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Biomedical subjects

G González-Martín

Publications and source records attributed to G González-Martín.

7 recordsLinked to original sources
PubMed2000

Allopurinol encapsulated in polycyanoacrylate nanoparticles as potential lysosomatropic carrier: preparation and trypanocidal activity.

The activity of allopurinol-loaded polyethylcyanoacrylate nanoparticles against Trypanosoma cruzi was compared to that of free allopurinol using in vitro cultures of epimastigotes. Ethylcyanoacrylate nanoparticles were prepared by an emulsion polymerization process, and formulations containing different concentrations of allopurinol, polyethylcyanoacrylate and surfactants were investigated and analyzed in size and amount of drug entrapped. The nanoparticles obtained were less than 200 nm in size, as measured by electron microscopy and cytometry. The peak amount of allopurinol entrapped in the nanoparticles was 62.8+/-1.9 microg mg(-1) of nanoparticles using 400 microl of polyethylcyanoacrylate, 200 microl of surfactant (Tween 20) and 20 mg of allopurinol in 50 ml of polymerization medium and the association efficiency was 100.7%. After 6 h of incubation at pH 7.4 the release of allopurinol from the nanoparticles was 7.4%, while at pH 1.2 only 3.1% was released after 4-6 h (t=42.8, P<0.0001). The in vitro studies, using cultures of T. cruzi epimastigotes, demonstrated considerable increases in the trypanocidal activity of the allopurinol-loaded nanoparticles in comparison with a standard solution of allopurinol (91.5 vs. 45.9%) at an allopurinol concentration of 16.7 microg ml(-1). In addition, it was shown that the unloaded nanoparticles, by mechanisms not completely elucidated, had a trypanocidal activity similar to that of standard solutions of allopurinol. To study cytotoxicity, increasing concentrations of unloaded nanoparticles were incubated on vero-line cell cultures. The concentration that killed 50% cells was 200 microg ml(-1), four times higher than that necessary to kill 50% of T. cruzi. It is concluded that the polyethylcyanoacrylate nanoparticles constitute a good carrier of drugs against the T. cruzi. The allopurinol loaded-nanoparticles significantly increased the trypanocidal activity in comparison to the free drug.

Adsorption↗
PubMed1999

Adverse drug reactions (ADRs) in patients with HIV infection. A prospective study.

AIM: A prospective drug surveillance method was used to monitor 50 ambulatory patients with HIV infection, who were controlled in the Sexual Transmission Disease Service at Dr. Sotero del Río Hospital (Santiago, Chile). The aim of this work was to characterize and study the frequency, characteristics, and associated factors of the ADRs in HIV-infected patients. PATIENTS AND METHODS: Patients were interrogated once or twice a month by a clinical pharmacist, who consigned data concerning the drug prescribed by the physician, drug-related signs and symptoms, and the laboratory's parameters as renal, hepatic, hematological function, and biochemical test. The ADR probability was assessed for an algorithm. RESULTS: The frequency of adverse drug reactions found in the group of patients studied was 32.0%. The dermatological, hepatic, and hematological systems were the most affected by adverse drug reactions. Trimethroprim-sulfamethoxazole and zidovudine were the drugs mainly associated with ADRs. Patients with lymphocytes CD4+ count of 200 or less, presented a higher frequency of ADRs. 48.5% of ADRs were classified as probable. Severe reactions were found in 18.5% of the patients, and moderate in 70.4%. 50% of patients with ADRs needed the withdrawal of the implicated drug, and an 18.5% dose decreased. 63% of the ADRs were dose-independent. CONCLUSION: There was a higher frequency of ADRs in those patients with multiple-drug therapy, but the frequency of ADR was not associated with age, gender, or hematological test.

Anti-Infective Agents↗
PubMed1997

[Adverse drug reactions among hospitalized elderly patients. Prospective study].

BACKGROUND: It is not clear if old age is a risk factor for adverse drug reactions. AIM: To study the incidence of adverse drug reactions and the effect of age in patients admitted to an Internal Medicine Service in an university hospital. PATIENTS AND METHODS: Two hundred one patients, hospitalized at the Clinical Hospital of the Catholic University, were studied. These patients were followed using a prospective pharmacological surveillance method. For statistical purposes, patients aged 65 years old or older were compared with those younger than 65 years old. RESULTS: Patients over 65 years old had a 33% incidence of adverse drug reactions, mainly involving cardiovascular system and provoking metabolic disturbances. Younger subjects had a 24% incidence of adverse drug reactions, mainly involving the gastrointestinal system and the skin. Sixteen percent of adverse drug reactions were classified as severe and there was a direct relationship between its frequency and the number of drugs prescribed, the hospitalization length and the presence of renal failure. Younger patients with adverse drug reactions had lower serum albumin levels than those without adverse reactions. This relationship was not observed in older patients. CONCLUSIONS: The frequency of adverse drug reactions in hospitalized patients, is related to the number of drugs prescribed and the length of hospitalization.

Age Factors↗
PubMed1983

Clinical pharmacokinetics of furosemide in children with nephrotic syndrome.

The pharmacokinetic disposition of furosemide has been investigated in seven children with nephrotic syndrome and in eight control children. Furosemide in plasma was analyzed by spectrofluorometry. After a single intravenous dose of furosemide (1 mg/kg body wt.) the nephrotic children showed lower initial plasma concentrations because of the larger volume of distribution. The mean half-life of furosemide in nephrotic children (38.5 +/- 7.8 min) was significantly longer than in the control group (28.0 +/- 7.7 min). The two groups did not differ in the body clearance of total furosemide. The average serum clearance was 4.95 +/- 1.7 ml/min/kg body wt. in the control group and 5.10 +/- 1.4 ml/min/kg body wt. in the nephrotic children. There was a significant reduction in urine sodium and distribution volume, whereas potassium excretion remained unchanged.

Child, Preschool↗