Comparative in vitro–in vivo study of two quinine rectal gel formulations

The main objective of this work was to develop and evaluate rectal quinine paediatric formulations to treat acute uncomplicated malaria attack in some African countries. Developed dosage forms must be able to assure a prolonged release in the rectum but not too much so as to avoid product expulsion by the child anus. Two quinine rectal gels, namely mucoadhesive (MA) gel and thermosensitive (TS) gel, containing 20 mg quinine base/g were developed and evaluated in vitro and in vivo in the rabbit. The MA and the TS gels contained hydroxypropyl methylcellulose 4000 (HPMC) and poloxamer 407, respectively. The calculated in vitro release exponent (n) values suggested that drug was released from both gels by non-Fickian diffusion. Both gels exhibit practically similar efficient of dissolution (ED%) which was not reflected in the plasma and, therefore, quinine bioavailability from MA gel was found to be higher than that obtained from TS gel and their AUC(0-infinity) were statistically different (P = 0.0006). The t(1/2) values of quinine were significantly higher for Hydrogels than for IV and rectal solutions. MRT values displayed by TS gel and MA gel were not statistically different but were about 3.8- and 1.3-fold, respectively, larger than those obtained for IV solution and rectal solution, respectively. These results confirm the sustained-release behaviour of both hydrogels in the rabbit. Tolerability study of hydrogels didn't show any damage on the rectal mucosa of the rabbit.

Improvement of norfloxacin oral bioavailability by EDTA and sodium caprate

The EDTA and sodium caprate (Na caprate) effects on the oral bioavailability of norfloxacin were tested. It was found that absorption kinetic of norfloxacin was markedly accelerated when mixed with EDTA or Na caprate in a ratio of 1:1. When mixed with the absorption enhancers in a ratio of 1:5, only Na caprate improved norfloxacin bioavailability significantly. In vitro dissolution tests demonstrated that EDTA and Na caprate increased norfloxacin dissolution kinetic. However, the correlation between bioavailability and in vitro dissolution improvement was not clearly established. So, we can conclude that the solubilizing property of EDTA and Na caprate did not take a prominent part in norfloxacin absorption.

Influence of a polymeric formulation of ketoprofen on its diffusion into cerebrospinal fluid in rats

Poly(D,L)lactide nanocapsules (NCs) have been proposed as an alternative carrier for many drugs. We investigated the influence of this formulation on the pharmacokinetics of ketoprofen in the plasma and cerebrospinal fluid (CSF). Male Wistar rats were given intraperitoneal dose of ketoprofen (5 mg/kg) in a suspension of NCs or in a carboxymethylcellulose (CMC) solution (reference preparation). Blood and CSF samples were collected at different times up to 24 h after dosing. The unbound fraction of ketoprofen in plasma (f(u)) was determined using ultrafiltration. The total (C(T)) and free (C(F)) concentrations of ketoprofen in plasma and the simultaneous CSF concentrations (C(CSF)) were measured by a HPLC method and the areas under the curve (AUC(T), AUC(F), AUC(CSF)) were calculated. AUC(T) of ketoprofen-loaded NCs in plasma was similar to that of the reference solution, while AUC(F) of the former (5.41 mg/l x h) was higher than that produced by the latter (4.03 mg/l x h). Accordingly, the unbound fraction (f(u)) was higher after administration of NCs than that of the solution (2.5 and 1.8%, respectively). Finally, AUC(CSF) were identical for both formulations. These findings suggest that the binding of ketoprofen to plasma proteins is not the major factor that governs its blood-to-CSF exchanges.

Design and in vitro evaluation of adhesive matrix for transdermal delivery of propranolol

Propranolol hydrochloride, a water-soluble drug, was incorporated in three transdermal delivery systems using three polymers (hydroxypropylmethylcellulose, polyisobutylene and Ucecryl MC808). The influence of different factors (polymeric material, matrix thickness, drug content, thickness of the adhesive layer and presence of a dissolution enhancer) was investigated. Microscopic observations and DSC thermograms have permitted to demonstrate that propranolol was essentially dissolved in the HPMC matrix and dispersed in the two other matrix types. In vitro dissolution study was carried out according to European Pharmacopoeia. Release from HPMC matrices without adhesive coating was fast. Release from these matrices became more regular (reduction of the burst effect) and slow when they are coated with a 12 microm thick Ucecryl layer. Release from different PIB matrices was too slow to be suitable as TDDS for propranolol. The best release modulation was obtained from Ucecryl matrices. In all matrices types, propylene glycol accelerated propranolol release rate. The kinetic of drug release from most matrix types was more closely described by the square-root model (Higuchi).

Corynebacterium diphtheriae osteomyelitis in an immunocompetent child: a case report

Septic osteomyelitis of the hip in a previously healthy child is described. A weakly toxigenic Corynebacterium diphtheriae strain was isolated from the bone aspirate. The results of the treatment were rapidly satisfactory, after surgical drainage and antibiotic therapy with pristinamycin.

