properties of the formulated cream. The spreadability rate was inversely proportional to the concentration of the cream in terms of oil content falling from 1.24 gm/s to 0.84 gm/s from concentrations 10% v/w to 20% v/w correspondingly. Skin irritation tests, however, indicated traces of irritation at 20% v/w. Repellency properties of the cream revealed a lasting effect on the mosquitoes, although this was dependent on concentration levels. Formulations of 17.5% v/w and 20% v/w neem seed oil cream had an equal repellency effect of 87.5%, whereas the synthetic repellent had a repellency of 75% within a justifiable time frame for all the formulations. This work shows that plant-based mosquito repellents promise a healthier approach in controlling mosquito bites, protecting the skin, and preventing malaria

Development and evaluation of natural gum-based extended release matrix tablets of two model drugs of different water solubilities by direct compression

The study was aimed at developing extended release matrix tablets of poorly water-soluble diclofenac sodium and highly water-soluble metformin hydrochloride by direct compression using cashew gum, xanthan gum and hydroxypropylmethylcellulose (HPMC) as release retardants. The suitability of light grade cashew gum as a direct compression excipient was studied using the SeDeM Diagram Expert System. Thirteen tablet formulations of diclofenac sodium (∼100 mg) and metformin hydrochloride (∼200 mg) were prepared with varying amounts of cashew gum, xanthan gum and HPMC by direct compression. The flow properties of blended powders and the uniformity of weight, crushing strength, friability, swelling index and drug content of compressed tablets were determined. In vitro drug release studies of the matrix tablets were conducted in phosphate buffer (diclofenac: pH 7.4; metformin: pH 6.8) and the kinetics of drug release was determined by fitting the release data to five kinetic models. Cashew gum was found to be suitable for direct compression, having a good compressibility index (ICG) value of 5.173. The diclofenac and metformin matrix tablets produced generally possessed fairly good physical properties. Tablet swelling and drug release in aqueous medium were dependent on the type and amount of release retarding polymer and the solubility of drug used. Extended release of diclofenac (∼24 h) and metformin (∼8–12 h) from the matrix tablets in aqueous medium was achieved using various blends of the polymers. Drug release from diclofenac tablets fitted zero order, first order or Higuchi model while release from metformin tablets followed Higuchi or Hixson-Crowell model. The mechanism of release of the two drugs was mostly through Fickian diffusion and anomalous non-Fickian diffusion. The study has demonstrated the potential of blended hydrophilic polymers in the design and optimization of extended release matrix tablets for soluble and poorly soluble drugs by direct compression. Keywords: Cashew gum, Xanthan gum, HPMC, Direct compression, SeDeM Diagram Expert System, Diclofenac sodium, Metformin hydrochlorid

Physicochemical and Microbiological Characteristics of Stem Bark Exudate Gum of Cordia millenii Tree in Conventional Release Tablets

The development of a raw material into an acceptable pharmaceutical excipient involves evaluation of the physicochemical and formulation properties of the potential raw material. Results from these evaluations may serve as a guide to subsequent use of the substance. The objective of the study was to evaluate the physicochemical and microbiological properties of the stem bark gum of Cordia millenii tree in conventional release paracetamol tablets. From the physicochemical evaluations, the gum was slightly acidic and soluble in all the aqueous-based solvents, except 0.1 N HCl in which it was sparingly soluble. All the absorptive properties of the gum indicated tablet disintegrating potential for tablet formulation. The total ash of the gum was higher than that of the international standard gum arabic. Micromeritic properties of the gum indicated the need for a flow aid to improve its flowability. There were no harmful microorganisms detected in the gum. Aerobic organisms and moulds and yeast were detected within permissible limits. Tablets formulated using six different concentrations of gum dispersions as a binder were generally soft and failed the USP T80 standard of dissolution, indicating poor binding and drug releasing properties. Quality control properties of three different batches of tablets containing varying concentrations of the dry gum as a disintegrating agent were comparable to tablets containing equal concentrations of corn starch. The in vitro drug releases were similar at all-time points of drug evaluation. The gum can therefore be considered as a good disintegrant in the formulation of conventional release tablets

Quality Assessment of Some Essential Children’s Medicines Sold in Licensed Outlets in Ashanti Region, Ghana

The quality of 68 samples of 15 different essential children’s medicines sold in licensed medicine outlets in the Ashanti Region, Ghana, was evaluated. Thirty-two (47.1%) of the medicines were imported, mainly from India (65.6%) and the United Kingdom (28.1%), while 36 (52.9%) were locally manufactured. The quality of the medicines was assessed using content of active pharmaceutical ingredient (API), pH, and microbial limit tests, and the results were compared with pharmacopoeial standards. Twenty-six (38.2%) of the samples studied passed the official content of API test while 42 (61.8%) failed. Forty-nine (72.1%) of the samples were compliant with official specifications for pH while 19 (27.9%) were noncompliant. Sixty-six (97.1%) samples passed the microbial load and content test while 2 (2.9%) failed. Eighteen (26.5%) samples passed all the three quality evaluation tests, while one (1.5%) sample (CFX1) failed all the tests. All the amoxicillin suspensions tested passed the three evaluation tests. All the ciprofloxacin, cotrimoxazole, flucloxacillin, artemether-lumefantrine, multivitamin, and folic acid samples failed the content of API test and are substandard. The overall API failure rate for imported products (59.4%) was comparable to locally manufactured (63.9%) samples. The results highlight the poor quality of the children’s medicines studied and underscore the need for regular pharmacovigilance and surveillance systems to fight this menace