Comparison in the Glucose Response of Flexible Liposomes Loaded with Insulin with the Addition of Different Surfactants in an Experimental Diabetes Model

Background:

Insulin has been included in a variety of dosage forms; nevertheless, liposomes have shown protection to degradation and better absorption. The addition of surfactant to liposomes could give the ability to deform and pass through intact membranes, and could increase the stability and the release of the drug.

Introduction:

Due to the limitations of the current treatment of insulin in diabetic patients, investigation in alternatives routes has increased. The oral route is the most convenient because of the similarity with the natural secretion of this hormone. The aim was to evaluate the in-vivo effect of fourteen formulations of Insulin-loaded flexible liposomes with different surfactants by oral and subcutaneous routes.

Methods:

Fourteen formulations of insulin were obtained with the addition of different surfactants. Size distribution, polydispersion index and Z potential were obtained for all formulations. In-vivo tests were performed in rats induced with experimental diabetes with streptozotocin, and glucose curves were obtained during 480 minutes.

Results:

All formulations by the subcutaneous route caused an optimal reduction in glucose levels. However, the addition of Brij L23 produced a better reduction, lasting for 420 minutes. By the oral route, the reduction of glucose did not reach the normal levels, but the addition of Poloxamer 407 and Brij S10 showed the best reduction in the glucose levels by this route.

Conclusion:

The addition of surfactants to the lipid structure can modify the release of the insulin by different routes of administration, but this behavior depends on the characteristics of the surfactant, such as the melting phase transition temperature of the lipid bilayer.

Disposition and pharmacokinetics of azithromycin in serum and a lung tissue of two modified-release formulations compared with an immediate-release product on the market

The aim of this study was to determine the disposition and pharmacokinetics in serum and a lung tissue homogenate in guinea pig (Cavia porcellus) of two experimental formulations of azithromycin, those were included in a modified release polymer matrix (MRF) after oral administration. The results obtained are compared with a commercial form of immediate release. 3 groups of animals were randomly formed in groups of 7 for control and 14 for each group of modified-release formulations (MRFs) were treated with a single dose of 8mg/kg of active principle. In lung tissue, comparisons of concentration of azithromycin, showed statistically significant differences between commercial product, MRF1 and MRF2. All pharmacokinetic parameters for MRF1 and MRF2 were significantly different with the exception of C_max with respect to commercial product. The treatment of the animals with MRFs may have several benefits over treatment with azithromycin alone since could increase dosing interval for the two MRFs evaluated and reduce the frequency of application, patient stress levels and toxicological risks by accumulation of the active principle.

[A new type of headache of ocular origin: ophthalmotonic headache. Diagnosis and treatment]

INTRODUCTION

In some patients it was seen that chronic headaches disappeared after laser iridectomies had been done to prevent glaucoma, in persons with normal intra-ocular pressure (IOP).

OBJECTIVE

To make a study of patients with headache, some of whom were treated with topical beta-blockers (carteolol) and others by Yag-laser iridectomies. The effect on headache and IOP was analyzed.

MATERIAL AND METHODS

A survey, ophthalmological examination and headache provocation test were carried out in patients with headaches, and the changes in IOP determined by pharmacologically inducing miosis and mydriasis were recorded. Three treatment groups were formed and the results analyzed statistically.

RESULTS

In the 12 patients treated pharmacologically, 62% improved and in 14% the headaches disappeared. In the 16 treated using laser 94% were cured and 6% improved. When both types of treatment were used on 9 patients, 22% improved and 78% were cured. The validity of the ocular pressure curve was checked in the diagnosis of blockage of the pupil.

CONCLUSIONS

Some headaches of ocular origin (ophthalmotonic), not previously described, occur due to abrupt changes in intraocular pressure, and improve significantly when the IOP is reduced by beta-blockers or Yag-laser iridectomies are done. A valid provocation tests for diagnosis of this type of headache is described. We consider that blockage of the pupil and/or of the angle of the anterior chamber are possible etiopathogenic mechanisms.