CONCLUSION

This case report shows that C. diphtheriae has not disappeared in the developed world and can be responsible of systemic infections.

[Present and future choice of pharmaceutical forms for intravaginal administration. II. Barrier systems and vaginal rings]

In part I of this review, various vaginal products for local and systemic treatment have been described and discussed. Part II is reserved to other intravaginal contraceptive systems. Some devices as diaphragms, sponges, ... have a mechanical contraceptive advantage associated or not with a spermicidal activity and can or cannot protect against venereal diseases. Other devices like intravaginal rings allow a long-acting and controlled release of contraceptive hormones and it is quite possible that they replace orale contraceptive dosage forms. Various approaches in designs, safety, effectiveness, inconvenience and advantages are discussed.

[Present and future choices of vaginal drug dosage forms. I. Classical forms]

The anatomy and physiology of vagina play a major role in the formulation of vaginal products. In this review, many classical dosage forms (tablets, suppositories, creams, gels, foams...), used either for local or systemic treatment are described and discussed. Formulation and essay are briefly reviewed. But emphasis is layed on the problems associated with the administration of these dosage forms, their advantages with regard to other vaginal products and the use of these products as contraceptive devices.

Influence of poly(DL-lactide) nanocapsules on the biliary clearance and enterohepatic circulation of indomethacin in the rabbit

Following intravenous administration, the uptake of colloidal drug carriers by cells of the mononuclear phagocyte system, mainly the Kuppfer cells, may concentrate an encapsulated drug close to the liver parenchymal cells and facilitate its biliary excretion and enterohepatic circulation. To test this hypothesis indomethacin was administered (10 mg/kg) in four groups of 10 rabbits each by intravenous infusion at a constant rate over 2 hr, either in its free form (aqueous solution) or as nanocapsules prepared from preformed poly(DL-lactide). Unchanged drug was assayed in plasma of the two control (sham-operated) groups and in both plasma and bile of the two bile-cannulated groups. Pharmacokinetic analysis led to the conclusion that the uptake of nanocapsules by liver macrophages reduces the concentration of the drug by enhancing its total clearance. This enhancement was due to an increase in biliary clearance, as a result of parallel increases in bile concentration and biliary excretion of the drug. It was also demonstrated that nanocapsules enhance the enterohepatic circulation of indomethacin.

Actinomycin synthesis in Streptomyces antibioticus. Purification and properties of a 3-hydroxyanthranilate 4-methyltransferase

A methyltransferase, which utilizes 3-hydroxyanthranilic acid (HAA) as a substrate, has been purified to near homogeneity from 30-36-h mycelium of the bacterium Streptomyces antibioticus. The enzyme was obtained in approximately 20% yield with a purification of 130-fold. Polyacrylamide gel electrophoresis under denaturing conditions indicates that the enzyme is composed of a single subunit with Mr of about 36,000. On chromatography in 0.5 M NaCl, the enzyme displays a molecular weight of about 37,000. The specific activity of the enzyme in S. antibioticus mycelium is maximal between 30 and 36 h following inoculation of galactose/glutamic acid medium and, at those times post-inoculation, the specific activity is essentially the same in extracts of mycelium obtained from cultures grown on glucose rather than galactose as the carbon source. The enzyme activity is stimulated by Na2EDTA (in crude extracts) and by 2-mercaptoethanol and the methyltransferase shows a strong preference for HAA as substrate as compared with a number of HAA analogs. Thin layer chromatography of ethyl acetate extracts of large-scale incubation mixtures confirms that the product of the reaction is 4-methyl-3-hydroxyanthranilic acid. The reaction product was also a substrate for phenoxazinone synthase and was incorporated into actinomycin by S. antibioticus mycelium. Kinetic parameters for the methyltransferase reaction was determined.

Zinc deficiency in surgical patients: a clinical study

Four stressed surgical patients who had different diseases are presented. They had dermatitis associated with low serum zinc levels but were not on total parenteral nutrition. The range of serum zinc varied between 25 and 56 mu/dl when first seen. All but one had hypoalbuminemia and anemia; one patient had diarrhea. When measured, other microelements were normal. These patients were thought to have zinc deficiency and all their symptoms responded favorably to oral zinc and nutritional support. A highlight of previous reported cases of zinc deficiency is presented along with a brief review of the subject. Acute stress including major operations will decrease the serum zinc level temporarily. Zinc deficiency may be the result of chronic zinc depletion caused by other conditions. Chronic leg ulcers are associated with low serum zinc levels and might precipitate zinc selectively. A zinc supplement will help in the healing of these ulcers and wounds in general. The possibility of an interrelationship of zinc and other microelements is raised but is not clear.

Adult intussusception due to metastatic tumors

We report three cases of adult intussusception emphasizing its difference from childhood intussusception. The indolent, intermittent intussusception of adults is sometimes missed.